Cyclin-dependent Kinase Research Articles

Discovery of a Novel Macrocyclic Noncovalent CDK7 Inhibitor for Cancer Therapy.

Cyclin-dependent kinase 7 (CDK7) is a key regulator of the cell cycle and transcription, making it a promising target for cancer therapy. Although current CDK7 inhibitors have improved in their selectivity and druglike properties, CDK7 inhibitors have failed to progress through clinical development due to severe gastrointestinal and hematotoxic side effects. To mitigate these limitations, we have developed novel, macrocyclic, noncovalent CDK7 hit compounds 2 and 3 using a macrocyclization platform that has optimized these compounds from SY-5609, a leading clinical asset. We conducted extensive structure-activity relationship (SAR) studies to improve their potency, enhance oral bioavailability, and reduce intestinal distribution, which resulted in compound 13. Compound 13 exhibits potent in vitro activity, good ADME properties, and robust in vivo antitumor activity in xenograft models as a monotherapy. Notably, compound 13 with lower basicity demonstrated improved Caco-2 permeability, reduced blood/plasma ratio, and reduced intestinal distribution in rats, thus mitigating gastrointestinal and hematotoxic side effects.

Cuproptosis-related lncRNA JPX regulates malignant cell behavior and epithelial-immune interaction in head and neck squamous cell carcinoma via miR-193b-3p/PLAU axis

The development, progression, and curative efficacy of head and neck squamous cell carcinoma (HNSCC) are influenced by complex interactions between epithelial and immune cells. Nevertheless, the specific changes in the nature of these interactions and their underlying molecular mechanisms in HNSCC are not yet fully understood. Cuproptosis, a form of programmed cell death that is dependent on copper, has been implicated in cancer pathogenesis. However, the understanding of cuproptosis in the context of HNSCC remains limited. In this study, we have discovered that cuproptosis-related long non-coding RNAs (CRLs) known as JPX play a role in promoting the expression of the oncogene urokinase-type plasminogen activator (PLAU) by competitively binding to miR-193b-3p in HNSCC. The increased activity of the JPX/miR-193b-3p/PLAU axis in malignant epithelial cells leads to enhanced cell proliferation, migration, and invasion in HNSCC. Moreover, the overexpression of PLAU in tumor epithelial cells facilitates its interaction with the receptor PLAUR, predominantly expressed on macrophages, thereby influencing the abnormal epithelial–immune interactome in HNSCC. Notably, the JPX inhibitor Axitinib and the PLAU inhibitor Palbociclib may not only exert their effects on the JPX/miR-193b-3p/PLAU axis that impacts the malignant tumor behaviors and the epithelial–immune cell interactions but also exhibit synergistic effects in terms of suppressing tumor cell growth and arresting cell cycle by targeting epidermal growth factor receptor (EGFR) and cyclin-dependent kinase (CDK4/6) for the treatment of HNSCC.

Swertiamarin and sweroside are potential inhibitors of COVID-19 based on the silico analysis.

The severity of the respiratory disease caused by the severe acute respiratory syndrome coronavirus 2 has escalated rapidly in recent years, posing a significant threat to global health. Sweroside and swertiamarin are bioactive iridoid glycosides extracted mainly from Swertia davidii Franch. It remains unclear how Swertia davidii Franch. Specifically affects COVID-19 and its underlying mechanisms. We first employed network pharmacology and molecular docking techniques to investigate how sweroside and swertiamarin affect COVID-19 in order to explore its potential mechanism. We found that 35 potential target genes can be used for the treatment of COVID-19, with androgen receptor (AR), HSP90AA1, RAC-alpha serine/threonine-protein kinase, cyclin-dependent kinase 1, epidermal growth factor receptor, and glycogen synthase kinase-3 beta emerging as particularly promising candidates. Additionally, sweroside and swertiamarin demonstrated unambiguous interactions with the 3CL protease AR through molecular docking research. At the active site, sweroside and swertiamarin can bind to AR (1T65), the main protease (5R82), and 3CL protease (6M2N), showing therapeutic potential.

From precursor to cancer: decoding the intrinsic and extrinsic pathways of pancreatic intraepithelial neoplasia progression.

