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One of the main regulators in the cell cycle is cyclin-dependent kinase 4 and 6 (CDK4/6). FDA has approved CDK4/6 inhibitors for the treatment of patients with metastatic breast cancer. However, the development of selective agents remains problematic due to the conservation of their ATP binding sites. In the previous in silico study, ZINC585292724, ZINC585292587, ZINC585291674, and ZINC585291474 have been identified as potential inhibitors. Therefore, the present study aimed to analyze the selectivity and inhibitory activity of the four compounds against CDK4/6 in vitro as well as determine the potential for their further development in silico. The in vitro results showed that the four compounds had good selectivity towards both kinases, due to their similar structure. In agreement with the in silico results, ZINC585291674 produced the best inhibitory activity against CDK4 and CDK6, with IC50 of 184.14 nM and 111.78 nM, respectively. Their ADMET profile were also similar to reference compound of Palbociclib. Based on this, ZINC585291674 can be used as a lead compound for further inhibitor development. [ABSTRACT FROM AUTHOR]

The cell cycle is driven by cyclin‐dependent kinases (Cdks). The decision whether the cell cycle proceeds is made during G1 phase, when Cdk4/6 functions. Cyclin‐dependent kinase inhibitor 2 (Cdkn2) is a specific inhibitor of Cdk4/6, and their interaction depends on D84 in Cdkn2 and R24/31 in Cdk4/6. This knowledge is based mainly on studies in mammalian cells. Here, we comprehensively analyzed Cdk4/6 and Cdkn2 in invertebrates and found that Cdk4/6 was present in most of the investigated phyla, but the distribution of Cdkn2 was rather uneven among and within the phyla. The positive charge of R24/R31 in Cdk4/6 was conserved in all analyzed species in phyla with Cdkn2. The presence of Cdkn2 and the conservation of the positive charge were statistically correlated. We also found that Cdkn2 has been tightly linked to Fas associated factor 1 (Faf1) during evolution. We discuss potential interactions between Cdkn2 and Cdk4/6 in evolution and the possible cause of the strong conservation of the microsynteny. [ABSTRACT FROM AUTHOR]

Background: Preclinical models of pancreatic cancer (PDAC) suggest a synergistic role for combined MEK and autophagy signaling inhibition, as well as MEK and CDK4/6 pathway targeting. Several case reports implicate clinical activity of the combination of either trametinib and hydroxychloroquine (HCQ) in patients with KRAS-mutant PDAC or trametinib with CDK4/6 inhibitors in patients with KRAS and CDKN2A/B alterations. However, prospective data from clinical trials is lacking. Here, we aim to provide clinical evidence regarding the use of these experimental regimens in the setting of dedicated precision oncology programs. Methods: In this retrospective case series, PDAC patients who received either trametinib/HCQ (THCQ) or trametinib/palbociclib (TP) were retrospectively identified across 11 participating cancer centers in Germany. Results: Overall, 34 patients were identified. 19 patients received THCQ, and 15 received TP, respectively. In patients treated with THCQ, the median duration of treatment was 46 days, median progression-free survival (PFS) was 52 days and median overall survival (OS) was 68 days. In the THCQ subgroup, all patients evaluable for response (13/19) had progressive disease (PD) within 100 days. In the TP subgroup, the median duration of treatment was 60 days, median PFS was 56 days and median OS was 195 days. In the TP subgroup, 9/15 patients were evaluable for response, of which 1/9 showed a partial response (PR) while 8/9 had PD. One patient achieved a clinical benefit despite progression under TP. Conclusion: THCQ and TP are not effective in patients with advanced PDAC harboring KRAS mutations or alterations in MAPK/CDKN2A/B. [ABSTRACT FROM AUTHOR]

Introduction: Initial treatment for hormone-receptor positive (HR+)/human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer (ABC) typically involves endocrine therapy (ET) combined with different targeted agents. When hormonal therapies fail, until recently, the only option available was chemotherapy (ChT), presenting a significant therapeutic challenge. However, the recent introduction of antibody–drug conjugates (ADCs) has provided new treatment alternatives in this context. Sacituzumab govitecan (SG), a novel trophoblast cell-surface antigen 2 (Trop-2)-targeting ADC, has been evaluated following disease progression to ET and ChT in HR+/HER2- ABC. Areas covered: This review examines the latest clinical trials, including phase I/II and III studies and evaluates the impact of SG on HR+/HER2- ABC. The literature search focused on clinical outcomes, particularly regarding efficacy and safety, comparing them with traditional ChT. Expert opinion: SG has demonstrated to be an effective treatment for patients with HR+/HER2- ABC after progression to ET and cyclin-dependent kinase 4/6 inhibitors (CDKi) in any setting, and at least two ChT-containing regimens in the advanced setting. With a manageable toxicity profile, SG represents a significant advancement in the treatment landscape for this patient population. However, further research is essential to optimize its application and establish long-term benefits. [ABSTRACT FROM AUTHOR]

Background: The combination of cyclin-dependent kinases 4/6 (CDK4/6) inhibitors and endocrine therapy is the standard treatment for patients with hormone receptor-positive (HR+)/HER2-negative (HER2-) advanced breast cancer. However, the role of CDK4/6 inhibitors in early breast cancer remains controversial. Methods: This study aimed to evaluate the efficacy and safety of CDK4/6 inhibitors combined with endocrine therapy versus endocrine therapy alone in patients with HR+, HER2- early breast cancer. A systematic review of Cochrane, PubMed and EMBASE databases was conducted. The efficacy endpoints of adjuvant therapy were invasive disease-free survival (IDFS), overall survival (OS) and distant relapse-free survival (DRFS). The efficacy endpoint included complete cell cycle arrest (CCCA) and complete pathologic response (PCR) with neoadjuvant therapy. Grade 3/4 adverse events (AEs) were assessed as safety outcomes. Results: Eight randomized controlled trials (RCTs) were included in the study. CDK4/6 inhibitors combined with endocrine therapy showed a significant improvement in IDFS (hazard ratio (HR) = 0.81, 95% confidence interval (CI) = 0.68-0.97, P = 0.024), but not DRFS (HR = 0.84, 95% CI = 0.56-1.29, P = 0.106) or OS (HR = 0.96, 95% CI = 0.77-1.19, P = 0.692) in adjuvant therapy. In the neoadjuvant therapy setting, CDK4/6 inhibitors improved CCCA compared with the control group (RR = 2.08, 95% CI = 1.33-3.26, P = 0.001). The risk of 3/4 grade AEs increased significantly with the addition of CDK4/6 inhibitors to endocrine therapy. Conclusion: The addition of CDK4/6 inhibitors in HR+/HER2- early breast cancer patients significantly improved IDFS in adjuvant therapy and CCCA in neoadjuvant. However, CDK4/6 inhibitors also showed significant toxicities during therapy. [ABSTRACT FROM AUTHOR]

PURPOSE: The National Cancer Institute-Children's Oncology Group Pediatric Molecular Analysis for Therapy Choice trial assigned patients age 1-21 years with relapsed or refractory solid tumors, lymphomas, and histiocytic disorders to phase II treatment arms of molecularly targeted therapies on the basis of genetic alterations detected in their tumor. Patients with tumors that harbored prespecified genomic alterations in the cyclinD-CDK4/6-INK4a-Rb pathway with intact Rb expression were assigned and treated with the cdk4/6 inhibitor palbociclib. METHODS: Patients received palbociclib orally once daily for 21 days of 28-day cycles until disease progression, intolerable toxicity, or up to 2 years. The primary end point was objective response rate; secondary end points included safety/tolerability and progression-free survival. RESULTS: Twenty-three patients (median age, 15 years; range, 8-21) were enrolled; 20 received protocol therapy and were evaluable for toxicity and response. Of the evaluable patients, the most common diagnoses were osteosarcoma (n = 9) and rhabdomyosarcoma (n = 6). A single actionable gene amplification was found in 19 tumors (CDK4 , n = 11, CDK6 , n = 2, CCND3 , n = 6), with one tumor harboring two amplifications (CDK4 and CCND2). Hematologic toxicities were the most common treatment-related events. No objective responses were seen. Two patients with tumors harboring CDK4 amplifications (neuroblastoma and sarcoma) had best response of stable disease for six and three cycles. Six-month progression was 10% (95% CI, 1.7 to 27.2). CONCLUSION: The CDK4/6 inhibitor palbociclib at 75 mg/m2 orally daily was tolerable in this heavily pretreated cohort. No objective responses were observed in this histology-agnostic biomarker-selected population with treatment-refractory solid tumors, demonstrating that pathway alteration alone is insufficient in pediatric cancers to generate a response to palbociclib monotherapy. Study reports on the NCI-COG Pediatric MATCH trial arm I (palbociclib)—no objective responses observed. [ABSTRACT FROM AUTHOR]

AbstractBackgroundMethodsResultsConclusion\nPLAIN LANGUAGE SUMMARYCyclin-dependent kinase 4/6 (CDK 4/6) inhibitors have emerged as a significant advancement in the treatment of HR+/HER2− metastatic breast cancer (MBC). Despite the clinical efficacy of CDK 4/6 inhibitors in HR+/HER2− metastatic breast cancer, there remains a significant gap in understanding their cost-effectiveness, particularly regarding the long-term economic impact and the key drivers of costs, when used in combination with endocrine therapy. This study aims to systematically review and conduct a meta-analysis of cost-effectiveness studies evaluating CDK4/6 inhibitors in treatment of HR+/HER2− advanced breast cancer and identify key drivers of costs of CDK4/6 inhibitors in combination with endocrine therapy.A comprehensive search of PubMed and Embase was conducted to identify peer-reviewed studies from February 2015 to March 2022 reporting cost-effectiveness of CDK4/6 inhibitors in MBC treatment. Incremental net benefits (INBs) were estimated, and meta-analysis was conducted. This review adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.We identified 120 articles, of which 18 were eligible for systematic review and 16 for meta-analysis. None of the three CDK4/6 inhibitors had positive INB compared to endocrine/aromatase inhibitors therapy alone. The pooled INB was estimated at −$149,266.87 (95% Confidence Interval (CI) = −$196,961.54, −$101,572.20).The combination of CDK4/6 inhibitors and letrozole/endocrine therapy for the treatment of postmenopausal patients with advanced HR+/HER2 − MBC was not cost-effective.Breast cancer, a significant health concern worldwide, represents around 30% of new cancer diagnoses and 25% of cancer related fatalities. Among these cases, approximately two-thirds are characterized by hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2−) tumors. In the metastatic stage, up to half of patients exhibit inherent resistance to endocrine therapy, leading to poorer survival rates, while others, initially responsive, eventually develop resistance, leading to disease progression and eventual mortality. Nevertheless, recent advancements in CDK4/6 inhibitors have shown efficacy in overcoming both inherent and acquired endocrine resistance, representing a substantial breakthrough in HR+/HER2− metastatic breast cancer treatment. This study conducts a review of literature focusing on comparative cost-effectiveness and economic evaluations of the three CDK4/6 inhibitors, evaluating the pooled incremental net benefit (INB) reported in these studies. It marks the first attempt to compare all three CDK4/6 inhibitors and employs a meta-analysis approach to ascertain the option demonstrating the most positive INB. Our findings indicate that CDK4/6 inhibitors fail to provide an economic advantage over letrozole or endocrine therapy alone. The aim of this study is to offer insights for clinical and reimbursement decision-making in the treatment of postmenopausal patients with advanced HR+/HER2− breast cancer, providing valuable guidance for policymakers, payers, and clinicians. [ABSTRACT FROM AUTHOR]

