CRIF1-CDK2 Interface Inhibitors: An Unprecedented Strategy for Modulation of Cell Radiosensitivity

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• Cyclin-dependent kinases (CDKs) are key regulators of the cell cycle and established cancer targets.
• CDK inhibitors often face selectivity challenges, leading to therapeutic failures.
• CR6-interacting factor 1 (CRIF1) negatively regulates cell cycle via interaction with CDK2.

Purpose of the Study:

• To identify novel small molecules targeting the CRIF1-CDK2 interaction interface.
• To evaluate the efficacy and selectivity of these inhibitors in osteosarcoma (OS) models.
• To assess the potential of these inhibitors to enhance radiosensitivity in OS cells.

Main Methods:

• In silico identification of the CRIF1-CDK2 interaction interface.
• Virtual screening of a large compound library against CRIF1.
• Cell proliferation assays using OS cell lines and bone mesenchymal stem cells (BMSC).
• Binding affinity studies and assessment of G2/M arrest and apoptosis induction.
• Evaluation of combination therapy with ionizing radiation (IR).

Main Results:

• Four compounds selectively inhibited OS cell proliferation without affecting BMSC.
• These inhibitors demonstrated significant binding affinity to CRIF1.
• Combination treatment with IR and inhibitors significantly enhanced tumor growth inhibition (from 19.9% to 59.6%).
• The inhibitors promoted G2/M arrest and apoptosis in OS cells, linked to CDK2 overactivation and phosphorylation changes.
• CRIF1 knockdown mimicked the effects of the interface inhibitors.

Conclusions:

• Novel lead molecules targeting the CRIF1-CDK2 interaction have been identified.
• These compounds offer a selective approach to CDK-targeting in cancer therapy.
• The identified inhibitors enhance the radiosensitivity of osteosarcoma cells, presenting a new therapeutic strategy.