Voruciclib treatment led to a decrease in MCL1 mRNA expression, downregulation of MYC and NF-κB transcriptional gene sets, and reduced phosphorylation of RNA polymerase II. Voruciclib on intermittent dosing was well tolerated, with no DLTs, paving the way for evaluation of the combination of voruciclib with venetoclax in patients with previously treated AML.

P1/2, N=130, Active, not recruiting, National Cancer Institute (NCI) | Trial completion date: Mar 2025 --> Jul 2029 | Trial primary completion date: Mar 2025 --> Jul 2024

P1/2, N=130, Active, not recruiting, National Cancer Institute (NCI) | Recruiting --> Active, not recruiting

CDK9 also promotes degradation of retinoic acid receptor α (RARα) via recruiting the E3 ligase HUWE1. Co-administration of CDK9-PROTAC (GT-02897) with all-trans retinoic acid (ATRA) leads to synergistic attenuation of tumor growth in vitro and in xenograft models, providing a potential translational treatment for complete eradication of CTCL.

Among the synthesised compounds, 2-(pyridin-3-yl)-4-(pyridin-3-yl)-5,6-dihydrobenzo[h]quinazoline 8b and 4-(2-(pyridin-3-yl)-5,6 dihydrobenzo[h]quinazolin-4-yl) phenol 5g exhibited potent anticancer activity compared to (R)-Roscovitine...Furthermore, the efficacy of compound 5g was validated through an in vitro CDK2/cyclin A2 enzyme inhibition assay. Interestingly, the observed CDK2 inhibitory activity showed a good correlation with the corresponding value for the antiproliferative activity of the tested compounds.

P1/2, N=280, Active, not recruiting, Kronos Bio | Recruiting --> Active, not recruiting

P1, N=110, Completed, Vincerx Pharma, Inc. | Active, not recruiting --> Completed

The results of MM/PBSA highlighted the strength of the new compounds in enhancing interactions with the target protein, which favors the results of molecular docking and MD simulation. These insights contribute to a deeper understanding of the mechanisms underlying CDK9 and CYP3A4 inhibition, offering potential avenues for the development of innovative and effective CDK9 inhibitors.

Ex-vivo studies confirmed higher efficacy of BTX-A51 on RUNX1 -mutated myeloblasts and demonstrate synergy with azacitidine and venetoclax. Although the overall efficacy was modest, this study lays the groundwork for future studies with improved patient selection and combination approaches.

FP reduced cell proliferation and induced apoptosis by inducing mitochondrial dysfunction and oxidative stress, as well as increasing BAX/BCL2 and pCDK1 levels. These results suggest that toxicity to the reproductive system should be considered when FP is used in clinical applications.

Compound 3 exhibited an IC50 of 0.30 µM for CDK2 inhibition, making it five times less active than Roscovitine, which has an IC50 of 0.06 µM. However, compound 3 demonstrated slightly better inhibition of PIM1 compared to Staurosporine. These findings suggest that compound 3 is a promising anticancer agent with the potential for further development into a highly active compound.

Furthermore, compound 29 displayed favorable oral bioavailability in mice, and oral administration of degrader 29 significantly depleted CDK9 protein in TNBC tumor tissues and exhibited tumor growth inhibition in TNBC xenograft mice models. Collectively, our work established that degrader 29 is a highly potent and selective degraders of CDK9 with satisfactory oral bioavailability, which holds promising potential for the treatment of TNBC.

CDK9 is markedly upregulated in AML patients, suggesting its potential utility as both a prognostic indicator and a therapeutic target, particularly for patients with unfavorable clinical and pathological characteristics and poor prognosis.

The three promising anti-proliferative hybrids (1a, 8a, 13a) were selected for the assessment of their in vitro inhibitory kinase activity against CDK2/GSK3β using roscovitine (IC50 = 0.88 μg mL-1) and CHIR-99021 (IC50 = 0.07 μg mL-1) as references, respectively...Moreover, it resulted in an increase in Bax and caspase-3 with a decrease in Bcl-2 levels in HepG2 cells compared with untreated cells. Finally, in silico drug likeness/ADME prediction for the three potent compounds as well as a molecular docking simulation study were conducted in order to explore the binding affinity and interactions in the binding site of each enzyme, which inspired their usage as anti-proliferative leads for further modification.

