Inhibition of HIF-1α accumulation in prostate cancer cells is initiated during early stages of mammalian orthoreovirus infection

Mammalian orthoreovirus (MRV) is a safe and effective cancer killing virus that has completed Phase I-III clinical trials against numerous cancer types. While many patients experience benefit from MRV therapy, pre-defined set points necessary for FDA approval have not been reached. Therefore, additional research into MRV biology and the effect of viral therapy on different tumor genetic subtypes and microenvironments is necessary to identify tumors most amenable to MRV virotherapy. In this work we analyzed the stage of viral infection necessary to inhibit HIF-1?, an aggressive cancer activator induced by hypoxia. We demonstrated that two viral capsid proteins were not necessary and that a step parallel with virus core movement across the endosomal membrane was required for this inhibition. Altogether, this work clarifies the mechanisms of MRV-induced HIF-1? inhibition and provides biological relevance for using MRV to inhibit the devastating effects of tumor hypoxia.

Automated summary

Mammalian orthoreovirus (MRV) is a safe and effective cancer killing virus that has completed Phase I-III clinical trials, but additional research into its biology and effects on different tumor genetic subtypes and microenvironments is necessary to identify the most suitable tumors for MRV therapy. This study analyzed the viral infection stage required to inhibit HIF-1?, an aggressive cancer activator induced by hypoxia, and found that two viral capsid proteins were not necessary for this inhibition. The findings provide insight into the mechanisms of MRV-induced HIF-1? inhibition and its potential for addressing tumor hypoxia.