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Vitamin D signals through the vitamin D receptor (VDR) to induce its end-organ effects. Hepatic stellate cells control development of liver fibrosis in response to stressors and vitamin D signaling decreases fibrogenesis. VDR expression in hepatocytes is low in healthy liver, and the role of VDR in hepatocyte proliferation is unclear. Hepatocyte-VDR null mice (hVDR) were used to assess the role of VDR and vitamin D signaling in hepatic regeneration. hVDR mice have impaired liver regeneration and impaired hepatocyte proliferation associated with significant differential changes in bile salts. Notably, mice lacking hepatocyte VDR had significant increases in expression of conjugated bile acids after partial hepatectomy, consistent with failure to normalize hepatic function by the 14-day time point tested. Real-time PCR of hVDR and control livers showed significant changes in expression of cell-cycle genes including cyclins D1 and E1 and cyclin-dependent kinase 2. Gene expression profiling of hepatocytes treated with vitamin D or control showed regulation of groups of genes involved in liver proliferation, hepatitis, liver hyperplasia/hyperproliferation, and liver necrosis/cell death. Together, these studies demonstrate an important functional role for VDR in hepatocytes during liver regeneration. Combined with the known profibrotic effects of impaired VDR signaling in stellate cells, the studies provide a mechanism whereby vitamin D deficiency would both reduce hepatocyte proliferation and permit fibrosis, leading to significant liver compromise. [ABSTRACT FROM AUTHOR]

Regulated cell cycle progression ensures homeostasis and prevents cancer. In proliferating cells, premature S phase entry is avoided by the E3 ubiquitin ligase anaphasepromoting complex/cyclosome (APC/C), although the APC/C substrates whose degradation restrains G1 -S progression are not fully known. The APC/C is also active in arrested cells that exited the cell cycle, but it is not clear whether APC/C maintains all types of arrest. Here, by expressing the APC/C inhibitor, EMI1, we show that APC/C activity is essential to prevent S phase entry in cells arrested by pharmacological cyclin-dependent kinases 4 and 6 (CDK4/6) inhibition (Palbociclib). Thus, active protein degradation is required for arrest alongside repressed cell cycle gene expression. The mechanism of rapid and robust arrest bypass from inhibiting APC/C involves CDKs acting in an atypical order to inactivate retinoblastoma-mediated E2F repression. Inactivating APC/C first causes mitotic cyclin B accumulation which then promotes cyclin A expression. We propose that cyclin A is the key substrate for maintaining arrest because APC/C-resistant cyclin A, but not cyclin B, is sufficient to induce S phase entry. Cells bypassing arrest from CDK4/6 inhibition initiate DNA replication with severely reduced origin licensing. The simultaneous accumulation of S phase licensing inhibitors, such as cyclin A and geminin, with G1 licensing activators disrupts the normal order of G1-S progression. As a result, DNA synthesis and cell proliferation are profoundly impaired. Our findings predict that cancers with elevated EMI1 expression will tend to escape CDK4/6 inhibition into a premature, underlicensed S phase and suffer enhanced genome instability. [ABSTRACT FROM AUTHOR]

Fibroblast Growth Factor Receptors (FGFRs) play a significant role in Estrogen Receptor-positive (ER+) breast cancer by contributing to tumorigenesis and endocrine resistance. This review explores the structure, signaling pathways, and implications of FGFRs, particularly FGFR1, FGFR2, FGFR3, and FGFR4, in ER+ breast cancer. FGFR1 is frequently amplified, especially in aggressive Luminal B-like tumors, and its amplification is associated with poor prognosis and treatment resistance. The co-amplification of FGFR1 with oncogenes like EIF4EBP1 and NSD3 complicates its role as a standalone oncogenic driver. FGFR2 amplification, though less common, is critical in hormone receptor regulation, driving proliferation and treatment resistance. FGFR3 and FGFR4 also contribute to endocrine resistance through various mechanisms, including the activation of alternate signaling pathways like PI3K/AKT/mTOR and RAS/RAF/MEK/ERK. Endocrine resistance remains a major clinical challenge, with around 70% of breast cancers initially hormone receptor positive. Despite the success of CDK 4/6 inhibitors in combination with endocrine therapy (ET), resistance often develops, necessitating new treatment strategies. FGFR inhibitors have shown potential in preclinical studies, but clinical trials have yielded limited success due to off-target toxicities and lack of predictive biomarkers. Current clinical trials, including those evaluating FGFR inhibitors like erdafitinib, lucitanib, and dovitinib, have demonstrated mixed outcomes, underscoring the complexity of FGFR signaling in breast cancer. The interplay between FGFR and other signaling pathways highlights the need for comprehensive molecular profiling and personalized treatment approaches. Future research should focus on identifying robust biomarkers and developing combination therapies to enhance the efficacy of FGFR-targeted treatments. In conclusion, targeting FGFR signaling in ER+ breast cancer presents both challenges and FGFR signaling pathway in breast cancer: FGF binds to the extracellular domain of FGFR leading to receptor dimerization and through phosphorylation inducing downstream activation of canonical pathways. Signaling pathways dependent of FGF-FGFR axis, include Fibroblast Growth Factor Receptor Substrate 2 (FRS2) Ras-mitogen-activated protein kinase (MAPK), phosphatidylinositol-3 kinase (PI3K), protein kinase B (AKT), phospholipase Cg1 (PLCg1) and signal transducer and activator of transcription (STAT). opportunities. A deeper understanding of the molecular mechanisms and resistance pathways is crucial for the successful integration of FGFR inhibitors into clinical practice, aiming to improve outcomes for patients with endocrine-resistant breast cancer. [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. Palbociclib met @ASCO #TAPUR criteria to declare antitumor activity in patients with CDK4-amplified liposarcoma. [ABSTRACT FROM AUTHOR]

Treatment resistance remains a major issue in aggressive prostate cancer (PC), and novel genomic biomarkers may guide better treatment selection. Circulating tumor DNA (ctDNA) can provide minimally invasive information about tumor genomes, but the genomic landscape of aggressive PC based on whole‐genome sequencing (WGS) of ctDNA remains incompletely characterized. Thus, we here performed WGS of tumor tissue (n = 31) or plasma ctDNA (n = 10) from a total of 41 aggressive PC patients, including 11 hormone‐naïve, 15 hormone‐sensitive, and 15 castration‐resistant patients. Across all variant types, we found progressively more altered tumor genomic profiles in later stages of aggressive PC. The potential driver genes most frequently affected by single‐nucleotide variants or insertions/deletions included the known PC‐related genes TP53, CDK12, and PTEN and the novel genes COL13A1, KCNH3, and SENP3. Etiologically, aggressive PC was associated with age‐related and DNA repair‐related mutational signatures. Copy number variants most frequently affected 14q11.2 and 8p21.2, where no well‐recognized PC‐related genes are located, and also frequently affected regions near the known PC‐related genes MYC, AR, TP53, PTEN, and BRCA1. Structural variants most frequently involved not only the known PC‐related genes TMPRSS2 and ERG but also the less extensively studied gene in this context, PTPRD. Finally, clinically actionable variants were detected throughout all stages of aggressive PC and in both plasma and tissue samples, emphasizing the potential clinical applicability of WGS of minimally invasive plasma samples. Overall, our study highlights the feasibility of using liquid biopsies for comprehensive genomic characterization as an alternative to tissue biopsies in advanced/aggressive PC. [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]

Cyclin-dependent kinases (CDKs) play essential roles in regulating the cell cycle and are among the most critical targets for cancer therapy and drug discovery. The primary objective of this research is to derive general structure–activity relationship (SAR) patterns for modeling the selectivity and activity levels of CDK inhibitors using machine learning methods. To accomplish this, 8592 small molecules with different binding affinities to CDK1, CDK2, CDK4, CDK5, and CDK9 were collected from Binding DB, and a diverse set of descriptors was calculated for each molecule. The supervised Kohonen networks (SKN) and counter propagation artificial neural networks (CPANN) models were trained to predict the activity levels and therapeutic targets of the molecules. The validity of models was confirmed through tenfold cross-validation and external test sets. Using selected sets of molecular descriptors (e.g. hydrophilicity and total polar surface area) we derived activity and selectivity maps to elucidate local regions in chemical space for active and selective CDK inhibitors. The SKN models exhibited prediction accuracies ranging from 0.75 to 0.94 for the external test sets. The developed multivariate classifiers were used for ligand-based virtual screening of 2 million random molecules of the PubChem database, yielding areas under the receiver operating characteristic curves ranging from 0.72 to 1.00 for the SKN model. Considering the persistent challenge of achieving CDK selectivity, this research significantly contributes to addressing the issue and underscores the paramount importance of developing drugs with minimized side effects. [ABSTRACT FROM AUTHOR]