Background: Absolute lymphocyte count (ALC) is a predictive and prognostic factor for various tumor types, including breast cancer. Palbociclib is a CDK4/6 inhibitor widely used for the treatment of metastatic estrogen receptor (ER)-positive, HER2-negative breast cancer. However, predictive biomarkers of the efficacy of palbociclib remain unelucidated. We conducted a retrospective study to examine the predictive value of the baseline ALC in patients treated with palbociclib. Methods: The medical records of patients with ER-positive, HER2-negative breast cancer treated with palbociclib plus hormonal therapy between December 2017 and December 2021 were analyzed retrospectively. The cutoff value of ALC was set at 1800 cells/μL at the initiation of palbociclib treatment. The clinical benefit rate (CBR) was defined as the rate of complete or partial response or stable disease for at least 6 months. Progression-free survival (PFS) rates were estimated using the Kaplan–Meier method and compared using the log-rank test. Univariate and multivariate analyses were performed using Cox proportional hazards regression. Results: All of the 202 patients were women, with a median age of 59 years and a performance status (PS) of ≤ 2. The median numbers of lines of chemotherapy and endocrine therapy before palbociclib treatment were 0 (range, 0–9) and 1 (range, 0–7), respectively. Fifty-one patients had liver metastases. Forty-six patients tested negative for progesterone receptor (PgR) expression. The median follow-up time was 9.1 months. The CBR was significantly higher in the ALC-high group than in the ALC-low group (79% vs. 60%; P = 0.018). The median PFS was significantly longer in the ALC-high group than in the ALC-low group (26.8 months vs. 8.4 moths, respectively; P = 0.000013). ALC, age, PS, PgR status, prior chemotherapy, prior endocrine therapy, and liver metastasis were entered into the multivariate analysis. ALC was identified as an independent factor for PFS (P = 0.00085), along with liver metastasis (P = 0.0020), PS (P = 0.026), and prior endocrine therapy (P = 0.019). Conclusion: ALC can serve as a predictor of palbociclib efficacy in patients with metastatic ER-positive, HER2-negative breast cancer. [ABSTRACT FROM AUTHOR]

Palbociclib, an oral inhibitor of cyclin-dependent kinase 4 and 6, is approved for the treatment of metastatic breast cancer. This study investigated the influence of diverse clinical and biological factors--age, renal function, genetic variations, and concomitant medications (pharmacokinetic covariates)--on palbociclib pharmacokinetics. Employing a validated LC-MS/MS method, we analyzed the minimum plasma concentrations (Ctrough) of palbociclib in 68 women and determined the percentage deviations from the median Ctrough for each dosage group. Variations in a panel of absorption, distribution, metabolism, and excretion (ADME) genes were assessed using end-point allele-specific fluorescence detection and pyrosequencing. Two distinct patient cohorts were defined based on median values of age, creatinine, and eGFR, which exhibited statistically significant differences in percentage deviations (p = 0.0095, p = 0.0288, and p = 0.0005, respectively). Homozygous carriers of the PPARA variants displayed larger positive percentage deviations than the other group (p = 0.0292). Similarly, patients concurrently taking CYP3A and P-glycoprotein inhibitors alongside anticancer therapy exhibited significant variations (p = 0.0285 and p = 0.0334, respectively). Furthermore, exploring the drug-drug-gene interactions between inhibitors of CYP3A and P-glycoprotein with their respective genetic variants revealed two patient groups with statistically different percentage deviations (p = 0.0075, p = 0.0012, and p = 0.0191, respectively). These results could help address cases where pharmacokinetic covariates or subclinical conditions impair palbociclib adherence or response, aiming to offer tailored dosing strategies or monitoring for individual patients. [ABSTRACT FROM AUTHOR]

This article discusses the diagnosis of mesothelioma in situ (MIS), which is a preinvasive stage of mesothelioma. The author raises concerns about cases of MIS that progress to invasive mesothelioma within a year of the initial diagnosis, despite meeting the criteria for MIS at the time of diagnosis. The author suggests that a follow-up period of at least 1 year should be considered before confirming a diagnosis of MIS, to allow for the progression to the visible invasive stage. The article emphasizes the importance of careful follow-up and suggests further research on the median time required for MIS to progress to an invasive tumor. [Extracted from the article]

This study examines the biological effects of palbociclib and ribociclib in hormone receptor-positive breast cancer, pivotal to the HARMONIA prospective phase III clinical trial. We explore the downstream impacts of these CDK4/6 inhibitors, focusing on cell lines and patient-derived tumor samples. We treated HR+ breast cancer cell lines (T47D, MCF7, and BT474) with palbociclib or ribociclib (100 nM or 500 nM), alone or combined with fulvestrant (1 nM), over periods of 24, 72, or 144 h. Our assessments included PAM50 gene expression, RB1 phosphorylation, Lamin-B1 protein levels, and senescence-associated β-galactosidase activity. We further analyzed PAM50 gene signatures from the CORALLEEN and NeoPalAna phase II trials. Both CDK4/6 inhibitors similarly inhibited proliferation across the cell lines. At 100 nM, both drugs partially reduced p-RB1, with further decreases at 500 nM over 144 h. Treatment led to reduced Lamin-B1 expression and increased senescence-associated β-galactosidase activity. Both drugs enhanced Luminal A and reduced Luminal B and proliferation signatures at both doses. However, the HER2-enriched signature significantly diminished only at the higher dose of 500 nM. Corresponding changes were observed in tumor samples from the CORALLEEN and NeoPalAna studies. At 2 weeks of treatment, both drugs significantly reduced the HER2-enriched signature, but at surgery, this reduction was consistent only with ribociclib. Our findings suggest that while both CDK4/6 inhibitors effectively modulate key biological pathways in HR+/HER2- breast cancer, nuances in their impact, particularly on the HER2-enriched signature, are dose-dependent, influenced by the addition of fulvestrant and warrant further investigation. [ABSTRACT FROM AUTHOR]

Background: The combination of CDK4/6 inhibitors (CDK4/6i) and endocrine therapy (ET) is currently the standard first-line treatment for patients with metastatic hormone receptor positive (HR+), and HER2-negative (HER2-) breast cancer. However, the impact of HER2 status on the prognosis of patients receiving CDK4/6i and ET remains unclear. The meta-analysis was conducted to evaluate different outcomes between HER2-low and HER2-zero patients in advanced HR+ breast cancer receiving CDK4/6i and ET. Methods: A systematic search was performed in PubMed and EMBASE databases for relevant published literature. Objective response rate (ORR), overall survival (OS), and progression-free survival (PFS) were pooled by fixed or random effects models. Results: Overall, 12 studies with 3567 patients were eligible for analysis. The pooled analysis suggested that no significant differences were observed in terms of ORR and OS between HER2-low and HER2-zero patients who underwent CDK4/6i and ET. Similarly, no significant difference in PFS was found between HER2-low and HER2-zero patients who underwent post-line CDK4/6i and ET or first-line Palbociclib and ET. However, in patients who received mixed-line (not a single treatment line) or first-line CDK4/6i and ET, the PFS was significantly shorter in the HER2-low subgroup than in the HER2-zero subgroup (mixed-line: HR = 1.36; 95% CI = 1.11–1.65; P = 0.002; first-line: HR = 1.14; 95% CI = 1.01– 1.28; P = 0.04). A similar phenomenon was observed in patients who received mixed-line or post-line Palbociclib and ET (mixed-line: HR = 1.60; 95% CI = 1.09–2.34; P = 0.02; post-line: HR = 1.43; 95% CI = 1.03–2.00; P = 0.03). Conclusion: These results indicated that HER2-low status did not have a significant association with ORR and OS, but it may have a worse impact on PFS in patients who received mixed-line or first-line CDK4/6i and ET, as well as mixed-line or post-line palbociclib plus ET. [ABSTRACT FROM AUTHOR]

Aging is a complex multifactorial process associated with epigenome dysregulation, increased cellular senescence, and decreased rejuvenation capacity. Short-term cyclic expression of octamer-binding transcription factor 4 (Oct4), sex-determining region Y-box 2 (Sox2), Kruppel-like factor 4 (Klf4), and cellular myelocytomatosis oncogene (cMyc) (OSKM) in wild-type mice improves health but fails to distinguish cell states, posing risks to healthy cells. Here, we delivered a single dose of adeno-associated viruses (AAVs) harboring OSK under the control of the cyclin-dependent kinase inhibitor 2a (Cdkn2a) promoter to specifically partially reprogram aged and stressed cells in a mouse model of Hutchinson-Gilford progeria syndrome (HGPS). Mice showed reduced expression of proinflammatory cytokines and extended life spans upon aged cell–specific OSK expression. The bone marrow and spleen, in particular, showed pronounced gene expression changes, and partial reprogramming in aged HGPS mice led to a shift in the cellular composition of the hematopoietic stem cell compartment toward that of young mice. Administration of AAVs carrying Cdkn2a-OSK to naturally aged wild-type mice also delayed aging phenotypes and extended life spans without altering the incidence of tumor development. Furthermore, intradermal injection of AAVs carrying Cdkn2a-OSK led to improved wound healing in aged wild-type mice. Expression of CDKN2A-OSK in aging or stressed human primary fibroblasts led to reduced expression of inflammation-related genes but did not alter the expression of cell cycle–related genes. This targeted partial reprogramming approach may therefore facilitate the development of strategies to improve health and life span and enhance resilience in the elderly. Editor's summary: Partial cellular reprogramming via cyclic expression of octamer-binding transcription factor 4, sex-determining region Y-box 2, Kruppel-like factor 4, and cellular myelocytomatosis oncogene (OSKM) improves health and life span in mouse models but may lead to tumor induction or organ damage. Here, Sahu and colleagues used adeno-associated viruses to deliver OSK under the control of the cyclin-dependent kinase inhibitor 2a (Cdkn2a) promoter to specifically target stressed and senescent cells in a mouse model of Hutchinson-Guilford progeria syndrome. Treatment extended life spans and improved overall fitness, associated with a shift in the transcriptome toward that seen in younger mice. Similar effects occurred in aged wild-type mice and treatment did not increase tumor occurrence, suggesting that targeting partial cellular reprogramming to specific cell populations may be a more viable rejuvenation strategy moving forward. —Melissa L. Norton [ABSTRACT FROM AUTHOR]

Background: Arginine deprivation therapy (ADT) hinders glioma cells' access to nutrients by reducing peripheral blood arginine, showing great efficacy in various studies, which suggests it as a potentially promising treatment for glioma. The aim of this systematic review was to explore the mechanism of ADT for gliomas, the therapeutic effect based on existing research, and possible combination therapies. Methods: We performed a systematic literature review of PubMed, ScienceDirect and Web of Science databases according to PRISMA guidelines, searching for articles on the efficacy of ADT in glioma. Results: We identified 17 studies among 786 search results, among which ADT therapy mainly based on Arginine free condition, Arginine Deiminase and Arginase, including three completed clinical trials. ADT therapy has shown promising results in vivo and in vitro, with its safety confirmed in clinical trials. In the early phase of treatment, glioblastoma (GBM) cells develop protective mechanisms of stress and autophagy, which eventually evolve into caspase dependent apoptosis or senescence, respectively. The immunosuppressive microenvironment is also altered by arginine depletion, such as the transformation of microglia into a pro-inflammatory phenotype and the activation of T-cells. Thus, ADT therapy demonstrates glioma-killing effect in the presence of a combination of mechanisms. In combination with various conventional therapies and investigational drugs such as radiotherapy, temozolomide (TMZ), cyclin-dependent kinase inhibitors (CDK) inhibitors and autophagy inducers, ADT therapy has been shown to be more effective. However, the phenomenon of drug resistance due to re-expression of ASS1 rather than stem cell remains to be investigated. Conclusion: Despite the paucity of studies in the literature, the available data demonstrate the therapeutic potential of arginine deprivation therapy for glioma and encourage further research, especially the exploration of its combination therapies and the extrapolation of what we know about the effects and mechanisms of ADT from other tumors to glioma. [ABSTRACT FROM AUTHOR]

