Selective cytotoxic effects of low-power laser irradiation on human oral cancer cells

Wei Zhe Liang, Pei Feng Liu, Earl Fu, Hao Sheng Chung, Chung Ren Jan, Chih Hsuan Wu, Chih Wen Shu, Yao Dung Hsieh*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

16 Scopus citations


Background and Objectives Low-power laser irradiation (LPLI) is known to regulate cell proliferation and migration in clinical use. Recent studies have shown that LPLI induces cell death in some certain types of cancer cell lines. However, the cytotoxic selectivity of LPLI for cancer cells is not fully understood. The aim of this study was to compare the cytotoxic effects of LPLI in both human oral cancer OC2 cells and normal human gingival fibroblast (HGF) cells. Materials and Methods LPLI at 810 nm with an energy density from 10 to 60 J/cm2 was used to irradiate human oral cancer OC2 cells and normal HGF cells. Results We found that LPLI significantly diminished cell viability of human oral cancer OC2 cells due to cell cycle arrest at the G1 phase and the induction of cell death but that it had no or little effects on cell cycle progression and death in normal HGF cells. Moreover, the production of reactive oxygen species (ROS) and the loss of mitochondrial membrane potential (MMP) were elevated in human oral cancer OC2 cells compared with the un-irradiated cells. In contrast, these effects remained unchanged in normal HGF cells after exposure to LPLI. LPLI also induced apoptosis in caspase-3 dependent manner in human oral cancer OC2 cells, a mode of action that could be mediated by ROS and mitochondrial damage. Conclusion Our findings imply LPLI might be a potential therapy for oral cancers. Lasers Surg. Med. 47:756-764, 2015.

Original languageEnglish
Pages (from-to)756-764
Number of pages9
JournalLasers in Surgery and Medicine
Issue number9
StatePublished - 11 2015
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.


  • apoptosis
  • low-power laser irradiation
  • mitochondria membrane potential
  • oral cancer
  • reactive oxygen species


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