Identification of 8-(2-methyl phenyl)-9H-benzo[f]indeno[2,1-c]quinolin-9-one (C-5635020) as a novel and selective TGFβ RII kinase inhibitor for breast cancer therapy.

OBJECTIVE AND SIGNIFICANCE

Transforming growth factor-beta (TGF-β) plays a pivotal role in breast development by modulating tissue composition during the developmental phase. The TGFβ type II receptor (TGFβ RII) is implicated in breast cancer and represents a valuable therapeutic target. Due to the off-target side effects of many existing TGFβI/TGFβ RII inhibitors, a more targeted approach to drug discovery is necessary. This study used computational modeling and molecular dynamics simulations to screen the ChemBridge small molecule library against TGFβ RII.

METHODS

This study employed high-throughput virtual screening, molecular dynamics simulations, and binding free energy calculations to identify potential inhibitors targeting TGF-β RII. MDA-MB 231 and MCF-7 breast cancer cells were used in anti-proliferative, tans-endothelial migration, and flow cytometric assays for in vitro validations.

RESULTS

We identified 8-(2-methylphenyl)-9H-benzo[f]indeno[2,1-c]quinolin-9-one (C-5635020) as a potent and selective inhibitor. Protein-ligand modeling analysis revealed that C-5635020 targets the kinase domain of TGFβ RII with superior binding affinities compared to the standard drug, staurosporine. Computational results suggest that C-5635020 selectively binds and inhibits TGFβ RII activity, thereby controlling cell proliferation in breast cancer. In vitro, experiments corroborated these predictions, where C-5635020 inhibited TGFβ RII and p-Smad 2/3 positive population in MDAMB-231 and MCF-7 cells. The compound dose-dependently inhibited cell proliferation, trans-endothelial migration, and increased apoptosis in both breast cancer cell lines.

CONCLUSION

The strong binding affinity, stability, and favorable thermodynamics of C-5635020 with established in vitro efficacy highlight its potential as a lead compound for further preclinical and clinical developments for breast cancer treatment.