Increase in cell motility by carbon ion irradiation via the Rho signaling pathway and its inhibition by the ROCK inhibitor Y-27632 in lung adenocarcinoma A549 cells

This study aimed to investigate the effect of carbon ion (c-ion) irradiation on cell motility through the ras homolog gene family member (rho) signaling pathway in the human lung adenocarcinoma cell line a549. cell motility was assessed by a wound-healing assay,and the formation of cell protrusions was evaluated by f-actin staining. cell viability was examined by the wst-1 assay. the expression of myosin light chain 2 (mlc2) and the phosphorylation of mlc2 at ser19 (p-mlc2-s19) were analyzed by western blot. at 48 h after irradiation,the wound-healing assay demonstrated that migration was significantly greater in cells irradiated with c-ion (2 or 8 gy) than in unirradiated cells. similarly,f-actin staining showed that the formation of protrusions was significantly increased in cells irradiated with c-ion (2 or 8 gy) compared with unirradiated cells. the observed increase in cell motility due to c-ion irradiation was similar to that observed due to x-ray irradiation. western-blot analysis showed that c-ion irradiation (8 gy) increased p-mlc2-s19 expression compared with in unirradiated controls,while total mlc2 expression was unchanged. exposure to a non-toxic concentration of y-27632,a specific inhibitor of rho-associated coiled-coil-forming protein kinase (rock),reduced the expression of p-mlc2-s19 after c-ion irradiation (8 gy),resulting in a significant reduction in migration. these data suggest that c-ion irradiation increases cell motility in a549 cells via the rho signaling pathway and that rock inhibition reduces that effect. © 2014 the author.