Background: Streptococcus pneumoniae (Spn) is a major causative agent of pneumonia, which can disseminate to the bloodstream and brain. Pneumonia remains a leading cause of death among children aged 1–59 months worldwide. This study aims to investigate the role of Kruppel-like factor 2 (KLF2) in lung injury caused by Spn in young mice. Methods: Young mice were infected with Spn to induce pneumonia, and the bacterial load in the bronchoalveolar lavage fluid was quantified. KLF2 expression in lung tissues was analyzed using real-time quantitative polymerase chain reaction and Western blotting assays. Following KLF2 overexpression, lung tissues were assessed for lung wet-to-dry weight ratio and Myeloperoxidase activity. The effects of KLF2 on lung injury and inflammation were evaluated through hematoxylin and eosin staining and enzyme-linked immunosorbent assay. Chromatin immunoprecipitation and dual-luciferase assay were conducted to examine the binding of KLF2 to the promoter of microRNA (miR)-222-3p and cyclin-dependent kinase inhibitor 1B (CDKN1B), as well as the binding of miR-222-3p to CDKN1B. Levels of miR-222-3p and CDKN1B in lung tissues were also determined. Results: In young mice with pneumonia, KLF2 and CDKN1B were downregulated, while miR-222-3p was upregulated in lung tissues. Overexpression of KLF2 reduced lung injury and inflammation, evidenced by decreased bacterial load, reduced lung injury, and lower levels of proinflammatory factors. Co-transfection of miR-222-3p-WT and oe-KLF2 significantly reduced luciferase activity, suggesting that KLF2 binds to the promoter of miR-222-3p and suppresses its expression. Transfection of CDKN1B-WT with miR-222-3p mimics significantly reduced luciferase activity, indicating that miR-222-3p binds to CDKN1B and downregulates its expression. Overexpression of miR-222-3p or downregulation of CDKN1B increased bacterial load in BALF, lung wet/dry weight ratio, MPO activity, and inflammation, thereby reversing the protective effect of KLF2 overexpression on lung injury in young mice with pneumonia. Conclusions: KLF2 alleviates lung injury in young mice with Spn-induced pneumonia by transcriptional regulation of the miR-222-3p/CDKN1B axis. [ABSTRACT FROM AUTHOR]

Background: There are limited real-world data (RWD) regarding the use of cyclin-dependent kinase (CDK) 4/6 inhibitors in western Balkan. The aim of our study was thus to analyze factors influencing progression-free survival (PFS) and overall survival (OS), along with the differences in adverse effects of CDK 4/6 therapy in a tertiary healthcare center in Croatia. Methods: We evaluated medical and demographic data for 163 consecutive patients with metastatic breast cancer treated with CDK4/6 inhibitors for at least one month, from October 2018, after the drug became available in Croatia. Eligible patients in our study were those patients who were treated with palbociclib, ribociclib, or abemaciclib. Results: The median PFS of CDK4/6 inhibitors treatment was 2.2 years (95% CI 1.8–3.3), with the longest ongoing treatment for 5.4 years. Treatment with CDK4/6 inhibitors in the first line was associated with a longer PFS compared to the second line or beyond (HR 0.50, 95% CI 0.3–0.9), and patients without liver metastasis exhibited longer survival compared to patients with liver metastasis (HR 0.46, 95% CI 0.2–0.8) (both p < 0.05). Regarding the choice of CDK4/6 inhibitors, ribociclib exhibited longer PFS compared to palbociclib (HR 0.49, 95% CI 0.29–0.82) (p = 0.0032), although the effect was not statistically significant when separating patients who were treated with CDK4/6 inhibitors in the first-line (HR 0.59, 95% CI 0.29–1.2), or second- or later-line therapy (0.49, 95% CI 0.15–1.55); the trend was present in both lines, however. The presence of liver metastasis (p = 0.04), initial luminal A grade (p = 0.039), and time to metastasis up to 5 years from the initial cancer (p = 0.002) were the only factors that remained statistically significant for PFS in multivariate analysis. Median OS since the diagnosis of metastatic disease was 4.5 years (95% CI 3.9–6.3), median OS since the start of CDK4/6 inhibitors treatment was 3.7 years (95% CI 3.4–4.4), while median OS from initial cancer diagnosis was 15.8 years (95% CI 13.8–18.3). There was no difference in OS based on the choice of CDK4/6 inhibitor (p = 0.44) or the adjuvant hormonal therapy (p = 0.12), although a nonsignificant trend for better OS with ribociclib was present for both regardless of whether it was in first- or second/later-line therapies (p > 0.05). In a multivariate analysis, only the presence of liver metastasis (p = 0.0003) and time to metastasis under 5 years from primary breast cancer (p = 0.03) were associated with a worse OS. Conclusions: Our study provides the RWD with the use of CDK4/6 inhibitors in the treatment of metastatic HR+/HER2− breast cancer. To our best knowledge, there are limited RWD regarding CDK 4/6 inhibitors use in western Balkan; thus, our study provides valuable data from everyday clinical practice for this region of Europe, bridging the gap between randomized clinical trials and clinical reality in western Balkan. [ABSTRACT FROM AUTHOR]

Background. Cyclin-dependent kinase 8 (CDK8) is a multifaceted regulator and represents a catalytic component of the transcriptional Mediator complex. CDK8 activity, on the one hand, increases transcriptional elongation by the recruitment of Mediator/super elongation complexes, but, on the other hand, negatively regulates CDK7-controlled transcriptional initiation through inactivating cyclin H phosphorylation. Recently, these combined properties of CDK8 have also suggested its rate-limiting importance for herpesviral replication. Objectives. In this paper, we focused on human cytomegalovirus (HCMV) and addressed the question of whether the pharmacological inhibition or knock-down of CDK8 may affect viral replication efficiency in cell culture models. Methods. A number of human and animal herpesviruses, as well as non-herpesviruses, were used to analyze the importance of CDK8 for viral replication in cell culture models, and to assess the antiviral efficacy of CDK8 inhibitors. Results. Using clinically relevant CDK8 inhibitors (CCT-251921, MSC-2530818, and BI-1347), HCMV replication was found strongly reduced even at nanomolar drug concentrations. The EC50 values were consistent for three different HCMV strains (i.e., AD169, TB40, and Merlin) analyzed in two human cell types (i.e., primary fibroblasts and astrocytoma cells), and the drugs comprised a low level of cytotoxicity. The findings highlighted the following: (i) the pronounced in vitro SI values of anti-HCMV activity obtained with CDK8 inhibitors; (ii) a confirmation of the anti-HCMV efficacy by CDK8–siRNA knock-down; (iii) a CDK8-dependent reduction in viral immediate early, early, and late protein levels; (iv) a main importance of CDK8 for viral late-stage replication; (v) several mechanistic aspects, which point to a strong impact on viral progeny production and release, but a lack of CDK8 relevance for viral entry or nuclear egress; (vi) a significant anti-HCMV drug synergy for combinations of inhibitors against host CDK8 and the viral kinase vCDK/pUL97 (maribavir); (vii) finally, a broad-spectrum antiviral activity, as seen for the comparison of selected α-, β-, γ-, and non-herpesviruses. Conclusions. In summary, these novel data provide evidence for the importance of CDK8 as a positive regulator of herpesviral replication efficiency, and moreover, suggest its exploitability as an antiviral target for novel strategies of host-directed drug development. [ABSTRACT FROM AUTHOR]

Endometrial cancer (EC) is a common gynecologic malignancy with a rising incidence due to obesity, comorbid conditions, and related lifestyle factors. The standard of care for primary disease consists of surgical resection with/without chemotherapy ± radiotherapy for select patients. Recurrence is common in patients with advanced-stage disease and/or high-risk features, who primarily are treated with systemic therapy. The identification of novel targets in malignant EC has led to the development of wide-range inhibitors. Abemaciclib is an orally active unique cyclin-dependent kinase (CDK) inhibitor, selective for the CDK4 and CDK6 cell cycle pathways. This agent has potential anti-neoplastic activity and is indicated in combination with various therapies such as endocrine therapy, aromatase inhibitors, and hormone therapies, primarily in breast cancer (BC). Herein, we sought to summarize the biochemical/pharmacological properties of abemaciclib and its therapeutic potential in EC. While the therapeutic role(s) of abemaciclib was fairly established in a subset of patients with advanced/metastatic BC through the pivotal MONARCH trials, its attributes and clinical utility in EC are limited. Thus, based on some promising pre-clinical/translational insights and a recent phase II study, we highlight abemaciclib's properties and potential clinical usefulness in patients with EC, particularly in recurrent estrogen-receptor-positive cases. [ABSTRACT FROM AUTHOR]

Introduction: Hotspots (HS) mutations in the PIK3CA gene may lead to poorer oncological outcomes and endocrine resistance in advanced breast cancer (BC), but their prognostic role in early‐stage disease remains controversial. The overall agreement within plasma and tissue methods has not been well explored. Our aim was to correlate tissue and plasma approaches and to analyze the prognostic impact of PIK3CA mutations (PIK3CAm) in HR+/HER2− BC. Methods: A retrospective and unicentric analysis of PIK3CA mutational status in tissue and plasma samples by Cobas®PIK3CA Mutation Kit in patients with HR+/HER2− BC. Results: We analyzed 225 samples from 161 patients with luminal BC. PIK3CA mutations were identified in 62 patients (38.5%), of which 39.6% were found in tissue and 11.8% in plasma. In advanced disease, plasma and tissue correlation rate was performed in 64 cases, with an overall agreement of 70.3%. Eighty patients were treated with CDK4/6 inhibitors + endocrine therapy. We observed a moderately worse progression‐free survival (PFS) in PIK3CAm versus wild‐type (WT) (24 m vs. 30 m; HR = 1.39, p = 0.26). A subanalysis was carried out based on exons 9 and 20, which showed a statistically poorer PFS in PIK3CAm exon 9 versus 20 population (9.7 m vs. 30.3 m; HR = 2.84; p = 0.024). Furthermore, detection of PIK3CAm in plasma was linked to a worse PFS vs PIK3CAm detection just in tissue (12.4 vs. 29.3; HR = 2.4; p = 0.08). Conclusions: Our findings suggest the PIK3CA evaluation in tissue as the diagnostic method of choice, however, additional investigations are required to improve the role of liquid biopsy in the PIK3CA assessment. PIK3CAm show worse outcomes in advanced luminal BC, especially in exon 9 mutation carriers, despite visceral involvement, prior exposure to endocrine therapy or detection of PIK3CAm in plasma, with an unclear prognosis in early‐stage disease. Nonetheless, this should be validated in a prospective cohort study. [ABSTRACT FROM AUTHOR]

