Tetraspanins in digestive­system cancers: Expression, function and therapeutic potential (Review).

The tetraspanin family of membrane proteins is essential for controlling different biological processes such as cell migration, penetration, adhesion, growth, apoptosis, angiogenesis and metastasis. The present review summarized the current knowledge regarding the expression and roles of tetraspanins in different types of cancer of the digestive system, including gastric, liver, colorectal, pancreatic, esophageal and oral cancer. Depending on the type and context of cancer, tetraspanins can act as either tumor promoters or suppressors. In the present review, the importance of tetraspanins in serving as biomarkers and targets for different types of digestive system­related cancer was emphasized. Additionally, the molecular mechanisms underlying the involvement of tetraspanins in cancer progression and metastasis were explored. Furthermore, the current challenges are addressed and future research directions for advancing investigations related to tetraspanins in the context of digestive system malignancies are proposed.

circRACGAP1 Promotes Proliferation of Non-Small Cell Lung Cancer Cells through the miR-1296/CDK2 Pathway.

Circular RNAs (circRNAs) have played an essential role in cancer development. This study aimed to illustrate the impact and potential mechanism of circRACGAP1 action in NSCLC development. The expression patterns of circRACGAP1, miR-1296, and CDK2 in NSCLC tissues and cell lines were analysed by RT-qPCR. The function of circRACGAP1 in NSCLC cell proliferation and apoptosis was investigated using the CCK-8 assay, flow cytometry, TUNEL staining, and Western blot. The interaction among circRACGAP1, miR-1296, and CDK2 was clarified by dual-luciferase reporter assay while the correlation was confirmed by the Pearson correlation coefficient. The expression of circRACGAP1 and CDK2 was up-regulated in NSCLC tissues, while the expression of miR-1296 was down-regulated. Cell function studies further revealed that circRACGAP1 could promote NSCLC cell proliferation, accelerate the cell cycle process, up-regulate B-cell lymphoma 2 (Bcl2) expression, and down-regulate Bcl2-associated X (Bax) expression. miR-1296 was identified as a downstream target to reverse circRACGAP1-mediated cell proliferation. miR-1296 directly targeted the 3'-UTR of CDK2 to regulate proliferation and apoptosis of NSCLC cells. Additionally, the dual-luciferase reporter assay and Pearson correlation coefficient analysis proved that circRACGAP1 acted in NSCLC cells by negatively regulating miR-1296 expression and positively regulating CDK2 expression. In summary, our study revealed that circRACGAP1 promoted NSCLC cell proliferation by regulating the miR-1296/CDK2 pathway, providing potential diagnostic and therapeutic targets for NSCLC.

Dalpiciclib in combination with letrozole/anastrozole or fulvestrant in HR-positive and HER2-negative advanced breast cancer: results from a phase Ib study.

Background: Dalpiciclib is a novel cyclin-dependent kinase 4/6 inhibitor which showed tolerability and preliminary efficacy as monotherapy for pretreated advanced breast cancer (BC). Objectives: To further assess dalpiciclib with endocrine therapy (ET) in hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative BC. Design: A multicenter, open-label, phase Ib trial. Methods: Patients with locally recurrent or metastatic BC were enrolled in five cohorts. Patients without prior treatment for advanced disease (cohorts 1-2) were given dalpiciclib (125 or 150 mg) plus letrozole/anastrozole; patients who progressed after ET (cohorts 3-5) were given dalpiciclib (125, 150, or 175 mg) plus fulvestrant. Dalpiciclib was administered orally once daily in 3-weeks-on/1-week off schedule. The primary endpoint was safety. Results: A total of 58 patients received dalpiciclib with letrozole/anastrozole and 46 received dalpiciclib with fulvestrant. No maximum tolerated dose of dalpiciclib was reached with letrozole/anastrozole or fulvestrant. Across all cohorts, 86.7%-93.8% of patients had a grade ⩾3 adverse event, with the most common being neutropenia (grade 3, 40.0% for dalpiciclib 175 mg and 61.8%-87.5% for lower doses; grade 4, 46.7% and 4.2%-20.6%, respectively) and leukopenia (grade 3, 80.0% for 175 mg and 33.3%-54.2% for lower doses; grade 4, 0% for all doses). At tested dose levels, steady-state areas under the concentration curve and peak concentration of dalpiciclib increased with dose when combined with letrozole/anastrozole and fulvestrant. Dalpiciclib at 150 mg was associated with a numerically higher objective response rate in both patients untreated for advanced disease (67.6%; 95% confidence interval (CI) 49.5-82.6) and patients progressing after ET (53.3%; 95% CI 26.6-78.7); as of July 30, 2022, the median progression-free survival with dalpiciclib 150 mg was 24.1 months (95% CI 16.9-46.0) with letrozole/anastrozole and 16.7 months (95% CI 1.9-24.1) with fulvestrant. Conclusion: Dalpiciclib plus letrozole/anastrozole or fulvestrant showed an acceptable safety profile. The recommended phase III dose of dalpiciclib was 150 mg. Trial registration: ClinicalTrials.gov identifier: NCT03481998.