This review explores the progression of pancreatic intraepithelial neoplasia (PanIN) to pancreatic ductal adenocarcinoma through a dual lens of intrinsic molecular alterations and extrinsic microenvironmental influences. PanIN development begins with Kirsten rat sarcoma viral oncogene (KRAS) mutations driving PanIN initiation. Key additional mutations in cyclin-dependent kinase inhibitor 2A (CDKN2A), tumor protein p53 (TP53), and mothers against decapentaplegic homolog 4 (SMAD4) disrupt cell cycle control and genomic stability, crucial for PanIN progression from low-grade to high-grade dysplasia. Additional molecular alterations in neoplastic cells, including epigenetic modifications and chromosomal alterations, can further contribute to neoplastic progression. In parallel with these alterations in neoplastic cells, the microenvironment, including fibroblast activation, extracellular matrix remodeling, and immune modulation, plays a pivotal role in PanIN initiation and progression. Crosstalk between neoplastic and stromal cells influences nutrient support and immune evasion, contributing to tumor development, growth, and survival. This review underscores the intricate interplay between cell-intrinsic molecular drivers and cell-extrinsic microenvironmental factors, shaping PanIN predisposition, initiation, and progression. Future research aims to unravel these interactions to develop targeted therapeutic strategies and early detection techniques, aiming to alleviate the severe impact of pancreatic cancer by addressing both genetic predispositions and environmental influences.

Hepatitis B Virus-Induced Resistance to Sorafenib and Lenvatinib in Hepatocellular Carcinoma Cells: Implications for Cell Viability and Signaling Pathways

Background/Objectives: Sorafenib and lenvatinib are tyrosine kinase inhibitors used in hepatocellular carcinoma (HCC) treatment. This study investigates how hepatitis B virus (HBV) infection affects their efficacy in HepG2 hepatoma cells. Methods: HepG2 and HBV-infected HepG2/2215 cells were treated with varying concentrations of both drugs. The cell viability, cell cycle gene expression, cycle progression, and phosphorylation levels of ERK and AKT were analyzed. Results: The HBV-infected cells showed significant alterations in their cell cycle gene expressions, with an 80-fold increase in CCND2 expression and a higher proportion of cells in the G2/M phase, indicating enhanced proliferation. While both drugs decreased HepG2 cell viability in a concentration-dependent manner, HBV infection conferred resistance, as evidenced by the increased viable cells in the HepG2/2215 cultures. Sorafenib and lenvatinib decreased key cyclin and cyclin-dependent kinase expressions in uninfected cells, with less effect on the HBV-infected cells. Both drugs lowered the pERK and pAKT levels in the HepG2 cells. In the HBV-infected cells, sorafenib reduced the pERK and pAKT levels to a lesser extent. However, treatment with lenvatinib elevated the levels of pERK and pAKT. Conclusions: In conclusion, HBV infection increases resistance to both sorafenib and lenvatinib in hepatoma cells by influencing the cell cycle regulatory genes and critical signaling pathways. However, the resistance mechanisms likely differ between the two medications.

Treatment sequences and survival outcomes in advanced HR + HER2- breast cancer patients: a real-world cohort.

Palliative treatment options for HR + HER2- advanced breast cancer (ABC) patients have increased, but data is lacking about the optimal treatment sequence. We used real-world data from a comprehensive cancer center to describe applied treatment sequences and we determined treatment-related and survival outcomes. Patients aged 18 years and older with HR + HER2- ABC treated with systemic treatment were included in this historic cohort study. Sequential treatment schedules, time to treatment discontinuation, time to chemotherapy, and overall survival (OS) were determined, stratified by first-line treatment. 202 patients were included. They received a total of 650 treatment lines (median 3; range: 1-11). 91 (45%), 25 (12%), 24 (12%), 28 (14%), 22 (11%) and 12 (6%) patients started first-line treatment with non-steroidal aromatase inhibitors (NSAI), NSAI + cyclin dependent kinase 4/6-inhibitors (CDK4/6i), fulvestrant + CDK4/6i, tamoxifen, chemotherapy and other treatment, respectively. 10, 13, and 14 different treatment regimens were given in first, second and third-line, respectively. Of the patients who started first-line NSAI monotherapy (n = 91), 3 (3%) died before receiving second-line treatment. In this real-world cohort, we observed a wide variety of different treatment sequences applied in daily clinical practice, some of which were in discordance with the current guidelines. Fear that patients may never get around to treatment with CDK4/6i if a patient did not start with a CDK4/6i was not supported by our study results.

