WSG, a glucose-enriched polysaccharide from Ganoderma lucidum, suppresses tongue cancer cells via inhibition of EGFR-mediated signaling and potentiates cisplatin-induced apoptosis

Tongue cancer, a kind of oral cancer, is common in Southeast Asian countries because of dietary habits. However, there is no specific targeted drug that could effectively inhibit oral cancer. WSG, as a water soluble glucose-enriched polysaccharide from Ganoderma lucidum, exerts excellent pharmacological efficacy of anti-lung cancer. However, its anticancer functions and mechanisms in human tongue cancer need to be further explored. Herein, we showed that WSG dramatically reduced cell viability and colony formation of tongue cancer cells. WSG increased subG1 and G2/M populations as well as induced apoptotic responses. In parallel, WSG enhanced apoptosis-related Bax/Bcl2 ratio. Mechanistic studies showed that WSG reduced phosphorylation of EGFR and AKT. In addition, we found a synergistic effect of WSG with cisplatin in inhibition of cell viability and induction of apoptosis. WSG significantly reduced the inhibition concentration 50% (IC50) of cisplatin. More importantly, WSG ameliorated cisplatin-induced cytotoxicity in normal human oral epithelial SG cells. In conclusion, our findings provided important insights into the anti-tongue cancer effects of WSG via inhibition of EGFR/AKT axis and induction of apoptosis, which indicated that WSG could be a promising supplement for tongue cancer treatment.