Due to multidimensional complexity of solid tumor, development of rational T‐cell combinations and corresponding formulations is still challenging. Herein, a triple combination of T cells are developed with Indoleamine 2,3‐dioxygenase inhibitors (IDOi) and Cyclin‐dependent kinase 4/6 inhibitors (CDK4/6i). To maximize synergism, a spatiotemporally controlled T‐cell engineering technology to formulate triple drugs into one cell therapeutic, is established. Specifically, a sequentially responsive core‐shell nanoparticle (SRN) encapsulating IDOi and CDK4/6i is anchored onto T cells. The yielded SRN‐T cells migrated into solid tumor, and achieved a 1st release of IDOi in acidic tumor microenvironment (TME). Released IDOi restored tryptophan supply in TME, which activated effector T cells and inhibited Tregs. Meanwhile, 1st released core is internalized by tumor cells and degraded by glutathione (GSH), to realize a 2nd release of CDK4/6i, which induced up‐regulated expression of C‐X‐C motif chemokine ligand 10 (CXCL10) and C‐C motif chemokine ligand 5 (CCL5), and thus significantly increased tumor infiltration of T cells. Together, with an enhanced recruitment and activation, T cells significantly suppressed tumor growth, and prolonged survival of tumor‐bearing mice. This study demonstrated rationality and superiority of a tri‐drug combination mediated by spatiotemporally controlled cell‐engineering technology, which provides a new treatment regimen for solid tumor. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is a malignant disease that causes abnormal immunoglobulin synthesis by bone marrow plasma cells. The relationship between MM and the TP53 pathway has not been fully elucidated in the literature. Investigation of the effect of the expression of genes in the TP53 pathway on the molecular pathogenesis and prognosis of multiple myeloma disease. We assessed the expression of 18 genes in the TP53 pathway in 48 MM patients and 31 healthy subjects by RT2-profiler PCR array technique, and investigated their possible association with the presence of cytogenetic aberrations. Twelve of the 18 genes (APAF1, ATM, BAX, CASP9, CDK4, CDKN1A, CDKN2A, E2F1, MCL1, MDM2, MDM4, PTEN) expression levels were found to be statistically up-regulated in MM patients compared to controls. The CDK4, CDKN1A and MCL1 genes were found to have remarkable diagnostic power distinguishing MM and healthy controls (AUC=0.89;AUC=0.86;AUC=0.77, respectively and p<0.001 for all three) via using Receiver operating characteristic (ROC) analysis. Overexpression of CDK4 and CDKN1A, which are involved in the cell cycle, and MCL1, which is an important gene in the anti-apoptotic process, were found to be excessively increased in MM patients compared to controls in terms of mRNA fold change. In addition, the high sensitivity of these genes found in the ROC analysis results suggests that they may be suggested as potential biomarkers for MM. [ABSTRACT FROM AUTHOR]

Protein synthesis underpins cell growth and controls when cells commit to a new round of cell division at a point in late G1 of the cell cycle called Start. Passage through Start also coincides with the duplication of the microtubule-organizing centers, the yeast spindle pole bodies, which will form the 2 poles of the mitotic spindle that segregates the chromosomes in mitosis. The conserved Mps1p kinase governs the duplication of the spindle pole body (SPB) in Saccharomyces cerevisiae. Here, we show that the MPS1 transcript has a short upstream open reading frame (uORF) that represses the synthesis of Mps1p. Mutating the MPS1 uORF makes the cells smaller, accelerates the appearance of Mps1p in late G1, and promotes completion of Start. Monitoring the SPB in the cell cycle using structured illumination microscopy revealed that mutating the MPS1 uORF enabled cells to duplicate their SPB earlier at a smaller cell size. The accelerated Start of MPS1 uORF mutants depends on the G1 cyclin Cln3p and the transcriptional repressor Whi5p but not on the Cln1 ,2p G1 cyclins. These results identify growth inputs in mechanisms that control duplication of the microtubule-organizing center and implicate these processes in the coupling of cell growth with division. [ABSTRACT FROM AUTHOR]

To investigate the value of serum cell cycle protein-dependent kinase 1 (CDKI) and aurora kinase A (AURKA) in the diagnosis of patients with hepatitis B virus-related hepatocellular carcinoma (HBV-HCC). Methods A total of 50 HBV-HCC patients, 50 patients with hepatitis B virus-related liver cirrhosis (HBV-LC), and 50 chronic hepatitis B (CHB) patients who were hospitalized in Department of Gastroenterology, Gansu Provincial Hospital, fmm June 2022 to December 2023 were enrolled, and 50 healthy individuals, matched for age and sex, who received physical examination at Physical Examination Center during the same period of time were enrolled as control group. Related data were reconded for all patients, including age, sex, complications, and the results of routine blood test, liver function, and onagulation for the first time after admission. ELISA was used to measure the serum levels of CDK1 and AURKA. A one-way analysis of variance was used for comparison of normally distributed continuous data between multiple groups, and the least significant difference t-test was used for further comparison between two groups; the Kruskal-Wallis H test was used for comparison of non-normally distributed continuous data between multiple groups and the least significant difference Bonferroni test was used for further comparison between two groups, the chi- square test or the Fisher's exact test was used for comparison of categorical data between groups. The Spesaman correlation analysis was used to investigate the correlation between CDKI and AURKA, and the woeier operating characteristic (ROC) curve and the arra under the ROC curve (AUC) were used to investigate the value of CDK1 and AURKA in the diamosis of HBV-HCC. Results There were significant differences in liver function garameters between the HBV-HCC patients and the control group (all P<0.05); there were significant differences between the CHB group and the HBV-HCC group in albumin, Glh, dirret hilirubin, aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT) and alkaline phosphatase (all P<0.05); there were significant differences between the HIIV-LC group and the HBV-HCC group in Glb, AST, aml GGT (all P<0.05). The HBV- HCC group had significantly higher serum levels of CDKI and AURKA than the HBV-LC group, the CHB group, and the control group (all P<0.05). There was a significant positive correlation between CDKI and AURKA in the overall study population and the HBV-HCC patients (r=0.526 6 and 0.815 2. P<0.001), With the control group as reference, CDKI had an AUC of 0.832 3 in the diagnosis of HBV-HCC, with a sensitivity of 92.86% and a specificity of 75%, and AURKA had an ALC of 0.886 6 in the diagnosis of HCC. with a sensitivity of 95.80% and a specificity of 74%. With the CHB group as reference, CDKI had an AUC of 0.833 3 in the diagnosis of HBV-HCC, with a sensitivity of 93.75% and a specificity of 75%, and AURKA had an AUC of 0.972 7 in the diagnosis of HBV-HCC, with a sensitivity of 95.83% aml a specificity of 91.67%. With the HBV-LC group as reference. CDKI had an AUC of 0.608 5 in the diagnosis of HBV-HCC, with a sensitivity of 66.67% and a specificity of 54.17%, and AURKA had an AUC of 0.762 2 in the diagnosis of HBV-HCC, with a sensitivity of 95.83% and a specificity of 47.92%. Conclusion The serum levels of CDK1 and AURKA increase with the progression of hepatitis B-associated chronic liver disease, and significant increases in serum CDKI and AURKA have a certain value in the diagnosis of HBV HOC. [ABSTRACT FROM AUTHOR]

Introduction: Although exogenous nitric oxide (NO) is used as medicine, in the previous we showed its inhibitory effect on the proliferation ability of rat bone marrow mesenchymal stem cells (BMSCs). In the present investigation, the inhibitory role of exogenous NO on BMSCs cell cycle was studied. Methods: BMSCs after the third passage were treated for one hour every 48 hours with 100μM of sodium nitroprusside as an NO donor. Then, after 5,10,15, and 20 days of treatment, the viability, proliferation, and cell cycle of the BMSCs was investigated. In addition, the expression of the Raf1, CDK2, CDK4, P53, and GAPDH genes was studied. Results: Cell treatment caused a significant reduction in viability and proliferation at 5,10,15, and 20 days. Also, the treatment caused cell cycle arrest at G1 after 20 days. In addition, it was found that the CDK2 and CDK4 expression were down-regulated whereas the P53 expression was up-regulated, but the expression of Raf1 as well as GAPDH remained the same. Conclusion: This study showed that prolonged treatment with a NO donor arrest the BMSCs cell cycle due to overexpression of P53, which inhibits the expression of Cdk2 and Cdk4. [ABSTRACT FROM AUTHOR]

Poly L-lactic acid (PLLA) fillers stimulate collagen synthesis by activating various immune cells and fibroblasts. Piezo1, an ion channel, responds to mechanical stimuli, including changes in extracellular matrix stiffness, by mediating Ca2+ influx. Given that elevated intracellular Ca2+ levels trigger signaling pathways associated with fibroblast proliferation, Piezo1 is a pivotal regulator of collagen synthesis and tissue fibrosis. The aim of the present study was to investigate the impact of PLLA on dermal collagen synthesis by activating Piezo1 in both an H2O2-induced cellular senescence model in vitro and aged animal skin in vivo. PLLA elevated intracellular Ca2+ levels in senescent fibroblasts, which was attenuated by the Piezo1 inhibitor GsMTx4. Furthermore, PLLA treatment increased the expression of phosphorylated ERK1/2 to total ERK1/2 (pERK1/2/ERK1/2) and phosphorylated AKT to total AKT (pAKT/AKT), indicating enhanced pathway activation. This was accompanied by upregulation of cell cycle-regulating proteins (CDK4 and cyclin D1), promoting the proliferation of senescent fibroblasts. Additionally, PLLA promoted the expression of phosphorylated mTOR/S6K1/4EBP1, TGF-β, and Collagen I/III in senescent fibroblasts, with GsMTx4 treatment mitigating these effects. In aged skin, PLLA treatment similarly upregulated the expression of pERK1/2/ERK1/2, pAKT/AKT, CDK4, cyclin D1, mTOR/S6K1/4EBP1, TGF-β, and Collagen I/III. In summary, our findings suggest Piezo1′s involvement in PLLA-induced collagen synthesis, mediated by heightened activation of cell proliferation signaling pathways such as pERK1/2/ERK1/2, pAKT/AKT, and phosphorylated mTOR/S6K1/4EBP1, underscoring the therapeutic potential of PLLA in tissue regeneration. [ABSTRACT FROM AUTHOR]

