Search

Introduction: Abemaciclib is an oral inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6). Data from the clinical trial monarchE (2023) showed improved survival from invasive disease. The aim of the present article was to conduct an economic assessment of adjuvant treatment with abemaciclib in women with luminal, HER2- and node-positive breast cancer. Methods: A Markov model was constructed with four mutually exclusive health states (disease-free, local recurrence, distal recurrence and death). Analyses were based on the clinical trial monarchE which compared an intervention group (abemaciclib + hormone therapy [HT]) with HT alone. The effectiveness measure used was quality-adjusted life years (QALY), with unit costs and utilities being obtained from existing literature. The incremental cost–utility ratio (ICUR) was used to compare the two treatment strategies. Results: Total costs were €98,765 and €17,935 for the abemaciclib plus HT group and the HT alone group, respectively. The health outcome was 10.076QALY for the intervention group and 9.495QALY for the control group, with the ICUR being€139,173/QALY. Conclusion: Despite the significant gains of abemaciclib as adjuvant treatment in terms of progression-free survival, this treatment is not cost-effective for the Spanish National Health System at published prices. It may be cost-effective with an appropriate discount on the official price. [ABSTRACT FROM AUTHOR]

Phosphorylation of substrates by cyclin-dependent kinases (CDKs) is the driving force of cell cycle progression. Several CDK-activating cyclins are involved, yet how they contribute to substrate specificity is still poorly understood. Here, we discover that a positively charged pocket in cyclin B1, which is exclusively conserved within B-type cyclins and binds phosphorylated serine- or threonine-residues, is essential for correct execution of mitosis. HeLa cells expressing pocket mutant cyclin B1 are strongly delayed in anaphase onset due to multiple defects in mitotic spindle function and timely activation of the E3 ligase APC/C. Pocket integrity is essential for APC/C phosphorylation particularly at non-consensus CDK1 sites and full in vitro ubiquitylation activity. Our results support a model in which cyclin B1's pocket facilitates sequential substrate phosphorylations involving initial priming events that assist subsequent pocket-dependent phosphorylations even at non-consensus CDK1 motifs. How cyclins contribute to CDK1 substrate specificity during cell division is poorly understood. Here, the authors show that a phosphate-binding pocket in cyclin B1 is critical for accurate CDK1 substrate phosphorylation ensuring mitotic fidelity. [ABSTRACT FROM AUTHOR]

Cancer remains a leading cause of morbidity and mortality worldwide, highlighting the urgent need for novel therapeutic agents. This study investigated the synthesis and biological evaluation of O-alkyl (E)-chalcone derivatives (4a–4v) as potential anticancer agents. The compounds were synthesized via aldol condensation of substituted aldehydes and acetophenones, with structures confirmed by IR, NMR, and mass spectrometry. In vitro cytotoxicity assays revealed varying effectiveness, with compounds 4a, 4b, 4q, and 4v exhibiting potent activity against MDA-MB-231 and MCF-7, showing IC50 values between 2.08 and 13.58 µM, besides HCT-116 and HeLa cancer cell lines (IC50 values between 6.59 and 22.64 µM). Notably, compound 4b displayed remarkable selectivity, with an IC50 of 54.59 µM against the non-cancerous WI-38 cell line. Additionally, protein kinase inhibition assays indicated that compounds 4b and 4q effectively inhibited EGFR and VEGFR-2, with 4b outperforming the standard inhibitor erlotinib. Molecular docking studies of compound 4q showed strong binding affinities in the ATP-binding pockets of EGFR, HER2, VEGFR2, and CDK2. In silico analyses further highlighted the favorable pharmacokinetic properties of compound 4q, underscoring its potential as a selective tyrosine kinase inhibitor. These findings suggest the therapeutic promise of O-alkyl (E)-chalcone derivatives in cancer treatment. [ABSTRACT FROM AUTHOR]

Background/Objectives: In Romania, breast cancer is the second most common cancer, the third leading cause of cancer death, and the most prevalent cancer overall. De novo advanced-stage breast cancer often presents in clinical practice, and treatment decisions are best made in a multidisciplinary tumor board (MTD) involving surgeons, radiotherapists, and medical oncologists. Significant advances in systemic therapies, particularly in progression-free survival (PFS) and overall survival (OS), have surpassed traditional palliative mastectomy and radiotherapy for local control. Therefore, the purpose of this study is to emphasize the importance of the initial choice of treatment for patient prognosis. Methods: We expose two cases of patients with de novo severe, advanced-stage, hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer and their management and outcome using cyclin-dependent kinase (CDK) 4/6 inhibitor and radiotherapy. An extensive review of the literature from the past five years was also conducted. Results: The role of palliative mastectomy is diminishing, as many patients are opting for novel therapies, including cyclin-dependent kinase (CDK) 4/6 inhibitors, which may improve quality of life. Conclusions: First-line therapy for locally advanced breast cancer has suffered changes due to the implementation of systemic targeted therapy. However, drug resistance—either de novo or acquired—remains a critical consideration. MTD discussions and informed patient decisions are essential to achieving a personalized, evidence-based treatment outcome. [ABSTRACT FROM AUTHOR]

Simple Summary: Breast cancer continues to pose significant treatment challenges, driving the search for new therapeutic agents with innovative mechanisms of action. Ruthenium-based compounds are emerging as promising anticancer agents due to their unique properties, which differ from those of traditional platinum-based therapies. This study investigates the effects of the ruthenium complex Bis(quinolin-8-olato)bis(triphenylphosphine)ruthenium(II) (Ru(quin)2) in hormone receptor-positive and triple-negative breast cancer cell models. Our results demonstrate that this compound effectively reduces cancer cell viability by inducing programmed cell death, stimulating autophagy, and causing cell cycle arrest. These findings highlight the potential of Ru(quin)2 as a novel therapeutic candidate for breast cancer, warranting further exploration to evaluate its in vivo efficacy and potential for clinical application. Background/Objectives: Breast cancer (BC) remains one of the most prevalent and deadly cancers worldwide, with limited access to advanced treatments in developing regions. There is a critical need for novel therapies with unique mechanisms of action, especially to overcome resistance to conventional platinum-based drugs. This study investigates the anticancer potential of the ruthenium complex Bis(quinolin-8-olato)bis(triphenylphosphine)ruthenium(II) (Ru(quin)2) in ER-positive (T47D) and triple-negative (MDA-MB-231) BC cell lines. Results: Ru(quin)2 demonstrated dose-dependent cytotoxicity, with IC50 values of 48.3 μM in T47D cells and 45.5 μM in MDA-MB-231 cells. Its cytotoxic effects are primarily driven by apoptosis, as shown by increased BAX expression, enhanced caspase-3 activity, reduced Aurora B kinase levels, and elevated histone release. Ru(quin)2 also induced autophagy, evidenced by LC3-I to LC3-II conversion and reduced SQSTM1, partially mediated through MAPK signaling. Furthermore, Ru(quin)2 induced G0/G1 cell cycle arrest by downregulating cyclin D1, CDK4, and CDK6, alongside upregulation of the CDK inhibitor p21. Conclusions: Ru(quin)2 emerges as a potent candidate for BC treatment, with multiple mechanisms of action involving apoptosis, autophagy, and cell cycle arrest. Further studies are warranted to elucidate its detailed molecular mechanisms and evaluate its therapeutic potential in vivo, moving toward clinical applications for both ER-positive and triple-negative BC management. [ABSTRACT FROM AUTHOR]

Cyclin-dependent kinases 4 and 6 (CDK4/6) are crucial regulators of cell cycle progression and represent important therapeutic targets in breast cancer. This study employs a comprehensive computational approach to identify novel CDK4/6 inhibitors from marine natural products. We utilized structure-based virtual screening of the CMNPD database and MNP library, followed by rigorous filtering based on drug-likeness criteria, PAINS filter, ADME properties, and toxicity profiles. From an initial hit of 9,497 compounds, 2,344 passed drug-likeness and PAINS filters. Further ADME filtering yielded 50 compounds, of which 25 exhibited non-toxic profiles. These 25 candidates underwent consensus molecular docking using seven distinct algorithms: AutoDockTools 4.2, idock, LeDock, Qvina 2, Smina, AutoDock Vina 1.2.0, PLANTS, and rDock. Based on these results, six top-scoring compounds were selected for comprehensive 500 nanosecond all-atom molecular dynamics simulations to evaluate their structural stability and interactions with CDK4/6. Our analysis revealed that compounds CMNPD11585 and CMNPD2744 demonstrated superior stability in their interactions with CDK4/6, exhibiting lower RMSD and RMSF values, more favorable binding free energies, and persistent hydrogen bonding patterns. These compounds also showed lower Solvent Accessible Surface Area values, indicating better compatibility with the CDK4/6 active site. Subsequent in-vitro studies using MTT assays on MCF-7 breast cancer cells confirmed the cytotoxic effects of these compounds, with CMNPD11585 showing the highest potency, followed by CMNPD2744. [ABSTRACT FROM AUTHOR]

