Samuraciclib HCl

Samuraciclib HCl (CAS No.: 1805789-54-1) is a synthetic ATP-competitive small-molecule inhibitor of cyclin-dependent kinase 7 (CDK7), also known as CT7001 or ICEC0942, and is commonly used as a chemical probe for studies of cell cycle and transcriptional regulation in tumor-related systems; it exhibits low-nanomolar biochemical inhibitory activity against CDK7 (representative IC50 approximately 40 nM) and shows significant kinase selectivity, with markedly reduced activity against CDK1, CDK2, CDK5, and CDK9 (selectivity approximately 45-, 15-, 230-, and 30-fold, with a CDK2 IC50 of approximately 578 nM), consistent with the characteristics of a targeted kinase inhibitor. Mechanistically, CDK7, as the catalytic subunit of the CDK-activating kinase (CAK) within the transcription factor IIH (TFIIH) complex, is responsible for phosphorylating the activation loops of CDK1, CDK2, CDK4, and CDK6, and regulates early transcriptional events through phosphorylation of the C-terminal domain of RNA polymerase II; inhibition of CDK7 can attenuate these processes and, in defined cellular models, is associated with phenotypes such as restricted transcription initiation, cell cycle arrest (including G2/M phase), and programmed cell death. In vitro, this molecule generally shows inhibitory effects on cell proliferation in the submicromolar to low-micromolar range across various tumor-derived cell lines, for example, GI50 values of approximately 0.2–0.3 μM in some breast cancer cell lines; in in vivo studies, it has been used in rodent tumor xenograft models to analyze CDK7-dependent tumor biology and transcriptional networks. Its typical research applications include target validation, pathway mapping of CDK7-dependent transcriptional programs, mechanistic elucidation of cell cycle control, and use in cascade screening within drug discovery workflows; the concentrations or doses used in experiments usually depend on the specific experimental design and research objectives. For laboratory research use only, not for human or veterinary use, clinical application, or consumption.