Aims and objectives: Human epidermal growth factor receptor 2 (HER2)-low breast cancer (BC) is a new entity considered a biologically distinct subtype from HER2-zero BC. However, the importance of HER2 low expression on the activity of cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) remains unclear. Methods/materials: We conducted a single-center retrospective study including hormone receptor-positive (HR +) /HER2- metastatic BC (mBC) patients treated with CDK4/6i plus endocrine treatment (ET) as first-line therapy. Clinical outcomes were analyzed according to HER2 expression. Results: 258 women were analyzed with a median follow-up of 25.4 months; 39.9% had HER2 low, and 60.1% had HER2 zero BC. Median progression-free survival (mPFS) in the HER2-low group was 27.6 months compared with 44.3 months in the HER2-zero group (p = 0.341). In patients receiving ribociclib, the mPFS in the HER2-low group was 24.2 months compared with 53.1 months in the HER2-zero group (multivariate-adjusted HR: 1.981, 95 Cl 1.094–3.586; p = 0.024). The survival probabilities at 24, 36 and 48 months for the HER2 low and HER2 zero groups were 82%, 69%, 69% and 83%, 75% and 69%, respectively (p = 0.336). Objective response rate (p = 0.179) and disease control rate (p = 0.338) did not significantly differ between HER-2-low and HER-2-zero groups. Conclusions: The mPFS in the Her2-zero group was almost twice that of the Her2-low group, but the difference was not statistically significant. mPFS was significantly longer in the HER2-zero group compared to the HER2-low group in patients receiving ribociclib. More prospective studies are needed to understand the actual consequences of this biomarker. [ABSTRACT FROM AUTHOR]

The incidence and mortality rates of esophageal squamous cell carcinoma (ESCC) have been significantly increasing in China. Indole-3-carbinol (I3C), a naturally occurring component in cruciferous vegetables, is an effective cancer therapy. Yet, its effect and action mechanism in ESCC are still not fully understood. This study explored the role of I3C in ESCC in vitro and in vivo by focusing on the Wnt/β-catenin signaling pathway. MTT and flow cytometry were used to assess cell viability and apoptosis in EC18 and TE1 cells, while wound healing and transwell assays were used to investigate cell migration and invasion in vitro. Expression of β-catenin, c-myc, and cyclin D1 was determined by Western blot; LiCl (an agonist of the canonical Wnt signaling that inhibits GSK3β activity) was used to assess the role of I3C on the Wnt/β-catenin signaling pathway. For in vivo experiments, nude BALB/c mice bearing EC18 xenografts were treated with I3C and/or LiCl. I3C promoted ESCC apoptosis and inhibited cell migration and invasion by downregulating β-catenin, c-myc, and cyclin D1 in vitro and decreased the tumor growth in vivo; this process was reversed by LiCl treatment. In summary, I3C inhibits ESCC malignant behavior by suppressing the Wnt/β-catenin signaling pathway, thus deeming it a promising drug for ESCC treatment. [ABSTRACT FROM AUTHOR]

Herein, the synthesis and biological evaluation of 6-fluoro-3-(piperidin-4-yl)benzo[d]isoxazole sulfonamide hybrids are discussed. All the synthesized molecules were assessed for anti-cancer and anti-TB activities using in vitro and in silico methods. The molecular docking study with CDK8 as a possible target for anti-cancer activity demonstrated that compounds 2, 3, 5, 7, 8, and 9 have a good binding affinity ranging from −8.7 to −10.3 kcal/mol against CDK8 (PDB 6T41) protein as compared with the standard drug 5-Fluorouracil (−5.0 kcal/mol). The in vitro anti-mycobacterial screening reveals that compounds 2 and 3 elicited moderate anti-TB activity with a MIC value of 25 µM. Compounds 2 and 3 exhibited moderate in vitro anti-proliferative potency against the cancer cell lines MCF-7 and HCT-116. Moreover, compound 3 exhibited a better anti-oxidant effect among all tested compounds. Some quantum chemical parameters and drug-likeness profiling of the molecules were modeled by density functional theory (DFT) and ADME studies. The obtained theoretical results are in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Radiotherapy promotes the binding of CDK2 and TRIM32, thus leading to increased CDK2-dependent phosphorylation of TRIM32 at serines 328 and 339. • Cis-trans isomerization of TRIM32 recruit PIN1, which resulting in importin α3 binding to TRIM32 and contributing to its nuclear translocation. • Nuclear TRIM32 inhibits TC45-dephosphorylated STAT3, Leading to increased transcription of STAT3 and radioresistance in triple-negative breast cancer (TNBC). • Regulating the CDK2/TRIM32/STAT3 pathway is a promising strategy for reducing radioresistance in TNBC, which is important for TNBC therapy. Despite radiotherapy being one of the major treatments for triple-negative breast cancer (TNBC), new molecular targets for its treatment are still required due to radioresistance. CDK2 plays a critical role in TNBC. However, the mechanism by which CDK2 promotes TNBC radioresistance remains to be clearly elucidated. We aimed to elucidate the relationship between CDK2 and TRIM32 and the regulation mechanism in TNBC. We performed immunohistochemical staining to detect nuclear TRIM32, CDK2 and STAT3 on TNBC tissues. Western blot assays and PCR were used to detect the protein and mRNA level changes. CRISPR/Cas9 used to knock out CDK2. shRNA-knockdown and transfection assays also used to knock out target genes. GST pull-down analysis, immunoprecipitation (IP) assay and in vitro isomerization analysis also used. Tumorigenesis studies also used to verify the results in vitro. Herein, tripartite motif-containing protein 32 (TRIM32) is revealed as a substrate of CDK2. Radiotherapy promotes the binding of CDK2 and TRIM32, thus leading to increased CDK2-dependent phosphorylation of TRIM32 at serines 328 and 339. This causes the recruitment of PIN1, involved in cis–trans isomerization of TRIM32, resulting in importin α3 binding to TRIM32 and contributing to its nuclear translocation. Nuclear TRIM32 inhibits TC45-dephosphorylated STAT3, Leading to increased transcription of STAT3 and radioresistance in TNBC. These results were validated by clinical prognosis confirmed by the correlative expressions of the critical components of the CDK2/TRIM32/STAT3 signaling pathway. Our findings demonstrate that regulating the CDK2/TRIM32/STAT3 pathway is a promising strategy for reducing radioresistance in TNBC. [ABSTRACT FROM AUTHOR]

Cyclin-dependent kinases 4 and 6 (CDK4/6) play a pivotal role in cell cycle and cancer development. Targeting CDK4/6 has demonstrated promising effects against breast cancer. However, resistance to CDK4/6 inhibitors (CDK4/6i), such as palbociclib, remains a substantial challenge in clinical settings. Using high-throughput combinatorial drug screening and genomic sequencing, we find that the microphthalmia-associated transcription factor (MITF) is activated via O-GlcNAcylation by O-GlcNAc transferase (OGT) in palbociclib-resistant breast cancer cells and tumors. Mechanistically, O-GlcNAcylation of MITF at Serine 49 enhances its interaction with importin α/β, thus promoting its translocation to nuclei, where it suppresses palbociclib-induced senescence. Inhibition of MITF or its O-GlcNAcylation re-sensitizes resistant cells to palbociclib. Moreover, clinical studies confirm the activation of MITF in tumors from patients who are palbociclib-resistant or undergoing palbociclib treatment. Collectively, our studies shed light on the mechanism regulating palbociclib resistance and present clinical evidence for developing therapeutic approaches to treat CDK4/6i-resistant breast cancer patients. Targeting CDK4/6 in breast cancer has been demonstrated to be initially effective but often, resistance develops. Here, the authors identify microphthalmia-associated transcription factor-A (MITF-A) as a driver of CDK4/6 inhibitor resistance in breast cancer and show that MITF-A activity is mediated through O-GlcNAcylation at Serine 49, promoting its nuclear import. [ABSTRACT FROM AUTHOR]

Purpose: There is no clear information in the literature about the relationship between the efficacy of CDK 4/6i combined with ET and HR positivity. However, we know that the longest overall survival was in the ER-strong positive/PR intermediate or strong positive groups. Therefore, we aimed to investigate CDK4/6i treatments that create positivity in HR. Methods: Patients with the diagnosis of HR+/HER2- MBC who were treated with CDK 4/6i and HR >10% were retrospectively evaluated. To analyze the role of HR positivity, ER was moderately positive (10-49%) and ER was strongly positive (50-100%); PR was grouped as moderately positive (10-49%) and PR strongly positive (50-100%). Results: Median follow-up of 150 patients included in the study was 15.2 months (95% CI, 2.1-40.9 months). The highest response in the whole group was obtained in the ER-strong positive/PR moderate or strong positive group, and the ER moderate positive/PR moderate or strong group. This was followed by the ER strong positive/PR negative group, and then the ER moderate positive/PR negative group. Although these advantages were not statistically significant, they were numerically higher (ORR: 83.8% vs. 83.3% vs. 77.4% vs. 62.5%, p=0.488, respectively). The highest survival in the whole group was achieved in the ER strong positive/PR moderate or strongly positive group, followed by the ER moderately positive/PR moderate or strongly positive group, the ER strongly positive/PR negative group followed by the ER moderate positive/PR negative group, respectively(p=0.410). However, these advantages were not statistically significant. Conclusion: As a result, HR+/HER2- MBC patients receiving CDK 4/6i combined with ET suggest that the percentage of HR positivity may have a predictive and prognostic role. [ABSTRACT FROM AUTHOR]