Upregulation of Cyclin E1 and subsequent activation of CDK2 accelerates cell cycle progression from G1 to S phase and is a common oncogenic driver in gynecological malignancies. WEE1 kinase counteracts the effects of Cyclin E1/CDK2 activation by regulating multiple cell cycle checkpoints. Here we characterized the relationship between Cyclin E1/CDK2 activation and sensitivity to the selective WEE1 inhibitor azenosertib. We found that ovarian cancer cell lines with high levels of endogenous Cyclin E1 expression or forced overexpression were exquisitely sensitive to azenosertib and these results extended to in vivo models of ovarian and uterine serous carcinoma. Models with high Cyclin E1 expression showed higher baseline levels of replication stress and enhanced cellular responses to azenosertib treatment. We found azenosertib synergized with different classes of chemotherapy and described distinct underlying mechanisms. Finally, we provided early evidence from an ongoing phase I study demonstrating the clinical activity of monotherapy azenosertib in patients with Cyclin E1/CDK2-activated ovarian and uterine serous carcinomas. [ABSTRACT FROM AUTHOR]

Background and Objectives: Early-onset breast cancer (EOBC), particularly in patients under 40, presents with distinct biological characteristics and worse survival outcomes compared to late-onset cases. Despite intensive treatments, EOBC patients, especially those with hormone receptor-positive, HER2-negative (HR+/HER2-) subtypes, show poorer prognosis. CDK4/6 inhibitors, combined with endocrine therapy (ET) have become the standard for HR+/HER2- metastatic breast cancer, yet younger patients are underrepresented in clinical trials. This study aims to evaluate the efficacy of ribociclib and palbociclib with ET in HR+/HER2- metastatic breast cancer, addressing the critical gap in understanding treatment outcomes in younger patient populations. Materials and Methods: This multicenter, retrospective study evaluated the efficacy and safety of cyclin-dependent kinase 4 and 6 (CDK 4/6) inhibitors, ribociclib, and palbociclib, in combination with endocrine therapy in patients with hormone receptor-positive and human epidermal growth factor receptor 2-negative metastatic breast cancer. Results: A total of 198 patients treated between 2019 and 2023 were analyzed for progression-free survival, overall survival, and prognostic factors. Very early-onset breast cancer, which is diagnosed before the age of 35, was identified as an independent prognostic factor for poor progression-free survival. Additional factors associated with poorer outcomes included liver metastasis, progesterone receptor negativity, high tumor grade, and the concurrent use of fulvestrant with CDK4/6 inhibitors. Both ribociclib and palbociclib demonstrated similar efficacy, and dose reductions due to treatment-related adverse events did not compromise therapeutic outcomes. Conclusions: This study is the first to focus specifically on the treatment of early-onset breast cancer with CDK4/6 inhibitors, providing critical insights into the unique challenges faced by this patient population. The findings underscore the urgent need for personalized treatment strategies, routine genetic testing, and dedicated clinical trials designed to address the specific needs of these high-risk subgroups. By advancing our understanding of the clinical and molecular landscape of early-onset breast cancer and very early-onset breast cancer, this study lays the groundwork for improving outcomes in these underserved patients through tailored therapeutic approaches. [ABSTRACT FROM AUTHOR]

Objective: Hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer is the most common subtype. Abemaciclib, an inhibitor of cyclin-dependent kinases 4 and 6, was approved to reduce risk of recurrence in high-risk, HR+, HER2-, early breast cancer based on the monarchE trial. The most common adverse events reported in monarchE were diarrhea, neutropenia, and fatigue. Real-world tolerability data and incidence of adverse events with abemaciclib in the adjuvant setting versus the metastatic setting is lacking. Data Sources: This is a retrospective analysis of HR+, HER2- breast cancer patients on abemaciclib from March 2018 to September 2021 at Robert H. Lurie Comprehensive Cancer Center in Chicago, Illinois. Incidence, grade of adverse events, dose reductions, and discontinuations were evaluated in patients taking abemaciclib in the adjuvant setting and the metastatic setting. Data Summary: Of the 30 patients included in this analysis, 100% experienced an adverse event of any grade. During treatment, 12.5% treated in the adjuvant setting and 35.7% in the metastatic setting experienced grade ≥3 adverse events. Adverse events leading to discontinuation of abemaciclib occurred in 18.8% of patients in the adjuvant setting and 57.1% in the metastatic setting. Conclusions: This data suggests abemaciclib is better tolerated in high-risk, HR+, HER2-, node-positive, early breast cancer treated in the adjuvant setting compared to the metastatic setting. Management of adverse events is crucial to help patients stay on therapy to improve clinical outcomes. Real-world tolerability of abemaciclib in both the adjuvant and metastatic settings is of importance. [ABSTRACT FROM AUTHOR]

Ribociclib, a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor, is commonly used to treat hormone receptor-positive (HR+), human epidermal growth factor receptor 2/neu negative (HER2/neu-) breast cancer. While effective in inhibiting cancer cell proliferation, ribociclib has been associated with various dermatologic side effects, including vitiligo. This condition, characterized by the loss of skin pigmentation, occurs due to the destruction of melanocytes. In breast cancer patients undergoing ribociclib therapy, though the exact pathophysiological mechanisms remain under investigation, a possible hypothesis suggests that the development of vitiligo may signal an immune-mediated response, potentially reflecting the drug's influence on immune modulation. This report presents a case of HR+ and HER2/neu− metastatic breast carcinoma treated with CDK4/6 inhibitor plus endocrine therapy with the development of vitiligo during the treatment. [ABSTRACT FROM AUTHOR]

Background: Although CDK4/6 inhibitors combined with endocrine therapies have improved outcomes in HR+ HER2-negative metastatic breast cancer, predictive biomarkers for treatment response and adverse effects remain limited. This study assessed the prognostic and predictive value of large unstained cells (LUC), a subset of white blood cells that may reflect immune status or treatment response. Methods: A retrospective analysis of 210 patients with HR+ HER2-negative metastatic breast cancer treated with CDK 4/6 inhibitors between 2021 and 2024 was conducted. Clinical data, including demographics, tumor characteristics, and treatment regimens, were analyzed. Based on LUC levels, progression-free survival (PFS), overall survival (OS), and adverse events were evaluated. Results: The cohort had a median age of 57, of which 78% were postmenopausal. Common metastatic sites included bone (67%) and liver (24%). At a median follow-up of 18.5 months, the PFS and OS rates were 65% and 83%. Patients with low LUC levels had significantly shorter PFS (OR: 1.91; p = 0.014) and OS (OR: 2.39; p = 0.012), while high LUC levels correlated with a lower incidence of grade 3 neutropenia (OR: 0.49; p = 0.017). Liver metastasis and prior treatments were also linked to shorter survival. Conclusions: LUC levels emerge as a promising biomarker for predicting survival outcomes and the risk of neutropenia in HR+ HER2-negative metastatic breast cancer patients treated with CDK 4/6 inhibitors and endocrine therapy, showing their potential to guide personalized treatment approaches. [ABSTRACT FROM AUTHOR]

In this study, we applied comparative transcriptomics and proteomics techniques to systematically investigate the dynamic expression patterns of genes and proteins at various stages of early embryonic development of the gastropod Neptunea arthritica cumingii. Twelve cyclin-dependent kinase (CDKs) genes and five downstream proteins associated with these CDKs were identified. Through techniques such as qRT-PCR, our data elucidate for the first time the regulatory functions of CDK family genes and establish CDKs as a pivotal gene cluster in the early embryonic development of N. cumingii. These findings not only enhance the understanding of molecular developmental biology in N. cumingii and marine gastropods in general but also provide significant insights into the mechanisms involved in early embryonic development in N. cumingii. Furthermore, our results provide theoretical guidance for advancing artificial breeding technology for N. cumingii. [ABSTRACT FROM AUTHOR]

Drug resistance remains a major obstacle in cancer treatment, leading to treatment failures and high mortality rates. Despite advancements in therapies, overcoming resistance requires a deeper understanding of its mechanisms. This review highlights CDK2's pivotal role in both intrinsic and acquired resistance, and its potential as a therapeutic target. Cyclin E upregulation, which partners with CDK2, is linked to poor prognosis and resistance across various cancers. Specifically, amplifications of CCNE1/CCNE2 are associated with resistance to targeted therapies, immunotherapy, endocrine therapies and chemo/radiotherapy. Given CDK2's involvement in resistance mechanisms, investigating its role presents promising opportunities for developing novel strategies to combat resistance and improve treatment outcomes. Graphical Abstract Article highlights CCNE and CycE drive resistance to chemotherapies in cancer. CycE and LMWE contribute to resistance against endocrine therapies; combining CDK2 inhibitor with endocrine therapy shows promise in overcoming the resistance. CDK2 inhibition can restore sensitivity to trastuzumab in HER2+ cancers by counteracting resistance linked to CCNE overexpression and SMAD3 phosphorylation. Elevated CDK2 activity allows cancer cells to resist CDK4/6 inhibitors by preserving RB phosphorylation; CDK2 plus CDK4/6 inhibitor may improve treatment efficacy. Combining CDK2 and PARP inhibition may enhance efficacy and overcome resistance in cancers with CCNE1 amplification. CDK2 inhibition can enhance immune responses by increasing IFN-I and promoting effector T-cell infiltration, potentially overcoming tumor immune escape. [ABSTRACT FROM AUTHOR]