Amide Functionalized Novel Pyrrolo-pyrimidine Derivative as Anticancer Agents: Synthesis, Characterization and Molecular Docking Studies.

The development of new therapies targeting crucial kinases involved in cancer progression is a promising area of research. Pyrazolo pyrimidine derivatives have emerged as potential candidates for this purpose. This study aims to synthesize pyrazolo pyrimidine derivatives (5a-5r), evaluate their molecular docking against key kinases, and assess their anticancer activity. The synthesis involved a multi-step procedure starting with the cyclization of 6-amino-2- methylpyrimidin-4(3H)-one (1) to form 2-methyl-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-4-ol (2). This was followed by chlorination to yield 4-chloro-2-methyl-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidine (3) and nucleophilic substitution to produce 2-methyl-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-4-amine (4). The final derivatives (5a-5r) were synthesized through amide bond formation with various carboxylic acids using DCC and DMAP. Structural elucidation was confirmed via NMR, mass spectrometry, and HRMS. Molecular docking studies were conducted against Janus kinase 1 (JAK1), Janus kinase 2 (JAK2), and cyclin-dependent kinase 4 (CDK4). Anticancer activity was evaluated against MCF-7, SET-2, and HCT-116 cell lines. Structural elucidation confirmed the successful synthesis of the derivatives. Molecular docking studies revealed promising binding affinities for selected derivatives, particularly those with heterocyclic substitutions. Anticancer activity evaluation showed diverse potency profiles, with several derivatives demonstrating IC50 values comparable to the reference drug, doxorubicin. Derivatives featuring nitro and heterocyclic moieties exhibited significant anticancer activity. The synthesized pyrazolo pyrimidine derivatives showed potential as lead compounds for further development due to their promising binding affinities and significant anticancer activity, particularly those with nitro and heterocyclic moieties.

Exploring the role of Cdk5 on striatal synaptic plasticity in a 3-NP-induced model of early stages of Huntington’s disease

Impaired mitochondrial function has been associated with the onset of neurodegenerative diseases. Specifically, certain mitochondrial toxins, such as 3-nitropropionic acid (3-NP), initiate cellular changes within the striatum that closely resemble the pathology observed in Huntington’s disease (HD). Among the pivotal signaling molecules contributing to neurodegeneration, cyclin-dependent kinase 5 (Cdk5) stands out. In particular, Cdk5 has been implicated not only in cellular pathology but also in the modulation of synaptic plasticity. Given its widespread presence in the striatum, this study seeks to elucidate the potential role of Cdk5 in the induction of corticostriatal synaptic plasticity in murine striatal cells subjected to subchronic doses of 3-NP in vivo, aiming to mimic the early stages of HD. Immunostaining analyses revealed an increase in Cdk5 in tissues from animals treated with 3-NP, without a significant change in protein levels. Regarding striatal plasticity, long-term depression (LTD) was induced in both control and 3-NP cells when recorded in voltage clamp mode. The Cdk5 inhibitor roscovitine-reduced LTD in most cells. A minority subset of cells exhibited long-term potentiation (LTP) generation in the presence of roscovitine. The inhibitor of D1 receptors SCH23390 prevented LTP in three of nine cells, implying that MSN cells lacking D1/PKA activation were capable of LTP induction when Cdk5 was also blocked. Nevertheless, the co-administration of H89, a PKA inhibitor, along with roscovitine, prevented the generation of any type of plasticity in all recorded cells. These findings show the impact of 3-NP treatment on striatal plasticity and suggest that Cdk5 during early neurodegeneration may attenuate signaling pathways that lead neurons to increase their activity.

Suppression of CDK1/Drp1-Mediated Mitochondrial Fission Attenuates Dexamethasone-Induced Extracellular Matrix Deposition in the Trabecular Meshwork.

