H2O2 inhibits proliferation and mediates suppression of migration via DLC1/RhoA signaling in cancer cells.

Background: RhoGTPase-activating proteins (RhoGAPs) regulate RhoGTPases in cells, but whether individual reactive oxygen species (ROS) regulate RhoGAPs is unknown. Our previous published papers have shown that deleted in liver cancer 1 (DLC1) inhibits cancer cell migration by its RhoGAP activity. The present study was designed to explore the role of H2O2 in regulation of DLC1.
Materials and Methods: We treated cells with H2O2 for 24h and phenotypic changes were analyzed by MTT, RT-PCR, Western blotting, immunofluorescence staining and wound healing assays.
Results: H2O2 downregulated cyclin D1 and cyclin E to inhibit proliferation, and upregulated BAX to induce apoptosis in MCF-7 cells. Compared with non-tumorigenic cells, H2O2 increased expression of DLC1 and reduced activity of RhoA in cancer cells. Stress fiber production and migration were also suppressed by H2O2 in MDA-MB-231 cells.
Conclusions: Our study suggests that H2O2 inhibits proliferation through modulation of cell cycle and apoptosis-related genes, and inhibits migration by decreasing stress fibers via DLC1/RhoA signaling.