Macrophages play a key role in ozone-induced lung injury by regulating both the initiation and resolution of inflammation. These distinct activities are mediated by pro-inflammatory and anti-inflammatory/proresolution macrophages which sequentially accumulate in injured tissues. Macrophage activation is dependent, in part, on intracellular metabolism. Herein, we used RNA-sequencing (seq) to identify signaling pathways regulating macrophage immunometabolic activity following exposure of mice to ozone (0.8 ppm, 3 h) or air control. Analysis of lung macrophages using an Agilent Seahorse showed that inhalation of ozone increased macrophage glycolytic activity and oxidative phosphorylation at 24 and 72 h post-exposure. An increase in the percentage of macrophages in S phase of the cell cycle was observed 24 h post ozone. RNA-seq revealed significant enrichment of pathways involved in innate immune signaling and cytokine production among differentially expressed genes at both 24 and 72 h after ozone, whereas pathways involved in cell cycle regulation were upregulated at 24 h and intracellular metabolism at 72 h. An interaction network analysis identified tumor suppressor 53 (TP53), E2F family of transcription factors (E2Fs), cyclin-dependent kinase inhibitor 1A (CDKN1a/p21), and cyclin D1 (CCND1) as upstream regulators of cell cycle pathways at 24 h and TP53, nuclear receptor subfamily 4 group a member 1 (NR4A1/Nur77), and estrogen receptor alpha (ESR1/ERα) as central upstream regulators of mitochondrial respiration pathways at 72 h. To assess whether ERα regulates metabolic activity, we used ERα−/− mice. In both air and ozone-exposed mice, loss of ERα resulted in increases in glycolytic capacity and glycolytic reserve in lung macrophages with no effect on mitochondrial oxidative phosphorylation. Taken together, these results highlight the complex interaction between cell cycle, intracellular metabolism, and macrophage activation which may be important in the initiation and resolution of inflammation following ozone exposure. [ABSTRACT FROM AUTHOR]

CAPItello-291 is an ongoing phase 3 trial in which capivasertib–fulvestrant significantly improved progression-free survival versus placebo–fulvestrant in patients with hormone receptor-positive, HER2-negative advanced breast cancer who had relapse or disease progression during or after aromatase inhibitor treatment, in both the overall population and in patients with PIK3CA , AKT1 , or PTEN -altered tumours. This study further explored patient-reported health-related quality of life (HRQOL), functioning, symptoms, and symptom tolerability in CAPItello-291. This phase 3, randomised, double-blind, placebo-controlled trial, which was conducted across 193 hospitals and cancer centres in 19 countries, enrolled women with any menopausal status or men, aged ≥18 years (≥20 years in Japan), with hormone receptor-positive, HER2-negative locally advanced or metastatic breast cancer who had relapse or disease progression during or after treatment with an aromatase inhibitor, with or without previous cyclin-dependent kinase (CDK) 4 or 6 inhibitor therapy. Patients had an Eastern Cooperative Oncology Group/WHO performance score of 0 or 1 and could have received up to two previous lines of endocrine therapy and up to one previous line of chemotherapy for advanced disease. Patients were randomly assigned (1:1) using block randomisation (stratified according to the presence or absence of liver metastases, previous use of a CDK4/6 inhibitor [yes vs no], and geographical region) to receive oral capivasertib 400 mg (twice daily for 4 days, followed by 3 days off) plus intramuscular fulvestrant 500 mg (every 14 days for the first three injections, then every 28 days) or placebo with matching fulvestrant dosing. The dual primary endpoint of the trial was investigator-assessed progression-free survival assessed both in the overall population and among patients with PIK3CA , AKT1 , or PTEN -altered tumours. The EORTC Quality of Life Questionnaire 30-item core module (QLQ-C30) and breast module (QLQ-BR23), Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE), and Patient Global Impression of Treatment Tolerability (PGI-TT) questionnaires were used to assess patient-reported outcomes. Evaluation of EORTC QLQ-C30 and EORTC QLQ-BR23 were secondary endpoints and evaluation of PRO-CTCAE and PGI-TT were pre-defined exploratory endpoints, and these endpoints are the subject of analysis in this Article. Data were collected at baseline and prespecified timepoints. Patient-reported outcomes were analysed in all randomly assigned patients with an evaluable baseline assessment and at least one evaluable post-baseline assessment. Change from baseline was assessed using mixed model with repeated measures for EORTC QLQ-C30 and summarised for QLQ-BR23. Time to deterioration was described using the Kaplan–Meier method. PGI-TT and PRO-CTCAE responses were summarised at each treatment cycle. Patient-reported outcomes were not prospectively powered for statistical comparison. The trial is registered with ClinicalTrials.gov , NCT04305496. Between June 2, 2020, and Oct 13, 2021, 901 patients were enrolled, of whom 708 patients were randomly assigned to receive capivasertib–fulvestrant (n=355) or placebo–fulvestrant (n=353). The median age of the patients was 59 years (IQR 51–67) in the capivasertib–fulvestrant group and 58 years (IQR 49–66) in the placebo–fulvestrant group. At data cutoff (Aug 15, 2022), the median duration of follow-up for progression-free survival in censored patients was 13·0 months (IQR 9·1–16·7) for capivasertib–fulvestrant and 12·7 months (IQR 2·0–16·4) for placebo–fulvestrant in the overall population. EORTC QLQ-C30 global health status/quality of life (GHS/QOL) scores were maintained from baseline and were similar between treatment groups throughout the study period (difference in mean change from baseline of −2·5 [95% CI −4·5 to −0·6] with capivasertib–fulvestrant vs −5·6 [−7·9 to −3·4] with placebo–fulvestrant; treatment difference 3·1 [95% CI 0·2 to 6·0]). Median time to deterioration in EORTC QLQ-C30 GHS/QOL was 24·9 months (95% CI 13·8 to not reached) in the capivasertib–fulvestrant group and 12·0 months (10·2 to 15·7) in the placebo–fulvestrant group (hazard ratio [HR] 0·70, 95% CI 0·53 to 0·92). Time to deterioration HRs for all EORTC QLQ-C30 and QLQ-BR23 subscale scores showed little difference between the treatment groups, except for diarrhoea, which was worse in the capivasertib–fulvestrant group than in the placebo–fulvestrant group (HR 2·75, 95% CI 2·01–3·81). In PRO-CTCAE symptom assessment, the proportion of patients reporting loose and watery stools "frequently" or "almost constantly" was 29% higher at cycle 1, day 15 in the capivasertib–fulvestrant group than in the placebo–fulvestrant group, decreasing at subsequent cycles. Other PRO-CTCAE-reported symptoms (rash, mouth or throat sores, itchy skin, and numbness or tingling in hands or feet) were absent or mild in most patients in both groups throughout treatment. According to the PGI-TT, most patients in both groups reported "not at all" or "a little bit" of bother from treatment side-effects. Patient-reported outcomes from CAPItello-291 demonstrated that capivasertib–fulvestrant delayed time to deterioration of GHS/QOL and maintained other dimensions of HRQOL (except symptoms of diarrhoea) similarly to fulvestrant. With the clinical efficacy and manageable safety profile, these exploratory results further support the positive benefit–risk profile of capivasertib–fulvestrant in this population. AstraZeneca. [ABSTRACT FROM AUTHOR]

In luminal breast cancer, adjuvant CDK4/6 inhibitors (eg, abemaciclib) improve invasive disease-free survival. In patients with T1–2, grade 1–2 tumours, and one or two sentinel lymph node metastases, completion axillary lymph node dissection (cALND) is the only prognostic tool available that can reveal four or more nodal metastases (pN2–3), which is the only indication for adjuvant abemaciclib in this setting. However, this technique can lead to substantial arm morbidity in patients. We aimed to pragmatically describe the potential benefit and harm of this strategy on the individual patient level in patients from the ongoing SENOMAC trial. In the randomised, phase 3, SENOMAC trial, patients aged 18 years or older, of any performance status, with clinically node-negative T1–T3 breast cancer and one or two sentinel node macrometastases from 67 sites in five European countries (Denmark, Germany, Greece, Italy, and Sweden) were randomly assigned (1:1), via permutated block randomisation (random block size of 2 and 4) stratified by country, to either cALND or its omission (ie, they had a sentinel lymph node biopsy only). The primary outcome is overall survival, which is yet to be reported. In this post-hoc analysis, patients from the SENOMAC per-protocol population, with luminal oestrogen-receptor positive, HER2-negative, T1–2, histological grade 1–2 breast cancer, with tumour size of 5 cm or smaller were selected to match the characteristics of cohort 1 of the monarchE trial who would only have an indication for adjuvant abemaciclib if found to have 4 or more nodal metastases. The primary study objective was to determine the number of patients who developed patient-reported severe or very severe impairment of physical arm function after cALND (as measured by the Lymphedema Functioning, Disability, and Health [Lymph-ICF] Questionnaire) 1 year after surgery to avoid one invasive disease-free survival event at 5 years with 2 years of adjuvant abemaciclib, using invasive disease-free survival event data from cohort 1 of the monarchE trial. The SENOMAC trial is registered with ClincialTrials.gov, NCT02240472, and is closed to accrual and ongoing. Between Jan 31, 2015, and Dec 31, 2021, 2766 patients were enrolled in SENOMAC and randomly assigned to cALND (n=1384) or sentinel node biopsy only (n=1382), of whom 2540 were included in the per-protocol population. 1705 (67%) of 2540 patients met this post-hoc study's eligibility criteria, of whom 802 (47%) had a cALND and 903 (53%) had a sentinel lymph node biopsy only. Median age at randomisation was 62 years (IQR 52–71), 1699 (>99%) of 1705 patients were female, and six (<1%) were male. Among 1342 patients who responded to questionnaires, after a median follow-up of 45·2 months (IQR 25·6–59·8; data cutoff Nov 17, 2023), patient-reported severe or very severe impairment of physical arm function was reported in 84 (13%) of 634 patients who had cALND versus 30 (4%) of 708 who had sentinel lymph node biopsy only (χ2 test p<0·0001). To avoid one invasive disease-free survival event at 5 years with adjuvant abemaciclib, cALND would need to be performed in 104 patients, and would result in nine patients having severe or very severe impairment of physical arm function 1 year after surgery. As a method to potentially identify an indication for abemaciclib, and subsequently avoid invasive disease-free survival events at 5 years with 2 years of adjuvant abemaciclib, cALND carries a substantial risk of severe or very severe arm morbidity and so cALND should be discouraged for this purpose. Swedish Research Council, the Swedish Cancer Society, the Nordic Cancer Union, and the Swedish Breast Cancer Association. [ABSTRACT FROM AUTHOR]

In equine regenerative medicine using bone marrow-derived mesenchymal stem/stromal cells (BM-MSC), the importance of the quality management of BM-MSC has been widely recognized. However, there is little information concerning the relationship between cellular senescence and the stemness in equine BM-MSC. In this study, we showed that stemness markers (NANOG, OCT4, SOX2 and telomerase reverse transcriptase) and colony forming unit-fibroblast apparently decreased accompanied with incidence of senescence-associated ß-galactosidasepositive cells by repeated passage. Additionally, we suggested that down-regulation of cell proliferation in senescent BM-MSC was related to increased expression of cyclin-dependent kinase inhibitor 2B (CDKN2B). On the other hand, forced expression of NANOG into senescent BM-MSC brought upregulation of several stemness markers and downregulation of CKDN2B accompanied with restoration of proliferation potential and osteogenic ability. These results suggested that expression of NANOG was important for the maintenance of the stemness in equine BM-MSC. [ABSTRACT FROM AUTHOR]