Aims: Deposition of extracellular matrix (ECM) in the trabecular meshwork (TM), as induced by dexamethasone (Dex), is believed to play an important role in the onset of glucocorticoid-induced glaucoma (GIG). Abnormal ECM deposition is a consequence of mitochondrial dysfunction. We aimed to clarify how mitochondrial dysfunction leads to ECM deposition within the TM and to support the development of novel therapeutic strategies. Results: In primary human TM cells (pHTMCs) and a Dex acetate-induced murine model of GIG, glucocorticoid administration stimulated both mitochondrial fission and ECM deposition. Excessive mitochondrial fission leads to dysfunction and the overexpression of ECM proteins in pHTMCs. Notably, when pHTMCs were treated with the dynamin-related protein 1 (Drp1) inhibitor Mdivi-1 or with Drp1 siRNA, we observed a marked reduction in Dex-induced mitochondrial damage and ECM proteins in vitro. Furthermore, in C57BL/6J mice, treatment with Mdivi-1 mitigated mitochondrial damage and blocked ECM deposition within the TM. We then used Ro3306 to inhibit the cyclin-dependent kinase (CDK)1-mediated phosphorylation of Drp1 at Ser 616, which restored mitochondrial function and diminished Dex-induced ECM protein expression in pHTMCs. Innovation: This study illuminates the pathogenic mechanism linking mitochondrial dysfunction to ECM deposition in GIG. Our innovative approach revealed that Dex stimulates mitochondrial fission via CDK1-mediated p-Drp1s616 overexpression, which drives ECM accumulation. It offered a novel therapeutic strategy for reducing ECM protein expression by inhibiting excessive mitochondrial fission and restoring mitochondrial function. Conclusion: By targeting the CDK1/Drp1-driven mitochondrial fission process, we can counteract Dex-induced ECM deposition in the TM both invivo and in vitro.

Computer-aided Drug Discovery of Epigenetic Modulators in Dual-target Therapy of Multifactorial Diseases.

Numerous studies suggest that common genetic and epigenetic factors such as p53, histone deacetylase (HDAC), brain-derived neurotrophic factor (BDNF), the (Ataxia Telangiectasia mutated) ATM gene, cyclin-dependent kinase 5 (CDK5), glycogen synthase kinase 3 (GSK3) and altered expression of microRNA (miRNA) play a crucial role in cancer and neurodegeneration. As there is growing evidence that epigenetic aberrations in cancer and neurological diseases lead to complex pathophysiological changes, the simultaneous targeting of epigenetic and other related pathways by dual-target inhibitors may contribute to the discovery of more effective and personalized therapeutic options. Computer-Aided Drug Design (CADD) provides comprehensive bioinformatic, chemoinformatic, and chemometric approaches for the design of novel chemotypes of epigenetic dual-target inhibitors, enabling efficient discovery of new drug candidates for innovative treatments of these multifactorial diseases. The detailed anticancer mechanisms by which the epigenetic dual-target inhibitors alter metastatic and tumorigenic properties, influence the tumor microenvironment, or regulate the immune response are also presented and discussed in the review. To improve our understanding of the pathogenesis of cancer and neurodegeneration, this review discusses novel therapeutic agents targeting different molecular mechanisms involved in these multifactorial diseases.

Comprehensive Analysis of the Significance of Cyclin Dependent Kinase Inhibitor Genes in the Prognosis of Cervical Cancer

Comprehensive Analysis of the Significance of Cyclin Dependent Kinase Inhibitor Genes in the Prognosis of Cervical Cancer

Embryotrophic effect of exogenous protein contained adipose-derived stem cell extracellular vesicles

