Effect of Spider Venom on Cell Apoptosis and Necrosis Rates in MCF-7 Cells

The purpose of this study was to examine the effects of antitumor activity of the venom from the spider Macrothele raven (Araneae, Hexathelidae) on the human breast carcinoma cell line, MCF-7. The spider venom affected cell viability in a dose- and time-dependent manner as observed by [3H]-methyl thymidine incorporation assay. Cytotoxicity changes in MCF-7 cells caused by the spider venom at concentrations of 10, 20, and 40 μg/mL were determined by lactate dehydrogenase release assay. Flow cytometry showed that the spider venom induced apoptosis and necrosis of MCF-7 cells at these concentrations. MCF-7 cells treated with spider venom were accumulated on the G2/M and G0/G1 phases. In addition, Western blotting analysis indicated that one of the pharmacological mechanisms of spider venom was to activate the expression of p21. In vivo examination of the inhibition of tumor growth in nude mice by the spider venom (at concentrations of 1.6, 1.8, and 2.0 μg/g mice) revealed that tumor size significantly decrea...