Isothiocyanates (ITCs) are naturally occurring sulfur-containing compounds with diverse biological effects. This study investigated the effects of sulforaphane (SFN, an aliphatic ITC) and benzyl isothiocyanate (BITC, an aromatic ITC) on human acute myeloid leukemia SKM-1 cells, focusing on cell proliferation, cell death, and drug resistance. Both drug-sensitive SKM-1 cells and their drug-resistant SKM/VCR variant, which overexpresses the drug transporter P-glycoprotein, were used. SFN and BITC reduced cell viability in a dose-dependent manner, with BITC showing greater potency. IC50 values ranged from 7.0–8.0 µM for SFN and 4.0–5.0 µM for BITC in both cell types, with only slight differences between the variants. Both ITCs induced autophagy as evidenced by increased LC3-II production and caused a significant increase in the sub-G0/G1 cell population, especially with BITC. Apoptosis was more pronounced after BITC treatment, whereas SFN had a weaker effect. These results suggest that autophagy may act as a defense mechanism in response to ITC-induced apoptosis in human AML cells. [ABSTRACT FROM AUTHOR]

Meriolins (3-(pyrimidin-4-yl)-7-azaindoles) are synthetic hybrids of the naturally occurring alkaloids variolin and meridianin and display a strong cytotoxic potential. We have recently shown that the novel derivative meriolin 16 is highly cytotoxic in several lymphoma and leukemia cell lines as well as in primary patient-derived lymphoma and leukemia cells and predominantly targets cyclin-dependent kinases (CDKs). Here, we efficiently synthesized nine novel 2-aminopyridyl meriolin congeners (3a–3i), i.e., pyrimeriolins, using a one-pot Masuda borylation-Suzuki coupling (MBSC) sequence, with eight of them bearing lipophilic alkoxy substituents of varying length, to systematically determine the influence of the alkoxy sidechain length on the biological activity. All the synthesized derivatives displayed a pronounced cytotoxic potential, with six compounds showing IC50 values in the nanomolar range. Derivatives 3b–3f strongly induced apoptosis and activated caspases with rapid kinetics within 3–4 h in Jurkat leukemia and Ramos lymphoma cells. The induction of apoptosis by the most potent derivative 3e was mediated by the intrinsic mitochondrial death pathway, as it was blocked in caspase-9 deficient and Apaf-1 knockdown Jurkat cells. However, as recently shown for meriolin 16, derivative 3e was able to induce apoptosis in the Jurkat cells overexpressing the antiapoptotic protein Bcl-2. Since tumor cells often inactivate the intrinsic mitochondrial apoptosis pathway (e.g., by overexpression of Bcl-2), these meriolin congeners represent promising therapeutic agents for overcoming therapeutic resistance. [ABSTRACT FROM AUTHOR]

Simple Summary: In Romania, around 12,000 new cases of breast cancer are diagnosed each year, making it the second most common cause of cancer-related deaths, after lung cancer. The objective of this study is to evaluate the efficacy, safety, and adherence to Palbociclib in combination with either an aromatase inhibitor or fulvestrant in a real-world cohort of HR+/HER2− breast cancer patients from Romania. By examining clinical outcomes, such as time to treatment discontinuation, overall survival, and adherence, this study aims to contribute to the growing body of real-world data that support the use of Palbo in routine clinical practice. Understanding these factors in a real-world setting is essential for optimizing treatment strategies and improving patient outcomes globally, particularly in underrepresented regions where trial data are scarce. Our findings confirm pre-existing trial and real-world data, showing no significant differences in overall survival between the two treatment options. Background/Objectives: The first reimbursed prescription for palbociclib (Palbo) in breast cancer patients in Romania was issued in July 2018. The objective of this study is to assess the efficacy, safety, and adherence to Palbo in combination with aromatase inhibitor (AI) or fulvestrant in a real-world cohort of HR+/HER2− breast cancer patients from Romania. Methods: A retrospective analysis of reimbursed Palbo prescriptions was conducted using data extracted from the electronic database of the Romanian Health Insurance House, Dolj County, for disease code 124 (breast cancer), covering the period from 2018 to 2023. The primary outcome assessed was time to treatment discontinuation (TTD), with secondary outcomes including overall survival (OS) and Palbo adherence (which was measured by medication possession ratio). Results: A total of 125 patients were identified, with a median age of 62 years (IQR, 53–70), and 98% were female. Two treatment combinations were observed: Palbo + Aromatase Inhibitor (AI) in 104 patients (83.2%) and Palbo + fulvestrant in 21 patients (16.8%). The median TTD for the entire cohort was 19 months (95%CI, 19.3–24.9 months). In patients treated with Palbo + AI, the median TTD was not available/reached [NA] (95%CI, 36.0-NA months). For those receiving Palbo+fulvestrant, the median TTD was 25.0 months (95%CI, 13.0-NR months). No significant differences in TTD were observed among the two treatment combinations (χ2 = 1.33, df = 1, log-rank p = 0.249). The 12- and 36-month TTD rates were higher for Palbl combined with AI than combined with fulvestrant: 77.8% [95%CI, 69.7–86.7%] vs. 71.8% [95%CI, 53.6–96.2%], and 56.3% [95%CI, 45.9–69%] vs. 49.7% [95%CI, 29.7–83.2%], respectively. The median OS was 38 months (95%CI, 25.5–50.9). When treatment involved Palbo + AI, the median OS was NA (95%CI, 54.8-NA) months. When treatment involved Palbo + fulvestrant, the median was 50.8 (95%CI, 34.1-NA) months. Related to OS, no significant differences were found between the two types of treatments (log-rank p = 0.638). The 24- and 36-month OS rates were higher for Palbo combined with AI than combined with fulvestrant: 76.9% [95%CI, 69.2–85.5%] vs. 81% [95%CI, 65.8–99.6%], and 67.9% [95%CI, 59.2–77.8%] vs. 65.3% [95%CI, 47.4–90.0%], respectively. The mean adherence in our study was 0.91 ± 0.1. We found no correlation between adherence to Palbo and OS (Spearman's rho = 0.04, p = 0.593). Conclusions: While both AI and fulvestrant remain viable options, the lack of significant differences in survival between these combinations suggests that treatment choice can be tailored to individual patient needs. [ABSTRACT FROM AUTHOR]

Breast cancer (BC) remains a leading cause of cancer-related mortality in women, with hormone receptor-positive (HR+) tumors accounting for a significant proportion of cases. Despite advancements in endocrine therapy (ET), resistance remains a challenge in metastatic settings. The use of cyclin-dependent kinases 4/6 (CDK4/6) inhibitors in combination with endocrine therapy has notably improved survival. In China, when patients develop resistance to CDK4/6 inhibitors (CDK4/6i) or face financial constraints that prevent their use, chemotherapy becomes the standard treatment approach. This highlights an urgent need for effective treatments following CDK4/6i therapy. ESG401 is a novel trophoblast cell-surface antigen 2 (Trop2) directed antibody-drug conjugate (ADC) with promising preclinical and early clinical efficacy and safety data. We report a case of a 61-year-old female with HR+HER2- metastatic breast cancer (MBC) who developed resistance to fulvestrant and subsequent chemotherapy but achieved a durable partial response (PR) lasting more than 22.5 months following ESG401 treatment. This case underscores the potential role of Trop2-directed ADCs, such as ESG401, in overcoming endocrine resistance and providing meaningful clinical benefit in heavily pretreated patients with HR+/HER2- MBC. Furthermore, the patient's exceptionally long clinical benefit distinguishes her from other patients receiving ESG401 treatment. Further exploration of the use of ESG401 in HR+HER2- MBC patients, as well as a deeper understanding of the characteristics of patients that may impact sustained efficacy, in expanded clinical trials is warranted. [ABSTRACT FROM AUTHOR]

