Echinoside A from Pearsonothuria graeffei Exert the Cytotoxicity to MDA-MB-231 Cells via Mitochondrial Membrane and Modulation of PI3K/Akt/mTOR Pathway

A kind of triterpene glycosides echinoside A (EA) was extracted from sea cucumber Pearsonothuria graeffei, and its yield was about 0.78%. The purity of EA was 99.0%, and its molecular weight was 1206 Da. EA was a linear tetrasaccharide attached to a pentacyclic triterpene aglycon. It inhibited the growth of MDA-MB-231 cells in vitro. The antitumor effect was related to elevate ROS level, decrease mitochondrial membrane potential, enhance caspase-3 expression, induce cells apoptosis and arrest cell cycle at G2/M phase. EA also dose-dependently suppressed the expressions of phophorylation proteins p-PI3K, p-Akt, and p-mTOR as analyzed by western blotting. These results suggested that EA caused MDA-MB-231 cells apoptosis via intrinsic mitochondrial and PI3K/Akt/mTOR pathway. EA can be a potential anti-breast cancer agent to enhance the clinical efficacy.