The Effect of Low Intensity Laser Irradiation on Breast Cancer Cells and Breast Cancer Stem Cells

The Effect of Low Intensity Irradiation on Breast Cancer Cells and Breast Cancer Stem Cells. The mechanism by which tumor proliferation, invasiveness and recurrence are sustained in malignant cancer has not been fully elu-cidated. Taking into account the findings of previous researches, one have strong reasons to believe that it might result from a small pop-ulation of cells referred to as Cancer Stem Cells (CSCs). This study aimed to investigate and compare the photobiomodulative effect of Low Intensity Laser Irradiation (LILI) treatment on Breast Cancer Stem Cells (BCSCs) and Breast Cancer Cells (BCCs). BCSCs were isolated from the MCF-7 cell line based on their CD44+ phenotype using magnetic-activated cell sorting. CD44 antigen was detected in BCSCs using fluorescent microscopy. Cellular response to the treatment was evaluated based on their viability, proliferation and toxicity. Positive detection of CD44 confirmed the stemness of isolat ed BCSCs. Treated BCCs and BCSCs showed an increase in their proliferation and viability after being exposed to 5-40 J/cm2 using wavelengths of 636, 825 and 1060 nm. Membrane integrity assay revealed a decrease in cytotoxicity in both BCCs and BCSCs after treatment with low fluences of LILI. This study revealed that LILI did not have a bioinhibitory effect on both cell types.