Palbociclib: Randomized Studies and Real-world Evidence as the Basis for Therapeutic Planning in Metastatic Breast Cancer.

Endocrine-based combination therapy with an inhibitor of the cyclin-dependent kinases 4 and 6 (CDK4/6 inhibitors) is currently the first-line therapy of choice for patients with hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-), locally advanced or metastatic breast cancer (mBC). The efficacy and safety of the treatment with palbociclib, the first CDK4/6 inhibitor approved for this indication, have been confirmed in large randomized controlled clinical trials (RCTs) with strictly defined patient cohorts. Since then, many relevant questions about CDK4/6 inhibition with palbociclib for mBC have been investigated in RCTs and real-world studies. Based on this evidence, palbociclib is widely used in clinical practice since many years because of its efficacy and good tolerability. The aim of this review is to summarize findings from RCTs and RWE considering clinically relevant aspects such as safety, tolerability, quality of life and efficacy with a focus on specific questions and patient characteristics. A critical discussion and review of the overall evidence for endocrine-based therapy with the CDK4/6 inhibitor palbociclib can contribute to support therapy decisions in daily clinical practice.

FBXO45 Knockdown Restrains the Progression of Bladder Cancer via the ERK/Cyclin D1/CDK4 Pathway.

BACKGROUNDS: F-box protein 45 (FBXO45) has been implicated in the progression of several diseases. Whether FBXO45 is involved in the development of bladder cancer remains unclear. Thus, this study focused on the effect of FBXO45 on the malignant progression of bladder cancer cells. METHODS: FBXO45 small-interference fragment was transfected into RT4 and 5637 cells by liposome-mediated transfection, and the knockdown efficiency of FBXO45 was verified by Western blot assay. The growth rate between FBXO45 knockdown cell lines and control cell lines was compared by counting kit 8 and plate cloning experiments. The motility of bladder cancer cells was observed via the Transwell test and Wound healing test. The effects of FBXO45 silencing on apoptosis and cell division were confirmed by flow cytometry. Western blot assay was performed to determine the function of FBXO45 knockdown on key proteins of cell apoptosis and the ERK/Cyclin D1/CDK4 pathway. RESULTS: After FBXO45 knockdown, the proliferation of bladder cancer cells was blocked (p < 0.01), and the migration and invasion abilities were reduced (p < 0.01). FBXO45 knockdown reduced the number of S-phase cells (RT4, p < 0.01; 5637, p < 0.05) and enhanced the apoptotic rate (p < 0.01). FBXO45 knockdown decreased the levels of p-ERK1/2, CDK4 and Cyclin D1 (p < 0.01). CONCLUSIONS: This study revealed that FBXO45 plays a carcinogenic role in bladder cancer via the ERK/Cyclin D1/CDK4 pathway, which provides a reference for the clinical treatment of patients with bladder cancer.

Pirfenidone inhibits CCL2-mediated Treg chemotaxis induced by palbociclib and fulvestrant in HR+/HER2- breast cancer.

In human epidermal growth factor receptor 2-negative (HR+/HER2-) breast cancer, the most prevalent subtype, the pathological complete response (pCR) rate after neoadjuvant chemotherapy is less than 18 %, and the survival of patients with advanced-stage disease is approximately 34 %, highlighting the critical demand for more potent therapies. Recent research has underscored the substantial therapeutic benefits of the combination of CDK4/6 inhibitors and fulvestrant (Ful) in managing HR+/HER2- breast cancer. These therapeutics not only curtail tumor proliferation but also alter the tumor immune microenvironment, suggesting novel avenues for immunotherapy for this breast cancer subtype. Flow cytometry, PCR, WB, and RNA-seq experiments revealed that the combination of the CDK4/6 inhibitor palbociclib (Pal) with Ful upregulated CCL2 in tumor cells by inducing the SASP and activating the MAPK signaling pathway. CCL2 attracts Tregs to the tumor microenvironment, where it exerts an immunosuppressive effect. By administering the CCL2 inhibitor pirfenidone, we inhibited these effects and enhanced the antitumor efficacy of Pal + Ful. Our research revealed an immunosuppressive effect of CDK4/6 inhibitors and fulvestrant and suggested that CCL2 inhibitors may be a viable approach for treating patients with advanced HR+/HER2- breast cancer.