The most common toxicities associated with cyclin‐dependent kinase (CDK) 4/6 inhibitor therapy include decreased leukopenia and neutropenia due to the inhibition of CDK6 of leukocyte and neutrophil precursors in bone marrow. These hematological toxicities are more commonly observed with palbociclib administration than with abemaciclib administration, which is approximately 13 times more selective against CDK4 than CDK6. Thus, even though both successfully inhibit CDK4/6, the side effects of palbociclib and abemaciclib differ due to differences in selectivity. Recent reports have suggested an association between palbociclib and medication‐related osteonecrosis of the jaw; however, reports on this association are inconsistent. This study investigated the potential association of palbociclib and abemaciclib with MRONJ using the FAERS. Signals of "Osteonecrosis of jaw" were detected only in females using palbociclib (cROR025: 2.08). Other signals detected included stomatitis‐related adverse events with abemaciclib and intraoral soft tissue damage and infection with palbociclib. As previous exploratory studies have reported MRONJ signals for bisphosphonates and denosumab, we calculated the aROR for palbociclib‐induced osteonecrosis of the jaw using concomitant bisphosphonates and denosumab as covariates. A signal was detected even after adjusting for sex, age, and concomitant medications as covariates (aROR0025: 5.74). A proper understanding of the differences in CDK selectivity is necessary for the appropriate use of CDK4/6 inhibitors. To the best of our knowledge, this is the first report on CDK4/6 inhibitors and drug‐related osteonecrosis of the jaw. We believe that these results will offer new insights into adverse events related to the use of CDK4/6 inhibitors, and may aid in the proper use of CDK4/6 inhibitors. [ABSTRACT FROM AUTHOR]

Introduction: Patients with breast cancer, especially triple-negative breast cancer, have a poor prognosis. There is still no effective treatment for this disease. Due to resistance to traditional treatments such as chemotherapy and radiation therapy, there is a need to discover novel treatment strategies to treat this disease. Ribociclib is a selective CDK4/6 inhibitor. Approximately 20% of patients with HR+ breast cancer developed primary resistance to CDK4/6 inhibitors, and more than 30% experienced secondary resistance. Since most patients experience resistance during CDK4/6 inhibitor treatment, managing this disease is becoming more challenging. Many malignant tumors abnormally express microRNA (miR)-141, which participates in several cellular processes, including drug resistance, proliferation, epithelial–mesenchymal transition, migration, and invasion. Materials and methods: In the present study, we cultured MDA-MB-231 and MCF-7 cells in DMEM-F12 medium. By performing MTT assay we determined the cytotoxic effects of ribociclib on breast cancer cells, as well as determining the IC50 of it. Then, we treated the cells with ribociclib at two time points: 24 h and 72 h. After that, RNA was isolated and reverse transcribed to cDNA. Finally, we performed qRT‒PCR to evaluate how ribociclib affects the expression level of desired genes. Results and conclusion: We found that ribociclib can inhibit cell growth in a dose- and time-dependent manner. We examined the mRNA expression of 4 genes. After ribociclib treatment, the mRNA expression of CDK6 and MYH10 decreased (p < 0.01, p < 0.05). The mRNA expression of CDON increased (p<0.05), but no significant changes were observed in ZEB1 mRNA expression. Furthermore, the qRT‒PCR results for miR-141 showed that the expression of miR-141 increased (p<0.01) after 72 h of treatment with ribociclib. [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDAC) has quickly risen to become the third leading cause of cancer-related death in the United States. This is in part because of its fibrotic tumor microenvironment (TME) that contributes to poor vascularization and immune infiltration and subsequent chemo- and immunotherapy failure. Here, we investigated an immunotherapy approach combining delivery of stimulator of interferon genes (STING) and Toll-like receptor 4 (TLR4) innate immune agonists by lipid-based nanoparticle (NP) coencapsulation with senescence-inducing RAS-targeted therapies, which can remodel the immune suppressive PDAC TME through the senescence-associated secretory phenotype. Treatment of transplanted and autochthonous PDAC mouse models with these regimens led to enhanced uptake of NPs by multiple cell types in the PDAC TME, induction of type I interferon and other proinflammatory signaling pathways, increased antigen presentation by tumor cells and antigen-presenting cells, and subsequent activation of both innate and adaptive immune responses. This two-pronged approach produced potent T cell–driven and type I interferon–mediated tumor regression and long-term survival in preclinical PDAC models dependent on both tumor and host STING activation. STING and TLR4-mediated type I interferon signaling was also associated with enhanced natural killer and CD8+ T cell immunity in human PDAC samples. Thus, combining localized immune agonist delivery with systemic tumor-targeted therapy can orchestrate a coordinated type I interferon–driven innate and adaptive immune response with durable antitumor efficacy against PDAC. Editor's summary: Unlike other tumor types, existing immunotherapies have not proven very successful for pancreatic ductal adenocarcinoma (PDAC), necessitating the development of additional approaches. Here, Chibaya et al. developed a combination therapy approach that included nanoparticle delivery of STING and TLR4 agonists, which stimulate the immune response, in combination with the MEK inhibitor trametinib and CDK4/6 inhibitor palbociclib, which promote senescence of tumor cells. The combination therapy induced robust antitumor immune responses that controlled tumor burden in implanted and autochthonous PDAC mouse models. These data support further development of this potent combination therapy for PDAC. —Courtney Malo [ABSTRACT FROM AUTHOR]

Background: Does incorporating Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors into endocrine therapy (ET) effectively enhance survival outcomes, notably overall survival (OS), among individuals with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer? This remains a clinical controversy. We compared the antitumor efficacy and adverse effects (AEs) between CDK4/6 inhibitors + ET (CET) and placebo + ET (PET) by conducting a phase III randomized controlled trials (RCTs) based meta-analysis. Methods: Seven databases were searched to identify eligible studies, comprising Phase III RCTs comparing CET to PET. The primary endpoints were OS and progression-free survival (PFS), with secondary endpoints including responses and adverse events (AEs). Results: Seven RCTs (DAWNA-2, MONALEESA-2, MONALEESA-3, MONALEESA-7, MONARCH-3, PALOMA-2, and PALOMA-4) were included. The CET group exhibited significantly improved OS (HR: 0.81 [0.74, 0.88]), PFS (HR: 0.57 [0.52, 0.63]), objective response rate (RR: 1.31 [1.20, 1.43]), and clinical benefit rate (RR: 1.11 [1.07, 1.15]). These benefits were consistent across almost all subgroups. Additionally, the CET group showed better overall survival rates (OSR) from 24 to 60 months (OSR 24–60 m) and progression-free survival rates (PFSR) from 6 to 60 months (PFSR 6–60 m). However, more total AEs, grade 3–5 AEs, and serious AEs were found in CET group. The top 5 grade 3–5 AEs in the CET group were neutropenia (59.39%), leukopenia (24.11%), decreased white blood cell count (12.99%), hypertension (7.03%), and increased alanine aminotransferase (5.91%). Conclusions: The superiority of CET over PET in HR+/HER2- advanced breast cancer is evident, showing improved survival and responses. Nonetheless, the higher incidence of AEs, specifically hematologic AEs, requires cautious attention. [ABSTRACT FROM AUTHOR]

Objective: Cyclin-dependent kinase (CDK) 4 and 6 inhibitors (abemaciclib, palbociclib and ribociclib) have been recommended in the first-line treatment of hormone receptor-positive (HR+) breast cancer in China. Our study aims to evaluate the efficacy and safety of CDK4/6 inhibitors by processing survival data using fractional polynomial modeling methods. Methods: Phase II or III randomized controlled trials in treatment-naive HR + patients with advanced breast cancer were systematically searched through the preset search strategy. The fractional polynomial (FP) model was used to relax the proportional hazard assumption and obtain time-varying hazard ratio (HR). Progression-free life years (PFLYs) and life years (LYs) were calculated from the area under curve (AUC) of the predicted progression-free survival (PFS) and overall survival (OS) curves to evaluate the long-term efficacy benefit. Odds ratio (OR) of grade≥3 adverse events were analyzed for safety outcomes. Results: 6 randomized controlled trials with 2,638 patients were included. The first-order FP model (p = -1) and the first-order FP model (p = 1) were used to calculate the time-varying HR of PFS and OS, respectively. Extrapolating to 240 months, abemaciclib obtained a PFS benefit of 3.059 PFLYs and 6.275 LYs by calculating the AUC of the PFS and OS curves. Palbociclib obtained 2.302 PFLYs and 6.351 LYs. Ribociclib obtained 2.636 PFLYs and 6.543 LYs. In terms of safety, the use of CDK4/6 inhibitors resulted in a higher risk of adverse events (OR = 9.84, 95% CI: 8.13-11.95), especially for palbociclib (OR = 14.04, 95% CI: 10.52-18.90). Conclusion: The use of CDK4/6 inhibitors in treatment-naive patients with HR + advanced breast cancer significantly improves survival, but also increases the risk of adverse events. Abemaciclib and ribociclib may be the best options for prolonging PFS and OS in treatment-naïve patients, respectively. [ABSTRACT FROM AUTHOR]

Background: The current standard first-line treatment for hormone receptor-positive/human epidermal growth factor receptor 2 negative (HR + /HER2 −) advanced breast cancer (ABC) is a combination of aromatase inhibitor (AI) plus CDK4/6 inhibitors (CDK4/6i). Direct comparison trials of different CDK4/6i are scarce. This real-world study compared the effectiveness of first-line AI plus ribociclib versus palbociclib. Methods: This multicenter retrospective cohort study, conducted in six cancer centers in Thailand, enrolled patients with HR + /HER2 − ABC treated with first-line AI, and either ribociclib or palbociclib. Propensity score matching (PSM) was performed. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), overall response rate (ORR), time to chemotherapy (TTC), and adverse events. Results: Of the 250 patients enrolled, 134 patients with ribociclib and 49 patients with palbociclib were captured after PSM. Baseline characteristics were well-balanced between groups. Median PFS in patients receiving ribociclib and palbociclib were 27.9 and 31.8 months, respectively (hazard ratio: 0.87; 0.55–1.37). The median OS in the AI + ribociclib arm was 48.7 months compared to 59.1 months in the AI + palbociclib arm (hazard ratio: 0.55; 0.29–1.05). The median TTC in the AI + palbociclib group was 56 months, but not reached in the AI + ribociclib group (p = 0.42). The ORR of AI + ribociclib and AI + palbociclib were comparable (40.5% vs. 53.6%, p = 0.29). Patients receiving palbociclib demonstrated a higher proportion of neutropenia compared to those receiving ribociclib, despite a similar dose reduction rate (p = 0.28). Hepatitis rate was similar between the ribociclib (21%) and palbociclib groups (22%). Additionally, a low incidence of QT prolongation was observed in both the ribociclib (5%) and palbociclib groups (4%). Conclusion: This preliminary analysis of a real-world study demonstrated the comparable effectiveness of ribociclib and palbociclib with AI as an initial therapy for HR + /HER2 − ABC. No statistically significant difference in PFS, OS, and TTC was found in patients treated with AI combined with palbociclib or ribociclib. Longer follow-up and further prospective randomized head-to-head studies are warranted. [ABSTRACT FROM AUTHOR]

