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

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.

The contribution of orexin receptors within the ventral tegmental area to modulation of antinociception induced by chemical stimulation of the lateral hypothalamus in the animal model of orofacial pain in the rats.

Involvement of the ventral tegmental area (VTA) and the lateral hypothalamus (LH) in the modulation of formalin-induced nociception is well documented. In this study, we investigated the role of orexin 1 (OX1) and orexin 2 (OX2) receptors within the VTA in modulation of the LH-induced antinociception during both phases of orofacial formalin test. Male adult Wistar rats weighing 230-250 g were unilaterally implanted with two stainless steel guide cannulae in the VTA and LH. In two separate supergroups, animals received SB334867 (OX1 receptor antagonist) or TCS OX2 29 (OX2 receptor antagonist), at the doses of 3, 10, and 30 nM/rat into the VTA before intra-LH microinjection of carbachol (250 nM/rat) as a nonselective cholinergic receptor agonist for chemical stimulation of orexinergic neurons in this region. Rats were subcutaneously injected with 1% formalin (50 µl; s) into the orofacial region, 5 min after intra-LH microinjection of carbachol or saline. The blockade of both orexin receptors in the VTA reduced intra-LH carbachol-induced antinociception. However, this effect was greater during the late phases of the orofacial formalin test. The blockade of the OX1 but not OX2 receptors in the VTA affect the pain-related behaviors during the early phase, and also, the contribution of OX2 receptor to modulate the LH-induced antinociceptive responses was greater than OX1 receptor during the late phase of orofacial formalin test. The results indicated the neural pathway projected from the LH to the VTA contributes to the modulation of formalin-induced orofacial pain. Orexinergic drugs might be considered as therapeutic agents for inflammatory pain treatment.