High energy density LED-based photobiomodulation inhibits squamous cell carcinoma progression in co-cultures in vitro

Current management of oral potentially malignant disorders is careful monitoring. Unfortunately, the 'watch and wait' approach only generates anxiety and a feeling of powerlessness, especially to those caring for patients. Photobiomodulation (PBM) has emerged as a potential strategy to inhibit possible transforming cells. The aim of this study was to investigate the effect of LED-based PBM on the progression of malignant invasion into a fibroblast-based stroma. An in vitro model of carcinoma in situ (CIS) containing stromal fibroblasts and carcinoma cells in co-culture was used to study the effect of PBM on the expansion of CIS colonies. A second model of co-culture (cells separated by membrane), was used to study cell counts, viability and apoptosis following PBM at high doses (36 J/cm²). The data was analyzed using Kruskal-Wallis, Dunn's test and non-linear regression, wherever appropriate. PBM was able to inhibit the expansion of CIS colonies as well as the total number of colonies after 72 h of treatment (p < 0.05). Cell viability, apoptosis and death assays revealed an overall advantage of stromal fibroblasts over carcinoma cells after high-dose PBM. In conclusion, LED-based PBM at high doses inhibited the progression and number of oral squamous cell carcinoma colonies without affecting the surrounding stromal fibroblasts in vitro.