Evidence That beta 1-Integrin Is Required for the Anti-Viability and Anti-Proliferative Effect of Resveratrol in CRC Cells

The beta 1-integrin receptor is broadly expressed on tumor and other cells in the tumor microenvironment (TME), and is an unfavorable prognostic factor for cancers. Nature-derived resveratrol has preventive and apoptotic effects on tumors, but whether resveratrol can exert its suppressive actions on TME-induced tumorigenesis through beta 1-integrin on the surface of CRC cells is still unknown. HCT116 or SW480 cells were exposed to inhibitory antibodies against beta 1-integrin, bacitracin (selective beta 1-integrin inhibitor), integrin-binding RGD (Arg-Gly-Asp) peptide, and/or resveratrol. We evaluated the anti-tumor actions and signaling impacts of resveratrol in colorectal cancer (CRC)-TME. We found that resveratrol completely altered the beta 1-integrin distribution pattern and expression on the surface of CRC cells in TME. Moreover, resveratrol down-regulated CRC cell proliferation, colony formation, viability, and up-regulated apoptosis in a concentration-dependent way. These actions of resveratrol were antagonized mainly by inhibitory antibodies against beta 1-integrin but not beta 5-integrin, and by an integrin-binding RGD peptide but not by RGE peptide, and by bacitracin in TME. Similarly, resveratrol-blocked TME-induced p65-NF-kB and its promoted gene markers linked to proliferation (cyclin D1), invasion (focal adhesion kinase, FAK), or apoptosis (caspase-3), were largely abrogated by anti-beta 1-integrin or RGD peptide, suggesting that beta 1-integrin is a potential transmission pathway for resveratrol/integrin down-stream signaling in CRC cells. The current results highlight, for the first time, the important gateway role of beta 1-integrins as signal carriers for resveratrol on the surfaces of HCT116 and SW480 cells, and their functional cooperation for the modulatory effects of resveratrol on TME-promoted tumorigenesis.

Automated summary

This study found that resveratrol can exert its suppressive actions on tumor microenvironment (TME)-induced tumorigenesis in colorectal cancer (CRC) cells through the beta 1-integrin receptor. Resveratrol altered the distribution pattern and expression of beta 1-integrin on the surface of CRC cells in TME, leading to decreased cell proliferation and viability, and increased apoptosis. Inhibition of beta 1-integrin or interruption of downstream signaling pathway attenuated the anti-tumor effects of resveratrol. The results highlight the important role of beta 1-integrins as signal carriers for resveratrol in CRC cells.