Cyclin-dependent Kinase Inhibitor Research Articles

Identification of naturally occurring flavonoids as anticancer agents: In silico studies

It is recognized that flavonoids have a variety of functions in nature, including anti-inflammatory, antibacterial, antioxidant, anticancer, anti-HIV and neuroprotective properties. In the present study, molecular docking experiment was performed on 15 naturally occurring flavonoids as anticancer agents. The analysis of results was performed on the basis of docking score, glide energy and interaction with amino acids. Each flavonoid showed a specific interaction with target protein. Naringin showed interactions with amino acids GLN131, ASP145, PHE80, VAL83, GLU8, ILE10, THR89 (docking score −12.48) involved with the protein PDB ID: 1gij (inhibitor of cyclin-dependent kinase 4). Naringin further showed interactions with THR887, THR886, LYS833, ASP836 amino acids (docking score −15.078) involved with PDB ID: 5jhb (inhibitor of PI3K and tubulin). Orientin showed interactions with amino acids ASN150, ASP163, LYS43, VAL101 (docking score −13.89) with PDB ID: 2euf as inhibitor of cyclin-dependent kinase 6. Quercetin showed interactions with amino acids PHE1047, LEU840, CYS919, GLU917 (docking score −11.7) with PDB ID: 4agd as inhibitor of VEGF receptor tyrosine kinase inhibitor. Epigallocatechin gallate showed interactions with amino acids LYS868, GLU885, THR916, ASP1046 using protein PDB ID: 3ewh (docking score −10.004) as inhibitor of Tie-2 kinase. The given flavonoid drugs interaction with cancer targets shows their possible potential against various forms of cancer. Epigallocatechin gallate when docked with 3ewh showed best docking score with important interaction required for anticancer activity. In molecular dynamic study, Epigallocatechin gallate in complex with VEGFR2 kinase protein (PDB ID: 3ewh) with RMSD indicates the protein remained stable through the simulation of 100ns with fluctuation in the range of 1.5–3.5 Å. The provided docking results may be useful for the development of novel drug candidate for anticancer targets.

Relationship between GTSE1 and Cell Cycle and Potential Regulatory Mechanisms in Lung Cancer Cells

The regulation of the cell cycle is essential for maintaining normal cellular function, especially in the development of diseases such as lung cancer. The cell cycle consists of four major phases (G1, S, G2 and M phases), which are characterized by a series of precise molecular events to ensure proper cell proliferation and division. In lung cancer cells, cell cycle dysregulation can lead to disordered proliferation and increased invasiveness of cancer cells. G2 and S-phase expressed 1 (GTSE1) is a regulatory protein found in the cytoplasm of the cell, which plays a key role in the cell cycle distribution of a wide range of cancer cells and is involved in life processes such as cell proliferation and apoptosis. GTSE1 affects cell cycle progression by interacting with cyclin-dependent kinase inhibitor 1A (p21) and maintaining the stability of p21, which in turn inhibits the activity of cyclin-dependent kinase 1/2 (CDK1/2). In addition, GTSE1 is also involved in the regulation of tumor protein 53 (p53) signaling pathway. With the assistance of mouse double minute 2 homolog (MDM2), GTSE1 is able to transport p53 from the nucleus to the cytoplasm and promote its ubiquitination and degradation, thus affecting cell cycle and cell death-related signaling pathways. This paper reviews the expression of GTSE1 in lung cancer cells and its effects on lung cancer, as well as its potential mechanisms involved in cell cycle regulation. .

Transcriptional profiling of lung macrophages following ozone exposure in mice identifies signaling pathways regulating immunometabolic activation.

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

BIOM-08. CDKN2A --AN INDEPENDENT CYCLIN-DEPENDENT KINASE INHIBITOR VARIANT ASSOCIATED WITH MALIGNANCY AND WITH SMALL VESSEL STROKE, AS A POTENTIAL MARKER FOR RISK OF LARGE-VESSEL STROKE COMPLICATING BENIGN TERATOMA

