Effects of photobiomodulation by low power lasers on the in vitro proliferation and aggressiveness of breast cancer cells

Abstract

Through the metastatic process, cancer cells spread through the body by migrating and invading via the extracellular matrix. Photobiomodulation therapy (PBMT) on oncologic patients is controversial as it could stimulate cell proliferation and aggravate the metastatic process. Thus, this study aimed to investigate PBMT induced by low power red and infrared lasers on cell proliferation, migration and invasion and on mRNA levels from Rat sarcoma virus (RAS) oncogenes in MDA-MB-231 breast cancer cells. MDA-MB-231 cells were irradiated with low power red and infrared lasers at 25 and 50 J cm−2, cell proliferation was evaluated using water-soluble tetrazolium salt assay, cell migration was evaluated using wound healing assay, cell invasion was performed using Matrigel transwell assay and real-time quantitative polymerase chain reaction was performed to evaluate mRNA of RAS oncogenes. Exposure to low power infrared laser could increase MDA-MB-231 cell proliferation at 25 J cm−2. Neuroblastoma RAS oncogene (NRAS) mRNA relative levels reduced when irradiating with low power infrared at 25 J cm−2 and for low power red laser at 50 J cm−2. Kirsten rat sarcoma viral oncogene (KRAS) mRNA relative levels were not modified. Cell migration and invasion after exposure to low power red and infrared lasers at both fluences evaluated did not change. These results show that PBMT could modify MDA-MB-231 cell proliferation and NRAS mRNA relative levels, but no effects were found on KRAS mRNA relative levels, cell migration and invasion in both red and infrared lasers. Therefore, the screening for therapies should be tested by searching for safe conditions and herein the PBMT using red lasers altered the proliferation ratio and changed the aggressiveness phenotype of breast cancer cells.