Introduction: Esophageal adenocarcinoma (EAC) remains a devastating disease and second line treatment options in the metastatic space are limited. Homologous recombination (HR) defects have been described in EAC in up to 40% of patients. Poly (ADP-ribose) polymerase (PARP)1 and PARP2 inhibitors have shown efficacy in HR defective prostate and ovarian cancers. Here, we describe the activity of the PARP inhibitor niraparib in metastatic EAC with HR defects. Methods: In this single arm Simon two-stage Phase II study, we assessed the safety and efficacy of niraparib in patients with metastatic EAC previously treated with platinum containing chemotherapy harboring defective HR. Defective HR was defined as deleterious alterations in the following HR genes: BRCA1/2, PALB2, ATM, BARD1, BRIP1, CDK12, CHEK2, FANCA, RAD51, RAD51B, RAD51C, RAD51D, RAD54L, NBN, ARID1A and GEN1. Results: 14 patients were enrolled in this study. The trial was stopped early due to slow accrual. 3 patients did not have post-treatment scans because of rapid clinical decline. The overall response rate (ORR) (95% exact CI) was 0/11 = 0% (0%, 28.49%). The disease control rate (DCR) (95% exact CI) was 2/11 = 18.2% (2.3%, 51.8%). The median PFS was 1.8 months (95% CI = 1.0-3.7). The median OS for evaluable patients was 6.6 months (95% CI =2.7-11.4) and 5.7 months for all patients (95% CI =2.7-10.1). The most common adverse events seen were anemia, fatigue, and thrombocytopenia. Conclusion: In patients with metastatic EAC, single agent niraparib as second line therapy is not an effective option. [ABSTRACT FROM AUTHOR]

Background: Metastatic breast cancer especially in disseminated carcinomatosis of bone marrow (DCBM) poses a life-threatening risk, often requiring systemic chemotherapy. This situation lacks a cure, emphasizing symptom relief and quality of life. The documented occurrence of DCBM is merely 0.17% in metastatic breast cancer and ranges from 0.6 to 1.7% in solid tumors. Until now, there is no official medical guideline for treating patients with luminal breast cancer (LBC) who have DCBM. This case report highlights LBC patient with DCBM, treated at diagnosis with first-line therapy combining endocrine therapy (ET) and a CDK4/6 inhibitor. Case presentation: A 36-year-old premenopausal female of Javanese ethnicity with advanced de novo luminal breast cancer diagnosed in 2020. The immunohistochemistry showed estrogen receptor (ER)+ (90%), progesterone receptor (PR)+ (20%), human epidermal growth factor receptor 2 (HER-2) negative, and a high Ki-67 staining result at 60%. The patient had visceral crisis, which involved bone marrow infiltration and liver metastasis with preserved liver function. After intolerance of side effects from first line treatment with tamoxifen, the treatment plan was adjusted to letrozole, ribociclib, and leuprorelin injection. After completing the sixth cycle of treatment, blood parameters in the laboratory were found to have returned to normal. The patient's response to this regimen was remarkable, with significant alleviation of symptoms and improvement in quality of life observed. Conclusion: Notably, the combined approach of ET and CDK4/6 inhibitor represents a novel intervention in managing DCBM in patients with LBC. [ABSTRACT FROM AUTHOR]

Tumor immune microenvironment (TIME) plays a key role to understand how tumors respond to prostate cancer (PC) therapies and potential mechanisms of resistance. Previous research has suggested that specific genomic aberrations, such as microsatellite instability (MSI) or CDK12 bi-allelic loss can allow PC patients more likely to respond to immune checkpoint inhibitors (ICI) or other immune therapies. However, responses to these treatments remain highly variable even in selected patients. Thus, it is essential to obtain more information about tumor immune cells that infiltrate these tumors, and on their plasticity and interactions, in order to better understand the underlying biology to allow development of new therapeutic strategies. This review analyzes: 1) How interactions among immune cell populations and other cells infiltrating the tumor stroma can modulate the progression of PC, 2) How the standard therapies to treat PC (such as androgen deprivation therapy, new androgen-directed hormone therapy or chemotherapy) may influence the dynamic changes of the immunome and 3) What are the limitations in characterizing the immune landscape of the host´s response to tumors. [ABSTRACT FROM AUTHOR]

From numerous threats, malignancies are outstanding as one of the most hazardous diseases facing human life in the current time. Thus, novel medicines that selectively target tumor cells will inevitably add to the therapeutic arsenal already possessed for curing these malignancies. In light of this, the current study strives to create a novel class of small compounds with the advantageous benzimidazole scaffold that may be used as CDK2 inhibitors versus cancer. The synthesized candidates 2a–2c and 4 markedly impeded the development of the four cell lines under investigation with IC50 values of 4.36 ± 0.27 to 11.54 ± 0.29 μM against MCF-7, 9.48 ± 0.28 to 25.94 ± 0.33 μM against HCT-15, 41.76 ± 0.76 to 70.61 ± 1.45 against K-562, and 15.04 ± 0.70 to 32.38 ± 1.13 against HepG2. Moreover, compounds 2a–2c and 4 showed robust CDK2 inhibitory effect (IC50 = 0.76 ± 0.28, 1.26 ± 0.049, 0.84 ± 0.075, and 1.37 ± 0.062 μM, respectively). In order to assess the selectivity towards cancer cells, their cytotoxicity against normal kidney epithelial cells Vero was evaluated. The examined compounds were found to be more selective toward cancer cells when compared to the reference standard (SI = 2.13), and compound 2a demonstrated higher selectivity for the breast cancer MCF-7 cell line with the highest selectivity index (SI = 14.98), followed by compound 2c (SI = 8.42). Ultimately, a molecular docking study was performed to examine the potential binding pattern and interactions of benzimidazole derivatives with CDK2 kinase, suggesting it as an enzymatic target. In the final result, benzimidazole derivatives 2a–2c and 4, especially compound 2a, showed significant anticancer efficacy in addition to their ability to inhibit CDK2. [ABSTRACT FROM AUTHOR]

Background/Objectives: Palbociclib, an oral CDK 4/6 inhibitor, was evaluated in a Pediatric Brain Tumor Consortium (PBTC) phase 1 (NCT02255461; PBTC-042) study to treat children and young adults with recurrent, progressive, or refractory brain tumors. The objectives of this study were to characterize the palbociclib population pharmacokinetics in children enrolled on PBTC-042, to conduct a population pharmacodynamic analysis in this patient population, and to perform a simulation study to assess the role of palbociclib exposure on neutropenia and thrombocytopenia. Methods: The palbociclib population pharmacokinetics and pharmacodynamics were characterized in this patient population (n = 34 patients; 4.9–21.6 years old). Population pharmacokinetics were modeled using a one-compartment model with first-order absorption and elimination. Covariate analysis was performed, evaluating demographics, laboratory values, and concomitant medications. A pharmacodynamic model was used to describe the relation between palbociclib plasma exposure and changes in the ANC and platelet counts. Results: The population estimates for the apparent oral volume, apparent oral clearance, and absorption rate constant were 664.5 L/m2, 36.8 L/h/m2, and 0.48 h−1, respectively. The palbociclib apparent oral clearance was decreased in patients with higher AST values (p = 0.0066). The ANC and platelet pharmacodynamic models estimated that the median (5th–95th percentile) time individuals had grade 3 or greater neutropenia was 4 (0, 21) days. Simulations showed that given 75 mg/m2 palbociclib, 49% of the individuals were expected to have grade 3 or greater neutropenia. Conclusions: Palbociclib pharmacokinetics and pharmacodynamics were adequately characterized in this patient population, no unexpected adverse reactions were noted, and the drug was well tolerated. [ABSTRACT FROM AUTHOR]

Dysregulation of the cell cycle is a molecular hallmark of cancer, which leads to uncontrolled proliferation and self-renewal of neoplastic cells. To maintain this phenotype, cells acquire multiple molecular alterations and bypass several cellular checkpoints that are involved in the prevention of genomic instability and uncontrolled cell proliferation. Therefore, targeting cell cycle regulators could prove to be a promising anti-cancer approach. Recent advancements in the understanding of cancer cell susceptibilities have revealed a therapeutic opportunity to selectively target the cell cycle in malignant cells. This review highlights major cell cycle dysregulation in cancerous cells and the latest developments on anti-cancer agents that target cell cycle factors which are either in clinical practice or in clinical trials at present. In light of increasing drug resistance in cancer patients, the article also discusses mechanistic insights for the exploration of probable therapies that could be used to target these cell cycle factors. Additionally, it outlines the future research necessary to develop new therapies and optimize existing ones to achieve maximum efficacy. Thus, this article aims to provide a comprehensive understanding of the advancements in cancer therapies targeting dysregulated cell cycle factors. [ABSTRACT FROM AUTHOR]