Abstract BACKGROUND Cyclin-dependent kinase inhibitor variants, particularly those of CDKN2A are known to be associated with autosomal dominant Familial Atypical Multiple Mole/Melanoma Syndrome and pancreatic cancer predisposition. These variants are associated with risk of small vessel stroke in African/ African-American populations, and are risk factors for stroke in Nordic populations with hypertension, independent of cardiovascular risk factors. METHODS We performed a case review of a female presenting in late infancy with a central nervous system teratoma, that later was complicated by a right hemispheric middle cerebral artery (MCA)stroke, associated with a CDKN2A germline mutation. RESULTS This 14month old female presented with transient alterations of consciousness and apparent abdominal migraine events with pernicious vomiting. Neuroimaging revealed a right heterogeneous para- suprasellar mass and bilateral complex arachnoid adjacent cysts. She was observed closely for any progression, as the lesion was immediately adjacent to the optic chiasm. One year after presentation, she developed an acute ischemic right middle cerebral artery (MCA) stroke and had radiographic evidence of severe stenosis and decreased flow primarily within the right supra-clinoid internal carotid artery, the M1 segment and portion of the right A1 segment of cerebral vessels, with decreased enhancement and number of vessels in the distal right MCA territory. The vessels did not appear to be compressed by any mass effect. The radiologic appearance was consistent with vasospasm. The patient upon stoke recovery, underwent near- complete resection of the mass with no evidence of disruption of the capsule surrounding it and no vascular infiltration. Pathology revealed the expected teratoma with prominence of pancreatic acinar structures, and molecular evidence of a variant of CDKN2A, which was present in the patient and mother in the germline. CONCLUSION We propose that the imaging evidence of a vasculopathy was related to the genotype at the cyclin- dependent kinase site.

The crosstalk role of CDKN2A between tumor progression and cuproptosis resistance in colorectal cancer.

Cuproptosis is a type of cell death characterized by excessive copper-lipid reactions in the tricarboxylic acid cycle, resulting in protein toxicity stress and cell death. Although known as a cuproptosis inhibitor through CRISPR-Cas9 screening, the role of cyclin-dependent kinase inhibitor 2A (CDKN2A) in cuproptosis resistance and its connection to tumor development remains unclear. In this study, we combined single-cell sequencing, spatial transcriptomics, pathological image analysis, TCGA multi-omics analysis and in vitro experimental validation to comprehensively investigate CDKN2A distribution, expression, epigenetic modification, regulation and genomic features in colorectal cancer cells. We further explored the associations between CDKN2A and cellular pathway, immune infiltration and spatial signal communication. Our findings showed an increasing trend in cuproptosis in the trajectory of tumor progression, accompanied by an upward trend of CDKN2A. CDKN2A underwent transcriptional activation by MEF2D and via the SNHG7/miR-133b axis, upregulating glycolysis, copper metabolism and copper ion efflux. CDKN2A likely drives epithelial-mesenchymal transition (EMT) and progression by activating Wnt signaling. CDKN2A is associated with high genomic instability and sensitivity to radiation and chemotherapy. Tumor regions expressing CDKN2A exhibit distinctive SPP1+ tumor-associated macrophage (TAM) infiltration and MMP7 enrichment, along with unique signaling crosstalk with adjacent areas. CDKN2A mediates cuproptosis resistance through regulating glycolysis and copper homeostasis, accompanied by a malignant phenotype and pro-tumor niche. Radiation and chemotherapy are expected to potentially serve as therapeutic approaches for cuproptosis-resistant colorectal cancer with high CDKN2A expression.

Sm-like 5 knockdown inhibits proliferation and promotes apoptosis of colon cancer cells by upregulating p53, CDKN1A and TNFRSF10B.

The role of Sm-like 5 (LSM5) in colon cancer has not been determined. In this study, we investigated the role of LSM5 in progression of colon cancer and the potential underlying mechanism involved. To determine the role of LSM5 in the progression of colon cancer and the potential underlying mechanism involved. The Gene Expression Profiling Interactive Analysis database and the Human Protein Atlas website were used for LSM5 expression analysis and prognosis analysis. Real-time quantitative polymerase chain reaction and Western blotting were utilized to detect the expression of mRNAs and proteins. A lentivirus targeting LSM5 was constructed and transfected into colon cancer cells to silence LSM5 expression. Proliferation and apoptosis assays were also conducted to evaluate the growth of the colon cancer cells. Human GeneChip assay and bioinformatics analysis were performed to identify the potential underlying mechanism of LSM5 in colon cancer. LSM5 was highly expressed in tumor tissue and colon cancer cells. A high expression level of LSM5 was related to poor prognosis in patients with colon cancer. Knockdown of LSM5 suppressed proliferation and promoted apoptosis in colon cancer cells. Silencing of LSM5 also facilitates the expression of p53, cyclin-dependent kinase inhibitor 1A (CDKN1A) and tumor necrosis factor receptor superfamily 10B (TNFRSF10B). The inhibitory effect of LSM5 knockdown on the growth of colon cancer cells was associated with the upregulation of p53, CDKN1A and TNFRSF10B. LSM5 knockdown inhibited the proliferation and facilitated the apoptosis of colon cancer cells by upregulating p53, CDKN1A and TNFRSF10B.

