Impact of blue 465nm LED on suppression of cancer growth.

767 Background: Recent studies demonstrate the efficacy of irradiation from light emitting diodes (LED) for wound healing and anti-inflammation and anti-cancertherapies. In this study, the blue LED (465nm) suppressed the tumor growth in various cancers. Methods: < Experiment 1, Effect of blue LED on colon cancer > Human colon cancer cells (HT29 or HCT116) were seeded onto laboratory dishes that were put on LED irradiation equipment with a blue LED (465 nm). Irradiation at 15 or 30 mW was performed 10 min/day, each day for 5 days. Cell counting kit8 was then used to measure cell viability. Apoptosis and expression of several mRNAs (caspase, MAPK and autophagy pathway) in HT29 cultures irradiated with 465 nm LED were evaluated via AnnexinV/PI and RT-PCR, respectively. < Experiment 2, Effect of blue LED on pancreas cancer > Human colon cancer cells (SUIT2) were examined by same way and additionally cell cycle was checked. < Experiment 3, Effect of LED on CSCs > Cancer sphere were seeded onto laboratory dishes that were then put on LED irradiation equipment with a 465 nm-LED. Stemness gene and cell surface markers of CSCs expressions were analyzed by RT-PCR. Results: < Experiment 1 > Viability of HT29 and HCT116 cells was lower in blue LED irradiated cultures than in control cultures. Moreover, the expression of FAS, caspase3, capase8, and JUK were significantly higher in 465 nm-LED irradiated cultures than in control cultures, and expression of ERK1/2 and LC3 was lower in blue LED-irradiated cells. < Experiment 2 > Viability of SUIT2 cells was lower in blue LED irradiated cultures than in control cultures. And the CCND1 mRNA expression was significantly lower in blue LED group (p < 0.05). The cells of phase G2/M was decreased. < Experiment 3 > Cell viability of cancer sphere were significantly decreased by LED irradiation(p < 0.05). And, stemness gene and cell surface markers of CSCs expressions were significantly decreased by LED irradiation (p < 0.05) Conclusions: Blue LED irradiation inhibited tumor growth in various cancer cell lines.