Fucoxanthin inhibits the proliferation and stem cell formation of oral squamous cell carcinoma (OSCC) cells by regulating JAK/STAT3 pathway

Abstract

Purpose: To investigate the effect and regulatory mechanism of fucoxanthin (FX) on oral squamous cell carcinoma (OSCC). Methods: Human OSCC SCC9 and Cal27 cells were treated with different concentrations of FX (7.5, 15, and 30 μM) to determine cell viability, number of colonies, and apoptosis rate using methyl thiazolyl diphenyl-tetrazolium bromide (MTT) assay, crystal violet staining, and flow cytometry, respectively. In addition, the number of spheres of OSCC cells was determined by a cell sphere-forming assay. The stem cells and levels of pathway-related proteins were evaluated by western blotting. Results: Fucoxanthin decreased SCC9 and Cal27 cell viability and the number of colonies, but increased apoptosis in a dose-dependent manner. The expression levels of SOX2 and POU5F1 were down-regulated, while the number of spheres was reduced in SCC9 and Cal27 cells treated with 7.5 or 15 μM of FX (p < 0.05). Moreover, FX attenuated p-JAK/JAK and p-STAT3/STAT3 expression levels in a dose-dependent manner (p < 0.05). Conclusion: Fucoxanthin accelerates apoptosis and inhibits cell mobility and OSCC stem cell formation by suppressing JAK/STAT3 pathway in OSCC, thus providing an experimental basis for research on the anti-tumor effect of kelp extract and the development of new drugs from marine plants.