Identification of Novel PKC Alpha Inhibitors: Structural and Functional Characterization Using In Silico and In Vitro Studies.

INTRODUCTION Protein Kinase C alpha (PKCα), a key regulator of cellular signaling, is frequently dysregulated in breast cancer. Despite its clinical relevance, there is a dearth of selective and safe PKCα inhibitors. This study aims to identify and characterize novel PKCα inhibitors using computational and experimental methodologies.

Methods

A structure-based virtual screening of the Enamine Hinge Binders Library against the PKCα receptor (PDB ID: 3IW4) was performed using the Glide module of Schrödinger Suite. Analysis of docking scores, protein-ligand interactions, binding free energies, and ADMET profiles helped identify lead candidates. The stability of protein-ligand complexes was confirmed using MD simulations. The functional activity of identified candidates was validated using a kinase assay, and cell death was analyzed using an MTT assay on breast cancer cell lines.

Results

Compounds Z3077775938 (P1) and Z22177390 (P2) exhibited strong binding and stability within the hinge-binding region of PKCα and showed favorable drug-likeness profiles. Structural analysis revealed P1 and P2 as novel scaffolds. The kinase assay revealed dosedependent inhibition of PKCα's ATP-binding activity with IC50 values of P1 and P2 as 0.92 nM and 15.27 nM, respectively. Both compounds induced dose-dependent cytotoxicity in breast cancer cells.

Discussion

This study identified two novel, structurally diverse PKCα inhibitors. Their low IC50 values and dose-dependent cytotoxicity, as observed in both ER+ and triple-negative breast cancer cell lines, validate their functional efficacy and highlight therapeutic potential for breast cancer treatment.

Conclusion

Overall, this study identified two PKCα inhibitors that provide a foundation for further optimization as selective therapeutic agents in PKCα-driven malignancies.