Autophagy upregulation may explain inhibition of oral carcinoma in situ by photobiomodulation in vitro

There is currently no clear understanding on the pathways involved in the process of cell inhibition by photobiomodulation (PBM). The present study evaluated the influence of PBM on the expression of autophagy markers in vitro in an in situ model of oral carcinoma. Oral squamous cell carcinoma (Cal27) and stromal fibroblasts (FG) cultures were used. The independent variables were ‘cell type’ (FG and CAL27) ‘culture condition’ (monocultures or co-cultures) and PBM (placebo and 36 J/cm2). The cultures were irradiated from a red LED source for mRNA expression and protein expression analyses. The autophagy markers evaluated were Beclin-1, LC3B and p62 as well as adjuvant markers (BAX Bcl-2, VEGF, CD105, CD34, PRDX1, PRDX4 and GRP78). The Cal27 cells upregulated the autophagy markers upon exposure to PBM both at the mRNA and protein expression levels, providing evidence to explain malignant cell inhibition by PBM. •Photobiomodulation triggers autophagy markers in oral carcinoma cells.•Upregulation of autophagy markers inhibit cell proliferation in vitro.•Co-cultures of malignant and stromal cells behave differently to isolated cells.•Manipulation of autophagy could be a strategy to treat oral carcinoma in vivo.