ACTX-8, a cytotoxic L-amino acid oxidase isolated from Agkistrodon acutus snake venom, induces apoptosis in Hela cervical cancer cells.
ACTX-8 is a protein isolated from Agkistrodon acutus snake venom in our laboratory. It demonstrates cytotoxic activity on various carcinoma cell lines in vitro. However, the mechanism by which ACTX-8 inhibits cell proliferation remains poorly understood. In this study the influence of ACTX-8 on the activation of apoptotic pathway in Hela cells was investigated. We demonstrated that cell death induced by ACTX-8 was concentration- and time-dependent. Apoptotic changes such as phosphatidyl serine externalization and DNA fragmentation were detected in ACTX-8-treated cells. Caspase activation and reactive oxygen species (ROS) production were involved in ACTX-8-induced apoptosis, but pan caspase inhibitor, z-VAD-fmk, could not inhibit cell death induced by ACTX-8 completely, which proved the existence of another pathway for ACTX-8-induced cell death. We found cytochrome c release into cytosol and mitochondrial membrane potential (MMP) dissipation in ACTX-8-treated cells, which indicated that mitochondrial pathway played a role in ACTX-8-induced cell apoptosis. The ratio of expression levels of pro- and anti-apoptotic Bcl-2 family members was not changed by ACTX-8 treatment. However Bad and Bax were translocated from cytosol into mitochondria, and the coimmunoprecipitation result indicated that in mitochondria Bak and Bcl-xL dissociation was followed by the binding of Bad and Bcl-xL. Taken together, the study indicated mitochondrial pathway played an important role in the ACTX-8-induced apoptosis, which was regulated by Bcl-2 family members.
Zhang
Liang
L
School of Pharmacy, Soochow University, Soochow, Jiangsu Province, 215123, China. cpuzl@163.com
Wei
Li-Jun
LJ
D017836:Agkistrodon; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000096:biosynthesis; D053453:Caspase 9 / Q000096:biosynthesis; D061945:Caspase Inhibitors; D002458:Cell Fractionation; D002470:Cell Survival / Q000187:drug effects; D003435:Crotalid Venoms / Q000737:chemistry* / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006367:HeLa Cells / Q000473:pathology; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000473:pathology*
C518366:ACTX-8 protein, Agkistrodon acutus; D000970:Antineoplastic Agents; D061945:Caspase Inhibitors; D003435:Crotalid Venoms; D004791:Enzyme Inhibitors; D010718:Phosphatidylserines; D019253:Proto-Oncogene Proteins c-bcl-2; D045304:Cytochromes c; D053148:Caspase 3; D053453:Caspase 9