title: Cytotoxic effect of ICD-85 (venom-derived peptides) on HeLa cancer cell line and normal LK cells using MTT Assay.
abstract: BACKGROUND
  Cancer is the fifth leading cause of death worldwide. There are considerable efforts to identify naturally occurring substances for use as new drugs in cancer therapy. Some components of animal venoms have been identified that possess substantial anticancer properties. In our previous studies, the cytotoxic effects of ICD-85 (venom-derived peptides) have been reported on HL-60 and MDA-MB231 cell lines. This has prompted us to investigate the comparative cytotoxic effects of ICD-85 on the HeLa cell line and normal lamb kidney (LK) cells.
  
  
  METHODS
  Cells were exposed to various concentrations (8 × 10-4 to 5.6 × 10 µg/ml) of ICD-85 at various incubation times (24, 48 and 72 hours). Cell viability was measured by the MTT assay. A morphological study was also carried out using an inverted microscope. Caspase-8 activity was assayed by the Caspase-8 Colorimetric Assay Kit in HeLa cells that were exposed to ICD-85 for 48 hours.
  
  
  RESULTS
  Data analysis showed that ICD-85 has a dose-dependent cytotoxic effect on HeLa cells with an inhibitory concentration 50% (IC50) of 26.62 ± 2.13 µg/ml at 24 hours, 27.33 ± 2.35 µg/ml at 48 hours, and 28.13 ± 2.52 µg/ml at 72 hours. Results also indicated that the cytotoxic effect of ICD-85, at 48 and 72 hours incubation times did not show significant alteration compared to 24 hours of exposure. Interestingly, the minimum concentration of ICD-85 which showed a cytotoxic effect on LK cells was found to be 3500-fold less than the minimum concentration that showed a cytotoxic effect on the HeLa cancer cells. While morphological analysis revealed a significant difference that included the characteristic rounding of dying cells by treatment with ICD-85 compared with untreated HeLa cells, this difference was not observed in normal cells. ICD-85 increased caspase-8 activity in HeLa cells after 48 hours of exposure.
  
  
  CONCLUSIONS
  ICD-85 has a dose-dependent cytotoxic effect on HeLa cancer cells in contrast with its negligible effect on normal LK cells.
authors.affiliation: Department of Venomous Animals and Antivenom Production, Razi Vaccine and Serum Research Institute, Karaj, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Sarzaeem
authors.forename: Abbas
authors.initials: A
authors.lastname: Zare Mirakabadi
authors.forename: Saeed
authors.initials: S
authors.lastname: Moradhaseli
authors.forename: Hasan
authors.initials: H
authors.lastname: Morovvati
authors.forename: Mohsen
authors.initials: M
authors.lastname: Lotfi
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053181:Caspase 8 / Q000378:metabolism; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D007668:Kidney / Q000166:cytology; D010455:Peptides / Q000494:pharmacology*; D012756:Sheep; D014688:Venoms / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; C578028:ICD-85 peptide; D010455:Peptides; D014688:Venoms; D053181:Caspase 8