SAYP and Bap170, subunits of the SWI/SNF remodeling complex, have the ability to support enhancer-dependent transcription when artificially recruited to the promoter on a transgene. We found that the phenomenon critically depends on two subunits of the Mediator kinase module, Med12 and Med13 but does not require the two other subunits of the module (Cdk8 and CycC) or other subunits of the core part of the complex. A cooperation of the above proteins in active transcription was also observed at endogenous loci, but the contribution of the subunits to the activity of a particular gene differed in different loci. The factors SAYP/Bap170 and Med12/Med13 did not form sufficiently stable interactions in the extract, and their cooperation was apparently local at regulatory elements, the presence of SAYP and Bap170 in a locus being necessary for stable recruitment of Med12 and Med13 to the locus. In addition to the above factors, the Nelf-A protein was found to participate in the process. The cooperation of the factors, independent of enzymatic activities of the complexes they are part of, appears to be a novel mechanism that maintains promoter activity and may be used in many loci of the genome. Extended intrinsically disordered regions of the factors were assumed to sustain the mechanism. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancer (TNBC) presents a significant challenge for treatment due to its aggressive nature and the lack of effective therapies. This study developed dual inhibitors against cell division cycle 25 (CDC25) and histone deacetylases (HDACs) for TNBC treatment. CDC25 phosphatases are crucial for activating cyclin-dependent kinases (CDKs), the master regulators of cell cycle progression. HDACs regulate various biological processes by deacetylating histone and non-histone proteins, affecting gene expression, chromatin structure, cell differentiation, and proliferation. Dysregulations of HDAC and CDC25 are associated with several human malignancies. We generated a group of dual inhibitors for CDC25 and HDAC by combining the molecular structures of CDC25 (quinoline-5,8-dione) and HDAC (hydroxamic acid or benzamide) pharmacophores. The newly developed compounds were evaluated against various solid-tumor, leukemia, and non-malignant breast epithelial cells. Among the synthesized compounds, 18A emerged as a potent inhibitor, demonstrating significant cytotoxicity against TNBC cells, superior to its effects on other cancer types while sparing non-malignant cells. 18A possessed similar HDAC inhibitory activity as MS-275 and potently suppressed CDC25 activity in vitro and the CDK1 dephosphorylation in cells. Additionally, 18A hindered the progression of S and G2/M phases, triggered DNA damage, and induced apoptosis. These findings underscore the potential of 18A as a targeted therapy for TNBC and warrants further preclinical development. [ABSTRACT FROM AUTHOR]

Background: Appropriate adverse event (AE) management and maintenance of therapeutic intensity are necessary to achieve therapeutic benefits of CDK4/6 inhibitors (palbociclib and abemaciclib) in hormone receptor-positive, HER2-negative metastatic/recurrent breast cancer. Objective: This study was aimed at clarifying the effect of AEs associated with palbociclib and abemaciclib on treatment. Methods: A total of 62 and 49 patients were prescribed palbociclib and abemaciclib, respectively, at our hospital from January 1, 2018 to June 30, 2023. The rate and reasons for treatment discontinuation, interruption of administration, and changes in dose and dosing schedule, treatment duration, and relative dose intensity (RDI) were compared between the groups of patients prescribed the 2 treatments. Results: Treatment discontinuation due to AEs occurred more frequently with abemaciclib (12 patients) because of interstitial lung disease and hepatic and renal events than with palbociclib (5 patients; P =.008). Administration was interrupted in 57 (91.9%) and 35 (71.4%) patients treated with palbociclib and abemaciclib, respectively (P =.004). Dose reduction occurred in 37 (67.3%) and 19 (47.5%) patients treated with palbociclib and abemaciclib, respectively (P =.053). The median [range] treatment duration was 301 [21-1643] days for palbociclib and 238 [70-1526] days for abemaciclib (log-rank test, P =.581). The median RDI was 59.7% and 59.6% for palbociclib and abemaciclib, respectively (P =.539). Although the AEs of palbociclib and abemaciclib affected the treatment considerably, the treatment duration and RDI were similar. Conclusion: CDK4/6 inhibitors should be selected based on the tolerability and manageability of each AE. [ABSTRACT FROM AUTHOR]

Background: The increasing prevalence of drug resistance in cancer therapy underscores the urgent need for novel therapeutic approaches. Dual enzyme inhibitors, targeting critical kinases such as CDK2 and TRKA, represent a promising strategy. The goal of this investigation was to design, synthesize, and evaluate a set of pyrazolo[1,5-a]pyrimidine derivatives for their dual inhibition potential toward CDK2 and TRKA kinases, along with their potential antiproliferative against cancer cell lines. Methods: A set of pyrazolo[1,5-a]pyrimidine derivatives (6a–t, 11a–g, and 12) was synthesized and subjected to in vitro enzymatic assays to determine their inhibitory activity against CDK2 and TRKA kinases. Selected compounds were further assessed for antiproliferative effects across the set of 60 cell lines from the NCI, representing various human cancer types. Additionally, simulations of molecular docking were conducted to explore the modes of binding for the whole active compounds and compare them with known inhibitors. Results: Compounds 6t and 6s exhibited potent dual inhibitory activity, showing an IC50 = 0.09 µM and 0.23 µM against CDK2, and 0.45 µM against TRKA, respectively. These results were comparable to reference inhibitors ribociclib (CDK2, IC50 = 0.07 µM) and larotrectinib (TRKA, IC50 = 0.07 µM). Among the studied derivatives, compound 6n displayed a notable broad-spectrum anticancer activity, achieving a mean growth inhibition (GI%) of 43.9% across 56 cell lines. Molecular docking simulations revealed that the synthesized compounds adopt modes of binding similar to those of the lead inhibitors. Conclusions: In this study, prepared pyrazolo[1,5-a]pyrimidine derivatives demonstrated significant potential as dual CDK2/TRKA inhibitors, and showed potent anticancer activity toward diverse cancer cell lines. These findings highlight their potential as key compounds for the design of novel anticancer therapeutics. [ABSTRACT FROM AUTHOR]

Genetic variants of deregulated long noncoding RNAs (lncRNAs) have been implicated in tumorigenesis, cancer progression and cancer recurrence. Single‐nucleotide polymorphisms (SNPs) of the lncRNA cyclin‐dependent kinase inhibitor 2B antisense RNA 1 (CDKN2B‐AS1) have been associated with the risk and progression of various cancers; however, their role in prostate cancer (PCa) remains underexplored. In this case–control study, we investigated the associations of CDKN2B‐AS1 expression levels and variants with PCa risk and progression. For this, five SNPs of CDKN2B‐AS1—rs564398, rs1333048, rs1537373, rs2151280 and rs8181047—were genotyped using a TaqMan allelic discrimination assay; data were collected from 695 patients with PCa and 695 healthy controls. Our findings revealed that, under a dominant model, patients with PCa carrying at least one minor C allele of rs1333048 exhibited an increased risk of developing tumours with high Gleason grades; this risk was particularly high in patients without biochemical recurrence. Data from the Genotype‐Tissue Expression database indicated upregulated CDKN2B‐AS1 expression in the prostates of individuals carrying the polymorphic C allele of rs1333048. Genotype screening of rs1333048 in PCa cell lines showed that cells with at least one minor C allele had higher CDKN2B‐AS1 levels than those with the AA genotype. Furthermore, data from The Cancer Genome Atlas indicated that higher CDKN2B‐AS1 levels in PCa tissues were correlated with larger tumour sizes (T3 + T4), more lymph node metastasis (N1), higher Gleason scores and shorter progression‐free survival. In conclusion, the polymorphic variants of CDKN2B‐AS1 at rs1333048 may modulate CDKN2B‐AS1 expression, thus accelerating PCa progression. [ABSTRACT FROM AUTHOR]

O-GlcNAc transferase (OGT) coordinates with regulators of transcription, including cyclin-dependent kinase 12 (CDK12), the major transcription elongation kinase. Here, we use inhibitor- and knockdown-based strategies to show that co-targeting of OGT and CDK12 is toxic to prostate cancer cells. OGT catalyzes all nucleocytoplasmic O-GlcNAcylation and due to its essentiality in higher eukaryotes, it is not an ideal drug target. Our glycoproteomics-data revealed that short-term CDK12 inhibition induces hyper-O-GlcNAcylation of the spliceosome-machinery in different models of prostate cancer. By integrating our glycoproteomics-, gene essentiality- and clinical-data from CDK12 mutant prostate cancer patients, we identify the non-essential serine-arginine protein kinase 1 (SRPK1) as a synthetic lethal partner with CDK12 -inactivation. Both normal and cancer cells become highly sensitive against inhibitors of OGT and SRPK1 if they have lowered activity of CDK12. Inactivating mutations in CDK12 are enriched in aggressive prostate cancer, and we propose that these patients would benefit from therapy targeting the spliceosome. [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. [ABSTRACT FROM AUTHOR]

PURPOSE: Targeted Agent and Profiling Utilization Registry (TAPUR) is a phase II basket trial evaluating the antitumor activity of commercially available targeted agents in patients with advanced cancer and genomic alterations known to be drug targets. Results of a cohort of patients with soft tissue sarcoma with cyclin-dependent kinase 4 (CDK4) amplification treated with palbociclib are reported. METHODS: Eligible patients had measurable disease, Eastern Cooperative Oncology Group performance status 0 to 2, adequate organ function, and no standard treatment options. The primary end point was disease control (DC), defined as objective response (OR) or stable disease (SD) of at least 16+ weeks duration (SD16+) according to RECIST v1.1. The DC rate was estimated with a 90% CI. Secondary end points included OR, progression-free survival (PFS), overall survival (OS), duration of response, duration of SD, and safety. RESULTS: Forty-two patients with CDK4 amplification were enrolled. One patient was not evaluable for efficacy. One patient with partial response and 18 with SD16+ were observed for DC and OR rates of 46% (90% CI, 36 to 100) and 2% (95% CI, <1 to 13), respectively. Median PFS was 16 weeks (95% CI, 9 to 28) and median OS was 69 weeks (95% CI, 31 to 111) for evaluable patients. Twenty patients had at least one grade 3 to 4 adverse event (AE) at least possibly related to palbociclib, including alanine aminotransferase increase, anemia, fatigue, hypophosphatemia, leukopenia, neutropenia, and thrombocytopenia. No serious AEs were reported. CONCLUSION: Palbociclib met prespecified criteria to declare a signal of antitumor activity in patients with sarcoma and CDK4 amplification. [ABSTRACT FROM AUTHOR]