The combination of cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) with endocrine therapy (ET) is the standard-of-care for estrogen receptor (ER)-positive, HER2-negative (ER+/HER2− advanced/metastatic breast cancer (mBC). However, the impact of CDK4/6i on circulating immune cells and circulating tumor cells (CTCs) in patients receiving CDK4/6i and ET (CDK4/6i+ET) remains poorly understood. This was a prospective cohort study including 44 patients with ER+/HER2− mBC treated with CDK4/6i+ET in either first or second line. Peripheral blood samples were collected before (baseline) and 3 months (t2) after therapy. Immune cell's subsets were quantified by flow cytometry, and microfluidic-captured CTCs were counted and classified according to the expression of cytokeratin and/or vimentin. Patients were categorized according to response as responders (progression-free survival [PFS] ≥ 6.0 months; 79.1%) and non-responders (PFS < 6.0 months; 20.9%). CDK4/6i+ET resulted in significant changes in the hematological parameters, including decreased hemoglobin levels and increased mean corpuscular volume, as well as reductions in neutrophil, eosinophil, and basophil counts. Specific immune cell subsets, such as early-stage myeloid-derived suppressor cells, central memory CD4+ T cells, and Vδ2+ T cells expressing NKG2D, decreased 3 months after CDK4/6i+ET. Additionally, correlations between the presence of CTCs and immune cell populations were observed, highlighting the interplay between immune dysfunction and tumor dissemination. This study provides insights into the immunomodulatory effects of CDK4/6i+ET, underscoring the importance of considering immune dynamics in the management of ER+/HER2− mBC. [ABSTRACT FROM AUTHOR]

Cell cycle regulation is largely abnormal in cancers. Molecular understanding and therapeutic targeting of the aberrant cell cycle are essential. Here, we identified that an underappreciated serine/threonine kinase, cyclin-dependent kinase--like 3 (CDKL3), crucially drives rapid cell cycle progression and cell growth in cancers. With regard to mechanism, CDKL3 localizes in the nucleus and associates with specific cyclin to directly phosphorylate retinoblastoma (Rb) for quiescence exit. In parallel, CDKL3 prevents the ubiquitin-proteasomal degradation of cyclin-dependent kinase 4 (CDK4) by direct phosphorylation on T172 to sustain G1 phase advancement. The crucial function of CDKL3 in cancers was demonstrated both in vitro and in vivo. We also designed, synthesized, and characterized a first-in-class CDKL3-specific inhibitor, HZ1. HZ1 exhibits greater potency than CDK4/6 inhibitor in pan-cancer treatment by causing cell cycle arrest and overcomes acquired resistance to CDK4/6 inhibitor. In particular, CDKL3 has significant clinical relevance in colon cancer, and the effectiveness of HZ1 was demonstrated by murine and patient-derived cancer models. Collectively, this work presents an integrated paradigm of cancer cell cycle regulation and suggests CDKL3 targeting as a feasible approach in cancer treatment. [ABSTRACT FROM AUTHOR]

Purpose: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) combined with endocrine therapy have demonstrated significant clinical benefits in progression-free and overall survival. This study investigates the outcomes associated with two kinds of CDK4/6i in patients with hormone receptor (HR)-positive metastatic and relapsed breast cancer to inform real-world evidence of treatment strategies. Methods: This retrospective study included 340 Taiwanese patients with HR-positive advanced breast cancer from the Taipei Veterans General Hospital, between 2018 and 2023. We analyzed patient characteristics, treatment strategies and outcomes associated with two CDK4/6i. The efficacy of patients who experienced economic burden and interrupted CDK4/6i treatment after 2 years of National Health Insurance (NHI) reimbursement was also investigated. Results: Patients receiving ribociclib and palbociclib showed no significant differences in age, histology, body mass index(BMI), or pathologic status. The distribution of disease status and endocrine therapy partners was comparable between the two groups. Dose reduction was similar, while patients with palbociclib tended to discontinue CDK4/6i usage, and those with ribociclib tended to switch to the other CDK4/6i or endocrine partners. There was no significant difference in progression-free survival (PFS) between the two CDK4/6i in the first-line setting. Adverse prognostic factors were increasing HER2 IHC score, higher Ki-67 levels, visceral and liver metastasis, prior chemotherapy, and endocrine therapy resistance, while higher BMI, bone-only metastasis, and letrozole treatment were associated with a lower risk of progression. The limited follow-up time in our study was insufficient to assess the outcomes of patients treated with interrupted CDK4/6i for up to two years under the NHI reimbursement policy. Conclusion: Treatment outcomes between the two types of CDK4/6i did not differ significantly, indicating the safety and efficacy of CDK4/6i for the Asian population. Ribociclib and palbociclib showed similar efficacy in PFS in the real-world setting. [ABSTRACT FROM AUTHOR]

Introduction: According to WHO, Breast cancer is widely considered to be the first or second cause of cancer-related death almost universally. Cell cycle disruption, either in the form of uncontrolled expression of cyclins or because of the suspension in negative regulatory proteins (CDK inhibitors), was found to cause breast cancer. Palbociclib as specific CDK4/6 inhibitor is used for the treatment of ER+ metastatic cancers. In this study, we are looking to investigate the effect of palbociclib on breast cancer cells and evaluate the changes in the expression of some genes involved in the cell cycle as target genes of miR-141 after treatment with this drug. We used MCF7 as functional estrogen and non-invasive and MDA-MB-231 cell lines as triple-negative type of breast cancer and a model for more aggressive. Method & materials: MCF7 and MDA-MB-231 cell lines were cultured in DMEM medium. After counting cells and measuring viability, Palbociclib was administered at varying doses using the IC50 obtained from MTT, with the treatment given at two time points of 24 and 72 hours. RNA was extracted from untreated and treated cells and RNAs were converted to cDNA in the end. Gene expression changes were investigated by real-time PCR. Data management and analysis were conducted using GraphPad Prism 5.01 software. Result and conclusion: Among investigated genes, E2F3 gene was not significantly affected by Palbociclib in any of cell lines and time points. Besides, the expression of CCNE1 gene was significantly suppressed. It seems this drug was unable to reduce the expression of MDM2 gene significantly in triple negative (MDA-MB-231) cancer cells; however, a decrease was observed in luminal A (MCF-7) cells. CDKN2A and miR-141 genes expression increased significantly after treatment which can be aligned with palbociclib in proliferation inhibition. [ABSTRACT FROM AUTHOR]

Background: Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors marked a milestone in the breast cancer treatment. Due to the potential impact of adverse effects on treatment decisions and patient outcomes, careful consideration of the varying toxicities of CDK4/6 inhibitors is crucial, as three inhibitors—palbociclib, abemaciclib, and ribociclib—have been approved with differences in adverse event profiles. However, limitations in clinical trials call for urgent real-world safety studies to evaluate and compare the risk of adverse events (AEs) among these CDK4/6 inhibitors. Therefore, this study aimed to analyze AEs of CDK4/6 inhibitors and provide insights for clinical drug selection, using real world database. Methods: The AEs of CDK4/6 inhibitors in the FDA Adverse Event Reporting System (2015–2022) were analyzed. Four disproportionality methods were used to detect safety signals: reporting odds ratio (ROR), proportional reporting ratio, Bayesian Confidence Neural Network Propagation, and Multi-Item Gamma Poisson Shrinker. Venn analysis was used to compare and select common and specific AEs. Results: This study included 73,042 patients treated with palbociclib, 25,142 with ribociclib, and 7563 with abemaciclib. All three inhibitors had 27 common AEs. Palbociclib exhibited the highest ROR for hematologic toxicities, while ribociclib showed the highest ROR for macrocytosis, nail disorders, and hepatic lesions. Abemaciclib displayed the highest ROR for mucosal toxicity. Common signals for both palbociclib and ribociclib included hematologic toxicities, decreased immune responsiveness, and aphthous ulcers. Myelosuppression, oral pain, and pseudocirrhosis were common signals for palbociclib and abemaciclib. Anemia, hepatotoxicity, and pneumonitis were observed as common signals for ribociclib and abemaciclib. Furthermore, specific AEs associated with palbociclib included fatigue, alopecia, and stomatitis. For ribociclib, specific AEs included electrocardiogram QT prolongation, thrombocytopenia, and decreased hemoglobin. Abemaciclib was specifically linked to diarrhea, vomiting, and interstitial lung disease. Conclusion: Our analysis revealed that palbociclib showed a higher risk of hematologic toxicity. Ribociclib showed higher risks of hepatotoxicity, nephrotoxicity, and QT prolongation. Abemaciclib showed higher risks of hepatotoxicity, gastrointestinal effects, interstitial lung disease, and thrombosis. These findings provide valuable insights for CDK4/6 inhibitor selection. [ABSTRACT FROM AUTHOR]

Introduction: CDK4/6 inhibitors are the first-line treatment for HR+/HER2- advanced breast cancer. Despite their clinical benefit, they can increase healthcare expenditure. To date, there is no thorough comparison among the three approved CDK4/6 inhibitors in terms of their cost-effectiveness. Objective: To investigate and compare the cost-effectiveness of CDK4/6 inhibitors in combination with letrozole as a first-line treatment for advanced breast cancer with hormonal-receptor-positivity and HER-2-negativity versus one another and versus letrozole monotherapy. Methods: A 10-year within-cycle-corrected Markov’s model was employed from the healthcare payer perspective. Costs were obtained from the National Center for Cancer Care and Research (NCCCR) in Qatar. Utilities and transition probabilities were calculated from published landmark trials of PALOMA-2, MONALEESA-2, MONARCH-3, PO25, and other relevant literature. Costs, measured in Qatari Riyal (QAR), and effectiveness, measured in qualityadjusted-life-years (QALYs), were incremented and the incremental costeffectiveness ratio (ICER) was compared to a willingness-to-pay threshold (WTP) of 1.5 Qatari GDP (448,758 QAR). A deterministic sensitivity analysis was implemented to account for uncertainties. Results: Ribociclib was the most effective option, generating 4.420 QALYs, followed by palbociclib (4.406 QALYs), abemaciclib (4.220 QALYs), then letrozole monotherapy (2.093 QALYs). As for cost-effectiveness, ribociclib dominated palbociclib. However, it was not cost-effective compared to abemaciclib (ICER=1,588,545 QAR/QALY). Ribociclib remained dominant over palbociclib with all uncertainties. The base-case conclusion of ribociclib versus abemaciclib remained robust over all uncertainties. Conclusion: From the healthcare payer perspective in Qatar, ribociclib is the most effective CDK4/6 inhibitor. It was dominant over palbociclib in terms of cost-effectiveness; however, it was not cost-effective compared to abemaciclib at current prices. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancer (TNBC) is one of the most common malignancies in women. The majority of patients with TNBC have a poor prognosis. The main objective of this study is to review the profile and clinical evidence of the effectiveness of Olaparib in treating TNBC. A literature search was conducted using multiple electronic databases, including PubMed, Google Scholar, JSTOR, and Scopus. The search was focused on articles published up to June 2024, ensuring the inclusion of the latest and relevant studies. The primary objective was to investigate the mechanism of action, toxicity profile, resistance mechanisms, and therapeutic effectiveness of olaparib in the treatment of TNBC, regardless of their prior chemotherapy treatment for metastatic breast cancer, prior platinum-based chemotherapy, or usage of cyclin-dependent kinase 4/6 inhibitors (Balmana et al., 2022). The results of this research suggest that the pharmacological efficacy and safety characteristics of this medication in TNBC patients are similar to those reported in the OlympiAD study. Furthermore, stratification of patients for this medication is possible due to the diagnostic techniques that can predict the presence of the BRCA mutation in order to optimize its efficacies. Additionally, developing and validating new biomarkers beyond BRCA mutations for patient stratification could optimize targeted therapy approaches. [ABSTRACT FROM AUTHOR]

