Open AccessBlue light‐emitting diodes induce autophagy in colon cancer cells by Opsin 3
Author(s) -
Yoshimoto Toshiaki,
Morine Yuji,
Takasu Chie,
Feng Rui,
Ikemoto Tetsuya,
Yoshikawa Kozo,
Iwahashi Syuichi,
Saito Yu,
Kashihara Hideya,
Akutagawa Masatake,
Emoto Takahiro,
Kinouchi Yosuke,
Shimada Mitsuo
Publication year - 2018
Publication title -
annals of gastroenterological surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.308
H-Index - 15
ISSN - 2475-0328
DOI - 10.1002/ags3.12055
Subject(s) - gene knockdown , viability assay , apoptosis , autophagy , microbiology and biotechnology , cell culture , cancer research , programmed cell death , cancer cell , chemistry , biology , cancer , biochemistry , genetics
Background Light emitting‐diodes ( LED ) have various effects on living organisms and recent studies have shown the efficacy of visible light irradiation from LED for anticancer therapies. However, the mechanism of LED 's effects on cancer cells remains unclear. The aim of the present study was to investigate the effects of LED on colon cancer cell lines and the role of photoreceptor Opsin 3 (Opn3) on LED irradiation in vitro. Methods Human colon cancer cells ( HT ‐29 or HCT ‐116) were seeded onto laboratory dishes and irradiated with 465‐nm LED at 30 mW /cm 2 for 30 minutes. Cell Counting Kit‐8 was used to measure cell viability, and apoptosis and caspase 3/8 expression were evaluated by AnnexinV/ PI and reverse transcription‐polymerase chain reaction ( RT ‐ PCR ), respectively. Autophagy and expression of LC ‐3 and beclin‐1 were also evaluated by autophagy assays, RT ‐ PCR and Western blotting. We further tested Opn3 knockdown by Opn3 si RNA and the G i/o G‐protein inhibitor NF 023 in these assays. Results Viability of HT ‐29 and HCT ‐116 cells was lower in 465‐nm LED ‐irradiated cultures than in control cultures. LC ‐3 and beclin‐1 expressions were significantly higher in LED ‐irradiated cultures, and autophagosomes were detected in irradiated cells. The reductive effect of cancer cell viability following blue LED irradiation was reversed by Opn3 knockdown or NF 023 treatment. Furthermore, increased LC ‐3 and beclin‐1 expression that resulted from blue LED irradiation was suppressed by Opn3 knockdown or NF 023 treatment. Conclusion Blue LED irradiation suppressed the growth of colon cancer cells and Opn3 may play an important role as a photoreceptor.