Extracellular Caspase-8 Dependent Apoptosis on HeLa Cancer Cells and MRC-5 Normal Cells by ICD-85 (Venom Derived Peptides)

Abstract 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±2.15µg/ml. furthermore, treatment of hela cells with icd-85 at concentrations of 1.6×10 and 2.6×10µg/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 2.6×10µg/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.