Morpho-histological and Transcriptome Analysis Reveal the Unreduced Sperm Formation Mechanism in cdk1-Depletion Zebrafish.

Cyclin-dependent kinases (Cdks) are major molecules related to cell cycle regulation. Polyploidy can be caused by the production of unreduced gametes, which is often related to the abnormal cell cycle of germ cells. Here, we successfully constructed a cdk1 mutation line (cdk1+/-) in zebrafish, a commonly used model organism. It showed that cdk1 depletion resulted in the generation of both polyploid and aneuploid embryos of WT♀ × cdk1+/-♂ zebrafish. In addition to normal sperms (1N), the depletion of cdk1 in zebrafish also led to the production of some large-head 2N sperms and higher ploidy sperms. Results of bivalent analysis of testis and ultrastructure analysis of spermatogonia suggested that the production of these large-head sperms was due to spermatogonia chromosome doubling in cdk1+/- zebrafish. Transcriptome analysis revealed aberrant expressions of some cell cycle and DNA replication-related genes in the early testis of cdk1+/- zebrafish relative to WT zebrafish. Through STRING correlation analysis, we further proved that cdk1 depletion affected the mitosis process and endoduplication initiation of spermatogonia by regulating expressions of some proteins related to cell cycle (i.e., Espl1 and Pp1) and DNA replication (i.e., Orc1 and Rnaseh2b), thereby leading to the formation of unreduced sperms. This study provides important information on revealing the molecular mechanisms of unreduced gamete formation caused by cdk1 mutation. Meanwhile, it also provides an important reference for the creation of fish polyploid germplasm.

Combined inhibition of CDK4/6 and AKT is highly effective against the luminal androgen receptor (LAR) subtype of triple negative breast cancer.

Luminal Androgen Receptor (LAR) triple-negative breast cancers (TNBC) express androgen receptors (AR), exhibit high frequency of PIK3CA mutations and intact RB. Herein, we investigated combined blockade of the CDK4/6 and PI3K signaling with palbociclib, alpelisib, and capivasertib, which inhibit CDK4/6, PI3Kα, and AKT1-3, respectively. The combination of palbociclib/capivasertib, but not palbociclib/alpelisib, synergistically inhibited proliferation of MDA-MB-453 and MFM-223 LAR cells [synergy score 7.34 (p=5.81x10-11) and 4.78 (p=0.012), respectively]. The AR antagonist enzalutamide was inactive against MDA-MB-453, MFM-223, and CAL148 cells and did not enhance the efficacy of either combination. Palbociclib/capivasertib inhibited growth of LAR patient-derived xenografts more potently than palbociclib/alpelisib. Treatment of LAR cells with palbociclib suppressed phosphorylated-RB and resulted in adaptive phosphorylation/activation of S473 pAKT and AKT substrates GSK3ß, PRAS40, and FoxO3a. Capivasertib blocked palbociclib-induced phosphorylation of AKT substrates more potently than alpelisib. Treatment with PI3Kß inhibitors did not block phosphorylation of AKT substrates, suggesting that PI3Kß did not mediate the adaptive response to CDK4/6 inhibition. Phosphokinase arrays of MDA-MB-453 cells treated with palbociclib showed time-dependent upregulation of PDGFRß, GSK3ß, STAT3, and STAT6. RNA silencing of PDGFRß in palbociclib-treated MDA-MB-453 and MFM-223 cells blocked the upregulation of S473 pAKT, suggesting that the adaptive response to CDK4/6 blockade involves PDGFRß signaling. Finally, treatment with palbociclib and the PDGFR inhibitor CP637451 arrested growth of MDA-MB-453 and MFM-223 cells to the same degree as palbociclib/capivasertib. These findings support testing the combination of CDK4/6 and AKT inhibitors in patients with LAR TNBC, and further investigation of PDGFR antagonists in this breast cancer subtype.

