Effect of Apis dorsata venom on cell viability and regulation of CASP8 and BCL2 genes in human lung carcinoma A549 cells

Abstract

Cancer is still one of the most common causes of death worldwide. It is a group of diseases characterized by insufficient apoptosis, thereby resulting to uncontrolled growth and proliferation of malignant cells. Hence, development of natural products capable of inducing apoptosis is necessitated. The potential of the Southeast Asian Apis dorsata venom to induce apoptosis among cancer cells was investigated. The effects of A. dorsata sac venom, collected through surgical removal, and A. dorsata venom crystals, collected through electric shock method, on the in vitro cell viability and gene expression profiles of the pro-apoptotic CASP8 gene and anti-apoptotic BCL2 gene of the Human Lung Carcinoma A549 cells were examined. The gene expression profiles were used to elucidate the affected metabolic pathway. Moreover, both types of venom were screened for putative bioactive metabolites that can account for their activities. Cell viability profiles were determined using MTT assay, gene expression profiles through quantitative reverse transcription – polymerase chain reaction (RT-qPCR), metabolic pathway analysis via KEGG pathway database, and molecular profiles using liquid chromatography - mass spectrometry (LC-MS). A. dorsata sac venom significantly decreased viability of A549 cells at all doses compared to the control whereas A. dorsata venom crystal treatment resulted to an erratic trend on A549 cell viability due to its oxidation that lowered its healing potency. The half maximal inhibitory concentration (IC50) of sac venom was 17.59 ppm, which qualified for the required concentration of anticancer agents (= 20 ppm). Sac venom treatment resulted to CASP8 upregulation, which activated execution caspases that culminated into apoptosis. Sac venom treatment also resulted to BCL2 upregulation, which did not hinder sac venom treatment’s reduction of cell viability, thereby implicating BCL2 upregulation insensitivity of sac venom-treated A549 cells, which was a characteristic of type I cell death. Lastly, the molecular profile of A. dorsata sac venom revealed 56 identified constituent putative metabolites. Of which, 14 were anticancer. On the other hand, the molecular profile of A. dorsata venom crystals revealed 31 identified constituent putative metabolites. Of which, 8 were anticancer. However, the effects of the anticancer metabolites present in A. dorsata venom crystal were not observed in Phases 1 and 2 of the study. In conclusion, A. dorsata sac venom exhibited anticancer potential by decreasing cell viability in A549 cells by means of causing apoptosis through upregulation of a pro-apoptotic gene and induction of type I cell death.