title: Low-Intensity Laser Irradiation at 636 nm Induces Increased Viability and Proliferation in Isolated Lung Cancer Stem Cells.
abstract: OBJECTIVE
  The purpose of this in vitro study was to evaluate the effects of low-intensity laser irradiation (LILI) on isolated lung cancer stem cells (CSCs) after several time intervals, using a wavelength of 636 nm and fluences between 5 and 20 J/cm2.
  
  
  BACKGROUND
  LILI has been proven to have a biomodulatory effect on various diseased conditions. A number of studies have been conducted on CSCs.
  
  
  METHODS
  Lung CSCs were isolated from lung cancer cells (A549), using cell surface marker CD 133. Isolated lung CSCs were divided into four groups: group 1 consisted of control cells receiving no irradiation; groups 2, 3, and 4 were exposed to laser irradiation at fluences of 5, 10, and 20 J/cm2, respectively. LILI was performed using a 636 nm diode laser with a power output of ±85 mW. Cellular responses were evaluated after 24, 48, or 72 h, and included cell morphology, viability, and proliferation.
  
  
  RESULTS
  Cellular morphology indicated an increase in cell density caused by cell proliferation over time. Biostimulatory effects were achieved in lung CSCs when examining viability and proliferation.
  
  
  CONCLUSIONS
  It should, therefore, be noted that a low wavelength of 636 nm at various fluences induces biostimulation, which may have detrimental effects when using LILI as a form of regeneration.
authors.affiliation: Laser Research Centre, Faculty of Health Sciences, University of Johannesburg , Johannesburg, South Africa .
authors.forename: Anine
authors.initials: A
authors.lastname: Crous
authors.affiliation: Laser Research Centre, Faculty of Health Sciences, University of Johannesburg , Johannesburg, South Africa .
authors.forename: Heidi
authors.initials: H
authors.lastname: Abrahamse
mesh_terms: D000704:Analysis of Variance; D049109:Cell Proliferation / Q000528:radiation effects*; D002470:Cell Survival / Q000528:radiation effects*; D005455:Fluorescent Antibody Technique; D006801:Humans; D054023:Lasers, Semiconductor; D028022:Low-Level Light Therapy / Q000379:methods*; D008175:Lung Neoplasms / Q000532:radiotherapy; D014411:Neoplastic Stem Cells / Q000528:radiation effects*; D012016:Reference Values; D012494:Sampling Studies; D014407:Tumor Cells, Cultured / Q000528:radiation effects
keywords: cancer; photobiology; photoradiation; stem cells