Olaparib combined with CDK12-IN-3 to promote genomic instability and cell death in ovarian cancer.

Large-scale phase III clinical trials of Olaparib have revealed benefits for ovarian cancer patients with BRCA gene mutations or homologous recombination deficiency (HRD). However, fewer than 50% of ovarian cancer patients have both BRCA mutations and HRD. Therefore, improving the effect of Olaparib in HR-proficient patients is of great clinical value. Here, a combination strategy comprising Olaparib and CDK12-IN-3 effectively inhibited the growth of HR-proficient ovarian cancer in cell line, patient-derived organoid (PDO), and mouse xenograft models. Furthermore, the combination strategy induced severe DNA double-strand break (DSB) formation, increased NHEJ activity in the G2 phase, and reduced HR activity in cancer cells. Mechanistically, the combination treatment impaired Ku80 poly(ADP-ribosyl)ation (PARylation) and phosphorylation, resulting in PARP1-Ku80 complex dissociation. After dissociation, Ku80 occupancy at DSBs and the resulting Ku80-primed NHEJ activity were increased. Owing to Ku80-mediated DNA end protection, MRE11 and Rad51 foci formation was inhibited after the combination treatment, suggesting that this treatment suppressed HR activity. Intriguingly, the combination strategy expedited cGAS nuclear relocalization, further suppressing HR and, conversely, increasing genomic instability. Moreover, the inhibitory effect on cell survival persisted after drug withdrawal. These findings provide a rationale for the clinical application of CDK12-IN-3 in combination with Olaparib.

MOF-mediated acetylation of CDK9 promotes global transcription by modulating P-TEFb complex formation.

Cyclin-dependent kinase 9 (CDK9), a catalytic subunit of the positive transcription elongation factor b (P-TEFb) complex, is a global transcriptional elongation factor associated with cell proliferation. CDK9 activity is regulated by certain histone acetyltransferases, such as p300, GCN5 and P/CAF. However, the impact of males absent on the first (MOF) (also known as KAT8 or MYST1) on CDK9 activity has not been reported. Therefore, the present study aimed to elucidate the regulatory role of MOF on CDK9. We present evidence from systematic biochemical assays and molecular biology approaches arguing that MOF interacts with and acetylates CDK9 at the lysine 35 (i.e. K35) site, and that this acetyl-group can be removed by histone deacetylase HDAC1. Notably, MOF-mediated acetylation of CDK9 at K35 promotes the formation of the P-TEFb complex through stabilizing CDK9 protein and enhancing its association with cyclin T1, which further increases RNA polymerase II serine 2 residues levels and global transcription. Our study reveals for the first time that MOF promotes global transcription by acetylating CDK9, providing a new strategy for exploring the comprehensive mechanism of the MOF-CDK9 axis in cellular processes.

Molecular insights into kaempferol derivatives as potential inhibitors for CDK2 in colon cancer: pharmacophore modeling, docking, and dynamic analysis.

Cyclin-dependent kinase 2 (CDK2) has been recognized as one of the crucial factors in cell cycle regulation and has been proposed as a potential target for cancer therapies, particularly for colorectal cancer (CRC). Due to the increased incidence rate of CRC and challenges associated with existing treatment options, there is a need for efficient and selective anti-cancer compounds. The current work aims to explore the ability of novel kaempferol derivatives as CDK2 inhibitors by performing conceptual pharmacophore modeling, molecular docking, and molecular dynamic analysis. Kaempferol and its derivatives were obtained from PubChem, and the optimized 3D structures of the compounds were generated using Maestro Ligprep. Subsequently, a pharmacophore model was developed to identify compounds with high fitness values, resulting in the selection of several kaempferol derivatives for further study. We evaluated the ADMET properties of these compounds to assess their therapeutic potential. Molecular docking was conducted using Maestro and BIOVIA Discovery Studio version 4.0 to predict the binding affinities of the compounds to CDK2. The top candidates were subjected to MM-GBSA analysis to predict their binding free energies. Molecular dynamics simulations using GROMACS were performed to assess the thermodynamic stability of the ligand-protein complexes. The results revealed several kaempferol derivatives with high predicted binding affinities to CDK2 and favorable ADMET properties. Specifically, compounds 5281642, 5318980, and 14427423 demonstrated binding free energies of -30.26, -38.66, and -34.2 kcal/mol, respectively. Molecular dynamics simulations indicated that these ligand-protein complexes remained stable throughout the simulation period, with RMSD values remaining below 2 Å. In conclusion, the identified kaempferol derivatives show potential as CDK2 inhibitors based on computational predictions and demonstrate stability in molecular dynamics simulations, suggesting their future application in CRC treatment by targeting CDK2. These computational findings encourage further experimental validation and development of kaempferol derivatives as anti-cancer agents.

