%0 Journal Article %T Extracellular Caspase-8 Dependent Apoptosis on HeLa Cancer Cells and MRC-5 Normal Cells by ICD-85 (Venom Derived Peptides) %A Abbas Zare Mirakabadi %A Ali Sarzaeem %J Iranian Journal of Cancer Prevention %D 2012 %I Shahid Beheshti University of Medical Sciences %X Background: Our previous studies revealed an inhibitory effect of ICD-85 (venom derived peptides) on MDA-MB231 and HL-60 cell lines, through induction of apoptosis. The purpose of this study was to investigate apoptosis-induced mechanism on HeLa and MRC-5 cells by ICD-85 through activation of caspase-8.Methods: Cell viability, cytosolic enzyme Lactate Dehydrogenase (LDH) and cell morphology were assessed under unexposed and ICD-85 exposed conditions.Caspase-8 activity was assayed by caspase-8 colorimetric assay Kit. Results: The results show that Inhibitory Concentration 50% (IC50) value of ICD-85 for HeLa cells at 24 h was estimated and found to be 25.32¡À2.15¦Ìg/ml. Furthermore, treatment of HeLa cells with ICD-85 at concentrations of 1.6¡Á10 and 2.6¡Á10¦Ìg/ml did not significantly increase LDH release. Morphological changes in HeLa cells on treatment with ICD-85 compared with untreated HeLa cells consistent with an apoptotic mechanism of cell death, such as cell shrinkage which finally results in the generation of apoptotic bodies. However, when MRC-5 cells were exposed to ICD-85, no significant changes in cell morphology and LDH were observed at concentrations below 2.6¡Á10¦Ìg/ml. Also, the apoptosis-induction mechanism by ICD-85 on HeLa cells was found through activation of caspase-8 and the activity of caspase-8 in HeLa cells was 1.5 folds more than its activity on MRC-5 cells. Conclusion: Therefore, the apoptosis-induced mechanisms by ICD-85 are through activation of caspase-8 and concerning the least cytotoxic effect on MRC-5 cells, ICD-85 may be used as anticancer compound to inhibit growth of cancer cells. %K Caspase-8 %K Apoptosis %K Extrinsic pathway %K Hela cells %U http://journals.sbmu.ac.ir/index.php/cp/article/view/3262/3254