α-Mangostin suppresses human gastric adenocarcinoma cells in vitro via blockade of Stat3 signaling pathway

Aim: To investigate the anti-tumor effects of a-mangostin, a major xanthone identified in the pericarp of mangosteen (Garcinia mangostana Linn), against human gastric adenocarcinoma cells in vitro, and the mechanisms of the effects. Methods: Human gastric adenocarcinoma cell lines BGC-823 and SGC-7901 were treated with alpha-mangostin. The cell viability was measured with MU assay, and cell apoptosis was examined using flow cytometry and TUNEL assay. The expression of the relevant proteins was detected using Western blot. Results: Treatment with a-mangostin (3-10 mu g/mL) inhibited the viability of both BGC-823 and SGC-7901 cells in dose- and time-manners. Furthermore, a-mangostin (7 mu g/mL) time-dependently increased the apoptosis index of the cancer cells, reduced the mitochondrial membrane potential of the cancer cells, and significantly increased the release of cytochrome c and AIF into cytoplasm. Moreover, the a-mangostin treatment markedly suppressed the constitutive Stat3 protein activation, and Stat3-regulated Bcl-xL and Mcl-1 protein levels in the cancer cells. Conclusion: The anti-tumor effects of alpha-mangostin against human gastric adenocarcinoma cells in vitro can be partly attributed to blockade of Stat3 signaling pathway.