Unraveling the CDK9/PP2A/ERK Network in Transcriptional Pause Release and Complement Activation in KRAS-mutant Cancers.

Selective inhibition of the transcription elongation factor (P-TEFb) complex represents a promising approach in cancer therapy, yet CDK9 inhibitors (CDK9i) are currently limited primarily to certain hematological malignancies. Herein, while initial responses to CDK9-targeted therapies are observed in vitro across various KRAS-mutant cancer types, their efficacy is far from satisfactory in nude mouse xenograft models. Mechanistically, CDK9 inhibition leads to compensatory activation of ERK-MYC signaling, accompanied by the recovery of proto-oncogenes, upregulation of immediate early genes (IEGs), stimulation of the complement C1r-C3-C3a cascade, and induction of tumor immunosuppression. The "paradoxical" regulation of PP2Ac activity involving the CDK9/Src interplay contributes to ERK phosphorylation and pause-release of RNA polymerase II (Pol II). Co-targeting of CDK9 and KRAS/MAPK signaling pathways eliminates ERK-MYC activation and prevents feedback activation mediated by receptor tyrosine kinases, leading to more effective control of KRAS-mutant cancers and overcoming KRASi resistance. Moreover, modulating the tumor microenvironment (TME) by complement system intervention enhances the response to CDK9i and potently suppresses tumor growth. Overall, the preclinical investigations establish a robust framework for conducting clinical trials employing KRASi/SOS1i/MEKi or immunomodifiers in combination with CDK9i to simultaneously target cancer cells and their crosstalk with the TME, thereby yielding improved responses in KRAS-mutant patients.

QTc prolongation across CDK4/6 inhibitors: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Cyclin-dependent kinases (CDK) 4/6 inhibitors have significantly improved outcomes for patients with ER+/HER2- breast cancer. Nevertheless, they differ from each other in terms of chemical, biological, and pharmacological features, as well as toxicity profiles. We aim to determine whether QTc prolongation is caused by CDK4/6i in general or if it is associated with ribociclib only. METHODS: We systematically searched PubMed, Embase, and Cochrane Library for randomized controlled trials (RCTs) comparing the prevalence of QTc prolongation as an adverse event in HR+ breast cancer patients treated with CDK4/6i vs those without CDK4/6i. We pooled risk ratio (RR) and mean difference (MD) with 95% confidence interval (CI) for the binary endpoint of QT prolongation. RESULTS: We included 14 RCTs comprising 16,196 patients, of whom 8,576 underwent therapy with CDK4/6i. An increased risk of QTc prolongation was associated with the use of CDK4/6i (RR 2.35; 95% CI 1.67-3.29; p < .001; I2=44%). Subgroup analyses revealed a significant increase in the QTc interval for the ribociclib and palbociclib cohorts. The ribociclib subgroup showed a risk ratio of 3.12 (RR 3.12; 95% CI 2.09-4.65; p < .001; I2 = 12%) while the palbociclib subgroup had a risk ratio of 1.51 (RR 1.51; 95% CI 1.05-2.15; p = .025, I2=0%). CONCLUSION: Palbociclib was associated with QTc prolongation, however, the RR for any grade QTc was quantitively twice with ribociclib. Furthermore, grade 3 QTc prolongations were observed exclusively with ribociclib. These results are important for guiding clinical decision-making and provide reassurance regarding the overall safety profile of this drug class.

NaV1.1 contributes to the cell cycle of human mesenchymal stem cells by regulating AKT and CDK2.