Novel meriolin derivatives potently inhibit cell cycle progression and transcription in leukemia and lymphoma cells via inhibition of cyclin-dependent kinases (CDKs)

A key feature of cancer is the disruption of cell cycle regulation, which is characterized by the selective and abnormal activation of cyclin-dependent kinases (CDKs). Consequently, targeting CDKs via meriolins represents an attractive therapeutic approach for cancer therapy. Meriolins represent a semisynthetic compound class derived from meridianins and variolins with a known CDK inhibitory potential. Here, we analyzed the two novel derivatives meriolin 16 and meriolin 36 in comparison to other potent CDK inhibitors and could show that they displayed a high cytotoxic potential in different lymphoma and leukemia cell lines as well as in primary patient-derived lymphoma and leukemia cells. In a kinome screen, we showed that meriolin 16 and 36 prevalently inhibited most of the CDKs (such as CDK1, 2, 3, 5, 7, 8, 9, 12, 13, 16, 17, 18, 19, 20). In drug-to-target modeling studies, we predicted a common binding mode of meriolin 16 and 36 to the ATP-pocket of CDK2 and an additional flipped binding for meriolin 36. We could show that cell cycle progression and proliferation were blocked by abolishing phosphorylation of retinoblastoma protein (a major target of CDK2) at Ser612 and Thr82. Moreover, meriolin 16 prevented the CDK9-mediated phosphorylation of RNA polymerase II at Ser2 which is crucial for transcription initiation. This renders both meriolin derivatives as valuable anticancer drugs as they target three different Achilles’ heels of the tumor: (1) inhibition of cell cycle progression and proliferation, (2) prevention of transcription, and (3) induction of cell death.

Gangliosides in neural stem cell fate determination and nerve cell specification--preparation and administration.

Gangliosides are sialylated glycosphingolipids with essential but enigmatic functions in healthy and disease brains. GD3 is the predominant species in neural stem cells (NSCs) and GD3-synthase (sialyltransferase II; St8Sia1) knockout (GD3S-KO) revealed reduction of postnatal NSC pools with severe behavioral deficits including cognitive impairment, depression-like phenotypes, and olfactory dysfunction. Exogenous administration of GD3 significantly restored the NSC pools and enhanced the stemness of NSCs with multipotency and self-renewal, followed by restored neuronal functions. Our group discovered that GD3 is involved in the maintenance of NSC fate determination by interacting with epidermal growth factor receptors (EGFRs), by modulating expression of cyclin-dependent kinase (CDK) inhibitors p27 and p21, and by regulating mitochondrial dynamics via associating a mitochondrial fission protein, the dynamin-related protein-1 (Drp1). Furthermore, we discovered that nuclear GM1 promotes neuronal differentiation by an epigenetic regulatory mechanism. GM1 binds with acetylated histones on the promoter of N-acetylgalactosaminyltransferase (GalNAcT; GM2 synthase (GM2S); B4galnt1) as well as on the NeuroD1 in differentiated neurons. In addition, epigenetic activation of the GM2S gene was detected as accompanied by an apparent induction of neuronal differentiation in NSCs responding to an exogenous supplement of GM1. Interestingly, GM1 induced epigenetic activation of the tyrosine hydroxylase (TH) gene, with recruitment of Nurr1 and PITX3, dopaminergic neuron-associated transcription factors, to the TH promoter region. In this way, GM1 epigenetically regulates dopaminergic neuron specific gene expression, and it would modify Parkinson's disease. Multifunctional gangliosides significantly modulate lipid microdomains to regulate functions of important molecules on multiple sites: the plasma membrane, mitochondrial membrane, and nuclear membrane. Versatile gangliosides regulate functional neurons as well as sustain NSC functions via modulating protein and gene activities on ganglioside microdomains. Maintaining proper ganglioside microdomains benefits healthy neuronal development and millions of senior citizens with neurodegenerative diseases. Here, we introduce how to isolate GD3 and GM1 and how to administer them into the mouse brain to investigate their functions on NSC fate determination and nerve cell specification.

