Rational Design of Oxazolonylflavone Derivatives as Novel CDK4/9 Inhibitors with Potent Antitumor Efficacy and Oral...

Area of Science:

• Oncology
• Medicinal Chemistry
• Molecular Biology

Background:

• Cyclin-dependent kinases 4 and 9 (CDK4 and CDK9) are critical regulators of cell cycle and transcription.
• Concurrent inhibition of CDK4 and CDK9 shows therapeutic promise in cancer treatment.
• Natural products offer a scaffold for drug discovery, as exemplified by kushenmin K.

Purpose of the Study:

• To develop novel dual CDK4/CDK9 inhibitors based on the natural product kushenmin K.
• To evaluate the antiproliferative and pharmacokinetic properties of the novel compound HS-36.
• To assess the efficacy of HS-36 in preclinical cancer models, including resistant ones.

Main Methods:

• Screening of a natural product library identified kushenmin K.
• Structure-guided design and scaffold hopping were employed to synthesize HS-36.
• In vitro assays measured CDK4 and CDK9 inhibition, cell cycle progression, apoptosis, and antiproliferative activity.
• Pharmacokinetic profiling and in vivo efficacy studies in a xenograft model were conducted.

Main Results:

• HS-36 potently inhibited CDK4 (IC50 = 18.9 nM) and CDK9 (IC50 = 4.2 nM).
• HS-36 induced cell cycle arrest and apoptosis, demonstrating significant antiproliferative effects.
• The compound maintained efficacy in CDK4/6 inhibitor-resistant cell models.
• HS-36 exhibited favorable pharmacokinetics, including 41.8% oral bioavailability, and achieved 68.8% tumor growth inhibition in vivo.

Conclusions:

• HS-36 is a promising dual CDK4/CDK9 inhibitor with potent anticancer activity.
• The compound demonstrates efficacy in preclinical models and has a favorable pharmacokinetic profile.
• This study validates a rational drug design approach using natural product scaffolds for oncology drug development.