Epithelioid glioblastoma (eGBM) is a rare subtype of GBM. Given the update of the definition of GBM, the understanding of the molecular characteristics and prognosis of "true" adult eGBM remains limited. Herein, we retrospectively analyzed the clinicopathological data of 39 adult eGBM cases. Adult eGBM primarily affected females, with a male‐to‐female ratio of 1:2.3. The average age of diagnosis was 53 years, and the tumor affected the temporal lobe in 41% of cases (16/39, 41%). Microscopically, the tumors consisted mainly or entirely of epithelioid cells. Perivascular infiltration (10/39, 25.6%) and leptomeningeal dissemination (7/39, 17.9%) were not uncommon. BRAF V600E mutation was detected in 40.9% of cases (n = 9/22). Next‐generation sequencing revealed that CDKN2A/B homogeneous deletion was the most frequently mutated gene (8/10, 80%), followed by TERT promoter mutation (7/10, 70%), Cyclin‐dependent kinases 4 or 6 (CDK4/6) amplification (5/10, 50%) and BRAF V600E mutation (50%, 5/10). Notably, the incidence of ARID1B mutation in eGBM was 50% (5/10), representing the first report of such a mutation in this subtype of GBM. ARID1B was known to be a subunit of the SWI/SNF chromatin remodeler. Chromosome analysis showed a 7+/10‐ signature in 90% (9/10) cases. Adult eGBM carried a dismal prognosis compared to GBM with IDH and H3 wild‐type (typical GBM) (OS: 13.89 vs 24.30 months; P =.003) and even typical GBM without MGMT promoter methylation (OS: 13.89 vs 22.08 months; P =.036). Based on these findings, it can be concluded that adult eGBM harbors a high frequency of the 7+/10− signature and alterations in the MAPK pathway, SWI/SNF complex and cyclin‐related genes and portends an extremely poor prognosis. [ABSTRACT FROM AUTHOR]

Background: Niraparib, a poly ADP-ribose polymerase inhibitors (PARPi), has been widely applied in the intervention of epithelial ovarian, fallopian tube, or primary peritoneal cancer. Nevertheless, as of the present moment, there are limited instances demonstrating favorable outcomes stemming from niraparib therapy in patients with clear cell renal cell carcinoma (ccRCC). Case presentation: Here, we report a case of a 50-year-old patient with ccRCC who subsequently developed distant metastasis. The patient received monotherapy with pazopanib and combination therapy with axitinib and tislelizumab, demonstrating limited efficacy. Liquid biopsy revealed missense mutations in the CDK12 and RAD51C of the homologous recombination repair (HRR) pathway, suggesting potential sensitivity to PARPi. Following niraparib treatment, the patient's condition improved, with no significant side effects. Conclusion: In summary, patients with ccRCC harboring HRR pathway gene mutation may potentially benefit from niraparib. This will present more options for ccRCC patients with limited response to conventional treatments. [ABSTRACT FROM AUTHOR]

In cells, signal transduction heavily relies on the intricate regulation of protein kinases, which provide the fundamental framework for modulating most signaling pathways. Dysregulation of kinase activity has been implicated in numerous pathological conditions, particularly in cancer. The druggable nature of most kinases positions them into a focal point during the process of drug development. However, a significant challenge persists, as the role and biological function of nearly one third of human kinases remains largely unknown. Within this diverse landscape, cyclin-dependent kinases (CDKs) emerge as an intriguing molecular subgroup. In human, this kinase family encompasses 21 members, involved in several key biological processes. Remarkably, 13 of these CDKs belong to the category of understudied kinases, and only 5 having undergone broad investigation to date. This knowledge gap underscores the pressing need to delve into the study of these kinases, starting with a comprehensive review of the less-explored ones. Here, we will focus on the PCTAIRE subfamily of CDKs, which includes CDK16, CDK17, and CDK18, arguably among the most understudied CDKs members. To contextualize PCTAIREs within the spectrum of human pathophysiology, we conducted an exhaustive review of the existing literature and examined available databases. This approach resulted in an articulate depiction of these PCTAIREs, encompassing their expression patterns, 3D configurations, mechanisms of activation, and potential functions in normal tissues and in cancer. We propose that this effort offers the possibility of identifying promising areas of future research that extend from basic research to potential clinical and therapeutic applications. [ABSTRACT FROM AUTHOR]

Background: The cyclin D1-cyclin dependent kinases (CDK)4/6 inhibitor palbociclib in combination with endocrine therapy shows remarkable efficacy in the management of estrogen receptor (ER)-positive and HER2-negative advanced breast cancer (BC). Nevertheless, resistance to palbociclib frequently arises, highlighting the need to identify new targets toward more comprehensive therapeutic strategies in BC patients. Methods: BC cell lines resistant to palbociclib were generated and used as a model system. Gene silencing techniques and overexpression experiments, real-time PCR, immunoblotting and chromatin immunoprecipitation studies as well as cell viability, colony and 3D spheroid formation assays served to evaluate the involvement of the G protein-coupled estrogen receptor (GPER) in the resistance to palbociclib in BC cells. Molecular docking simulations were also performed to investigate the potential interaction of palbociclib with GPER. Furthermore, BC cells co-cultured with cancer-associated fibroblasts (CAFs) isolated from mammary carcinoma, were used to investigate whether GPER signaling may contribute to functional cell interactions within the tumor microenvironment toward palbociclib resistance. Finally, by bioinformatics analyses and k-means clustering on clinical and expression data of large cohorts of BC patients, the clinical significance of novel mediators of palbociclib resistance was explored. Results: Dissecting the molecular events that characterize ER-positive BC cells resistant to palbociclib, the down-regulation of ERα along with the up-regulation of GPER were found. To evaluate the molecular events involved in the up-regulation of GPER, we determined that the epidermal growth factor receptor (EGFR) interacts with the promoter region of GPER and stimulates its expression toward BC cells resistance to palbociclib treatment. Adding further cues to these data, we ascertained that palbociclib does induce pro-inflammatory transcriptional events via GPER signaling in CAFs. Of note, by performing co-culture assays we demonstrated that GPER contributes to the reduced sensitivity to palbociclib also facilitating the functional interaction between BC cells and main components of the tumor microenvironment named CAFs. Conclusions: Overall, our results provide novel insights on the molecular events through which GPER may contribute to palbociclib resistance in BC cells. Additional investigations are warranted in order to assess whether targeting the GPER-mediated interactions between BC cells and CAFs may be useful in more comprehensive therapeutic approaches of BC resistant to palbociclib. [ABSTRACT FROM AUTHOR]

Background: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) represent the gold standard of the hormone receptor positive human epidermal growth factor receptor 2 (HER-2) negative advanced breast cancer. However, optimal treatment after disease progression is a matter of debate. We aimed to assess predictive and prognostic factors associated with the treatment outcome following CDK4/6i progression. Methods: We retrospectively analyzed patients who progressed on CDK4/6i treatment between 2018 and 2024. Treatment based on molecular findings (PIK3CA mutation), genetic findings (BRCA1/2 germline mutation), or adapted to the change in the tumor phenotype in rebiopsy (anti-HER2 therapy in the transformation to HER-2-positive disease) was grouped into tailored treatment and compared to the endocrine-based therapy and chemotherapy alone. Results: Five hundred twelve patients were treated with CDK4/6i. Two hundred patients with disease progression were enrolled in the study. Duration of response to CDK4/6i was not predictive of the response to subsequent treatment, whereas the progression in the central nervous system was the worst prognostic factor. Thirty patients were ineligible for subsequent treatment. Survival after CDK4/6i progression was significantly longer in patients eligible for tailored treatment. The median PFS in patients with tailored treatment (n=19) was 13.5 months vs. 4.9 months in patients with non-tailored therapy (n=151; p=0.045). 12-month PFS was 54.1% with tailored treatment [95% CI 24.1–76.7%] compared to 18.5% with non-tailored therapy [95% CI 11.6– 26.6%]. The median OS for patients treated with a tailored approach was not reached compared to 11.5 months with non-tailored treatment (p=0.016). The 24-month OS for patients treated with a tailored approach was 80.2% [95% CI 40.3–94.8%] compared to 21.1% [95% CI 12.2–31.7%] for patients with nontailored treatment. Conclusions: Tailoring of subsequent treatment strategy seems to be essential for achieving long-term benefit. Further studies are required, as the prognosis after CDK4/6i progression remains dismal, especially in cases affecting the central nervous system. [ABSTRACT FROM AUTHOR]

Simple Summary: A new class of therapy named cyclin-dependent kinase 4/6 inhibitors (CDK4/6is) is the recommended preferred treatment for patients with metastatic breast cancer (MBC) who have the HR+/HER2− subtype; however, several barriers may still exist that prevent or delay the initiation of this treatment. In this observational study, we examined how the social determinants of health (SDOH) (e.g., income status, insurance coverage) and other patient characteristics are associated with the initiation of CDK4/6i for HR+/HER2− MBC in a Medicare population of patients aged 65 years or older. Our analysis showed that Medicare patients residing in areas with high vs. low median household income and those living in areas with a high vs. low proportion of Medicare-only coverage had higher rates of initiating treatment with CDK4/6i. Our study findings highlight the influence of SDOH on access to novel and effective cancer therapies and a need for strategies to improve equity in cancer care. In hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2−) metastatic breast cancer (MBC), cyclin-dependent kinase 4/6 inhibitors (CDK4/6is) have replaced endocrine therapy alone as the standard of care; however, several barriers to treatment initiation still exist. We assessed social determinants of health (SDOH) and other factors associated with the initiation of CDK4/6i for HR+/HER2− MBC in the Medicare population. Using a retrospective cohort design, patients aged ≥65 years and diagnosed during 2015–2017 were selected from the SEER-Medicare database. Time from MBC diagnosis to first CDK4/6i initiation was the study outcome. The effect of SDOH measures and other predictors on the outcome was assessed using the multivariable Fine and Gray hazard modeling. Of 752 eligible women, 352 (46.8%) initiated CDK4/6i after MBC diagnosis (median time to initiation: 27.9 months). In adjusted analysis, SDOH factors significantly associated with CDK4/6i initiation included high versus low median household income (HHI) (hazard ratio [HR] = 1.70; 95% CI = 1.03–2.81) and the percentage of population with high versus low Medicare-only coverage (HR = 1.54; 95% CI = 1.04–2.27). In summary, older Medicare patients with HR+/HER2− MBC residing in areas with high median HHI and a high proportion of Medicare-only coverage had higher rates of initiating CDK4/6i, suggesting inequitable access to these novel, effective treatments and a need for policy intervention. [ABSTRACT FROM AUTHOR]

