Grammostola spatulata Spider Venom Peptide GsMTx-4 TFA Shows Anti-cancerEffect on Liver Cancer Cells in Vitro.

Liver cancer is a common type of cancers that are building great threat to humanity. Many of the peptides derived from spider venoms have been proven to exhibit anti-cancer effect against a variety of cancers. In this study, we investigated the anti-cancer effects of a peptide, named GsMTx-4 TFA, which is derived from spider Grammostola spatulata. We first examined its cytotoxicity in 4 different doses to Escherichia coli, a common type of bacteria. Results manifested that the GsMTx-4 TFA has no cytotoxicity to Escherichia coli under any doses we have utilized in the experiment. Next, we conducted an experiment to test the cytotoxicity of GsMTx-4 TFA to cells of liver cancer, HepG-2. We found out that the peptide exhibits anti-cancer effects in a dose-dependent manner. Under relatively low doses, the cytotoxicity is pretty low, and the survival rate of cancer cell was even bigger than the control group. Moreover, it seemed that the cytotoxicity of the peptide had been lowering between 4h to 24h, showed by the rising survival rates in each group from 4h to 24h, which manifested its relatively low cytotoxicity, poor drug persistence, and the strong adaptability of liver cancer cells. Nonetheless, if the cells were exposed under high doses, their viability was obviously decreased, showing the anti-cancer effect of GsMTx-4 TFA under high concentration. Considering the previous experiments with Escherichia coli, it is possible that the GsMTx-4 TFA has selectivity to cancer cells but not normal cells like Escherichia coli. But to know whether it is also toxic to normal cells in human body, and its anti-cancer mechanisms, further research and experiments are needed to be conducted. Furthermore, the results of mRNA analysis showed that the peptide can also inhibit the growth of cancer cells by regulating the expression of some important proteins, like BAX, BCL2 and mTOR, implying one potential deep mechanism of the anti-cancer effects of the peptide.