Cobra venom cytotoxins; apoptotic or necrotic agents?
Organs homeostasis is controlled by a dynamic balance between cell proliferation and apoptosis. Failure to induction of apoptosis has been implicated in tumor development. Cytotoxin-I (CTX-I) and cytotoxin-II (CTX-II) are two physiologically active polypeptides found in Caspian cobra venom. Anticancer activity and mechanism of cell death induced by these toxins have been studied. The toxins were purified by different chromatographic steps and their cytotoxicity and pattern of cell death were determined by MTT, LDH release, acridine orange/ethidium bromide (AO/EtBr) double staining, flow cytometric analysis, caspase-3 activity and neutral red assays. The IC50 of CTX-II in MCF-7, HepG2, DU-145 and HL-60 was 4.1 ± 1.3, 21.2 ± 4.4, 9.4 ± 1.8 μg/mL and 16.3 ± 1.9 respectively while the IC50 of this toxin in normal MDCK cell line was 54.5 ± 3.9 μg/mL. LDH release suddenly increase after a specific toxins concentrations in all cell lines. AO/EtBr double staining, flow cytometric analysis and caspase-3 activity assay confirm dose and time-dependent induction of apoptosis by both toxins. CTX-I and CTX-II treated cells lost their lysosomal membrane integrity and couldn't uptake neutral red day. CTX-I and CTX-II showed significant anticancer activity with minimum effects on normal cells and better IC50 compared to current anticancer drug; cisplatin. They induce their apoptotic effect via lysosomal pathways and release of cathepsins to cytosol. These effects were seen in limited rage of toxins concentrations and pattern of cell death rapidly changes to necrosis by increase in toxin's concentration. In conclusion, significant apoptogenic effects of these toxins candidate them as a possible anticancer agent.
Department of Toxicology, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Niayesh Junction, Vlie-asr Street, Tehran, Iran. Electronic address: k.najafabady@sbmu.ac.ir.
Karim
K
Ebrahim
Pharmaceutical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Niayesh Junction, Vlie-asr Street, Tehran, Iran. Electronic address: f.shirazi@sbmu.ac.ir.
Farshad H
FH
Shirazi
Department of Venomous Animals and Antivenom Production, Razi Vaccine and Serum Research Institute, Hesarak, Karaj, Iran. Electronic address: zareabbas83@gmail.com.
Abbas Zare
AZ
Mirakabadi
Department of Toxicology, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Niayesh Junction, Vlie-asr Street, Tehran, Iran. Electronic address: vatanpour.hossein@gmail.com.
Hossein
H
Vatanpour
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D003603:Cytotoxins / Q000302:isolation & purification / Q000633:toxicity*; D004285:Dogs; D004546:Elapid Venoms / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D017815:Elapidae; D005434:Flow Cytometry; D018922:HL-60 Cells; D056945:Hep G2 Cells / Q000737:chemistry; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D061986:MCF-7 Cells; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D008954:Models, Biological; D009336:Necrosis / Q000139:chemically induced*
D000970:Antineoplastic Agents; D003603:Cytotoxins; D004546:Elapid Venoms; C037375:cobra cytotoxin I; D007770:L-Lactate Dehydrogenase; D053148:Caspase 3
Apoptosis; Cancer; Cobra venom; Cytotoxin-I; Cytotoxin-II