PURPOSE: Outcomes data for DNA-damaging therapeutics for men with prostate cancer (PC) and non- BRCA1/2 homologous recombination repair (HRR) mutations are limited. We evaluated outcomes by HRR alteration in men with PC treated with poly(ADP-ribose)polymerase inhibitors (PARPi) and/or platinum chemotherapy. METHODS: Retrospective data from the PROMISE consortium were used. Clinical outcomes differences were assessed between patients with BRCA1 / 2 mutations (cohort A) and those with HRR mutations without direct BRCA complex interaction (cohort B: ATM , CDK12 , CHEK1 , CHEK2 , and FANCL). Outcomes in patients with HRR mutations with direct BRCA complex interaction were also explored (cohort C: RAD51B/C/D , RAD54L2 , BARD1 , GEN1 , PALB2 , FANCA , and BRIP1). RESULTS: One hundred and forty-six patients received PARPi (cohort A: 94, cohort B: 45, cohort C: 7) and 104 received platinum chemotherapy (cohort A: 48, cohort B: 44, cohort C: 10). PSA50 response rate to PARPi was higher in cohort A (61%) than cohort B (5%), P <.001. Median clinical/radiographic progression-free survival (crPFS) with PARPi in cohort A was significantly longer than in cohort B: 15.9 versus 8.7 months, P =.005. PSA50 response rate to platinum therapy was higher in cohort A (62%) than in cohort B (32%), P =.024, although crPFS was not significantly different. PSA50 response rate to PARPi and platinum was 40% and 32%, respectively, in cohort C. In multivariable analysis, cohort A had significantly improved overall survival and crPFS compared with cohort B with PARPi but not platinum chemotherapy. CONCLUSION: Patients with BRCA1/2 -mutated PC had significantly improved outcomes to PARPi but not platinum chemotherapy compared with those with HRR mutations without direct BRCA complex interaction. [ABSTRACT FROM AUTHOR]

PURPOSE: Genomic alterations have been identified in patients with breast cancer brain metastases (BCBMs), but large structural rearrangements have not been extensively studied. MATERIALS AND METHODS: We analyzed the genomic profiles of 822 BCBMs and compared them with 11,988 local, breast-biopsied breast cancers (BCs) and 15,516 non-CNS metastases (Non-CNS M) derived from formalin-fixed paraffin-embedded material using targeted capture sequencing. RESULTS: Nine genes with structural rearrangements were more prevalent within BCBMs as compared with local BCs and Non-CNS M (adjusted- P <.05) and displayed a prevalence of >0.5%. The most common rearrangements within BCBMs involves cyclin-dependent kinase 12 (CDK12 ; 3.53%) as compared with the local BC (0.86%; adjusted- P = 7.1 × 10–8) and Non-CNS M specimens (0.68%; adjusted- P = 3.7 × 10–10). CDK12 rearrangements had a significantly higher frequency within human epidermal growth factor receptor 2 (HER2)–positive BCBMs (14.59%) compared with HER2-positive BCs (7.80%; P = 4.6 × 10–3) and HER2-positive Non-CNS M (7.87%; P = 4.8 × 10–3). CONCLUSION: The most common structural rearrangements involve CDK12 with the higher prevalence in HER2-positive BCBMs. These data support more detailed investigation of the role and importance of CDK12 rearrangements in BCBMs. CDK12 the most common gene rearranged in breast cancer brain mets, with the highest prevalence in HER2+ disease. [ABSTRACT FROM AUTHOR]

Background Patients with cardiovascular disease (CVD) comorbidities are often excluded from participating in breast cancer clinical trials. Consequently, data to inform treatment decisions for patients with hormone receptor–positive/human epidermal growth factor receptor 2–negative (HR+/HER2−) metastatic breast cancer (mBC) and CVD are limited. Objective We compared the effectiveness of first-line palbociclib plus an aromatase inhibitor (AI) vs an AI alone and evaluated palbociclib treatment patterns in patients with HR+/HER2− mBC and CVD in routine clinical practice. Methods Data from the Flatiron Health Analytic Database were captured for patients with HR+/HER2− mBC and CVD who initiated first-line treatment with palbociclib plus an AI or an AI alone between February 2015 and March 2020 (data cutoff: September 30, 2020). Overall survival (OS), real-world progression-free survival (PFS), and treatment patterns were evaluated. Results Of the 469 patients with identifiable CVD, 160 received palbociclib plus an AI, and 309 received an AI alone. After stabilized inverse probability treatment weighting, both median OS (40.7 vs 26.5 months; hazard ratio [HR], 0.732 [95% CI, 0.537-0.997]; P  = .048) and median real-world PFS (20.0 vs 12.5 months; HR, 0.679 [95% CI, 0.512-0.900]; P  = .007) were significantly prolonged in patients treated with palbociclib plus an AI vs an AI alone. Among patients with a documented palbociclib starting dose, 78.5% started palbociclib at 125 mg/day, and 38.6% experienced dose adjustment. Conclusions In this real-world analysis, first-line palbociclib plus an AI was associated with improved effectiveness compared with an AI alone in patients with HR+/HER2– mBC and CVD. Trial Registration NCT05361655 (ClinicalTrials.gov) [ABSTRACT FROM AUTHOR]

The components of the mediator kinase module are highly conserved across all eukaryotic lineages, and cyclin‐dependent kinase 8 (CDK8) is essential for correct cell proliferation and differentiation in diverse eukaryotic systems. We show that CDK8 couples leaf development with the establishment of correct stomata patterning for prevailing CO2 conditions. In Arabidopsis, the basic helix‐loop‐helix (bHLH) transcription factor SPEECHLESS (SPCH) controls cellular entry into the stomatal cell lineage, and CDK8 interacts with and phosphorylates SPCH, controlling SPCH protein levels and thereby also expression of the SPCH target genes encoding key regulators of cell fate and asymmetric cell divisions. The lack of the CDK8‐mediated control of SPCH results in an increased number of meristemoid and guard mother cells, and increased stomata index in the cdk8 mutants. Increasing atmospheric CO2 concentrations trigger a developmental programme controlling cell entry into stomatal lineage by limiting the asymmetric divisions. In cdk8, the number of meristemoids and guard mother cells remains the same under ambient and high CO2 concentrations, as the accumulated levels of SPCH caused by the lack of CDK8 appear to override the negative regulation of increased CO2. Thus, our work provides novel mechanistic understanding of how plants alter critical leaf properties in response to increasing atmospheric CO2. Summary Statement: The components of the mediator kinase module are highly conserved across eukaryotic lines and cyclin‐dependent kinase 8 (CDK8) is essential for correct cell proliferation and development. We show here that control of leaf development is closely linked to the establishment of correct stomata patterning through the impact of CDK8. Comprehending the plasticity of plant morphology and the mechanisms behind it is essential for our understanding of plant environmental responses and the consequences of climate change. [ABSTRACT FROM AUTHOR]

The Mediator complex plays a pivotal role in facilitating RNA polymerase II-dependent transcription in eukaryotes. Within this complex, the CDK8 kinase module (CKM), comprising CDK8, Cyclin C (CycC), Med12 and Med13, serves as a dissociable subcomplex that modulates the activity of the small Mediator complex. Genetic studies in Drosophila have revealed distinct phenotypes associated with mutations inCKM subunits, but the underlying mechanisms have remained unclear. Using Drosophila as a model, we generated transgenic strains to deplete individually or simultaneously the four CKM subunits in all possible combinations, uncovering unique phenotypes in the eyes and wings. Depletion of CDK8-CycC enhanced E2F1 target gene expression and promoted cell-cycle progression, whereas Med12-Med13 depletion had no significant impact on these processes. Instead, depleting Med12-Med13 altered the expression of ribosomal protein genes and fibrillarin, and reduced nascent protein synthesis, indicating a severe reduction in ribosome biogenesis and cellular growth compared to the loss of CDK8-CycC. These findings reveal distinct in vivo roles for CKM subunits, with Med12-Med13 disruption having a more pronounced effect on ribosome biogenesis and protein synthesis than CDK8-CycC loss. [ABSTRACT FROM AUTHOR]