Self-Assembled PD-L1 Downregulator to Boost Photodynamic Activated Tumor Immunotherapy Through CDK5 Inhibition.

The immunosuppressive characteristics and acquired immune resistance can restrain the therapy-initiated anti-tumor immunity. In this work, an antibody free programmed death receptor ligand 1 (PD-L1) downregulator (designated as CeSe) is fabricated to boost photodynamic activated immunotherapy through cyclin-dependent kinase 5 (CDK5) inhibition. Among which, FDA approved photosensitizer of chlorin e6 (Ce6) and preclinical available CDK5 inhibitor of seliciclib (Se) are utilized to prepare the nanomedicine of CeSe through self-assembly technique without drug excipient. Nanoscale CeSe exhibits an increased stability and drug delivery efficiency, contributing to intracellular production of reactive oxygen species (ROS) for robust photodynamic therapy (PDT). The PDT of CeSe can not only suppress the primary tumor growth, but also induce the immunogenic cell death (ICD) to release tumor associated antigens. More importantly, the CDK5 inhibition by CeSe can downregulate PD-L1 to re-activate the systemic anti-tumor immunity by decreasing the tumor immune escape and therapy-induced acquired immune resistance. This work provides an antibody free strategy to activate systemic immune response for metastatic tumor treatment, which may accelerate the development of translational nanomedicine with sophisticated mechanism.

Cell cycle machinery in oncology: A comprehensive review of therapeutic targets.

The cell cycle is tightly regulated to ensure controlled cell proliferation. Dysregulation of the cell cycle machinery is a hallmark of cancer that leads to unchecked growth. This review comprehensively analyzes key molecular regulators of the cell cycle and how they contribute to carcinogenesis when mutated or overexpressed. It focuses on cyclins, cyclin-dependent kinases (CDKs), CDK inhibitors, checkpoint kinases, and mitotic regulators as therapeutic targets. Promising strategies include CDK4/6 inhibitors like palbociclib, ribociclib, and abemaciclib for breast cancer treatment. Other possible targets include the anaphase-promoting complex/cyclosome (APC/C), Skp2, p21, and aurora kinase inhibitors. However, challenges with resistance have limited clinical successes so far. Future efforts should focus on combinatorial therapies, next-generation inhibitors, and biomarkers for patient selection. Targeting the cell cycle holds promise but further optimization is necessary to fully exploit it as an anti-cancer strategy across diverse malignancies.

Meningioma: Molecular Updates from the 2021 World Health Organization Classification of CNS Tumors and Imaging Correlates.

Meningiomas, the most common primary intracranial neoplasms, account for more than one-third of primary CNS tumors. While traditionally viewed as benign, meningiomas can be associated with considerable morbidity, and specific meningioma subgroups display more aggressive behavior with higher recurrence rates. The risk stratification for recurrence has been primarily associated with the World Health Organization (WHO) histopathologic grade and extent of resection. However, a growing body of literature has highlighted the value of molecular characteristics in assessing recurrence risk. While maintaining the previous classification system, the 5th edition of the 2021 WHO Classification of Central Nervous System tumors (CNS5) book expands upon the molecular information in meningiomas to help guide management. The WHO CNS5 stratifies meningioma into 3 grades (1-3) based on histopathology criteria and molecular profile. The telomerase reverse transcriptase promoter mutations and cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) deletions now signify a grade 3 meningioma with increased recurrence risk. Tumor location also correlates with underlying mutations. Cerebral convexity and most spinal meningiomas carry a 22q deletion and/or NF2 mutations, while skull base meningiomas have AKT1, TRAF7, SMO, and/or PIK3CA mutations. MRI is the primary imaging technique for diagnosing and treatment-planning of meningiomas, while DOTATATE PET imaging offers supplementary information beyond anatomic imaging. Herein, we review the evolving molecular landscape of meningiomas, emphasizing imaging/genetic biomarkers and treatment strategies relevant to neuroradiologists.