Background: Globally, breast cancer in women is the fifth leading cause of cancer death. There is an urgent need to explore the molecular mechanism of breast cancer proliferation and metastasis. Method: TCGA database analysis was used to analyze genes expression in breast cancer and normal samples and the association between gene expression and prognosis. Immunohistochemical staining, qPCR and western blotting was sued to detected gene expression. The cell function tests were conducted to investigate the effects of TEX19 and CDK4 with abnormal expression on cell proliferation, migration, apoptosis, cell cycle, and colony formation. Bioinformatics analysis methods combined with CHX tracking experiment and Co-IP experiment were performed to screen and verify the downstream molecule and regulatory mechanism of TEX19. Besides, subcutaneous tumorigenesis model in nude mice was constructed. Results: TEX19 was significantly upregulated in breast cancer, and the TEX19 level was related to tumor invasion and prognosis. TEX19 knockdown inhibited the proliferation and migration of breast cancer cells, increased cell apoptosis, and blocked the cell cycle in the G2 phase. Besides, TEX19 suppressed the growth of tumors in the body. Mechanically, TEX19 upregulated the level of CDK4 protein, which depended on the E3 ubiquitin ligase SKP2. Specifically, TEX19 knockdown and SKP2 protein overexpression destroyed the stability of CDK4 protein and enhanced the ubiquitination of CDK4 protein. Additionally, CDK4 knockdown inhibited the proliferation, migration, and colony formation of breast cancer cells, and alleviated the promotion of TEX19 overexpression on the proliferation and migration of breast cancer cell. Conclusion: TEX19 and CDK4 were upregulated in breast cancer, and TEX19 increased the level of CDK4 protein by influencing SKP2-mediated ubiquitination of CDK4, thereby promoting the progression of breast cancer. [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]

A versatile division of apicomplexan parasites and a dearth of conserved regulators have hindered the progress of apicomplexan cell cycle studies. While most apicomplexans divide in a multinuclear fashion, Toxoplasma gondii tachyzoites divide in the traditional binary mode. We previously identified five Toxoplasma CDK-related kinases (Crk). Here, we investigated TgCrk4 and its cyclin partner TgCyc4. We demonstrated that TgCrk4 regulates conventional G2 phase processes, such as repression of chromosome rereplication and centrosome reduplication, and acts upstream of the spindle assembly checkpoint. The spatial TgCyc4 dynamics supported the TgCrk4–TgCyc4 complex role in the coordination of chromosome and centrosome cycles. We also identified a dominant TgCrk4–TgCyc4 complex interactor, TgiRD1 protein, related to DNA replication licensing factor CDT1 but played no role in licensing DNA replication in the G1 phase. Our results showed that TgiRD1 also plays a role in controlling chromosome and centrosome reduplication. Global phosphoproteome analyses identified TgCrk4 substrates, including TgORC4, TgCdc20, TgGCP2, and TgPP2ACA. Importantly, the phylogenetic and structural studies suggest the Crk4–Cyc4 complex is limited to a minor group of the binary dividing apicomplexans. Synopsis: Apicomplexan parasite division can yield between two and thousands of progenies, and how this process is regulated remains a mystery. This study identifies a presumed missing G2 phase, and the complex TgCrk4-TgCyc4-TgiRD1 that regulates G2 phase, in Toxoplasma gondii. Expression of the CDK-related kinase TgCrk4, of the cyclin TgCyc4, and of the inhibitor of the DNA and centrosome reduplication TgiRD1 is essential for binary division of T. gondii tachyzoites. Removing TgCrk4 and TgiRD1 triggers the reduplication of chromosomes and centrosomes, revealing their role as guardians of the "once per cycle" duplication rule. Although distantly related to fungal and metazoan CDT1, TgiRD1 does not license DNA replication in G1 phase. Comparative genomic studies imply that expression of the Crk4-Cyc4 complex is restricted to apicomplexan parasites undergoing binary division. A previously unrecognized G2 phase in apicomplexan parasites undergoing binary division depends on a novel CDK-related kinase, an atypical cyclin, and a Cdt1-related inhibitor of re-duplication. [ABSTRACT FROM AUTHOR]

Human dental pulp stem cells are a potentially useful resource for cell‐based therapies and tissue repair in dental and medical applications. However, the primary culture of isolated dental pulp stem cells has notably been limited. A major requirement of an ideal human dental pulp stem cell culture system is the preservation of efficient proliferation and innate stemness over prolonged passaging, while also ensuring ease of handling through standard, user‐friendly culture methods. In this study, we have engineered a novel human dental pulp stem cell line, distinguished by the constitutive expression of telomerase reverse transcriptase (TERT), and the conditional expression of the R24C mutant cyclin‐dependent kinase 4 (CDK4R24C) and Cyclin D1. We have named this cell line Tet‐off K4DT hDPSCs. Furthermore, we have conducted a comprehensive comparative analysis of their biological attributes in relation to a previously immortalized human dental pulp stem cells, hDPSC‐K4DT, which were immortalized by the constitutive expression of CDK4R24C, Cyclin D1 and TERT. In Tet‐off K4DT cells, the expression of the K4D genes can be precisely suppressed by the inclusion of doxycycline. Remarkably, Tet‐off K4DT cells demonstrated an extended cellular lifespan, increased proliferative capacity, and enhanced osteogenic differentiation potential when compared to K4DT cells. Moreover, Tet‐off K4DT cells had no observable genomic aberrations and also displayed a sustained expression of stem cell markers even at relatively advanced passages. Taken together, the establishment of this new cell line holds immense promise as powerful experimental tool for both fundamental and applied research involving dental pulp stem cells. Significance Statement: We have engineered a novel human dental pulp stem cell line, distinguished by the constitutive expression of telomerase reverse transcriptase (TERT), and the conditional expression of the R24C mutant cyclin‐dependent kinase 4 (CDK4R24C) and Cyclin D1 (hereafter referred to as Tet‐off K4DT). In Tet‐off K4DT cells, the expression of the K4D genes can be precisely suppressed by the inclusion of doxycycline. Tet‐off K4DT cells have demonstrated an extended cellular lifespan, increased proliferative capacity, and had no observable genomic aberrations and displayed a sustained expression of stem cell markers even at relatively advanced passages. [ABSTRACT FROM AUTHOR]

Background: Following the positive iDFS and OS results of the phase III clinical trials monarchE, NATALEE and OlympiA, new oral anticancer agents (the CDK4/6 inhibitors abemaciclib, ribociclib as well as the PARP inhibitor olaparib) have recently been introduced into the treatment of high-risk early breast cancer (eBC). However, only few male patients were included in these trials (0.4%, 0.6% and 0.3%, respectively). The objective of this real-world analysis was to determine the proportion of male patients with eBC fulfilling the clinical high-risk criteria of above-mentioned trials. Patients and methods: We conducted a data inquiry and analysis with the Cancer Registry of Baden-Württemberg of men with breast cancer diagnosed between January 1, 2015 and December 31, 2021. Men with eBC were identified and the number of patients at clinical high-risk according to the inclusion criteria of monarchE, NATALEE and OlympiA was assessed. Results: Of 397 men with eBC, 354 (89.1%) had a HR + /Her2− and 4 (1.0%) a triple-negative subtype. 84 patients (21.2%) met the clinical high-risk criteria according to the monarchE, 189 (47.6%) those according to the NATALEE and 50 (12.6%) those according to the OlympiA trial. Conclusion: In a large real-world sample, more men with eBC are at clinical high risk according to the inclusion criteria of monarchE, NATALEE and OlympiA than would be expected in women. This is most likely due to more advanced stages at initial diagnosis in men. To evaluate whether CDK4/6 and PARP inhibitors improve prognosis also in men should be the topic of future real- world analyses. [ABSTRACT FROM AUTHOR]

: This study examined the inhibitory effect of peiminine on the human colonic adenocarcinoma cell line SW480 and explored the underlying mechanisms. METHODS: SW480 and human normal colonic epithelial CCD-841CoN cells were treated with different concentrations of peiminine and subjected to the CCK-8 assay to select the optimal treatment time and concentration of the compound. SW480 cell migration and invasion were evaluated by the wound-healing and Transwell assays. Cell cycle progression was analyzed by flow cytometry. The expression levels of cell cycle-related proteins were examined by Western blot. SW480 xenograft tumor model was established in nude mice to examine the effect of peiminine on tumor growth and the expression of cell cycle-related proteins in vivo. RESULTS: Peiminine (110 mg/L) significantly inhibited the proliferation of SW480 cells compared with the control group (P<0.01), caused cell cycle arrest at G, phase, and significantly downregulated the expression of cyclin dependent kinase 2(CDK2), DK4, CDK6, cyclin D1, p-Rb/Rb, E2F1, E2F3, and E2F4 (P<0. 05). Peiminine inhibited SW480 xenograft tumor growth, prolonged the survival of model mice, and affected the expression of CDK2, CDK4, CDK6, and cyclin D1 in tumor tissues. CONCLUSION: Peiminine promotes G1 phase arrest by down-regulating the expression of CDK2, CDK4, CDK6, and cyclin D1, thereby inhibiting the proliferation of SW480 cells. [ABSTRACT FROM AUTHOR]

