Abstract: The effects of aplysin, nature extract from Laurencia, on the proliferation and apoptosis on human breast cancer SK-BR-3 cells were investigated in this study. After treatment with aplysin at a serial of concentrations, cell proliferation was investigated by using Cell Counting Kit-8 and apoptosis was analyzed by FITC-Annexin V/PI staining via flow cytometry. The total and phosphorylated proteins of EGFR, Akt, and ERK were detected by western blot. The results showed that that aplysin was able to inhibit SK-BR-3 cell proliferation in a concentration dependent manner within the concentration range of 20, 30, 40, 45, 50, 55, and 60 mg/L. Aplysin could induce significant apoptosis at the dose of IC25 and IC50. Phosphorylation levels of the receptor of EGFR and cytoplasmic protein of Akt and ERK were significantly down-regulated by aplysin at the dose of IC25 and IC50, while their total protein expression levels were not affected. The results indicated that aplysin could inhibit SK-BR-3 cell proliferation and induce apoptosis by blocking EGFR/Akt and EGFR/ERK signal pathways.

Key words: Aplysin, terpenoid, SK-BR-3, CCK-8, apoptosis, cell signaling pathway, EGFR, Akt, ERK, phosphorylation