Background: Cutaneous melanoma (CM) is the most common type in Caucasians, while acral melanoma (AM) and mucosal melanoma (MM), which are resistant to immunotherapies and BRAF/MEK-targeted therapies, are more common in East Asians. Genomic profiling is essential for treating melanomas, but such data are lacking in Japan. Methods: Comprehensive genomic profiling data compiled in the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) were analyzed. Results: A total of 380 melanomas was analyzed, including 136 CM, 46 AM, 168 MM, and 30 uveal melanoma (UM). MM included conjunctival, sinonasal, oral, esophageal, anorectal, and vulvovaginal melanomas. No significant difference in the median tumor mutational burden (TMB) of CM (3.39 mutations/megabase), AM (2.76), and MM (3.78) was the key finding. Microsatellite instability-high status was found in one case. BRAF V600E/K was found in only 45 patients (12%). Key driver mutations in CM were BRAF (38%), NRAS (21%), NF1 (8%), and KIT (10%), with frequent copy number alterations (CNAs) of CDKN2A, CDKN2B, and MYC. AM was characterized by altered KIT (30%), NRAS (26%), and NF1 (11%) and CDKN2A, CDKN2B, CDK4, MDM2, and CCND1 CNAs. MM was characterized by altered NRAS (24%), KIT (21%), and NF1 (17%) and MYC, KIT, and CDKN2A CNAs, with differences based on anatomical locations. UM bore GNAQ or GNA11 driver mutations (87%) and frequent mutations in SF3B1 or BAP1. Conclusion: The distinct genomic profiling in Japanese patients, including lower TMB, compared to Caucasians, is associated with poorer treatment outcomes. This result underscores the need for more effective therapeutic agents. [ABSTRACT FROM AUTHOR]

It has been reported that CDK8 plays a key role in acute myeloid leukaemia. Here, a total of 40 compounds were rational designed and synthesised based on the previous SAR. Among them, compound 12 (3-(3-(furan-3-yl)-1H-pyrrolo[2,3-b]pyridin-5-yl)benzamide) showed the most potent inhibiting activity against CDK8 with an IC50 value of 39.2 ± 6.3 nM and anti AML cell proliferation activity (molm-13 GC50 = 0.02 ± 0.01 μM, MV4-11 GC50 = 0.03 ± 0.01 μM). Mechanistic studies revealed that this compound 12 could inhibit the phosphorylation of STAT-1 and STAT-5. Importantly, compound 12 showed relative good bioavailability (F = 38.80%) and low toxicity in vivo. This study has great significance for the discovery of more efficient CDK8 inhibitors and the development of drugs for treating AML in the future. [ABSTRACT FROM AUTHOR]

Background/Objectives: Tonsil-derived mesenchymal stem cells (TMSCs) are in the limelight in regenerative medicine due to their high proliferation and differentiation potential. It is important to conduct studies to determine the optimal conditions for achieving the maximum yield while maintaining the optimal differentiation capacity of TMSCs. Methods: This study explores the impact of serial subculture on TMSCs by analyzing gene expression at passages 2, 4, 6, and 8. For each culture passage, genes with significant differences in RNA expression from previous passages were selected and their characteristics were observed performing enrichment analysis including KEGG (Kyoto Encyclopedia of Genes and Genomes) and Reactome pathway. Results: At each passage, a "cell cycle" term was ranked high with statistical significance in the KEGG and Reactome pathway. Cell cycle gene expression, including Cyclin-dependent kinases (CDKs) and cyclins, increased until passage 6, then decreased by passage 8. The cell cycle is known to be important not only for proliferation but also for determining whether stem cells maintain pluripotency or differentiate into various lineages. Conclusions: The results suggest that cell cycle gene expression can guide the timing for differentiation induction, with passage 6 potentially being a critical point for initiating differentiation. [ABSTRACT FROM AUTHOR]

Introduction: Cyclin-dependent kinase (CDK) 4/6 inhibitors have significantly changed the treatment strategy for patients with locally advanced or metastatic hormone receptor positive (HR+), human epidermal growth factor 2 negative (HER2) breast cancer. The purpose of the study was to determine the prevalence of drug-drug interactions (DDI) in breast cancer patients using CDK 4/6 inhibitors and the extent of DDI reflected in the clinic and to increase clinical awareness among physicians. Method: The data of 115 metastatic breast cancer patients using CDK 4/6 inhibitors who were admitted to the Medical Oncology outpatient clinic between July 2021 and July 2023 were retrospectively reviewed. The Drugs.com® Drug Interaction Checker application was used for the interaction between the CDK 4/6 inhibitor and other drugs. Results: Among patients included in the study, 97.3% had at least one additional drug use. We have identified a total of 170 potential DDI risks in 63.5 % of patients. Among these, 50.5% had a major potential DDI. In our study, there was a potential risk of QT prolongation in 45.2% of 170 DDI, an increase in the potential toxicity of the additional drug in 44.1%, an increase in the potential toxicity of the CDK 4/6 inhibitor in 5.3%, a decrease in the potential efficacy of the CDK 4/6 inhibitor in 2.9%, a decrease in the potential efficacy of the additional drug in 1.1%, and a serious potential infection risk in 1.1%. Most of the drug interactions were QT prolongation and increased toxicity of the additional drug. In terms of cardiovascular events, grade-2 and grade-3 QTc prolongation was found in 4.3% and 1.7% of these interactions, respectively. When evaluated in terms of CDK 4/6 inhibitor subtype, there was a potential risk of DDI at major level with Ribocilib and at moderate level with Palbociclib. Conclusion: If CDK 4/6 inhibitors interact with concomitant drugs, they may cause an increase in the incidence of cardiac side effects and a decrease in the effect of the CDK 4/6 inhibitor or additional drug or an increase in toxicity. Increasing awareness of this issue will help to reduce the rates of side effects or toxicity and provide effective antitumour therapy. [ABSTRACT FROM AUTHOR]

On the basis of typical for secondary amino group reactions a number of derivatives of alkaloid (+)-salsolidine was synthesised. Cytotoxic properties of obtained compounds towards the HEK293, A549, MCF-7 and SH-SY5Y cell lines have been evaluated. As a result of the screening, the hit compound − 2-(chloroacetyl)-6,7-dimethoxy-1-methyl-1,2,3,4-tetrahydroisoquinoline (11) was identified, that inhibited the metabolic activity of A-549, MCF-7 and SH-SY5Y tumour cell lines with the IC50 values of 3.83 ± 0.78 µM, 5.84 ± 1.62 µM and 2.89 ± 0,92 µM correspondingly. Based on the effect of 11 on the cell cycle progression and the molecular docking data, it was preliminary assumed that the cytotoxic activity of the 11 can be realised through its interaction with the active site of the cyclin-dependent kinase CDK9 (PDB code 3BLR). [ABSTRACT FROM AUTHOR]

Copyright of Namık Kemal Tıp Dergisi is the property of Galenos Yayinevi Tic. LTD. STI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: With the widespread use of CDK4/6 inhibitors, the number of discontinuations and reductions due to adverse events is increasing. Therefore, we examined the risk of dose reduction, discontinuation, and occurrence of serious adverse events and death due to adverse events when CDK4/6 inhibitors are combined with endocrine drugs. Methods: We searched English-language articles published up to February 10, 2024, using RR values (risk ratio) to indicate the risk of discontinuation, dose reduction, death, and the risk of serious adverse events. Results: When CDK4/6 inhibitors were used in combination with endocrine drugs, abemaciclib resulted in the highest risk of discontinuation, dose reduction, and serious adverse events. Ribociclib caused the highest risk of death. Conclusion: When using CDK4/6 inhibitors in the clinical setting, a comprehensive evaluation should be performed to avoid dosage reductions and discontinuations and to choose the most appropriate treatment regimen. [ABSTRACT FROM AUTHOR]

Background: The global landscape of public health faces significant challenges attributed to the prevalence of cancer and the emergence of treatment resistance. This study addresses these challenges by focusing on Cyclin-dependent Kinase 2 (CDK2) and employing a systematic computational approach for the discovery of novel cancer therapeutics. Results: Initial ligand-based pharmacophore modelling, utilizing a training set of five reported CDK2 inhibitors, yielded a robust model characterized by Aro|Hyd| and |Acc|Don| features. Screening this validated model against the ZINC database identified 1881 hits, which were further subjected to molecular docking studies. The top 10 compounds (Z1–Z10) selected from the docking studies underwent Pharmacokinetic parameters Absorption, Distribution, Metabolism, Excretion and Toxicity profiling, Density Functional Theory (DFT) studies and the top two went for 100ns molecular dynamics (MD) simulations by comparing them with the standard Roscovitine. Compounds Z1 and Z2 emerged as the most promising, with docking scores of − 8.05 kcal/mol and − 8.02 kcal/mol, respectively. DFT analysis of the top 10 compounds revealed minimal variations in highest occupied molecular orbital–lowest unoccupied molecular orbital energy gaps, indicating consistent electronic stability and reactivity across the candidates. MD simulations of Z1 and Z2 confirmed their stable interactions with CDK2, with root mean square deviation (RMSD) values ranging from 1.4 to 2.5 Å for Z1 and 1.5 to 2.4 Å for Z2. Conclusion: The current research identified compounds Z1 and Z2, which demonstrated significant potential as potent CDK2 inhibitors for cancer therapy, providing valuable insights into the development of more effective CDK2 inhibitors and addressing the critical need for innovative therapeutic strategies in cancer treatment. [ABSTRACT FROM AUTHOR]

