In vitro and preclinical evaluation of newcastle disease virus strain V4UPM as an oncolytic virus candidate for novel human malignant glioma theraphy
Loading...
Date
2014-09
Authors
Mustafa, Mohd Zulkifli
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Oncolytic viruses are replicating viruses that have been used to infect neoplastic cells and are widely studied as a form of antitumor therapy. Oncolytic viruses specifically target tumorigenic cells because they are able to exploit the aberrations on the cellular level that promote tumor growth and the viruses preferentially infect cancer cells without interfering with normal cells. Brain cancer is a malignant growth within the skull and glioma is the most common human brain cancer arising from glial cells. Grade IV glioma is known as glioblastoma multiforme (GBM) where the proliferation and invasive behavior in GBM was associates with upregulation of Rac1 protein. Newcastle disease virus (NDV), an avian virus in the Paramyxovirus family, is one of the oncolytic viruses that inherit natural selectivity towards cancer. It is reported to robustly induce syncytium and apoptosis in multiple types of cancer cells but found to be safe for clinical injection into human. In this study, the NDV strain V4UPM has been evaluated as a potential agent for brain cancer therapy. The cytotoxicity and molecular mechanism of V4UPM effects on GBM was evaluated in in vitro model using microtetrazolium (MTT) assay, apoptosis assay, live cell imaging, fluorescence microscopy and western blot technique. The oncolytic NDV induce GBM regression were also evaluated in in vivo and ex vivo models. Findings have shown that V4UPM at 9 HAU induces the apoptosis of human brain cancer cells with the onset of cytolysis occurring less than 12 hours after infection. Besides, it is non-toxic to normal human astrocytes cell lines (p>0.05). The three-dimensional imaging analysis of NDV co-localization with the actin cytoskeleton revealed a
potential of caveolae-mediated endocytosis as a viral entry mechanism. V4UPM infection also led to the reorganization of the actin cytoskeleton in syncytium cells and was associated with the upregulation of Rac1 and NFKB proteins in early phase of infection, but subsequently downregulated after 12 hours. Preclinical evaluation in immune-compromised athymic nude mice revealed that V4UPM at 520 HAU could induce the subcutaneous regression (p<0.05) of homogenous glioma xenografts without inducing any acute toxicity (p>0.05) in the host. V4UPM was subsequently tested on ex vivo heterogeneous glioma slices obtained from Hospital Universiti Sains Malaysia patients and found to decrease (p<0.05) of tissue viability 48 hours after treatment. In conclusion, V4UPM seems to exploit cellular actin for viral entry and induces actin reorganization to sustain replication via the Rac1 signaling pathway, subsequently inducing apoptosis. Preclinical study demonstrates the therapeutic potential of V4UPM against GBM in in vivo and ex vivo with a promising safety margin. Therefore, V4UPM is found to be a potential candidate for subsequent analyses in non-rodent models and non-human primate as novel therapies for human brain tumors.
Description
Keywords
Oncolytic viruses