N-acetylcysteine (NAC), roscovitine and Mdivi-1 ameliorated SE-induced PV neuronal degeneration by mitigating CDK5 Y15 hyperphosphorylation, aberrant mitochondrial fragmentation and reduced GPx1-mediated NF-κB inhibition. Furthermore, SN50 (a NF-κB inhibitor) alleviated SE-induced PV neuronal degeneration, independent of dysregulation of mitochondrial fission, CDK5 hyperactivation and GPx1 downregulation. These findings provide an evidence that oxidative stress may activate CDK5-DRP1- and GPx1-NF-κB-mediated signaling pathways, which would be possible therapeutic targets for preservation of PV neurons in various diseases.

Our results indicated that dinaciclib and alvocidib exhibited similar activity and sensitivity in the neuroendocrine cluster. Also, a lineage factor named KLF5 recognized by inferred transcriptional factors activity could be suppressed by verteporfin.

Additionally, 5g and 5i demonstrated 7.80-fold and 1.54-fold greater cytotoxicity against PA-1 and MCF-7, with IC50s of 1.08 µM and 3.54 µM, respectively, compared to seliciclib (8.43 µM and 5.46 µM)...Moreover, it triggered cell death by apoptosis and cell cycle arrest in G2/M. Taken together, 5g merits further investigation in PKPD research to discover a potential therapeutic candidate against cancer.

PAAD with high MCM3 expression was sensitive to c-75, brivanib, flavopiridol and VNLG/124 drugs, with stable molecular docking models. MCM3 is likely to be a critical element in promoting the initiation and growth of PAAD. Flavopiridol may exert its anti-PAAD effect through the interaction between MCM3, classic CDK1 targets in the cell cycle checkpoint and p53 pathway as well as related molecules in other pathways.

Treatment with roscovitine-a clinically applicable Cdk5 inhibitor-alone or combined with immune checkpoint inhibitors, significantly reduces BrM burden and increases tumour-infiltrating functional CD8+ lymphocytes in mice. Thus, astrocyte-induced Cdk5 overexpression endorses BrM immune evasion, whereas therapeutically targeting Cdk5 markedly improves the efficacy of immune checkpoint inhibitors and inhibits BrM growth.

P1, N=8, Completed, Cyclacel Pharmaceuticals, Inc. | Active, not recruiting --> Completed | Trial completion date: Feb 2024 --> May 2024 | Trial primary completion date: Mar 2023 --> Feb 2024

This phosphorylation promotes the transition from transcription initiation to elongation. This review examines recent advancements in CDK9 modulators, with a particular emphasis on compounds currently in clinical trials.

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.

In the mouse model of diet-induced obesity, flavopiridol attenuated obesity-associated adipose tissue inflammation and improved serum lipid profile, glucose tolerance as well as insulin sensitivity. In conclusion, the FDA approved drug flavopiridol could be placed as a potential drug candidate for the treatment of cancer and obesity comorbid patients.

P1, N=274, Recruiting, Prelude Therapeutics | N=104 --> 274 | Trial completion date: Apr 2025 --> Mar 2026 | Trial primary completion date: Apr 2025 --> Nov 2025

Phosphorylations in both motifs depend on CDK9, catalytic subunit of positive transcription elongation factor b (P-TEFb); their different timing of accumulation on chromatin and function during the transcription cycle might reflect their removal by different phosphatases, different kinetics of phosphorylation by CDK9, or both. Perturbations of SPT5 regulation have profound impacts on viability and development in model organisms through largely unknown mechanisms, while enzymes that modify SPT5 have emerged as potential therapeutic targets in cancer; elucidating a putative SPT5 code is therefore a high priority.

Molecular docking revealed a strong interaction between Vitexin and CDK1 (Docking score - 9.497), with molecular dynamics simulations confirming the stability of the Vitexin-CDK1 complex and comparable inhibitory effects to Flavopiridol. Vitexin can inhibit the expression of CDK1/cyclin B proteins in HCT-116 cells, with an IC50 of 58.06 ± 3.07 μmol/L. Vitexin may inhibit colon cancer HCT-116 cell proliferation by suppressing CDK1/cyclin B expression, leading to cell cycle arrest in the G2/M phase.

Starting from BTX-A51, a CK1α inhibitor that also targets CDK7 and CDK9, we designed and synthesized a series of 2,4-diaminopyrimidine derivatives as potent CDK7 inhibitors...Compound 22 effectively inhibited the phosphorylation of RNA polymerase II and CDK2 and resulted in G1/S phase cell cycle arrest and apoptosis in MV4-11 cells. It appears to be a promising lead compound for the development of a CDK7 inhibitor for cancer therapy.