The consensus linear view of G1/S regulation has served the research community for many years. Recent data indicate considerable heterogeneity in cancer cycles as controlled by distinct cyclin-dependent kinase (CDK) and cyclin complexes. Adaptation and unexpected dependencies reveal emerging themes that support a malleable model for cancer cell division. The growing complexity of the cell cycle offers challenges and opportunities in rationally targeting proliferative control. In the commonly accepted paradigm for control of the mammalian cell cycle, sequential cyclin-dependent kinase (CDK) and cyclin activities drive the orderly transition from G1 to S phase. However, recent studies using different technological approaches and examining a broad range of cancer cell types are challenging this established paradigm. An alternative model is evolving in which cell cycles utilize different drivers and take different trajectories through the G1/S transition. We are discovering that cancer cells in particular can adapt their drivers and trajectories, which has important implications for antiproliferative therapies. These studies have helped to refine an understanding of how CDK inhibition impinges on proliferation and have significance for understanding fundamental features of cell biology and cancer. [ABSTRACT FROM AUTHOR]

SERENA-1 (NCT03616587) is a phase I, multi-part, open-label study of camizestrant in pre- and post-menopausal women with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2−) advanced breast cancer. Parts A and B aim to determine the safety and tolerability of camizestrant monotherapy and define doses for clinical evaluation. Women aged ≥18 years with metastatic or recurrent ER+, HER2− breast cancer, refractory (or intolerant) to therapy, were assigned 25 mg up to 450 mg once daily (QD; escalation) or 75, 150, or 300 mg QD (expansion). Safety and tolerability, antitumor efficacy, pharmacokinetics, and impact on mutations in the estrogen receptor gene (ESR1 m) circulating tumor (ct)DNA levels were assessed. By 9 March 2021, 108 patients received camizestrant monotherapy at 25-450 mg doses. Of these, 93 (86.1%) experienced treatment-related adverse events (TRAEs), 82.4% of which were grade 1 or 2. The most common TRAEs were visual effects (56%), (sinus) bradycardia (44%), fatigue (26%), and nausea (15%). There were no TRAEs grade 3 or higher, or treatment-related serious adverse events at doses ≤150 mg. Median t max was achieved ∼2-4 h post-dose at all doses investigated, with an estimated half-life of 20-23 h. Efficacy was observed at all doses investigated, including in patients with prior cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) and/or fulvestrant treatment, with and without baseline ESR1 mutations, and with visceral disease, including liver metastases. Camizestrant is a next-generation oral selective ER antagonist and degrader (SERD) and pure ER antagonist with a tolerable safety profile. The pharmacokinetics profile supports once-daily dosing, with evidence of pharmacodynamic and clinical efficacy in heavily pre-treated patients, regardless of ESR1 m. This study established 75-, 150-, and 300-mg QD doses for phase II testing (SERENA-2, NCT04214288 and SERENA-3, NCT04588298). • SERENA-1 (A/B): safety and efficacy of camizestrant monotherapy (25-450 mg) in women with ER+ HER2- advanced breast cancer. • Efficacy was observed at all doses, regardless of prior treatment with CDK4/6i or fulvestrant, or of ESR1 mutation status. • At all doses investigated, median t max was achieved ∼2-4 h post-dose, with an estimated half-life of 20-23 h. • In total, 86.1% of patients experienced TRAEs, with none beyond grade 2 at ≤150 mg camizestrant. • Camizestrant is a next-generation oral SERD and pure ER antagonist with a tolerable safety profile, suitable for QD dosing. [ABSTRACT FROM AUTHOR]

The objective of this study is to create a nanoemulgel formulation of Ribociclib (RIBO), a highly selective inhibitor of CDK4/6 through the utilization of spontaneous emulsification method. An experimental investigation was conducted to construct pseudo-ternary phase diagram for the most favourable formulation utilizing rice bran oil, which is known for its diverse anticancer properties. The formulation consisted of varying combination of the surfactant and as the co-surfactant (Tween 80 and Transcutol, respectively) referred to as Smix and the trials were optimized to get the desired outcome. The nanoemulsion (NE) formulations that were developed exhibited a droplet size of 179.39 nm, accompanied with a PDI of 0.211. According to the data released by Opt-RIBO-NE, it can be inferred that the Higuchi model had the most favourable fit among many kinetics models considered. The results indicate that the use of nanogel preparations for the topical delivery of RIBO in breast cancer therapy, specifically RIBO-NE-G, is viable. This is supported by the extended release of the RIBO, and the appropriate level of drug permeation observed in Opt-RIBO-NE-G. Due to RIBO and Rice Bran oil, RIBO-NE-G had greater antioxidant activity, indicating its effectiveness as antioxidants. The stability of the RIBO-NE-G was observed over a period of three months, indicating a favourable shelf life. Therefore, this study proposes the utilization of an optimized formulation of RIBO-NE-G may enhance the efficacy of anticancer treatment and mitigate the occurrence of systemic side effects in breast cancer patients, as compared to the use of suspension preparation of RIBO. [ABSTRACT FROM AUTHOR]

[Display omitted] • Neutrophilic inflammation is a critical pathogenic hallmark in ARDS. • Ribociclib, a clinically-used CDK4/6 inhibitor, acts as a novel PDE4 inhibitor to regulate neutrophilic inflammation. • Ribociclib shows therapeutic potential in ARDS. • The drug repurposing of ribociclib provides a promising opportunity for neutrophil-associated diseases, including ARDS. Overwhelming neutrophil activation and oxidative stress significantly contribute to acute respiratory distress syndrome (ARDS) pathogenesis. However, the potential of repurposing ribociclib, a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor used clinically in cancer treatment, for treating neutrophilic ARDS remains uncertain. This study illustrated the ability and underlying mechanism of ribociclib for treating ARDS and neutrophilic inflammation. Primary human neutrophils were used to determine the therapeutic effects of ribociclib on respiratory bursts, chemotactic responses, and inflammatory signaling. In vitro and silico analyses were performed to determine the underlying molecular mechanisms. The potential of ribociclib repurposing was evaluated using an in vivo ARDS model in lipopolysaccharide (LPS)-primed mice. We found that treatment using ribociclib markedly limited overabundant oxidative stress (reactive oxygen species [ROS]) production and chemotactic responses (integrin levels and adhesion) in activated human neutrophils. Ribociclib was also shown to act as a selective inhibitor of phosphodiesterase 4 (PDE4), thereby promoting the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway, leading to the inhibition of extracellular signal-regulated kinase (ERK), c-Jun N -terminal kinase (JNK) phosphorylation, and calcium influx. Notably, prophylactic administration and post-treatment with ribociclib ameliorated neutrophil infiltration, lung inflammation, accumulation of oxidative stress, pulmonary destruction, and mortality in mice with LPS-induced ARDS. We demonstrated for the first time that ribociclib serves as a novel PDE4 inhibitor for treating neutrophilic inflammation and ARDS. The repurposing ribociclib and targeting neutrophilic PDE4 offer a potential off-label alternative for treating lung lesions and other inflammatory conditions. [ABSTRACT FROM AUTHOR]

Objective response rates. Each of the CDK4/6 inhibitors has been investigated in combination with ET in patients with early-stage HR-positive, HER2-negative breast cancer who are at high risk of relapse. In October 2021, abemaciclib was the first CDK4/6 inhibitor approved in combination with ET by the US Food and Drug Administration for adjuvant treatment of patients with HR-positive, HER2-negative, high-risk early breast cancer. Herein, we provide practical guidance on the use of abemaciclib in combination with ET for HR-positive, HER2-negative, high-risk early breast cancer to assist clinicians in their day-to-day practice, and we review clinically relevant topics of dosing, side effect management, sequencing and optimal timing for initiation, and patient selection. [ABSTRACT FROM AUTHOR]

BACKGROUND: The heart comprises many types of cells such as cardiomyocytes, endothelial cells (ECs), fibroblasts, smooth muscle cells, pericytes, and blood cells. Every cell type responds to various stressors (eg, hemodynamic overload and ischemia) and changes its properties and interrelationships among cells. To date, heart failure research has focused mainly on cardiomyocytes; however, other types of cells and their cell-to-cell interactions might also be important in the pathogenesis of heart failure. METHODS: Pressure overload was imposed on mice by transverse aortic constriction and the vascular structure of the heart was examined using a tissue transparency technique. Functional and molecular analyses including single-cell RNA sequencing were performed on the hearts of wild-type mice and EC-specific gene knockout mice. Metabolites in heart tissue were measured by capillary electrophoresis-time of flight-mass spectrometry system. The vaccine was prepared by conjugating the synthesized epitope peptides with keyhole limpet hemocyanin and administered to mice with aluminum hydroxide as an adjuvant. Tissue samples from heart failure patients were used for single-nucleus RNA sequencing to examine gene expression in ECs and perform pathway analysis in cardiomyocytes. RESULTS: Pressure overload induced the development of intricately entwined blood vessels in murine hearts, leading to the accumulation of replication stress and DNA damage in cardiac ECs. Inhibition of cell proliferation by a cyclin-dependent kinase inhibitor reduced DNA damage in ECs and ameliorated transverse aortic constriction-induced cardiac dysfunction. Single-cell RNA sequencing analysis revealed upregulation of Igfbp7 (insulin-like growth factor-binding protein 7) expression in the senescent ECs and downregulation of insulin signaling and oxidative phosphorylation in cardiomyocytes of murine and human failing hearts. Overexpression of Igfbp7 in the murine heart using AAV9 (adeno-associated virus serotype 9) exacerbated cardiac dysfunction, while EC-specific deletion of Igfbp7 and the vaccine targeting Igfbp7 ameliorated cardiac dysfunction with increased oxidative phosphorylation in cardiomyocytes under pressure overload. CONCLUSIONS: Igfbp7 produced by senescent ECs causes cardiac dysfunction and vaccine therapy targeting Igfbp7 may be useful to prevent the development of heart failure. [ABSTRACT FROM AUTHOR]

Immune cell-derived extracellular vesicles (EV) affect tumor progression and hold promise for therapeutic applications. Eosinophils are major effectors in Th2-related pathologies recently implied in cancer. Here, we evaluated the anti-tumor activities of eosinophil-derived EV following activation with the alarmin IL-33. We demonstrate that IL-33-activated mouse and human eosinophils produce higher quantities of EV with respect to eosinophils stimulated with IL-5. Following incorporation of EV from IL-33-activated eosinophils (Eo33-EV), but not EV from IL-5-treated eosinophils (Eo5-EV), mouse and human tumor cells increased the expression of cyclin-dependent kinase inhibitor (CDKI)-related genes resulting in cell cycle arrest in G0/G1, reduced proliferation and inhibited tumor spheroid formation. Moreover, tumor cells incorporating Eo33-EV acquired an epithelial-like phenotype characterized by E-Cadherin up-regulation, N-Cadherin downregulation, reduced cell elongation and migratory extent in vitro, and impaired capacity to metastasize to lungs when injected in syngeneic mice. RNA sequencing revealed distinct mRNA signatures in Eo33-EV and Eo5-EV with increased presence of tumor suppressor genes and enrichment in pathways related to epithelial phenotypes and negative regulation of cellular processes in Eo33-EV compared to Eo5-EV. Our studies underscore novel IL-33-stimulated anticancer activities of eosinophils through EV-mediated reprogramming of tumor cells opening perspectives on the use of eosinophil-derived EV in cancer therapy. [ABSTRACT FROM AUTHOR]

