OSTEOCLASTOGENIC POTENTIAL OF ORAL CARCINOMA CELLS CAN BE MODULATED BY LOW LEVEL LASER (LLL)

Abstract

This study aimed to analyze the effect of low-level laser on the osteoclastogenic potential of a squamous cell carcinoma cell line (SCC9). Irradiated SCC9 cells (660 /780 nm; 40 /70 mW; 2, 4 and 6 J/cm2) were cultured with human osteoclast precursors (PBMC). Co-cultures with non-irradiated SCC9 cells served as control. After 7, 14 and 21 days, the co-cultures (treated or not with specific inhibitors of MEK, NFkB, p38 and JNK pathways) were evaluated for the tartrate-resistant acid phosphatase (TRAP) activity (commercial kit). Monocultures of SCC9 cells (irradiated or not) were analyzed for the expression of IL-11 and PTHrP (by PCR). Irradiated SCC9 cells+PBMC co-cultures presented a significant reduction in TRAP activity (especially with 780 nm, 70 mW irradiation). Regardless the intracellular signaling pathway inhibitor, the decrease in TRAP activity observed in the co-cultures involving irradiated SCC9 cells was more notorious with 780 nm-4 J/cm2-70 mW. SCC9 cells irradiated with a low output power (780 nm-4 J/cm2-40 mW and 660 nm-4 J/cm2-40 mW) and cultured for 2 days presented increased expression of IL-11 and PTHrP. In 9 days cultures, expression of these molecules was lower than in non-irradiated cells. Laser irradiation (780 nm/70 mw/4 J/cm2) of SCC9 cells is able to decrease the pro-osteoclastogenic potential of those cells.