Discovery of Orally Bioavailable and Potent CDK9 Inhibitors for Targeting Transcription Regulation in Triple-Negative...

Area of Science:

• Oncology
• Medicinal Chemistry
• Molecular Biology

Background:

• Triple-negative breast cancer (TNBC) is aggressive with limited treatment options.
• Targeting cyclin-dependent kinase 9 (CDK9) is a potential therapeutic strategy for TNBC.
• Developing orally bioavailable and selective CDK9 inhibitors is crucial.

Purpose of the Study:

• To design, synthesize, and optimize novel aminopyrazolotriazine compounds as CDK9 inhibitors.
• To evaluate the efficacy of these compounds in inhibiting TNBC cell growth and tumor progression.
• To identify potent and selective CDK9 inhibitors with favorable pharmacokinetic properties.

Main Methods:

• Synthesis and chemical optimization of aminopyrazolotriazine derivatives.
• In vitro assays to determine enzymatic activity and cellular potency against TNBC cell lines.
• In vivo studies in TNBC mouse models to assess antitumor efficacy and oral bioavailability.
• Analysis of CDK9 downstream target modulation (e.g., MCL-1) and induction of apoptosis.

Main Results:

• A new series of orally bioavailable aminopyrazolotriazine compounds targeting CDK9 were developed.
• Compound C35 exhibited low-nanomolar potency and improved selectivity for CDK9 over CDK2.
• C35 effectively downregulated CDK9 targets like MCL-1, induced apoptosis in TNBC cells, and suppressed tumor growth in vivo.
• Oral administration of C35 demonstrated significant antitumor effects in TNBC mouse models.

Conclusions:

• Targeting transcriptional regulation via CDK9 inhibition is a viable strategy for TNBC treatment.
• Compound C35 is a promising orally bioavailable and selective CDK9 inhibitor with significant preclinical efficacy.
• Further development of C35 holds potential for a novel targeted therapy for triple-negative breast cancer.