DCAF2 regulates the proliferation and differentiation of mouse progenitor spermatogonia by targeting p21 and thymine DNA glycosylase.

DDB1-Cullin-4-associated factor-2 (DCAF2, also known as DTL or CDT2), a conserved substrate recognition protein of Cullin-RING E3 ligase 4 (CRL4), recognizes and degrades several substrate proteins during the S phase to maintain cell cycle progression and genome stability. Dcaf2 mainly expressed in germ cells of human and mouse. Our study found that Dcaf2 was expressed in mouse spermatogonia and spermatocyte. The depletion of Dcaf2 in germ cells by crossing Dcaf2fl/fl mice with stimulated by retinoic acid gene 8(Stra8)-Cre mice caused a reduction in progenitor spermatogonia and differentiating spermatogonia, eventually leading to the failure of meiosis initiation and male infertility. Further studies showed that depletion of Dcaf2 in germ cells caused abnormal accumulation of the substrate proteins, cyclin-dependent kinase inhibitor 1A (p21) and thymine DNA glycosylase (TDG), decreasing of cell proliferation, increasing of DNA damage and apoptosis. Overexpression of p21 or TDG attenuates proliferation and increases DNA damage and apoptosis in GC-1 cells, which is exacerbated by co-overexpression of p21 and TDG. The findings indicate that DCAF2 maintains the proliferation and differentiation of progenitor spermatogonia by targeting the substrate proteins p21 and TDG during the S phase.

A phase 2 trial of the CDK4 inhibitor dalpiciclib in well-differentiated or dedifferentiated liposarcoma.

11547 Background: The oncogene cyclin-dependent kinase 4 (CDK4) is amplified in > 90% of well-differentiated liposarcomas (WDLS) and dedifferentiated liposarcomas (DDLS). Previous studies have already demonstrated the clinical benefit of CDK4 inhibitors in the treatment of WDLS and DDLS. Dalpiciclib is a more potent and novel CDK4 inhibitor. We designed a multi-center phase 2 study to evaluate the safety and efficacy of dalpiciclib in patients with advanced WDLS/DDLS. Methods: Eligible patients were adults aged 18 years and older, with a confirmed diagnosis of advanced WDLS/DDLS, measurable lesions according to RECIST 1.1, any (or no) priory therapy, and a history of progression by RECIST 1.1 in the 6 months prior to enrollment. All patients were required to have CDK4 amplification by fluorescence in situ hybridization and retinoblastoma (RB) protein expression by immunohistochemistry. All patients were treated with dalpiciclib 150 mg orally once per day for 21 consecutive days within a 28-day treatment cycle. The primary endpoint was progression free survival (PFS) at 12 weeks. Secondary end points included objective response rate and adverse events. Results: From August 2022 to October 2023, a total of 32 patients were enrolled, and 30 were evaluable for the primary end point. Median (range) age was 59 (40-76) years; 22 patients (69%) were male. At 12 weeks, PFS was 61.3% (95% CI, 44-78.5%). The median PFS was 17.4 weeks (95% CI, 10.65-24.15 weeks). Only one patient had a partial response to the treatment. Grade 3 to 4 events included neutropenia (37.5%), anemia (6.25%), thrombocytopenia (6.25%), and nausea (3.13%). Conclusions: Treatment with the CDK4 inhibitor dalpiciclib was associated with a favorable PFS rate in patients with advanced CDK4-amplified and RB-expressing WDLS/DDLS. Clinical trial information: ChiCTR2200062868.

Real world experience with cyclin dependent kinase inhibitors in metastatic breast cancer from India.

Real world experience with cyclin dependent kinase inhibitors in metastatic breast cancer from India.

Study on the mechanism of quercetin in Sini Decoction Plus Ginseng Soup to inhibit liver cancer and HBV virus replication through CDK1.

