In vitro anti-tumor effect of low-power laser irradiation (LPLI) on gastroenterological carcinoma cells

Primary hepatocellular carcinoma (HCC) and colon carcinoma are two of the most common clinical malignancies along with high morbidity and mortality. As low-power laser irradiation (LPLI) can induce cytotoxicity or cell apoptosis on several types of hyperplasia, LPLI may be a potential alternative treatment for gastroenterological cancers. The current in vitro study focused on LPLI-induced apoptosis and mechanism after 532-nm laser irradiation on two different carcinoma cells. Squamous cell carcinoma (VX2) and murine colon carcinoma (CT26) cells were cultured to test the feasibility of LPLI. The applied fluence varied from 0 to 600 J/cm(2). 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide analysis, fluorescence imaging, wound healing assay, and cell apoptosis tests were performed 24 h post-irradiation to monitor cellular responses. The current results demonstrated a dose-dependent stimulatory effect of LPLI on the cell viability, migration, and apoptosis of VX2 and CT26 cells. The therapeutic fluence of 600 J/cm(2) induced statistically significant inhibition in cell viability. Both the wound healing assay and the cell apoptosis tests confirmed that LPLI with high fluences could inhibit cell migration as well as induce cell apoptosis. The current findings demonstrate that LPLI might be a potential treatment for the carcinoma cells. Further studies will be performed to evaluate the feasibility of LPLI in in vivo tumor models.