He, we show that combined use of the EZH2 inhibitor GSK126 and the CDK4/6 inhibitor abemaciclib synergistically enhances antitumoral effects in preclinical GBM models. Dual blockade led to HIF1α upregulation and CalR translocation, accompanied by massive impairment of mitochondrial function. Basal oxygen consumption rate, ATP synthesis, and maximal mitochondrial respiration decreased, confirming disrupted endoplasmic reticulum-mitochondrial homeostasis. This was paralleled by mitochondrial depolarization and upregulation of the UPR sensors PERK, ATF6α, and IRE1α. Notably, dual EZH2/CDK4/6 blockade also reduced 3D-spheroid invasion, partially inhibited tumor growth in ovo, and led to impaired viability of patient-derived organoids. Mechanistically, this was due to transcriptional changes in genes involved in mitotic aberrations/spindle assembly (Rb, PLK1, RRM2, PRC1, CENPF, TPX2), histone modification (HIST1H1B, HIST1H3G), DNA damage/replication stress events (TOP2A, ATF4), immuno-oncology (DEPDC1), EMT-counterregulation (PCDH1) and a shift in the stemness profile towards a more differentiated state. We propose a dual EZH2/CDK4/6 blockade for further investigation. [ABSTRACT FROM AUTHOR]

Pulmonary fibrosis (PF) is a fatal interstitial lung disease associated with declining pulmonary function but currently with few effective drugs. Cellular senescence has been implicated in the pathogenesis of PF and could be a potential therapeutic target. Emerging evidence suggests wogonin, the bioactive compound isolated from Scutellaria baicalensis, owns the anti-senescence properties, however, the possible impact of wogonin on PF and the potential mechanisms remain unclear. In this study, a well-established mouse model of PF was utilized which mice were administrated with bleomycin (BLM). Strikingly, wogonin treatment significantly reduced fibrosis deposition in the lung induced by BLM. In vitro, wogonin also suppressed fibrotic markers of cultured epithelial cells stimulated by BLM or hydrogen peroxide. Mechanistic investigation revealed that wogonin attenuated the expressions of DNA damage marker y-H2AX and senescence-related markers including phosphorylated p53, p21, retinoblastoma protein (pRB), and senescence-associated β-galactosidase (SA-β-gal). Moreover, wogonin, as a direct and selective inhibitor of cyclin-dependent kinase 9 (CDK9), exhibited anti-fibrotic capacity by inhibiting CDK9 and p53/p21 signalling. In conclusion, wogonin protects against BLM-induced PF in mice through the inhibition of cell senescence via the regulation of CDK9/p53 and DNA damage pathway. This is the first study to demonstrate the beneficial effect of wogonin on PF, and its implication as a novel candidate for PF therapy. [ABSTRACT FROM AUTHOR]

Background: This study was designed to evaluate the effect of progesterone receptor (PR) status on the prognosis of advanced estrogen receptor (ER)-high human epidermal growth factor receptor 2 (HER2)-negative breast cancer patients receiving CDK4/6 inhibitor combined with endocrine as first-line therapy. Methods: Advanced ER-high HER2-negative breast cancer patients who were admitted to Harbin Medical University Cancer Hospital and received cyclin-dependent kinase (CDK)4/6 inhibitor combined with endocrine as first-line therapy were included for analysis. Patients were divided into PR-high group (11-100%), PR-low group (1-10%), and PR-negative group (< 1%) according to the expression of PR. Chi-square test was used to analyze the correlation of variables between groups. COX regression analysis were used to analyze the risk factors of survival. Kaplan-Meier survival curve was used to analyze the differences of progression-free survival (PFS) and overall survival (OS) between groups. Results: Among the 152 patients, 72 were PR-high, 32 were PR-low, and 48 were PR-negative. Compared with PR-negative group, the proportions of disease-free survival (DFS) ≥ 5 years and Ki-67 index ≤ 30% in PR-low group and PR-high group were significant higher. PR-negative patients were more likely to occur first-line progression of disease within 24 months (POD24) than PR-high(P = 0.026). Univariate and multivariate analysis showed that PR-negative and first-line POD24 occurrence were risk factors for survival. Survival curve analysis showed that compared with PR-high group, the PFS and OS were significantly lower in PR-negative group (P = 0.001, P = 0.036, respectively). Patients with first-line POD24 had shorter OS in the overall population as well as in subgroups stratified by PR status. Conclusions: PR-negative and first-line POD24 occurrence were risk factors of advanced ER-high HER2-negative breast cancer patients receiving CDK4/6 inhibitor combined with endocrine as first-line therapy. PR-negative patients had shortest PFS and OS. Regardless of PR status, first-line POD24 occurrence predicted shorter OS. [ABSTRACT FROM AUTHOR]

Introduction: Diffuse pleural mesothelioma (DPM) of the pleura is a highly aggressive and treatment-resistant cancer linked to asbestos exposure. Despite multimodal treatment, the prognosis for DPM patients remains very poor, with an average survival of 2 years from diagnosis. Cisplatin, a platinum-based chemotherapy drug, is commonly used in the treatment of DPM. However, the development of resistance to cisplatin significantly limits its effectiveness, highlighting the urgent need for alternative therapeutic strategies. New selective inhibitors of cyclin-dependent kinases 4 and 6 (CDK4/6) have shown promise in various malignancies by inhibiting cell cycle progression and suppressing tumor growth. Recent studies have indicated the potential of abemaciclib for DPM therapy, and a phase II clinical trial has shown preliminary encouraging results. Methods: Here, we tested abemaciclib, palbociclib, and ribociclib on a panel of DPM cell lines and non-tumor mesothelial(MET-5A) cells. Results: Specifically, we focused on abemaciclib, which was the mosteffective cytotoxic agent on all the DPM cell lines tested. Abemaciclib reduced DPM cell viability, clonogenic potential, and ability to grow as three-dimensional (3D) spheroids. In addition, abemaciclib induced prolonged effects, thereby impairing second-generation sphere formation and inducing G0/G1 arrest and apoptosis/necrosis. Interestingly, single silencing of RB family members did not impair cell response to abemaciclib, suggesting that they likely complement each other in triggering abemaciclib's cytostatic effect. Interestingly, abemaciclib reduced the phosphorylation of AKT, which is hyperactive in DPM and synergized with the pharmacological AKT inhibitor (AKTi VIII). Abemaciclib also synergized with cisplatin and reduced the viability of DPM cells with acquired resistance to cisplatin. Discussion: Overall, our results suggest that CDK4/6 inhibitors alone or in combination with standard of care should be further explored for DPM therapy. [ABSTRACT FROM AUTHOR]

Introduction: Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are first-line treatments for hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer. With their increasing clinical use, infectionrelated adverse events (AEs) associated with CDK4/6 inhibitors have been widely reported in recent years. This study aimed to analyze the occurrence of infections associated with the CDK4/6 inhibitors (palbociclib, ribociclib and abemaciclib) based on the real-world data from the US Food and Drug Administration Adverse Event Reporting System (FAERS) database. Methods: Data were extracted from the FAERS database between 2015Q1 and 2022Q3. The clinical characteristics of patients with primary suspected infectionrelated AEs were analyzed. A disproportionality analysis was performed to investigate the potential association between AEs and CDK4/6 inhibitors. The influencing factors were evaluated using Pearson's chi-square test. Results: Reports of infection-related AEs associated with ribociclib accounted for 8.58% of the total reports of AEs associated with ribociclib, followed by palbociclib (2.72%) and abemaciclib (1.24%). Ribociclib (67.65%) was associated with more serious outcome events than palbociclib (30%) or abemaciclib (48.08%). The sex and age were not associated with outcome severity. Disproportionality analysis showed that fourteen, sixteen and two infectionrelated preferred terms were detected for palbociclib, ribociclib and abemaciclib, respectively. Conclusion: Infection-related AEs were highly associated with three CDK4/6 inhibitors, especially palbociclib and ribociclib, based on the real-world data from the FAERS database. However, further causality assessment is required. [ABSTRACT FROM AUTHOR]

Breast cancer (BC) cells have a high risk of metastasis due to epithelial-mesenchymal transition (EMT). Palbociclib (CDK4/6 inhibitor) is an approved drug for BC treatment. However, the drug resistance and metastasis can impair the treatment outcome of Palbociclib. Understanding the mechanisms of EMT and Palbociclib drug resistance in BC is conducive to the formulation of novel therapeutic strategy. Here, we investigated the role of circHIAT1/miR-19a-3p/CADM2 axis in modulating EMT and Palbociclib resistance in BC. circHIAT1 and CADM2 were down-regulated in BC tissues and cell lines, and miR-19a-3p showed an up-regulation. circHIAT1 could interact with miR-19a-3p and suppress its activity, while miR-19a-3p functioned to negatively regulate CADM2. Forced over-expression of circHIAT1 could impaired the EMT status and migratory ability of BC cells, and this effect was inhibited by miR-19a-3p mimic. In addition, we also generated Palbociclib resistant BC cells, and showed that circHIAT1 and CADM2 were down-regulated in the resistant BC cells while miR-19a-3p showed an up-regulation. Forced circHIAT1 over-expression re-sensitized BC cells to Palbociclib treatment. Quercetin, a bioactive flavonoid, could suppressed the migration and invasion of BC cells, and re-sensitized BC cells to Palbociclib. The anti-cancer effect of quercetin could be attributed to its regulatory effect on circHIAT1/miR-19a-3p/CADM2 axis. In vivo tumorigenesis experiment further revealed that quercetin administration enhanced the anti-cancer effect of Palbociclib, an effect was dependent on the up-regulation of circHIAT1 by quercetin. In summary, this study identified quercetin as a potential anti-cancer compound to reverse Palbociclib resistance and impair EMT in BC cells by targeting circHIAT1/miR-19a-3p/CADM2 axis. [ABSTRACT FROM AUTHOR]

Background: The current study evaluated the disease burden, health care resource utilization and analyzed the cost burden due to events of special interest among patients with breast cancer (BC) diagnosed and treated in Dubai, United Arab Emirates (UAE), in general and in the subset of patients treated with cyclin-dependent kinase (CDK) 4/6 inhibitors. Methods: This retrospective cohort study, using insurance e-claims data from Dubai Real-World Database, was conducted from 01 January 2014 to 30 September 2021. Female patients aged ≥ 18 years with at least 1 diagnosis claim for BC and with continuous enrollment during the index period were included. Results: Overall, 8,031 patients were diagnosed with BC (median age: 49.0 years), with the majority (68.1%) being in 41–60-year age group. During the post-index period, BC-specific costs contributed to 84% of the overall disease burden among patients with BC. Inpatient costs (USD 16,956.2) and medication costs (USD 10,251.3) contributed significantly to BC-specific costs. In the subgroup of patients in whom CDK4/6 inhibitors were part of the treatment regimen (n = 174), CDK4/6 inhibitors were commonly prescribed in combination with aromatase inhibitors (41.4%) and estrogen receptor antagonists (17.9%). In patients with BC, health care costs due to events of special interest (n = 1,843) contributed to 17% of the overall disease cost burden. Conclusion: The study highlights the significant cost burden among patients with BC, with BC-specific costs contributing to 84% of the overall disease cost burden. Despite few limitations such as study population predominantly comprising of privately insured expatriate patients and only direct healthcare costs being assessed in the current study, most indicative costs have been captured in the study, by careful patient selection and cost comparisons, as applicable. The findings can guide key health care stakeholders (payers and providers) on future policy measures aiming to reduce the cost burden among patients with BC. [ABSTRACT FROM AUTHOR]