Document Type: Original Articles
Department of Microbiology, Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran
Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
Department of Pathology, Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran
Innovation of therapeutic modalities with better clinical efficacy is necessary for treating patients with advanced cancers. Newcastle disease virus (NDV), an avian pathogenic virus, is one of the most promising oncolytic viruses that can replicate selectively in human cancer cells. In human, NDV can cause a transient conjunctivitis and mild flu-like symptoms. But, this virus poses no hazard to human health. Elucidation of the mechanisms of cancer cell killing by NDV is helpful for the clinical application of NDV in cancer patients. The aim of this study was the evaluation of apoptosis induction by NDV vaccine strain LaSota in human breast carcinoma cells. MCF-7 cells, a human breast adenocarcinoma cell line, were infected with NDV in vitro. Tumor cell cytotoxicity, apoptosis induction, and the expression levels of apoptosis-related genes were examined in NDV-infected breast carcinoma cells. Tumor cell cytotoxicity was measured by MTT (3-[4,5-dimethylthiazol-2yl]2,5-diphenyl-tetrazoliumbromide) assay. Induction of apoptosis was assessed by annexin V/propidium iodide staining and the expression levels of apoptosis-related genes were evaluated by real-time RT-PCR technique. NDV showed cytotoxic effects on MCF-7 cells and induced apoptosis in infected carcinoma cells. Expression levels of BAX, caspase-9, and caspase-3, but not BAK-1, were increased in NDV-infected cancer cells when compared to the gene expression levels in non-infected cancer cells. These results suggest that induction of the intrinsic pathway of apoptosis is one of the mechanisms that can be contributed to the cancer cell killing by NDV. Additional studies are requisite to investigate other probable mechanisms involved in NDV-mediated cancer cell killing.