Simple Summary: The search for precision medicine applications in mesotheliomas (MM) is taking its first steps. After platinum and pemetrexed chemotherapy, the treatment for relapsed MM remains an unmet clinical need, and the prognosis of MM remains poor even if the recent introduction of immunotherapy. It is known that MM is mainly characterized by inactivanting tumor suppressor alterations and that these, along with some cellular targets or metabolic enzymes, could be potentially amenable to specific therapies The purpose of this review is to take a comprehensive excursus of the main targets and the related evidence regarding possible treatment activities intended for them. Mesothelioma (MM) is an aggressive and lethal disease with few therapeutic opportunities. Platinum-pemetrexed chemotherapy is the backbone of first-line treatment for MM. The introduction of immunotherapy (IO) has been the only novelty of the last decades, allowing an increase in survival compared to standard chemotherapy (CT). However, IO is not approved for epithelioid histology in many countries. Therefore, therapy for relapsed MM remains an unmet clinical need, and the prognosis of MM remains poor, with an average survival of only 18 months. Increasing evidence reveals MM complexity and heterogeneity, of which histological classification fails to explain. Thus, scientific focus on possibly new molecular markers or cellular targets is increasing, together with the search for target therapies directed towards them. The molecular landscape of MM is characterized by inactivating tumor suppressor alterations, the most common of which is found in CDKN2A, BAP1, MTAP, and NF2. In addition, cellular targets such as mesothelin or metabolic enzymes such as ASS1 could be potentially amenable to specific therapies. This review examines the major targets and relative attempts of therapeutic approaches to provide an overview of the potential prospects for treating this rare neoplasm. [ABSTRACT FROM AUTHOR]

We assessed the real-world effectiveness of cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors as first-line treatments in postmenopausal patients with HR+/HER2− advanced breast cancer, focusing on younger (<45 years) and older (>78 years) populations not considered in clinical trials. We analyzed nationwide claims data from the Health Insurance Review and Assessment Service between November 2016 and February 2021. In this retrospective cohort study, patients using CDK4/6 inhibitors and aromatase inhibitors were selected and grouped by age as follows: 45–78 years (trial-enrolled), <45 years (younger), and >78 years (older). We estimated the median real-world progression-free survival (rwPFS) and overall survival (OS) using the Kaplan-Meier method. We conducted Cox regression analysis using a sub-distribution hazard model to evaluate risk factors (age, history of prior systemic treatment, presence of metastasis, comorbidity index, and type of provider) and estimated hazard ratios (HR). Among the 2,830 patients who received CDK4/6 inhibitors as first-line therapy, we identified 358 (12.65%) younger and 148 (5.23%) older underrepresented patients. The younger patient group (50.84%) had the highest rate of prior systemic therapy, followed by the trial-enrolled (25.39%) and older patient groups (8.11%). The median rwPFS was shorter in the older group (19.30 months) than those in the younger and the trial-enrolled age groups (30.33 and 34.53 months, respectively; p =.002). The HR of older age for death was 1.59 (95% confidence interval (CI) = 1.24–2.03). For rwPFS, the HR of prior systemic therapy was 1.19 (95% CI = 1.04–1.37). The younger age group, which was underrepresented in the trial, did not show a significant difference in risk compared with the enrolled age group. However, the older age group, which was also underrepresented in the trial, faces a risk of mortality but not progression. Patients who fall outside the specified age groups for the clinical trial can still expect the same level of effectiveness in terms of progression. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is a hematologic malignancy caused by the clonal expansion of immunoglobulin-producing plasma cells in the bone marrow and/or extramedullary sites. Common manifestations of MM include anemia, renal dysfunction, infection, bone pain, hypercalcemia, and fatigue. Despite numerous recent advancements in the MM treatment paradigm, current therapies demonstrate limited long-term effectiveness and eventual disease relapse remains exceedingly common. Myeloma cells often develop drug resistance through clonal evolution and alterations of cellular signaling pathways. Therefore, continued research of new targets in MM is crucial to circumvent cumulative drug resistance, overcome treatment-limiting toxicities, and improve outcomes in this incurable disease. This article provides a comprehensive overview of the landscape of novel treatments and emerging therapies for MM grouped by molecular target. Molecular targets outlined include BCMA, GPRC5D, FcRH5, CD38, SLAMF7, BCL-2, kinesin spindle protein, protein disulfide isomerase 1, peptidylprolyl isomerase A, Sec61 translocon, and cyclin-dependent kinase 6. Immunomodulatory drugs, NK cell therapy, and proteolysis-targeting chimera are described as well. [ABSTRACT FROM AUTHOR]

Objective: Mutations in the cyclin‐dependent kinase‐like 5 gene (CDKL5) are associated with a wide spectrum of clinical presentations. Early‐onset epileptic encephalopathy (EOEE) is the most recognized phenotype. Here we describe phenotypic features in eight Tunisian patients with CDKL5‐related encephalopathy. Methods: We included all cases with clinical features consistent with CDKL5‐related encephalopathy: infantile epileptic spasm, acquired microcephaly, movement disorders and visual impairment. We collected data about seizure types, electroencephalogram, magnetic resonance imaging, and metabolic analysis. The diagnosis of CDKL5 mutation was made thanks to Sanger sequencing with an ABI PRISM 3100‐Avant automated DNA sequencer using a Big Dye Terminator Cycle Sequencing Reaction Kit v1.1. and Next Generation Sequencing (NGS) since the development of a gene panel responsible for DEE within the framework of "Strengthening the Sfax University Expertise for diagnosis and management of epileptic encephalopathies". Results: We collected four boys and four girls aged meanly 6 years old with confirmed mutation on CDKL5 gene. Overall, we identified five de novo CDKL5 mutations including three Frame‐shift mutations, one missense mutation, and a splicing variant. The mean age at first seizure onset was 4 months. The first seizure type was infantile epileptic spasm (4/8) followed by tonic (2/8) and myoclonic seizures (2/8). Out of eight cases, four exhibited two stages epileptic course while epilepsy in three other patients progressed on three stages. Regarding development, most cases (6/8) had psychomotor retardation from the start whilst the two others showed psychomotor regression with the onset of seizures. Additional clinical features included visual impairment (7/8), tone abnormalities (7/8), stereotypies (7/8), and acquired microcephaly (6/8). Significance: Our present report delineates an unusual phenotype of CDKL5‐related encephalopathy with male gender predominance and delayed onset epilepsy. It interestingly described new phenotypic features and uncommon benign developmental profiles in boys, different patterns of CDKL5‐epilepsy, neuroimaging findings, and CDKL5 mutational spectrum. [ABSTRACT FROM AUTHOR]

Background Ribociclib is approved for hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2−) advanced breast cancer (ABC) treatment, in combination with endocrine therapy. Hematological, hepatic, and cardiac adverse events (AEs) emerged from pivotal trials, but little is known about cutaneous adverse events (CAEs). Patients and Methods We report data from a retrospective cohort study of all patients with HR+/HER2− ABC treated with ribociclib at Humanitas Cancer Center between June 2017 and December 2022. We recorded clinical-pathological data, the incidence, and treatment of ribociclib-related CAEs. These were evaluated according to the NCI-CTCAE v5.0 classification. Progression-free survival (PFS) was estimated by Kaplan-Meier method and the log-rank test was used to analyze differences between groups. Results Thirteen of 91 patients (14.3%) experienced treatment-related CAEs (mean time to the occurrence: 3.9 months). The most frequent CAEs were eczematous dermatitis (53.8%) and maculo-papular reaction (15.4%). Itch was reported by all 13 patients. The grade was G3 in 8 cases, G2 in 4, and G1 in 1. An integrated approach based on ribociclib dose modulation and dermatological interventions (oral antihistamine, moisturized cream, topical, and/or systemic steroids) could prevent ribociclib discontinuation in most patients. At a median follow-up of 20 months, the median PFS was 13 months (range, 1-66) with a better PFS curves for patients experiencing CAEs (P  = .04). Conclusion We mapped frequency and types of ribociclib-induced CAEs. An interdisciplinary management of CAEs incorporated into routine care may reduce the rate of drug discontinuation thus potentially contributing to better long-term outcomes. [ABSTRACT FROM AUTHOR]

Objective: This study investigates the effects of ZNF862 on the proliferation and apoptosis of human gingival fibroblasts and their related mechanisms. Background: As a major transcription factor family, zinc finger proteins (ZFPs) regulate cell differentiation, growth, and apoptosis through their conserved zinc finger motifs, which allow high flexibility and specificity in gene regulation. In our previous study, ZNF862 mutation was associated with hereditary gingival fibromatosis. Nevertheless, little is known about the biological function of ZNF862. Therefore, this study was aimed to reveal intracellular localization of ZNF862, the influence of ZNF862 on the growth and apoptosis of human gingival fibroblasts (HGFs) and its potential related mechanisms. Methods: Immunohistochemistry, immunofluorescence staining, and western blotting were performed to determine the intracellular localization of ZNF862 in HGFs. HGFs were divided into three groups: ZNF862 overexpression group, ZNF862 interference group, and the empty vector control group. Then, the effects of ZNF862 on cell proliferation, migration, cell cycle, and apoptosis were evaluated. qRT‐PCR and western blotting were performed to further explore the mechanism related to the proliferation and apoptosis of HGFs. Results: ZNF862 was found to be localized in the cytoplasm of HGFs. In vitro experiments revealed that ZNF862 overexpression inhibited HGFs proliferation and migration, induced cell cycle arrest at the G0/G1‐phase and apoptosis. Whereas, ZNF862 knockdown promoted HGFs proliferation and migration, accelerated the transition from the G0/G1 phase into the S and G2/M phase and inhibited cell apoptosis. Mechanistically, the effects of ZNF862 on HGFs proliferation and apoptosis were noted to be dependent on inhibiting the cyclin‐dependent kinase inhibitor 1A (p21)‐retinoblastoma 1 (RB1) signaling pathway and enhancing the B‐cell lymphoma‐extra‐large (Bcl‐xL)‐Caspase 3 signaling pathway. Conclusion: Our results for the first time reveal that ZNF862 is localized in the cytoplasm of HGFs. ZNF862 can inhibit the proliferation of HGFs by inhibiting the p21‐RB1 signaling pathway, and it also promotes the apoptosis of HGFs by enhancing the Bcl‐xL‐Caspase 3 signaling pathway. [ABSTRACT FROM AUTHOR]

