Persian Gulf Snail Crude Venom (Conus textile): A Potential Source of Anti-Cancer Therapeutic Agents for Glioblastoma through Mitochondrial-Mediated Apoptosis

Abstract

Background: Research on animal toxins have shown toxicity potential on cancerous cell and tissues in the cultures. Conotoxins obtained from marine cone snails show the highest toxicity potential, so that several human deaths have been attributed to this species of snail. These toxins have proven to be valuable agents to inhibit enzymes, channels and proteins, in the nervous systems of humans.

Methods: We have studied the effects of Conus textile crude venom on U87MG human glioma cells and their mitochondria as main inducers of apoptosis and human embryonic kidney 293 cells (HEK293) as non-cancerous normal control cells. Cellular toxicity assessments including MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and measurement of caspase-3 activation as well as mitochondrial toxicity assays including measurement of the activity of succinate dehydrogenase (SDH) enzyme, mitochondrial swelling, reactive oxygen species (ROS) production, collapse of mitochondrial membrane potential (MMP) and cytochrome c release were performed in U87MG human glioma cells and HEK293 cells (as non-cancerous normal cells).

Results: The results illustrated the significant cytotoxic effect of Conus textile crude venom on U87MG human glioma cells, that inhibits 50% (IC50=10µg/mL) of the cell growth after 12 h of exposure. Viability measurement showed which the Conus textile crude venom is selectively cytotoxic to U87MG human glioma cells, and induced activation of caspase-3 and induction of cell apoptosis via through mitochondrial signaling. Conus textile crude venom also selectively increased mitochondria swelling, ROS formation, cytochrome c release and MMP decrease in cancerous mitochondria but not normal mitochondria. Conclusion; Based on the obtained results from this investigation, it is concluded that the Conus textile crude venom contains promising natural compounds to fight U87MG human glioma cells through activation of apoptosis intrinsic pathways.

Keywords: Apoptosis; Conotoxins; Conus Textile Crude Venom; Glioblastoma; mitochondria.