To explore the anti-tumor and anti-virus key active ingredients of Sini Decoction Plus Ginseng Soup (SNRS) and their mechanisms. The main ingredients of SNRS were analyzed by network pharmacology, and quercetin was identified as the key active ingredient. Then, we obtained the targets of quercetin by using Drugbank, PharmMapper, and SwissTargetPrediction databases. Then, the targets of HBV-related hepatocellular carcinoma (HBV-related HCC) were obtained by using Genecards database. In addition, using the gene expression profiles of HBV-related HCC patients in GEO database and the genes with the greatest survival difference in GEPIA 2 database identified the potential targets of quercetin. In addition, the mechanism of potential genes was studied through GO, KEGG analysis, and PPI network. Using AUC and survival analysis to evaluate the diagnostic and prognostic value of cyclin-dependent kinase 1 (CDK1) and CCNB1. Finally, the effects of quercetin on proliferation of Hep3B and HepG2215 cells and the level of CDK1 and CCNB1 were verified invitro. ELISA was used to measure the expression levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) after the intervention by quercetin for 24 h and 48 h in HepG2215 cell. The first 10 key ingredients of SNRS were identified, and quercetin was the most key ingredient. The 101 potential quercetin targets were identified for the treatment of HBV-related HCC. GO and KEGG showed that 101 potential target enrichment in cancer and cell cycle regulation. By Venn analysis, CDK1 and CCNB1 were intersection targets, which could be used as potential targets for the action of quercetin on HBV-related HCC. Moreover, the expression of CDK1 and CCNB1 was highly expressed in the high-risk group, while the OS rate was low. The 1-year, 3-year and 5-year area under the curve (AUC) curves of CDK1 and CCNB1 were 0.724, 0.676, 0.622 and 0.745, 0.678, 0.634, respectively. Moreover, experimental results also showed that quercetin inhibited cell proliferation and reduced CDK1 expression in Hep3B and HepG2215 cells. The expressions of HBsAg and HBeAg in HepG2215 cell supernatant and cell gradually decreased with the increase of intervention time of quercetin and CDK1 inhibitor. Quercetin is a key ingredient of anti-HBV-related HCC activity and inhibits HBV replication in SNRS by inhibiting CDK1.

First-in-human phase 1 study of SPH4336, a novel cyclin-dependent kinase 4/6 inhibitor, in patients with advanced solid tumors.

e15107 Background: The inhibition of cyclin-dependent kinases (CDKs) is a highly promising and attractive strategy for the development of anticancer drugs. SPH4336, a novel oral inhibitor with high selectivity and improved inhibition for CDK4/6, has demonstrated promising anti-tumor activity in preclinical studies. This was a first-in-human, multicenter, phase 1 dose-escalation and -expansion study to assess the safety, pharmacokinetics (PK) and preliminary efficacy of SPH4336 in patients with advanced solid tumors. Methods: Patients aged 18-70 years with histologically or cytologically confirmed advanced solid tumors that were refractory or intolerant to standard treatment or for which no standard treatment exists were included. Dose escalation of SPH4336 was conducted at doses of 50 mg, 100 mg, 200 mg, 300 mg, 400 mg and 600 mg once a day. Primary endpoint was to determine the maximum tolerated dose (MTD), dose-limiting toxicity (DLT) and pharmacokinetics of SPH4336. Secondary endpoints included assessment of adverse events (AEs) and efficacy. Descriptive statistics summarized safety, efficacy and PK parameters. Kaplan-Meier method was used to analyze time-to-event variables. Results: A total of 29 patients were enrolled with a median age of 55.0 years (23–66) and 72% being females. The most common tumor types were breast cancer (n=14, 48.3%) and sarcoma (n=8, 27.6%). No DLT was observed within 50 to 600 mg and MTD was not determined. Treatment-related adverse events (TRAEs) were reported in 29 (100%) patients, the most common TRAEs were white blood cell count decreased (n=21, 72.4%), diarrhea (n=20, 69.0%), neutrophil count decreased (n=19, 65.5%) and anemia (n=18, 62.1%). No grade 4 TRAEs were observed and death occurred in 1 patient (200 mg cohort) due to disease progression. Of the 27 evaluable patients, 1 patient achieved partial response lasting 169 days, and disease control rate was 59.3% (95% CI: 38.8%-77.6%). Regression of target lesion was observed in 100, 400 and 600 mg cohorts from baseline. PK assessments showed that the exposure of SPH4336 increased in a dose-dependent manner except with 600 mg dose. SPH4336 reached a steady state at 2 weeks of continuous dosing administration at 400 mg. Conclusions: This study demonstrated that SPH4336 was well tolerated at doses ranging from 50 to 600 mg dose levels. A dose of 400 mg could be considered for further clinical trials. Clinical trial information: NCT05905614 .

