ICEC0942, an Orally Bioavailable Selective Inhibitor of CDK7 for Cancer Treatment

Area of Science:

• Molecular Biology
• Cancer Research
• Pharmacology

Background:

• Cancer cells can be sensitive to transcription inhibition.
• Cyclin-dependent kinase (CDK)7 is crucial for transcription initiation and regulates transcription factors like estrogen receptor (ER)-α.
• Targeting transcriptional machinery offers novel cancer treatment strategies.

Purpose of the Study:

• To introduce and evaluate ICEC0942, a novel, orally bioavailable inhibitor of CDK7.
• To assess the efficacy of CDK7 inhibition in various cancer types.
• To explore the potential of ICEC0942 as a single agent or in combination therapy.

Main Methods:

• Development of a selective CDK7 inhibitor, ICEC0942.
• In vitro assessment of cancer cell sensitivity to CDK7 inhibition (GI50 values).
• In vivo studies using breast and colorectal cancer xenografts, including combination therapy with tamoxifen.

Main Results:

• ICEC0942 selectively inhibits CDK7 with high potency (IC50 = 40 nmol/L) and minimal off-target activity against related kinases.
• Broad in vitro sensitivity to CDK7 inhibition across various cancer types was observed (GI50 = 0.2–0.3 µmol/L).
• ICEC0942 demonstrated significant antitumor effects in breast and colorectal cancer xenografts and achieved complete growth arrest in ER-positive tumors when combined with tamoxifen.

Conclusions:

• CDK7 inhibition represents a promising new therapeutic avenue for cancer, especially ER-positive breast cancer.
• ICEC0942 is a potential drug candidate for monotherapy or combination treatment with hormone therapies.
• ICEC0942 may also benefit cancers dependent on transcription factors, such as acute leukemia and small-cell lung cancer.