Epigallocatechin gallate inhibits the growth of salivary adenoid cystic carcinoma cells via the EGFR/Erk signal transduction pathway and the mitochondria apoptosis pathway

Abstract

ACC is one of the most malignant tumors in salivary gland, and of poor prognosis. A critical role in ACC development and progression is played by EGFR family members including EGFR. EGCG, a low molecular weight polyphenol contained in green tea, has broad anticancer properties, but whether EGCG regulates activity of ACC is unknown. In the present study, the effects of EGCG were investigated in vitro with particular attention to the pathway of EGFR/Erk and mitochondria apoptosis in SACC-83 cell lines. The results of MTS assay and flow cytometry demonstrated that EGCG (20-80 μM) could inhibit proliferation and promote apoptosis of SACC-83 cells. Furthermore, by Western blotting with antibodies specific for EGFR, Erk 1/2 (p-Erk 1/2), Mek (p-Mek), Bcl-2, and Bax, it was demonstrated that EGCG could reduce the expression of EGFR, inhibit phosphorylation of Erk 1/2 and Mek, downregulate Bcl-2, and upregulate Bax. In addition, it was also shown that EGCG could inhibit mRNA expression of P90 RSK by RT-PCR. In conclusion, the results suggest that EGCG might be a potential therapeutic or adjuvant strategy for the treatment of patients with ACC, by inhibiting proliferation and inducing the apoptosis of the tumor cells.