Synthesis, structure analysis, Hirshfeld surface studies, molecular docking studies against cyclin-dependent kinases (CDKs) of sulfonamide decorated N6-benzyl aminopurines for cancer treatment

Cyclin-dependent kinases (CDKs) are recognized as the primary regulators of the cell cycle. CDKs are over-expressed in various types of cancer. Inhibiting CDKs with small molecules can reduce tumor growth and benefit cancer patients. In the current study, sulfonamide-decorated N6-benzyl aminopurines such as ligand 1: (α- alpha (Purin-6-ylamino)-p-toluenesulfonamide) and ligand 2: (α-(2-Amino purin-6-ylamino)-p-toluenesulfonamide)) purine were synthesized and explored for their anticancer efficacy. Crystallographic analysis revealed that ligand 1 crystallizes in P-1 of the triclinic and ligand 2 molecule in C2/c or P21/c of the monoclinic systems. Hirshfeld surface and X-ray crystallographic studies discovered that ligand 2 possesses stronger noncovalent interaction ability than roscovitine. In silico analysis showed that ligand 2 had a higher binding affinity for ATP binding sites of CDK1, CDK2, and CDK4 receptors than roscovitine (a known CDK inhibitor). The enhanced binding affinity of ligand 2 with CDKs was found to be associated with strong noncovalent interactions between ligand 2 and specific amino acids in CDKs. Cytotoxicity studies were conducted on the glioblastoma cell line (U251) by incubating cells with ligands 0, 1, and 2, roscovitine, and the established anticancer drug Temozolomide (TMZ). Ligand 2 (66.12 ± 1.09 µM) demonstrated better cytotoxicity compared to ligand 1 (81.22 ± 0.30 µM), roscovitine (127.10 ± 0.47 µM), and TMZ (165.11 ± 1 µM). It was well known that CDK inhibition can lead to cell cycle arrest. Intriguingly, ligand 2 induced G2/M phase cell cycle arrest by increasing the percentage of the G2/M phase cell population from 21.08 % to 47.79 % in U251 cells. Based on these results, ligand 2 showed anticancer properties by binding to the ATP binding site of CDKs. Hence, ligand 2 can serve as a potential lead molecule in the development of effective anticancer agents.

Clinically Available and Reproducible Prediction Models for IDH and CDKN2A/B Gene Status in Adult-type Diffuse Gliomas

PurposeIsocitrate dehydrogenase (IDH) and cyclin-dependent kinase inhibitor (CDKN) 2A/B status holds important prognostic value in diffuse gliomas. We aimed to construct prediction models using clinically available and reproducible characteristics for predicting IDH-mutant and CDKN2A/B homozygous deletion in adult-type diffuse glioma patients. Materials and MethodsThis retrospective, two-center study analysed 272 patients with adult-type diffuse glioma (230 for primary cohort and 42 for external validation cohort). Two radiologists independently assessed the patients’ images according to the Visually AcceSAble Rembrandt Images (VASARI) feature set. Least absolute shrinkage and selection operator (LASSO) regression analysis was used to optimise variable selection. Multivariable logistic regression analysis was used to develop the prediction models. Calibration plots, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA) were used to validate the models. Nomograms were developed visually based on the prediction models. ResultsThe interobserver agreement between the two radiologists for VASARI features was excellent (κ range, 0.833~1). For the IDH-mutant prediction model, the area under the curves (AUCs) were 0.88-0.96 in the internal and external validation sets, For the CDKN2A/B homozygous deletion model, the AUCs were 0.80-0.86 in the internal and external validation sets. The decision curves show that both prediction models had good net benefits. ConclusionsThe prediction models which basing on VASARI and clinical features provided a reliable and clinically meaningful preoperative prediction for IDH and CDKN2A/B status in diffuse glioma patients. These findings provide a foundation for precise preoperative non-invasive diagnosis and personalized treatment approaches for adult-type diffuse glioma patients.