Cyclin-dependent kinases (CDKs) are key mediators of cell proliferation and have been a subject of oncology drug discovery efforts for over two decades. Several CDK and activator cyclin family members have been implicated in regulating the cell division cycle. While it is thought that there are canonical CDK-cyclin pairing preferences, the extent of selectivity is unclear, and increasing evidence suggests that the cell-cycle CDKs can be activated by a pool of available cyclins. The molecular details of CDK-cyclin specificity are not completely understood despite their importance for understanding cancer cell cycles and for pharmacological inhibition of cancer proliferation. We report here a biolayer interferometry assay that allows for facile quantification of CDK binding interactions with their cyclin activators. We applied this assay to measure the impact of Cdk2 inhibitors on Cyclin A (CycA) association and dissociation kinetics. We found that Type I inhibitors increase the affinity between Cdk2 and CycA by virtue of a slowed cyclin dissociation rate. In contrast, Type II inhibitors and other small-molecule Cdk2 binders have distinct effects on the CycA association and dissociation processes to decrease affinity. We propose that the differential impact of small molecules on the cyclin binding kinetics arises from the plasticity of the Cdk2 active site as the kinase transitions between active, intermediate, and inactive states.

Background: RNA modifications of transfer RNAs (tRNAs) are critical for tRNA function. Growing evidence has revealed that tRNA modifications are related to various disease processes, including malignant tumors. However, the biological functions of methyltransferase-like 1 (METTL1)-regulated m7G tRNA modifications in breast cancer (BC) remain largely obscure. Methods: The biological role of METTL1 in BC progression were examined by cellular loss- and gain-of-function tests and xenograft models both in vitro and in vivo. To investigate the change of m7G tRNA modification and mRNA translation efficiency in BC, m7G-methylated tRNA immunoprecipitation sequencing (m7G tRNA MeRIP-seq), Ribosome profiling sequencing (Ribo-seq), and polysome-associated mRNA sequencing were performed. Rescue assays were conducted to decipher the underlying molecular mechanisms. Results: The tRNA m7G methyltransferase complex components METTL1 and WD repeat domain 4 (WDR4) were down-regulated in BC tissues at both the mRNA and protein levels. Functionally, METTL1 inhibited BC cell proliferation, and cell cycle progression, relying on its enzymatic activity. Mechanistically, METTL1 increased m7G levels of 19 tRNAs to modulate the translation of growth arrest and DNA damage 45 alpha (GADD45A) and retinoblastoma protein 1 (RB1) in a codon-dependent manner associated with m7G. Furthermore, in vivo experiments showed that overexpression of METTL1 enhanced the anti-tumor effectiveness of abemaciclib, a cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitor. Conclusion: Our study uncovered the crucial tumor-suppressive role of METTL1-mediated tRNA m7G modification in BC by promoting the translation of GADD45A and RB1 mRNAs, selectively blocking the G2/M phase of the cell cycle. These findings also provided a promising strategy for improving the therapeutic benefits of CDK4/6 inhibitors in the treatment of BC patients. [ABSTRACT FROM AUTHOR]

Background: Mucosal melanoma (MM) is a rare but devastating subtype of melanoma. Our previous studies have demonstrated robust anti-tumor effects of cyclin-dependent kinase 4/6 (CDK 4/6) inhibitors in head and neck MM (HNMM) patient-derived xenograft models with CDK4 amplification. Herein, we aimed to investigate the efficacy and safety of dalpiciclib (SHR6390), a CDK4/6 inhibitor, in HNMM patients harboring CDK4 amplification. Methods: The anti-tumor efficacy of dalpiciclib was assessed by HNMM patient-derived xenograft (PDX) models and patient-derived tumor cells (PDC) in vivo and in vitro. Immunohistochemical analyses and western blot were then performed to assess the markers of cell proliferation and CDK4/6 signaling pathway. For the clinical trial, advanced recurrent and/or metastatic HNMM patients with CDK4 amplification were treated with dalpiciclib 125 mg once daily for 21 consecutive days in 28-day cycles. The primary endpoint was disease control rate (DCR). Secondary endpoints included safety, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Results: Dalpiciclib profoundly suppressed growth of HNMM-PDX and PDC with CDK4 amplification, whereas it showed relatively weak suppression in those with CDK4 wild type compared with vehicle. And dalpiciclib resulted in a remarkable reduction in the expression levels of Ki-67 and phosphorylated Rb compared with control group. In the clinical trial, a total of 17 patients were enrolled, and 16 patients were evaluable. The ORR was 6.3%, and the DCR was 81.3%. The estimated median PFS was 9.9 months (95% CI, 4.8-NA), and the median OS was not reached. The rate of OS at 12 months and 24 months was 68.8% (95% CI, 0.494–0.957) and 51.6% (95% CI, 0.307–0.866), respectively. The most frequent adverse events were neutrophil count decrease, white blood cell count decrease, and fatigue. Conclusions: Dalpiciclib was well-tolerated and displayed a durable benefit for HNMM patients with CDK4 amplification in this study. Further studies on CDK4 inhibitors and its combination strategy for MM are worth further exploration. Trial registration: ChiCTR2000031608. [ABSTRACT FROM AUTHOR]

Mucosal melanoma (MM) is a rare and aggressive form of melanoma with a poorer prognosis compared to other subtypes. Recent large-scale next-generation sequencing studies, including our own research, have demonstrated that the molecular characteristics and potential oncogenic drivers of MM differ significantly from those of cutaneous melanoma. The emergence of selective CDK4/6 inhibitors, already approved for use in breast cancer and undergoing phase III clinical trials for other solid tumors, represents a promising development in the treatment of MM. Recent studies have shown that CDK4/6 inhibitors not only induce cell cycle arrest but also play a crucial role in facilitating the interaction between tumor cells and the host immune system. Moreover, our findings indicate that dysregulation of cell cycle progression due to cyclin‐dependent kinase 4 (CDK4) amplification is a significant genetic characteristic in a substantial portion of MM cases. Targeting CDK4 in specific MM patients shows promise for precision cancer therapy, utilizing molecularly characterized MM patient-derived xenograft (PDX) models and clinical trials. This paper provides an overview of existing literature on CDK4/6 dysregulation in MM, as well as preclinical and clinical investigations on CDK4/6 inhibitors and potential combination therapies for MM treatment. [ABSTRACT FROM AUTHOR]

Precision cancer medicine has changed the treatment paradigm of patients with non-small cell lung cancer (NSCLC) with specific molecular aberrations. A major challenge is management of the resistance that tumor cells eventually develop against targeted therapies, either through primary or acquired resistance mechanisms. We report a 61 year-old male patient with metastatic NSCLC harboring an EGFR exon 19 deletion, a PIK3CA mutation, and CDK4 amplification. After an initial partial response to osimertinib as mono-therapy (third-generation EGFR tyrosine kinase inhibitor), the patient had progression of disease after 4 months of treatment and was referred for combined osimertinib and palbociclib (CDK4/6 inhibitor) treatment. Though complicated by transient pneumonitis, the patient has an ongoing partial response for > 10 months and has experienced clinical improvement on this treatment regimen. As amplification of CDK4 occurs in ~ 10% of treatment-naïve patients with EGFR-mutated NSCLC, the successful treatment of our patient with osimertinib and palbociclib may be highly relevant for future patients with NSCLC. [ABSTRACT FROM AUTHOR]

Background: The CDK 4/6 inhibitors, including palbociclib and ribociclib, are the standard first-line treatment for hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer. Proton pump inhibitors are one of the most globally prescribed types of medications as part of the treatment for gastroesophageal reflux and heartburn complaints. Medication interactions have been demonstrated, leading to a decrease in the effectiveness of chemotherapy drugs such as capecitabine and pazopanib. However, their role and interaction with targeted therapies such as CDK inhibitors are still poorly understood. Methods: We searched PubMed, Embase and Web of Science databases for studies that investigated the use of PPI with CDK 4/6 inhibitors versus CDK4/ 6 alone for advanced or metastatic breast cancer. We systematically searched for the currently available CDK inhibitors: palbociclib, ribociclib and abemaciclib. We computed hazard ratios (HRs), with 95% confidence intervals (CIs). We used DerSimonian and Laird random-effect models for all endpoints. Heterogeneity was assessed using I² statistics. R, version 4.2.3, was used for statistical analyses. Results: A total of 2,737 patients with advanced breast cancer in 9 studies were included, with six studies described the status menopausal as 217 (7.9%) pre-menopause and 1851 (67.6%) post-menopause, for endocrine sensitivity only five studies described1489 (54.4%) patients were endocrine-sensitive and 498 (182%) endocrine-resistent, 910 (33.2%) patients used PPIs. The overall Progression-Free Survival was in favor of the PPI non-users (HR 2.0901; 95% CI 1.410-2.9498; p < 0.001). As well as the subgroup taking palbociclib, revealing statistical relevance for the PPI non-users (HR 2.2539; 95% CI 1.3213-3.8446; p = 0.003) and ribociclib subgroup with a slight decrease in hazard ratio (HR 1.74 95% CI 1.02-2.97; p = 0.04; I² = 40%). In the multivariate analysis, there was no statistical signifance with ECOG (HR 0.9081; 95% CI 0.4978-16566; p 0.753) and Age (HR 1.2772; 95% CI 0.8790-1.8559; p = 0.199). Either, the univariate analysis did not show statistical significance. Conclusion: Women with HR+ and HER2-advanced metastatic breast undergoing treatment with targeted therapies, specifically CDK 4/6 inhibitors, should be monitored for the use of proton pump inhibitors. Therefore, the use of PPIs should be discussed, weighing the advantages and disadvantages for specific cases. It should be individualized based on the necessity in clinical practice for these cases. Systematic Review Registration: identifier CRD42023484755 [ABSTRACT FROM AUTHOR]

