Differential Effects of 1,25-dihydroxyvitamin D₃on Oral Squamous Cell Carcinomas In Vitro

OBJECTIVE: The inverse association between vitamin D and cancer risk is well-established, but the relationship with oral cancer is less well-understood. To further the understanding of these relationships, this study sought to evaluate any growth-inhibiting effects of vitamin D on well-characterized oral cancers. METHODS: This study utilized 1,25-dihydroxy Vitamin D3 to evaluate any changes in growth using CAL27, SCC15, and SCC25 oral cancer cell lines at physiological and supraphysiological concentrations. RESULTS: These assays revealed that the growth of all three cancer cell lines was significantly reduced by vitamin D administration, with maximal inhibition in SCC15 of -6.8% at 50 nmol, -19.7% in CAL27, and -43.6% in SCC25 at 100 nmol (p < .05). In addition, the observed decreases in growth were associated with significant decreases in viability (ranging from -18% in SCC15, -23% in CAL27, and -47% in SCC25 cells), as well as activation of two key apoptotic pathways (caspase and bcl:bax). CONCLUSION: The results of this study demonstrate the growth-inhibitory effects of vitamin D administration in specific oral cancer cell lines, which will enhance the understanding of oral oncologists and oral health researchers in developing standards for generalizing the health-protective effects of diet and dietary supplements as treatment options for patients with oral cancer.