The impact of vitamin D levels on the progression-free survival of women with hormone receptor-positive, HER2-negative metastatic breast cancer treated with CDK4/6 inhibitors.

e13075 Background: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) halt the transition from the G1 to the S phase, a process governed by the hyperphosphorylation of the retinoblastoma (Rb) protein. Similarly, vitamin D3 has been demonstrated to induce cell cycle arrest through the inhibition of various cyclin-dependent kinases, including those responsible for phosphorylating the Rb protein. Therefore, we hypothesized that suboptimal vitamin D levels may compromise the efficacy of CDK4/6i used to treat hormone receptor (HR)-positive, HER2-negative metastatic breast cancer (MBC). Methods: We conducted a retrospective single-center study of women diagnosed with HR-positive, HER2-negative MBC and treated with any CDK4/6i between 2020 and 2023. Eligible patients were those who received at least one cycle of CDK4/6i, had a baseline 25-OH vitamin D measurement, and had a follow-up period of more than three months. Independent samples T-test, X2, and Fisher’s exact tests were used to evaluate associations between variables. Progression-free survival (PFS) was calculated using the Kaplan-Meier method and compared according to vitamin D levels using the log-rank test. Results: Among 31 patients, the mean age at diagnosis was 53 years (SD 14), 24 (77%) received CDK4/6i in the first-line setting, and 9 (29%) had suboptimal vitamin D levels (<20 ng/ml). Clinicopathological features based on vitamin D levels are shown (Table). The type of iCDK was different according to vitamin D levels (p = 0.036), with no other observed differences between groups. With a median follow-up of 26 months (95% CI 17-35) since iCDK initiation, median PFS was not reached for the entire cohort. A univariate analysis revealed that patients with suboptimal vitamin D levels had an inferior median PFS compared to patients with optimal levels (14 months [95%CI 4-24] vs. not reached [p=0.016]). Notably, no other parameter was associated with PFS in univariate analyses. Conclusions: In this cohort of Mexican patients with HR-positive, HER2-negativeMBC, suboptimal vitamin D levels adversely impacted PFS. Given the retrospective nature of this study and the limited number of patients, we emphasize the importance of studying these findings prospectively. [Table: see text]

CDKN2A deletion and radiation sensitivity in IDH-mutant astrocytomas.

2041 Background: IDH-mutant astrocytomas represent the most prevalent primary tumors in younger adults (<45yo). A substantial minority of these tumors exhibit the deletion of CDKN2A (Cyclin-Dependent Kinase Inhibitor Gene 2A). Homozygous deletion of this gene– which encodes the tumor suppressor protein p16 – is associated with a malignant phenotype and poorer prognosis in IDH-mutant astrocytoma. CDKN2A deletions are primarily observed in tumors that have received radiation therapy (RT), suggesting a potential mechanistic relationship between RT and deletion. This observation gives rise to two alternative hypotheses: either RT is causing DNA damage in irradiated cells, leading to the induction of subclonal CDKN2A deletion, or a subset of cells already possesses the CDKN2A deletion and is resistant to RT, resulting in the treatment selecting for the subsequent emergence of these cells. Here, we sought to ascertain the influence of CDKN2A deletion on IDH-mutant astrocytoma cellular response to RT. Methods: The antitumor effect of RT was evaluated in vitro using patient-derived IDH-mutant astrocytoma cells, MGG152. A homozygous CDKN2A deletion was engineered in this parental line, creating a paired line to permit an isogenic comparison between CDKN2A intact versus CDKN2A deleted tumor cells. A photon irradiator was used to deliver a range of clinically-relevant RT doses spanning from 0 to 20 gray (Gy). Differences in cell viability after a predetermined incubation period were examined and relevant statistical comparisons performed. Results: Dose-response curves in response to radiation therapy, comparing CDKN2A intact and deleted cell lines, were generated (Table). Both CDKN2A intact and deleted cell lines exhibited significant reductions in viability following radiation exposure at and above 2Gy (p < 0.001). CDKN2A-deleted cells displayed a small but significantly greater sensitivity than CDKN2A-intact at 1, 2, and 5Gy (Table). Conclusions: Our findings offer evidence indicating that p16 loss does not bestow radioresistance in IDH-mutant astrocytomas. These findings align with a hypothesis that radiotherapy (RT) might promote DNA damage, and consequently, subclonal CDKN2A deletion, in irradiated IDH-mutant tumors. [Table: see text]