Abstract | Newcastle disease viruses are now considered to be safe platforms for the development of oncolytic virotherapeutics due to lack of adverse consequences in clinical trials. In this study, we aimed to assess in-vitro the tumoricidal properties of local velogenic isolate NDV/2K/17 and mesogenic isolate NDV/2K/36 of Tamil Nadu in Human Breast Cancer Cell line (MCF-7). The NDV isolates were propagated in embryonated chicken eggs and purified and concentrated by ultracentrifugation. The monolayer of MCF-7 cells was infected with three different doses (16, 8 and 4 HAU) of each virus separately and cytopathic effects were studied by staining. Cell viability/cytotoxicity in infected cells was assessed using trypan blue dye exclusion test and MTT cell viability assay. The trypan blue staining of NDV/2K/17 and NDV/2K/36 infected cell line showed up to 68% and 82 % of cell death, 72h p.i. (post infection), respectively. MTT cell viability assay at 24h, 48h, 72h p.i. by 16 HAU of the NDV/2K/17, show decreased percentage of viable cells to 83.85, 55.7 and 35.58 %, respectively as compared to uninfected MCF-7 cells. Whereas at 24h, 48h and 72h p.i. by 16 HAU of mesogenic isolate NDV/ 2K/36, percent viable cells decreased to 87.54, 54.01 and 17.78, respectively showing decreased viability percent with time post infection. Besides, both isolates were found to induce cytotoxicity in MCF-7 cells in a dose dependent manner. With increasing dose of virus, percent cell viability decreased showing minimal at 72h p.i. (35.58 % by NDV/2K/17 and 17.78% by NDV/2K/36) by higher dose of each virus (16HAU). However, with lower dose (4HAU) of each virus resulted in comparatively higher cell viability at 72h p.i. (60.93 % by NDV/2K/17 and 29.39% by NDV/2K/36) in MCF-7 cells. In conclusion, our results indicated that both isolates of NDV were cytolytic to the MCF-7 cells and cell death induced was dependent on the strain and dose of the Newcastle disease virus used.
Keywords | NDV, Velogenic, Mesogenic, Ultracentrifugation, MCF-7 cells, MTT, Cytotoxicity