NFkB-dependent antiviral pathways in VSV-resistant cancer cells

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Antiviral responses are defective in many human tumors, leaving them susceptible to infection by “oncolytic” viruses such as vesicular stomatitis virus (VSV). In contrast, normal cells are not infected because they mount an innate immune response. Studies show that some cancers are resistant to VSV infection because they retain these antiviral responses. For example, many VSV-resistant prostate cell lines have constitutively active NFκB, while VSV-sensitive prostate cancer cell lines do not. Therefore it is important to delineate the mechanisms of sensitivity versus resistance of cancers to VSV. The wild-type M protein inhibits NFκB activation, the IFN response, and host gene expression, but different M protein mutations can selectively eliminate each of these functions. These findings have led us to conclude that the M protein uses at least two mechanisms to limit expression of antiviral genes: M-mediated inhibition of global host transcription (the first suppressor) and inhibition of NFκB activation (the second suppressor). Our preliminary in vitro and modeling data support our central hypothesis that VSV uses multiple strategies to control antiviral gene expression in response to VSV infection, including global host transcription inhibition, targeting of steps upstream of IKK in the RIG-I pathway, and suppression of antiviral genes controlled by NFκB. The objectives of this study are to enhance our understanding of the balance between the host’s ability to activate an NFκB-dependent antiviral response and the virus’s ability to evade these defenses; and how this impacts the use of oncolytic viruses to treat tumors that constitutively express antiviral genes. The goal of this study is to determine the effects of M protein mutations on NFκB-dependent responses in VSV-sensitive (LNCaP) versus VSV-resistant (PC3) prostate cancer cell lines using the innovative combination of in vitro and in silico modeling studies. In Aim 1, we will determine NFκB activation and expression of NFκB- dependent antiviral genes (e.g. interferon, IL-6 and TNF-α) in LNCaP and PC3 cells infected with viruses bearing different mutations in the M protein (Aim 1A). To determine the role of NFκB-dependent pathway activation in resistance to VSV, the transcriptomes of infected LNCaP and PC3 cells will be compared by RNA- seq (Aim 1B). We have developed an executable network model of the intracellular signaling pathways impacted by wildtype and M protein mutant VSV in mouse cells. We will tune this network using data specific to the context of VSV infection of human prostate cancer cell lines (generated in Aim 1) and perform simulations to identify key NFκB-dependent signaling molecules and interactions responsible for VSV sensitivity or resistance in prostate cancer cells (Aim 2A). Finally, new in vitro experiments will be performed to validate these predictions (Aim 2B). In addition to these scientific merits, this project will provide undergraduate and Master’s students with a quality biomedical research experience, foster collaborations, and significantly enhance the research environment at The Rochester Institute of Technology.