Background: Lipomatous tumors represent the most common type of soft tissue neoplasms. Mouse double minute 2 homolog (MDM2)/cyclin-dependent kinase 4 (CDK4) immunostaining is considered effective in differentiating between benign lipomas and intermediate malignant atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDLPSs). However, these tumors have traditionally been diagnosed histopathologically using hematoxylin and eosin-stained specimens, which is referred to here as morphological diagnosis. In this study, the accuracy of morphological diagnoses that had been made before MDM2/CDK4 immunostaining became available for distinguishing between lipoma and ALT/WDLPS was examined. Methods: The study participants were 109 patients with a morphological diagnosis of lipoma (68 patients) or ALT/WDLPS (41 patients) who had undergone surgical resection of the tumor in our hospital between 2009 and 2012. Tissue samples from all patients were used for MDM2/CDK4 immunostaining and the confirmation of MDM2/CDK4 amplification by fluorescence in situ hybridization (FISH). Results: Of the 41 patients with a morphological diagnosis of ALT/WDLPS, only 17 were positive for MDM2 FISH. In addition, one of the 68 patients with a morphological diagnosis of lipoma showed MDM2 amplification by FISH. When the definitive diagnosis of ALT/WDLPS was made by the positive results of MDM2 FISH, the sensitivity and specificity of morphological diagnosis were 41.5% and 98.5%, respectively. The sensitivity of MDM2 and CDK4 immunostaining was 55.6% and 40.0%, respectively, and their specificity was 87.0% and 84.6%, respectively. This indicates that the diagnostic accuracy of these immunostaining assays was not particularly high. The clinical features suggesting ALT/WDLPS were: patient age (older), maximum tumor diameter (large, cut-off value of 125 mm), tumor location (lower limb), and tumor depth (deep-seated). Conclusions: Morphological diagnosis alone can accurately diagnose lipomas. However, it has a propensity to overdiagnose ALT/WDLPS. Thus, MDM2 FISH should be used more proactively, not only for lesions with obvious morphological abnormalities, but also for lipomatous tumors that are clinically suggestive of ALT/WDLPS. [ABSTRACT FROM AUTHOR]

Embryonic axis formation is essential for patterning and morphogenesis in vertebrates and is tightly regulated by the dorsal organizer. Previously, we demonstrated that maternally derived Huluwa (Hwa) acts as a dorsal determinant, dictating axis formation by activating β-catenin signaling in zebrafish and Xenopus. However, the mechanism of activation and fine regulation of the Hwa protein remains unclear. Through candidate screening we identified a mutation at Ser168 in the PPNSP motif of Hwa that dramatically abolishes its axis-inducing activity. Mechanistically, mutating the Ser168 residue reduced its binding affinity to Tankyrase 1/2 and the degradation of the Axin protein, weakening β-catenin signaling activation. We confirmed that Ser168 is phosphorylated and that phosphorylation increases Hwa activity in β-catenin signaling and axis induction. Several kinases including Cdk16, Cdk2, and GSK3β, were found to enhance Ser168 phosphorylation in vitro and in vivo. Both dominant-negative Cdk16 expression and pHwa (Ser168) antibody treatment reduce Hwa function. Lastly, a knock-in allele mutating Ser168 to alanine resulted in embryos lacking body axes, demonstrating that Ser168 is essential to axis formation. In summary, Ser168 acts as a phosphorylation switch in Hwa/β-catenin signaling for embryonic axis induction, regulated by multiple kinases. Huluwa functions as the dorsal determinant during body axis formation in vertebrates, but how it is regulated remains unclear. Here they identify a phosphorylation switch in the conserved PPNSP motif of Huluwa required for axis induction, which is targeted by multiple kinases. [ABSTRACT FROM AUTHOR]

Huntington's disease (HD) is an autosomal dominant neurodegenerative disease caused by a single mutation in the huntingtin gene (HTT). Normal HTT has a CAG trinucleotide repeat at its N-terminal within the range of 36. However, once the CAG repeats exceed 37, the mutant gene (mHTT) will encode mutant HTT protein (mHTT), which results in neurodegeneration in the brain, specifically in the striatum and other brain regions. Since the mutation was discovered, there have been many research efforts to understand the mechanism and develop therapeutic strategies to treat HD. HTT is a large protein with many post-translational modification sites (PTMs) and can be modified by phosphorylation, acetylation, methylation, sumoylation, etc. Some modifications reduced mHTT toxicity both in cell and animal models of HD. We aimed to find the known kinase inhibitors that can modulate the toxicity of mHTT. We performed an in vitro kinase assay using HTT peptides, which bear different PTM sites identified by us previously. A total of 368 kinases were screened. Among those kinases, cyclin-dependent kinases (CDKs) affected the serine phosphorylation on the peptides that contain S1181 and S1201 of HTT. We explored the effect of CDK1 and CDK5 on the phosphorylation of these PTMs of HTT and found that CDK5 modified these two serine sites, while CDK5 knockdown reduced the phosphorylation of S1181 and S1201. Modifying these two serine sites altered the neuronal toxicity induced by mHTT. Roscovitine, a CDK inhibitor, reduced the p-S1181 and p-S1201 and had a protective effect against mHTT toxicity. We further investigated the feasibility of the use of roscovitine in HD mice. We confirmed that roscovitine penetrated the mouse brain by IP injection and inhibited CDK5 activity in the brains of HD mice. It is promising to move this study to in vivo for pre-clinical HD treatment. [ABSTRACT FROM AUTHOR]

Neoplastic cells are characterized by uncontrolled cell divisions caused by cell cycle dysregulation. Key regulatory proteins governing the transition from the G1 to the S phase are the CDK4 and CDK6 kinases, which are controlled by D-type cyclins. The CDK4/6 kinases enable the use of these proteins as targets for anticancer therapy because they prevent the growth and the development of malignant cells by inhibiting their activity. This paper surveys the clinical trial results concerning palbociclib, the first in-class FDA-approved anticancer drug for hormone-dependent breast cancer. It discusses the therapeutic applications in breast cancer as well as in solid tumors and hematopoietic malignancies. Additionally, the paper presents an analysis of palbociclib resistance acquired during therapy and explores new approaches, such as modifications to palbociclib that enhance its desired activity or open up new therapeutic possibilities (PROTACs). [ABSTRACT FROM AUTHOR]

Melanoma occurs in various forms and body areas, not only in the cutis, but also in mucous membranes and the uvea. Rarer subtypes of that cancer differ in genomic aberrations, which cause their minor sensibility to regular cutaneous melanoma therapies. Therefore, it is essential to discover new strategies for treating rare forms of melanoma. In recent years, interest in applying CDK inhibitors (CDKIs) in cancer therapy has grown, as they are able to arrest the cell cycle and inhibit cell proliferation. Current studies highlight selective CDK4/6 inhibitors, like palbociclib or abemaciclib, as a very promising therapeutic option, since they were accepted by the FDA for advanced breast cancer treatment. However, cells of every subtype of melanoma do not react to CDKIs the same way, which is partly because of the genetic differences between them. Herein, we discuss the past and current research relevant to targeting various CDKs in mucosal, uveal and acral melanomas. We also briefly describe the issue of amelanotic and desmoplastic types of melanoma and the need to do more research to discover cell cycle dysregulations, which cause the growth of the mentioned forms of cancer. [ABSTRACT FROM AUTHOR]

Acetaminophen (APAP) overdose is a major cause of drug‐induced liver injury (DILI) in many countries. Hepatocyte proliferation, autophagy and antioxidant capacity are crucial to the prognosis of APAP‐induced liver injury, but the underlying mechanisms are not fully understood. Here, we found that human antigen R (HuR) protein expression was markedly increased in the model of APAP‐induced liver injury, and conditional hepatocyte‐specific HuR knockout aggravated APAP‐induced liver injury in mice. Further investigation of the underlying mechanisms of HuR's protective effects showed that conditional hepatocyte‐specific HuR knockout reduced the protein expression of cyclin A1, cyclin B1, cyclin D1, CDK2, ATG3, ATG5, ATG7 and NRF2 in mice, reducing hepatocyte proliferation, autophagy and antioxidant capacity. Mechanistically, HuR could physically associate with the 3′‐untranslated regions (UTRs) of cyclin A1, cyclin B1, cyclin D1, Cdk2, Atg3, Atg5, Atg7 and Nrf2 mRNAs, thereby regulating their translation. These findings suggest that HuR attenuates APAP‐induced liver injury by regulating hepatocyte proliferation, autophagy and antioxidant capacity. [ABSTRACT FROM AUTHOR]