A novel kinase inhibitor, LZT-106, downregulates Mcl-1 and sensitizes colorectal cancer cells to BH3 mimetic ABT-199 by targeting CDK9 and GSK-3β signaling

Heterocyclic Compounds as CDK9 Inhibitors: Structural Diversity, Mechanism of Action, and Therapeutic Potential in Cancer and Beyond

Cyclin-dependent kinases (CDKs) are crucial proteins involved in key cellular processes, such as cell division and transcription. Their dysregulation plays a significant role in cancer development. Inhibiting cyclin-dependent kinase 9 (CDK9) impacts several survival pathways in cancer cells, presenting a promising therapeutic approach for various cancers. CDK9, in association with cyclin T1, forms the positive transcription elongation factor b (P-TEFb) complex, which phosphorylates the C-terminal domain (CTD) of RNA polymerase II (Pol II). 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.

CDK9 inhibitors for the treatment of solid tumors

Cyclin-dependent kinase 9 (CDK9) regulates mRNA transcription by promoting RNA Pol II elongation. CDK9 is now emerging as a potential therapeutic target for cancer, since its overexpression has been found to correlate with cancer development and worse clinical outcomes. While much work on CDK9 inhibition has focused on hematologic malignancies, the role of this cancer driver in solid tumors is starting to come into focus. Many solid cancers also overexpress CDK9 and depend on its activity to promote downstream oncogenic signaling pathways. In this review, we summarize the latest knowledge of CDK9 biology in solid tumors and the studies of small molecule CDK9 inhibitors. We discuss the results of the latest clinical trials of CDK9 inhibitors in solid tumors, with a focus on key issues to consider for improving the therapeutic impact of this drug class.

Advances in Cancer Therapy: A Comprehensive Review of CDK and EGFR Inhibitors

Protein kinases have essential responsibilities in controlling several cellular processes, and their abnormal regulation is strongly related to the development of cancer. The implementation of protein kinase inhibitors has significantly transformed cancer therapy by modifying treatment strategies. These inhibitors have received substantial FDA clearance in recent decades. Protein kinases have emerged as primary objectives for therapeutic interventions, particularly in the context of cancer treatment. At present, 69 therapeutics have been approved by the FDA that target approximately 24 protein kinases, which are specifically prescribed for the treatment of neoplastic illnesses. These novel agents specifically inhibit certain protein kinases, such as receptor protein-tyrosine kinases, protein-serine/threonine kinases, dual-specificity kinases, nonreceptor protein-tyrosine kinases, and receptor protein-tyrosine kinases. This review presents a comprehensive overview of novel targets of kinase inhibitors, with a specific focus on cyclin-dependent kinases (CDKs) and epidermal growth factor receptor (EGFR). The majority of the reviewed studies commenced with an assessment of cancer cell lines and concluded with a comprehensive biological evaluation of individual kinase targets. The reviewed articles provide detailed information on the structural features of potent anticancer agents and their specific activity, which refers to their ability to selectively inhibit cancer-promoting kinases including CDKs and EGFR. Additionally, the latest FDA-approved anticancer agents targeting these enzymes were highlighted accordingly.

Identification of a Novel Selective CDK9 Inhibitor for the Treatment of CRC: Design, Synthesis, and Biological Activity Evaluation

Cyclin-dependent kinase 9 (CDK9) is a member of the transcription CDK subfamily. In this work, we preliminarily demonstrated the feasibility of CDK9 as a potent target of treatment for colorectal cancer, and a series of novel CDK9 inhibitors were rationally designed and synthesized based on the structure of AZD5438 (a pan CDKs inhibitor reported by AstraZeneca). A novel selective CDK9 inhibitor named CLZX-205, which possessed significant CDK9 inhibitory activity (IC50 = 2.9 nM) with acceptable pharmacokinetic properties and antitumor efficacy in vitro and in vivo, was developed. Research on the mechanism indicated that CLZX-205 could induce apoptosis in the HCT116 cell line by inhibiting phosphorylation of RNA polymerase II at Ser2, which resulted in the inhibition of apoptosis-related genes and proteins expression, and these results were validated at the cellular and tumor tissue levels. Currently, CLZX-205 is undergoing further research as a promising candidate for CRC treatment.

Discovery of Selective and Potent Macrocyclic CDK9 Inhibitors for the Treatment of Osimertinib-Resistant Non-Small-Cell Lung Cancer

Effectiveness of epidermal growth factor receptor (EGFR) inhibitors, including Osimertinib, for treating non-small-cell lung cancer (NSCLC) is limited due to the continuous emergence of drug resistance. Hence, it is urgent to develop new therapeutic approaches. CDK9, a key regulator of RNA transcription, has emerged as a promising target for the development of antitumor drugs due to its crucial role in modulating the levels of antiapoptotic protein Mcl-1. Herein, we present the synthesis, optimization, and evaluation of selective CDK9 inhibitors with a macrocyclic scaffold that effectively suppresses the growth of NSCLC cells. Notably, compound Z11, a potent CDK9 inhibitor (IC50 = 3.20 nM) with good kinase selectivity, significantly inhibits cell proliferation and colony formation and induces apoptosis in Osimertinib-resistant H1975 cells. Furthermore, Z11 demonstrates a significant suppression of tumor growth in six patient-derived organoids, including three organoids resistant to Osimertinib. Overall, Z11 served as a promising macrocycle-based CDK9 inhibitor for treating Osimertinib-resistant NSCLC.