Non-excitable cells express sodium voltage-gated channel alpha subunit 1 gene and protein (SCN1A/NaV1.1); however, the functions of NaV1.1 are unclear. SCN1A was expressed in human mesenchymal stem cells (MSCs). Nav1.1 was abundantly expressed in the endoplasmic reticulum of MSCs; however, its expression was not found to be related to sodium currents. SCN1A-silencing reduced MSC proliferation and delayed the cell cycle in the S phase. SCN1A-silencing also suppressed the protein levels of CDK2 and AKT, despite similar mRNA expression, and inhibited AKT phosphorylation in MSCs. Cycloheximide-chase assay showed that SCN1A-silencing induced CDK2 but not AKT protein degradation in MSCs. Proteolysis inhibition assay using epoxomicin, bafilomycin A1, and NH4Cl, revealed that the ubiquitin-proteasome and autophagy/endo-lysosome systems were irrelevant to CDK2 and AKT protein reduction in SCN1A-silenced MSCs. AKT inhibitor LY294002 did not affect the degradation and nuclear localization of CDK2 in MSCs. Likewise, AKT activator SC79 did not attenuate the SCN1A-silencing effects on CDK2 in MSCs. These results suggest that NaV1.1 contributes to the cell cycle of MSCs by regulating the post-translational control of AKT and CDK2.

Predicting Inhibition of CDK2 with SAnDReS: The Application of Machine Learning to Navigate the Scoring Function Space.

CDK2 plays a pivotal role in controlling the progression of the cell cycle and is a target for anticancer drugs. The last 30 years of structural studies focused on CDK2 provided the basis for understanding its inhibition and furnished the data to develop machine-learning models to study intermolecular interactions. This review addresses the application of computational models to estimate the inhibition of CDK2. It focuses on machine-learning models developed to predict binding affinity against CDK2 using the program SAnDReS. A search of previously published articles on PubMed showed machine-learning models built to evaluate CDK2 inhibition. BindingDB information for CDK2 furnished the data to generate updated machine-learning models to predict the inhibition of this enzyme. The application of SAnDReS to model CDK2-inhibitor interactions showed that this approach can build machine-learning models with superior predictive performance compared with classical and deep-learning scoring functions. Also, the innovative DOME analysis of the predictive performance of machine learning and universal scoring function indicates that this method is adequate to select computational models to address protein-ligand interactions. The available structural and functional data about CDK2 is a rich source of information to build machine-learning models to predict the inhibition of this protein target. SAnDReS can build superior models to predict pKi and outperform universal scoring functions, including one developed using deep learning.

CDK4/6 inhibitor PD-0332991 suppresses hepatocarcinogenesis by inducing senescence of hepatic tumor-initiating cells.

INTRODUCTION: Owing to the limited treatment options for hepatocellular carcinoma (HCC), interventions targeting pre-HCC stages have attracted increasing attention. In the pre-HCC stage, hepatic tumor-initiating cells (hTICs) proliferate abnormally and contribute to hepatocarcinogenesis. Numerous studies have investigated targeted senescence induction as an HCC intervention. However, it remains to be clarified whether senescence induction of hTICs could serve as a pre-HCC intervention. OBJECTIVES: This study was designed to investigate whether senescence induction of hTICs in the precancerous stage inhibit HCC initiation. METHODS AND RESULTS: HCC models developed from chronic liver injury (CLI) were established by using Fah-/- mice and N-Ras + AKT mice. PD-0332991, a selective CDK4/6 inhibitor that blocks the G1/S transition in proliferating cells, was used to induce senescence during the pre-HCC stage. Upon administration of PD-0332991, we observed a significant reduction in HCC incidence following selective senescence induction in hTICs, and an alleviation liver injury in the CLI-HCC models. PD-0332991 also induced senescence in vitro in cultured hTICs isolated from CLI-HCC models. Moreover, RNA sequencing (RNA-seq) analysis delineated that the "Cyclin D-CDK4/6-INK4-Rb" pathway was activated in both mouse and human liver samples during the pre-HCC stage, while PD-0332991 exhibited substantial inhibition of this pathway, thereby inducing cellular senescence in hTICs. Regarding the immune microenvironment, we demonstrated that senescent hTICs secrete key senescence-associated secretory phenotypic (SASP) factors, CXCL10 and CCL2, to activate and recruit macrophages, and contribute to immune surveillance. CONCLUSION: We found that hTICs can be targeted and induced into a senescent state during the pre-HCC stage. The SASP factors released by senescent hTICs further activate the immune response, facilitating the clearance of hTICs, and consequently suppressing HCC occurrence. We highlight the importance of pre-HCC interventions and propose that senescence-inducing drugs hold promise for preventing HCC initiation under CLI.