Our work demonstrates that CDK9 inhibition disrupts multiple oncogenic pathways and positions CDKI-73 as a promising therapeutic agent for prostate cancer, particularly aggressive, therapy-resistant subtypes.

While inhibition of known RUNX1 serine/threonine kinases does not affect phosphoserine RUNX1 levels in primary MEP, specific inhibition of CDK9 in MEP leads to both decreased RUNX1 phosphorylation and increased erythroid commitment. Collectively, our findings show that serine/threonine phosphorylation of RUNX1 promotes Mk fate specification and introduce a novel kinase for RUNX1 linking the fundamental transcriptional machinery with activation of a cell-type specific transcription factor.

CDK9 inhibitors AZD4573 and atuveciclib reduced the IFN-γ induced PD-L1 expression in a dose-dependent manner. In conclusion, CDK9 inhibition could reduce the expression of PD-L1 in HCC cells. Using both CDK9 inhibitors and anti-PD-L1 antibodies is more effective than using either agent alone.

P2, N=53, Recruiting, Changzhou Qianhong Bio-pharma Co., Ltd.

The CDK inhibitor dinaciclib exhibited anti-tumorigenic properties both in vitro and in vivo in EHE models. Dinaciclib has been rigorously tested in clinical trials and displayed an acceptable toxicity profile. Therefore, there is a potential therapeutic window for repurposing dinaciclib for the treatment of EHE.

In conclusion, wogonin protects against BLM-induced PF in mice through the inhibition of cell senescence via the regulation of CDK9/p53 and DNA damage pathway. This is the first study to demonstrate the beneficial effect of wogonin on PF, and its implication as a novel candidate for PF therapy.

Patients in low ASR group responded more actively to traditional chemotherapy drugs (Erlotinib and Roscovitine). CellChat analysis revealed that high ARS cell groups communicated with immune cells via SPP1 (ITGA4-ITGB1) and MK (MDK-NCl) signaling pathways. In this research, integrative analysis based on the ARS model provided a potential direction for improving the diagnosis and treatment of LUAD.

In this study, we first demonstrated that CDIP1 was upregulated after treatment with the anticancer drug adriamycin in human breast cancer MCF-7 cells but was degraded rapidly in the lysosomal pathway. We also demonstrated that treatment with the cyclin-dependent kinase 5 (CDK5) inhibitor roscovitine led to an increase in the electrophoretic mobility of CDIP1...Treatment of cells expressing CDIP1 with SAR405, an inhibitor of the class III phosphatidylinositol 3-kinase VPS34, caused a reduction in autophagy and promoted apoptosis. Therefore, autophagy is thought to be a defense mechanism against CDIP1 expression-induced apoptosis.

Additionally, L055 suppressed the growth of organoids and tumors derived from T47D and MCF7 cells in nude mice. Thus, L055 represents a potential novel therapeutic agent for ERα-positive breast cancer and potentially other malignancies.

Enitociclib potently inhibited in vivo tumor growth of cell line-derived and patient-derived xenografts having therapeutic resistance. Our data demonstrate the potency of enitociclib in overcoming therapeutic resistance in MCL models and provide evidence in favor of its clinical investigation.

Moreover, with the desired oral bioavailability, oral administration of C35 could significantly suppress the tumor progression in two TNBC mouse models. This study demonstrates that target transcriptional regulation is an effective strategy and holds promising potential as a targeted therapy for the treatment of TNBC.

We propose a novel regulatory paradigm in which the activation of CDK7/CDK9-Rpb1 by nuclear proteostatic stress mediates transcriptional regulation to prime cancer cell paraptosis.

Currently, there are several CDK9 inhibitors in preclinical and clinical investigations. This review aims to highlight the recent discovery and results on the transcriptional role and therapeutic potential of CDK9 in sarcoma.

P1/2, N=160, Recruiting, Sellas Life Sciences Group | Trial completion date: Jun 2024 --> Dec 2025 | Trial primary completion date: Jun 2024 --> Jun 2025

In addition, cotreatment with Venetoclax and Flavopiridol significantly reduced the expression of endogenous mcl1a compared to vehicle, consist with AML. This new model of MLL-r-AML provides a novel tool to understand the molecular mechanisms underlying disease progression and a platform for drug discovery.