Current Advances and Future Strategies for BCL-2 Inhibitors: Potent Weapons against Cancers

Targeting the intrinsic apoptotic pathway regulated by B-cell lymphoma-2 (BCL-2) antiapoptotic proteins can overcome the evasion of apoptosis in cancer cells. BCL-2 inhibitors have evolved into an important means of treating cancers by inducing tumor cell apoptosis. As the most extensively investigated BCL-2 inhibitor, venetoclax is highly selective for BCL-2 and can effectively inhibit tumor survival. Its emergence and development have significantly influenced the therapeutic landscape of hematological malignancies, especially in chronic lymphocytic leukemia and acute myeloid leukemia, in which it has been clearly incorporated into the recommended treatment regimens. In addition, the considerable efficacy of venetoclax in combination with other agents has been demonstrated in relapsed and refractory multiple myeloma and certain lymphomas. Although venetoclax plays a prominent antitumor role in preclinical experiments and clinical trials, large individual differences in treatment outcomes have been characterized in real-world patient populations, and reduced drug sensitivity will lead to disease recurrence or progression. The therapeutic efficacy may vary widely in patients with different molecular characteristics, and key genetic mutations potentially result in differential sensitivities to venetoclax. The identification and validation of more novel biomarkers are required to accurately predict the effectiveness of BCL-2 inhibition therapy. Furthermore, we summarize the recent research progress relating to the use of BCL-2 inhibitors in solid tumor treatment and demonstrate that a wealth of preclinical models have shown promising results through combination therapies. The applications of venetoclax in solid tumors warrant further clinical investigation to define its prospects.

A patent review of selective CDK9 inhibitors in treating cancer

INTRODUCTION

The dysregulation of CDK9 protein is greatly related to the proliferation and differentiation of various cancers due to its key role in the regulation of RNA transcription. Moreover, CDK9 inhibition can markedly downregulate the anti-apoptotic protein Mcl-1 which is essential for the survival of tumors. Thus, targeting CDK9 is considered to be a promising strategy for antitumor drug development, and the development of selective CDK9 inhibitors has gained increasing attention.

AREAS COVERED

This review focuses on the development of selective CDK9 inhibitors reported in patent publications during the period 2020-2022, which were searched from SciFinder and Cortellis Drug Discovery Intelligence.

EXPERT OPINION

Given that pan-CDK9 inhibitors may lead to serious side effects due to poor selectivity, the investigation of selective CDK9 inhibitors has attracted widespread attention. CDK9 inhibitors make some advance in treating solid tumors and possess the therapeutic potential in EGFR-mutant lung cancer. CDK9 inhibitors with short half-life and intravenous administration might result in transient target engagement and contribute to a better safety profile in vivo. However, more efforts are urgently needed to accelerate the development of CDK9 inhibitors, including the research on new binding modes between ligand and receptor or new protein binding sites.

High-throughput screening identifies stevioside as a potent agent to induce apoptosis in bladder cancer cells

BACKGROUND

Bladder cancer (BC) is a global health issue that lacks effective treatment strategies. Growing evidence suggests that various natural products possess anti-tumour effects. This study aims to identify a novel agent that can be used in the treatment of BC.

METHODS

High-throughput screening was conducted to search for potential anti-BC natural agents. Cell viabilities were measured by the CCK-8 assay. Cell death, cellular reactive oxygen species (ROS), and mitochondrial outer membrane potential (MOMP) were measured by flow cytometry. RNA sequencing was conducted to identify the affected signalling pathways. Western blots were used to measure the change of proteins. Xenografts models were used to assess the anti-tumour effects in vivo.

RESULTS

Through high-throughput screening, we identified stevioside, a diterpenoid glycoside isolated from Stevia rebaudiana, which selectively inhibited the viability of BC cells and induced their intrinsic apoptosis sparing normal cells. Stevioside also induced mitochondrial stress in BC cells, and activated Bax by downregulating Mcl-1 and upregulating Noxa. RNA sequencing revealed that stevioside treatment caused activation of GSK-3β and endoplasmic reticulum (ER) stress signalling pathways. Activation of GSK-3β induced upregulation of FBXW7, which effectuated the downregulation of Mcl-1. In addition, activation of GSK-3β triggered ER stress, leading to the upregulation of Noxa. Further investigations revealed that the accumulation of ROS was responsible for the activation of the GSK-3β signalling pathway in BC cells. Moreover, we also found that stevioside inhibited the growth of BC cells in vivo.

CONCLUSIONS

Collectively, our data suggest that stevioside can be a potential agent for the treatment of BC.

CDK9 Inhibitors in Cancer Research

Cyclin dependent kinase 9 (CDK9) played an essential role in regulating transcriptional elongation. Aberrations in CDK9 activity have been observed in various cancers, which made CDK9 was an attractive therapeutic...

BH3-mimetics: recent developments in cancer therapy

The hopeful outcomes from 30 years of research in BH3-mimetics have indeed served a number of solid paradigms for targeting intermediates from the apoptosis pathway in a variety of diseased states. Not only have such rational approaches in drug design yielded several key therapeutics, such outputs have also offered insights into the integrated mechanistic aspects of basic and clinical research at the genetics level for the future. In no other area of medical research have the effects of such work been felt, than in cancer research, through targeting the BAX-Bcl-2 protein-protein interactions. With these promising outputs in mind, several mimetics, and their potential therapeutic applications, have also been developed for several other pathological conditions, such as cardiovascular disease and tissue fibrosis, thus highlighting the universal importance of the intrinsic arm of the apoptosis pathway and its input to general tissue homeostasis. Considering such recent developments, and in a field that has generated so much scientific interest, we take stock of how the broadening area of BH3-mimetics has developed and diversified, with a focus on their uses in single and combined cancer treatment regimens and recently explored therapeutic delivery methods that may aid the development of future therapeutics of this nature.