BackgroundExtracellular vesicles (EVs) regulate cell metabolism and various biological processes by delivering specific proteins and nucleic acids to surrounding cells. We aimed to investigate the effects of the cargo contained in EVs derived from adipose-derived stem cells (ASCs) on the porcine embryonic development.MethodsASCs were isolated from porcine adipose tissue and characterized using ASC-specific markers via flow cytometry. EVs were subsequently extracted from the conditioned media of the established ASCs. These EVs were added to the in vitro culture environment of porcine embryos to observe qualitative improvements in embryonic development. Furthermore, the proteins within the EVs were analyzed to investigate the underlying mechanisms.ResultsWe observed a higher blastocyst development rate and increased mitochondrial activity in early stage embryos in the ASC-EVs-supplemented group than in the controls (24.8% ± 0.8% vs. 28.6% ± 1.1%, respectively). The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay of blastocysts also revealed significantly reduced apoptotic cells in the ASC-EVs-supplemented group. Furthermore, through proteomics, we detected the proteins in ASC-EVs and blastocysts from each treatment group. This analysis revealed a higher fraction of proteins in the ASC-EVs-supplemented group than in the controls (1,547 vs. 1,495, respectively). Gene analysis confirmed that ASC-EVs showed a high expression of tyrosine-protein kinase (SRC), whereas ASC-EVs supplemented blastocysts showed a higher expression of Cyclin-dependent kinase 1 (CDK1). SRC is postulated to activate protein kinase B (AKT), which inhibits the forkhead box O signaling pathway and activates CDK1. Subsequently, CDK1 activation influences the cell cycle, thereby affecting in vitro embryonic development.ConclusionASC-EVs promote mitochondrial activity, which is crucial for the early development of blastocysts and vital in the downregulation of apoptosis. Additionally, ASC-EVs supply SRC to porcine blastocysts, thereby elongating the cell cycle.

Targeting the cyclin-dependent kinase family in anticancer drug discovery: From computational to experimental studies

Uncontrolled cell proliferation, primarily regulated by cyclin-dependent kinases (CDKs), is a critical driver of cancer progression, with dysregulation of CDKs contributing to various cancer types. CDKs have emerged as well-established targets for cancer therapy; however, traditional drug development methods have often proven to be time-consuming, challenging, and expensive. Recent advancements in CDK inhibitors (CDKIs) have shown immense clinical potential but many first-generation CDKIs face issues of non-selectivity and significant toxicity, limiting their clinical approval. To address these challenges, innovative computational approaches, particularly pharmacophore modeling, have the potential to streamline drug discovery. These methods can guide the selection of small molecules through target-specific structure-activity relationship (SAR) models and chemotypes screening across databases, thereby accelerating the identification of effective CDKIs. This review paper summarizes the latest developments on CDK inhibitors, highlights their structural features, and the methodologies (key databases & software tools) that can provide further suggestions for future drug development.

Sterile Alpha Motif Domain-Containing 5 Suppresses Malignant Phenotypes and Tumor Growth in Breast Cancer: Regulation of Polo-Like Kinase 1 and c-Myc Signaling in a Xenograft Model.

Background Breast cancer, particularly the triple-negative breast cancer (TNBC) subtype, remains a significant clinical challenge due to its resistance to standard chemotherapy and high recurrence rate. In this study, we explored the role of Sterile Alpha Motif Domain-Containing 5 (SAMD5) as a potential regulatory partner with the c-Myc oncogenic signaling pathway in breast cancer. Materials and methods Functional assays were conducted to investigate the effects of SAMD5 overexpression on cell viability, colony formation, and invasive behavior in TNBC cell lines. This study further assessed the expression levels of proliferation and invasion markers, including Ki67 (a marker for cell proliferation), Matrix Metalloproteinase-2 (MMP2), and Matrix Metalloproteinase-9 (MMP9). Mechanistic analyses identified a negative correlation between SAMD5 and Polo-like Kinase 1 (PLK1), a gene frequently overexpressed in breast cancer, particularly in TNBC. The effects of PLK1 knockdown on cell viability, colony formation, and invasion were observed, along with the impact of PLK1 overexpression on SAMD5's inhibitory activity. In vivo studies were performed using a xenograft tumor model in nude mice to evaluate the impact of SAMD5 overexpression on tumor weight and volume. Results SAMD5 overexpression significantly reduced cell viability, colony formation, and invasion in TNBC cells, and downregulated key proteins in the c-Myc signaling pathway, including c-Myc itself, β-catenin, Cyclin-Dependent Kinase 4 (CDK4), Cyclin-Dependent Kinase 6 (CDK6), and Cyclin D1. PLK1 overexpression was found to counteract SAMD5's inhibitory effects. In vivo experiments demonstrated that SAMD5 overexpression led to a marked reduction in tumor weight and volume, effects that were partially reversed by PLK1 overexpression. Conclusions SAMD5 acts as a tumor suppressor in breast cancer, particularly in TNBC, by inhibiting critical cellular processes and downregulating the c-Myc signaling pathway. This effect appears to be mediated, in part, through its negative association with PLK1. Targeting the SAMD5/PLK1 axis offers a promising therapeutic strategy for addressing aggressive breast cancers.