Dysregulation of cyclin-dependent kinase 8 (CDK8) activity has been associated with many diseases, including colorectal and breast cancer. As usual in the CDK family, the activity of CDK8 is controlled by a regulatory protein called cyclin C (CycC). But, while human CDK family members are generally activated in two steps, that is, the binding of the cyclin to CDK and the phosphorylation of a residue in the CDK activation loop, CDK8 does not require the phosphorylation step to be active. Another peculiarity of CDK8 is its ability to be associated with CycC while adopting an inactive form. These specificities raise the question of the role of CycC in the complex CDK8–CycC, which appears to be more complex than the other members of the CDK family. Through molecular dynamics (MD) simulations and binding free energy calculations, we investigated the effect of CycC on the structure and dynamics of CDK8. In a second step, we particularly focused our investigation on the structural and molecular basis of the protein–protein interaction between the two partners by finely analyzing the energetic contribution of residues and simulating the transition between the active and the inactive form. We found that CycC has a stabilizing effect on CDK8, and we identified specific interaction hotspots within its interaction surface compared to other human CDK/Cyc pairs. Targeting these specific interaction hotspots could be a promising approach in terms of specificity to effectively disrupt the interaction between CDK8. The simulation of the conformational transition from the inactive to the active form of CDK8 suggests that the residue Glu99 of CycC is involved in the orientation of three conserved arginines of CDK8. Thus, this residue may assume the role of the missing phosphorylation step in the activation mechanism of CDK8. In a more general view, these results point to the importance of keeping the CycC in computational studies when studying the human CDK8 protein in both the active and the inactive form. [ABSTRACT FROM AUTHOR]

Mediator kinases CDK19 and CDK8, pleiotropic regulators of transcriptional reprogramming, are differentially regulated by androgen signaling, but both kinases are upregulated in castration-resistant prostate cancer (CRPC). Genetic or pharmacological inhibition of CDK8 and CDK19 reverses the castration-resistant phenotype and restores the sensitivity of CRPC xenografts to androgen deprivation in vivo. Prolonged CDK8/19 inhibitor treatment combined with castration not only suppressed the growth of CRPC xenografts but also induced tumor regression and cures. Transcriptomic analysis revealed that Mediator kinase inhibition amplified and modulated the effects of castration on gene expression, disrupting CRPC adaptation to androgen deprivation. Mediator kinase inactivation in tumor cells also affected stromal gene expression, indicating that Mediator kinase activity in CRPC molded the tumor microenvironment. The combination of castration and Mediator kinase inhibition downregulated the MYC pathway, and Mediator kinase inhibition suppressed a MYC-driven CRPC tumor model even without castration. CDK8/19 inhibitors showed efficacy in patient-derived xenograft models of CRPC, and a gene signature of Mediator kinase activity correlated with tumor progression and overall survival in clinical samples of metastatic CRPC. These results indicate that Mediator kinases mediated androgen-independent in vivo growth of CRPC, supporting the development of CDK8/19 inhibitors for the treatment of this presently incurable disease. [ABSTRACT FROM AUTHOR]

With increasingly used assisted reproductive technology (ART), the acquisition of high-quality oocytes and early embryos has become the focus of much attention. Studies in mice have found that the transition of chromatin conformation from non-surrounded nucleolus (NSN) to surrounded nucleolus (SN) is essential for oocyte maturation and early embryo development, and similar chromatin transition also exists in human oocytes. In this study, we collected human NSN and SN oocytes and investigated their transcriptome. The analysis of differentially expressed genes showed that epigenetic functions, cyclin-dependent kinases and transposable elements may play important roles in chromatin transition during human oocyte maturation. Our findings provide new insights into the molecular mechanism of NSN-to-SN transition of human oocyte and obtained new clues for improvement of oocyte in vitro maturation technique. [ABSTRACT FROM AUTHOR]

Efficient milk production in mammals confers evolutionary advantages by facilitating the transmission of energy from mother to offspring. However, the regulatory mechanism responsible for the gradual establishment of milk production efficiency in mammals, from marsupials to eutherians, remains elusive. Here, we find that mammary gland of the marsupial sugar glider contained milk components during adolescence, and that mammary gland development is less dynamically cyclic compared to that in placental mammals. Furthermore, fused in sarcoma (FUS) is found to be partially responsible for this establishment of low efficiency. In mouse model, FUS inhibit mammary epithelial cell differentiation through the cyclin-dependent kinase inhibitor p57Kip2, leading to lactation failure and pup starvation. Clinically, FUS levels are negatively correlated with milk production in lactating women. Overall, our results shed light on FUS as a negative regulator of milk production, providing a potential mechanism for the establishment of milk production from marsupial to eutherian mammals. Efficient milk production in mammals confers advantages by facilitating the transmission of energy from mother to offspring. However, the factors for establishing the efficiency in mammals are unknown. Here, the authors identify FUS as a regulator of efficient milk production in mammals. [ABSTRACT FROM AUTHOR]

Background: In prostate cancer (PCa), well-established biomarkers such as MSI status, TMB high, and PDL1 expression serve as reliable indicators for favorable responses to immunotherapy. Recent studies have suggested a potential association between CDK12 mutations and immunotherapy response; however, the precise mechanisms through which CDK12 mutation may influence immune response remain unclear. A plausible explanation for immune evasion in this subset of CDK12-mutated PCa may be reduced MHC expression. Results: Using genomic data of CDK12-mutated PCa from 48 primary and 10 metastatic public domain samples and a retrospective cohort of 53 low-intermediate risk primary PCa, we investigated how variation in the expression of the MHC genes affected associated downstream pathways. We classified the patients based on gene expression quartiles of MHC-related genes and categorized the tumors into "High" and "Low" expression levels. CDK12-mutated tumors with higher MHC-expressed pathways were associated with the immune system and elevated PD-L1, IDO1, and TIM3 expression. Consistent with an inflamed tumor microenvironment (TME) phenotype, digital cytometric analyses identified increased CD8 + T cells, B cells, γδ T cells, and M1 Macrophages in this group. In contrast, CDK12-mutated tumors with lower MHC expression exhibited features consistent with an immune cold TME phenotype and immunoediting. Significantly, low MHC expression was also associated with chromosome 6 loss of heterozygosity (LOH) affecting the entire HLA gene cluster. These LOH events were observed in both major clonal and minor subclonal populations of tumor cells. In our retrospective study of 53 primary PCa cases from this Institute, we found a 4% (2/53) prevalence of CDK12 mutations, with the confirmation of this defect in one tumor through Sanger sequencing. In keeping with our analysis of public domain data this tumor exhibited low MHC expression at the RNA level. More extensive studies will be required to determine whether reduced HLA expression is generally associated with primary tumors or is a specific feature of CDK12 mutated PCa. Conclusions: These data show that analysis of CDK12 alteration, in the context of MHC expression levels, and LOH status may offer improved predictive value for outcomes in this potentially actionable genomic subgroup of PCa. In addition, these findings highlight the need to explore novel therapeutic strategies to enhance MHC expression in CDK12-defective PCa to improve immunotherapy responses. [ABSTRACT FROM AUTHOR]

Introduction: Alpelisib is approved in combination with endocrine therapy (ET) to treat patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2−) progressive metastatic breast cancer (MBC). The SOLAR-1 trial demonstrated the efficacy of this oral agent and showed that, while alpelisib improves outcomes compared to placebo, it is also associated with clinically relevant adverse events (AEs). There is a pressing need for improved knowledge on the effectiveness and tolerability of this agent in real-world patient populations. Methods: We conducted a retrospective cohort study of patients with HR+, HER2− MBC treated with alpelisib and ET. We assessed the safety, tolerability, and effectiveness of alpelisib in a real-world population. Deidentified patient-, tumor-, and outcome-related data, including AEs, were collected and summarized. Kaplan-Meier methods were applied for survival analyses, and stratified analyses of interest were conducted. A p value <0.05 was considered statistically significant. Results: A total of 76 women treated with alpelisib + ET were included in our cohort. Most had been previously treated with cyclin-dependent kinase (CDK) 4/6 inhibitors and chemotherapy for MBC. The estimated median progression-free survival was 5.2 months (95% CI, 4.1–8.0). The median overall survival was longer among patients without prior everolimus therapy (hazard ratio, 4.28 [95% CI, 1.64–11.16]; p = 0.0012), and no significant outcome differences were observed between patients treated with different starting doses of alpelisib. Approximately 31.6% of patients permanently discontinued alpelisib due to AEs, and 32.9% had at least one dose reduction. The most common grade 3/4 AEs were hyperglycemia (21%), fatigue (13.2%), and diarrhea (10.5%). Conclusions: For progressive HR+, HER2− MBC, alpelisib + ET showed effectiveness in a real-world patient population that was comparable to published clinical trial data, regardless of starting dose. However, the effectiveness of alpelisib following previous everolimus exposure may be limited and, hence, should be a consideration to decide sequencing of therapy in these patients. Patients treated with alpelisib are at risk for clinically relevant AEs and require close monitoring. [ABSTRACT FROM AUTHOR]