Ursolic Acid Attenuates TGF-β1-Induced Epithelial–Mesenchymal Transition in NSCLC by Targeting Integrin αVβ5/MMPs Signaling

Transforming growth factor-β1 (TGF-β1)-induced epithelial–mesenchymal transition (EMT) of non-small cell lung cancer (NSCLC) may contribute to tumor metastasis. TGF-β1-induced EMT in H1975 cells (a human NSCLC cell line) resulted in the adoption of mesenchymal responses that were predominantly mediated via the TGF-β1–integrin signaling pathway. Ursolic acid has been previously reported to inhibit tumor growth and metastasis in several cancers. However, whether ursolic acid can attenuate TGF-β1-induced EMT in H1975 cells and its underlying mechanisms remain unknown. In this study, ursolic acid significantly attenuated the TGF-β1-induced decrease in E-cadherin level and elevated the level of N-cadherin. Furthermore, ursolic acid inhibited the mesenchymal-like responses in H1975 cells, including cell migration, invasion, and activity of matrix metallopeptidase (MMP)-2 and -9. Finally, our new findings provided evidence that ursolic acid could inhibit EMT in NSCLC through TGF-β1 signaling pathway-mediated integrin αVβ5 expression, and this might be the potential mechanism of resveratrol on the inhibition of invasion and metastases in NSCLC. We conclude that ursolic acid attenuated TGF-β1-induced EMT in H1975 cells and thus might be a promising therapeutic agent for treating NSCLC.