Interplay of CDKs and Cyclins with glycolytic regulatory enzymes PFK and PK.

In plants, as in all eukaryotes, the cell cycle is regulated by the heterodimer formed by cyclins (Cycs) and cyclin-dependent kinases (CDKs), that phosphorylate serine/threonine residues in target proteins. The extensive involvement of these heterodimers in nuclear cell cycle-related processes has been demonstrated. However, recent findings have linked Cyc-CDK complexes to the regulation of cytosolic processes, including various metabolic pathways, suggesting close coordination between the cell cycle and catabolic/anabolic processes to maintain cellular energy homeostasis.This study extends the analysis of Cyc-CDK complex regulation in maize to two key regulators of glycolysis: phosphofructose kinase (PFK) and pyruvate kinase (PK). Both are cytosolic enzymes, highly regulated positively and negatively by different metabolites, showing a similar activation pattern in their homotetrameric form and low activity when as dimers/monomers. Each enzyme exhibits two putative minimal phosphorylation motives for Cyc-CDKs, conserved in some plant species and in four (PFK) and three (PK) isoforms in maize. This work demonstrates that both enzymes are active with fluctuating levels of activity along maize germination; also, that they associate with different maize Cycs and CDKs as demonstrated by pull-down assays, as well as their in vitro phosphorylation by recombinant CycD;2-CDKA or CycD2;2-CDKB complexes. Additionally, the inhibition of PFK and PK activity following phosphorylation by active Cycs-CDKB complexes obtained by immunoprecipitation from imbibed embryonic axis protein extracts suggests a narrow and negative regulation of glycolysis as the cell cycle progresses. A decreased carbon flow through this pathway is proposed to divert carbon from sugars towards the oxidative pentose phosphate pathway, thereby promoting de novo nucleic acid synthesis precursors to stimulate cell cycle progression.

Estrogen regulates PDPK1 to promote cell proliferation in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is a common estrogen-sensitive tumor that poses a serious threat to women 's health, and the mortality rate of EOC ranks first among malignant tumors in females. Studies have indicated a strong link between estrogen abnormality and EOC progression. We accidentally found that 3-phosphoinositide-dependent protein kinase-1 (PDPK1) is highly expressed in EOC tissues. Further, estrogen also up-regulates the expression of PDPK1 in EOC cells. Notably, the expression of PDPK1 is controlled strictly, and its expression can determine the fate of cells. However, to date, the molecular mechanism by which estrogen elicits PDPK1 expression in EOC cells, and the role of PDPK1 in estrogen-driven EOC cells are not well defined. In this research, we found that a high expression of PDPK1 was associated with poor prognosis in patients with ovarian cancer. Further, estrogen stimulated the increase of PDPK1 protein expression through estrogen receptor ESR1. The depletion or overexpression of PDPK1 affected the inhibition or amplification of estrogen-driven EOC cell proliferation, and the knockdown of PDPK1 suppressed the migration of EOC cells by estrogen while promoting cell apoptosis. This suggests a critical functional association between estrogen and PDPK1 in the process of EOC. The expression of messenger RNA for cyclin A1, cyclin-dependent kinase 2 (CDK2), matrix metallopeptidase 2 (MMP2), and bcl-2 associated x protein (Bax) is regulated by PDPK1 under estrogen treatment. Our results indicated that PDPK1 plays a role as an oncogene in the development of EOC; hence, elucidating the mechanism by which estrogen promotes EOC progression by regulating PDPK1 expression.

CDK6-mediated endothelial cell cycle acceleration drives arteriovenous malformations in hereditary hemorrhagic telangiectasia.

