Selective degradation of CDK6 by a palbociclib based PROTAC

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• Developing selective kinase inhibitors is challenging due to conserved ATP binding sites among homologous kinases.
• Palbociclib inhibits both cyclin-dependent kinase 4 (CDK4) and CDK6 with similar potency.
• Kinase inhibitors can probe enzymatic functions but not kinase-independent roles.

Purpose of the Study:

• To design and characterize a novel PROTAC (proteolysis-targeting chimera) based on palbociclib.
• To achieve selective degradation of CDK6 while sparing CDK4.
• To investigate the binding and degradation mechanism of the developed PROTAC.

Main Methods:

• Utilized a palbociclib-based PROTAC design.
• Employed competition studies to analyze binding characteristics.
• Investigated the mechanism of CDK6 degradation.

Main Results:

• Successfully developed a palbociclib-based PROTAC.
• Demonstrated selective degradation of CDK6.
• Showed that CDK4 was spared during the degradation process.
• Characterized the binding and mechanism of CDK6 degradation through competition studies.

Conclusions:

• A palbociclib-based PROTAC enables selective degradation of CDK6.
• This approach offers a potential strategy to differentiate between highly homologous kinases like CDK4 and CDK6.
• The developed PROTAC can be used to study both enzymatic and kinase-independent functions of CDK6.