Integrative Bioinformatics Analysis: Unraveling Variant Signatures and Single-Nucleotide Polymorphism Markers Associated with 5-FU-Based Chemotherapy Resistance in Colorectal Cancer Patients.

BACKGROUND: Drug resistance in colorectal cancer (CRC) is modulated by multiple molecular factors, which can be ascertained through genetic investigation. Single nucleotide polymorphisms (SNPs) within key genes have the potential to impair the efficacy of chemotherapeutic agents such as 5-fluorouracil (5-FU). Therefore, the identification of SNPs linked to drug resistance can significantly contribute to the advancement of tailored therapeutic approaches and the enhancement of treatment outcomes in patients with CRC. MATERIAL AND METHOD: To identify dysregulated genes in 5-FU-based chemotherapy responder or non-responder CRC patients, a meta-analysis was performed. Next, the protein-protein interaction (PPI) network of the identified genes was analyzed using the STRING database. The most significant module was chosen for further analysis. In addition, a literature review was conducted to identify drug resistance-related genes. Enrichment analysis was conducted to validate the main module genes and the genes identified from the literature review. The associations between SNPs and drug resistance were investigated, and the consequences of missense variants were assessed using in silico tools. RESULT: The meta-analysis identified 796 dysregulated genes. Then, to conduct PPI analysis and enrichment analysis, we were able to discover 23 genes that are intricately involved in the cell cycle pathway. Consequently, these 23 genes were chosen for SNP analysis. By using the dbSNP database and ANNOVAR, we successfully detected and labeled SNPs in these specific genes. Additionally, after careful exclusion of SNPs with allele frequencies below 0.01, we evaluated 6 SNPs from the HDAC1, MCM2, CDK1, BUB1B, CDC14B, and CCNE1 genes using 8 bioinformatics tools. Therefore, these SNPs were identified as potentially harmful by multiple computational tools. Specifically, rs199958833 in CDK1 (Val124Gly) was predicted to be damaging by all tools used. Our analysis strongly indicates that this specific SNP could negatively affect the stability and functionality of the CDK1 protein. CONCLUSION: Based on our current understanding, the evaluation of CDK1 polymorphisms in the context of drug resistance in CRC has yet to be undertaken. In this investigation, we showed that rs199958833 variant in the CDK1 gene may favor resistance to 5-FU-based chemotherapy. However, these findings need validation in an independent cohort of patients.

Discovery and preclinical profile of YK-2168, a differentiated selective CDK9 inhibitor in clinical development.

Emerging clinical evidence indicates that selective CDK9 inhibition may provide clinical benefits in the management of certain cancers. Many CDK9 selective inhibitors have entered clinical developments, and are being investigated. No clear winner has emerged because of unforeseen toxicity often observed in clinic with these agents. Therefore, a novel agent with differentiated profiles is still desirable. Herein, we report our design, syntheses of a novel azaindole series of selective CDK9 inhibitors. SAR studies led to a preclinical candidate YK-2168. YK2168 exhibited improved CDK9 selectivity over AZD4573 and BAY1251152; also showed differentiated intravenous PK profile and remarkable solid tumor efficacy in a mouse gastric cancer SNU16 CDX model in preclinical studies. YK-2168 is currently in clinical development in China (CTR20212900).

Breaking through therapeutic barriers: Insights into CDK4/6 inhibition resistance in hormone receptor-positive metastatic breast cancer.

The therapeutic landscape for hormone receptor-positive (HR+) breast carcinoma has undergone a significant transformation with the advent of cyclin-dependent kinase (CDK)4/6 inhibitors, particularly in combination with endocrine therapy as the primary regimen. However, the evolution of resistance mechanisms in response to CDK4/6 inhibitors in HR+ metastatic breast cancer presents substantial challenges in managing the disease. This review explores the diverse genomic landscape underlying resistance, including disturbances in the cell cycle, deviations in oncogenic signaling pathways, deficiencies in DNA damage response (DDR) mechanisms, and changes in the tumor microenvironment (TME). Additionally, it discusses potential strategies to surmount resistance, including advancements in endocrine therapy, targeted inhibition of cell cycle components, suppression of AKT/mTOR activation, exploration of the FGFR pathway, utilization of antibody-drug conjugates (ADCs), and integration of immune checkpoint inhibitors (ICIs) with endocrine therapy and CDK4/6 inhibitors, providing pathways for enhancing patient outcomes amidst treatment challenges.