Increased endothelial cell proliferation is a hallmark of arteriovenous malformations (AVMs) in hereditary hemorrhagic telangiectasia (HHT). Here, we report a cyclin-dependent kinase 6 (CDK6)-driven mechanism of cell cycle deregulation involved in endothelial cell proliferation and HHT pathology. Specifically, endothelial cells from the livers of HHT mice bypassed the G1/S checkpoint and progressed through the cell cycle at an accelerated pace. Phosphorylated retinoblastoma (pRB1)-a marker of G1/S transition through the restriction point-accumulated in endothelial cells from retinal AVMs of HHT mice and endothelial cells from skin telangiectasia samples from HHT patients. Mechanistically, inhibition of activin receptor-like kinase 1 signaling increased key restriction point mediators, and treatment with the CDK4/6 inhibitors palbociclib or ribociclib blocked increases in pRB1 and retinal AVMs in HHT mice. Palbociclib also improved vascular pathology in the brain and liver, and slowed cell cycle progression in endothelial cells and endothelial cell proliferation. Endothelial cell-specific deletion of CDK6 was sufficient to protect HHT mice from AVM pathology. Thus, clinically approved CDK4/6 inhibitors might have the potential to be repurposed for HHT.

Anti colorectal cancer activity and in silico studies of novel pyridine nortopsentin analog as cyclin dependent kinase 6 inhibitor

Nortopsentins are a vital class of deep-sea sponge metabolites which can be used as leads for antitumor agents. Although their action has been studied in several diseases’ contexts, their cytotoxic activity against colorectal carcinoma has not yet been fully investigated. Therefore, a series of 2,6-bis(1H-indol-3-yl)-4-(substituted-phenyl)pyridin-5-carbonitriles 4a–j (nortopsentin analogs) was investigated for their cytotoxic activity against colorectal carcinoma. The analog 4i showed the highest antitumor activity via inducing cell cycle arrest at G1 phase. Cell cycle arrest was induced due to expression downregulation of CDK2, CDK4, and CDK6. In addition, 4i suppressed the enzymatic activity of CDK6. The theoretical study of some basic quantum factors and the geometric shape of compound 4i proved that the compound is stable and a soft molecule, in which the EHOMO and ELUMO energies were negative and had a small ∆E gap. 4i also demonstrated a high potential for oral bioavailability due to its adherence to Lipinski’s rule of five. The molecular docking studies of 4i analog showed good binding mode with CDK6 active pocket through the formation of multiple interactions with its key amino acids.

Association Between Cyclin-Dependent Kinase 4/6 Inhibitors and Nephrotoxicity in Patients with Breast Cancer: A Systematic Review and Meta-analysis

Association Between Cyclin-Dependent Kinase 4/6 Inhibitors and Nephrotoxicity in Patients with Breast Cancer: A Systematic Review and Meta-analysis

Pim1 is Critical in T-cell-independent B-cell Response and MAPK Activation in B Cells

The Pim family consists of three members that encode a distinct class of highly conserved serine/threonine kinases. In this study, we generated and examined mice with hematopoiesis-specific deletion of Pim1 and bone marrow (BM) chimeric mice with B-cell-specific targeted deletion of Pim1. Pim1 was expressed at all stages of B-cell development and hematopoietic-specific deletion of Pim1 altered B-cell development in BM, spleen and peritoneal. However, Pim1 deficiency did not affect T-cell development. Studies of BM chimeric mice showed that Pim1 is required in a cell-intrinsic manner to maintain normal B-cell development. Pim1 deficiency led to significant changes in B cell antibody responses. Additionally, Pim1 deficiency resulted in reduced B cell receptor (BCR)-induced cell proliferation and cell cycle progression. Examination of the various BCR-activated signaling pathways in Pim1-deficient B cells reveals defective activation of mitogen-activated protein kinases (MAPKs), which are known to regulate genes involved in cell proliferation and survival. qRT-PCR analysis of BCR-engaged B cells from Pim1-deficient B cells revealed reduced expression of cyclin-dependent kinase (CDK) and cyclin genes, including CDK2, CCNB1 and CCNE1. In conclusion, Pim1 plays a crucial role in B-cell development and B cell activation.