RAS-activated and Interferon-defective tumor cell phenotype

RAS-activated / IFN-defective tumor cells represent a specific oncogenic phenotype characterized by constitutive signaling through the RAS/MAPK pathway and a compromised type I interferon (IFN) antiviral response (Coffey et al., 1998, Science). In healthy cells, viral infection triggers the production of IFNs, which activate double-stranded RNA-activated protein kinase (PKR) to inhibit cellular translation and halt viral replication. However, in many cancers, RAS activation leads to the inhibition of PKR, while defects in the IFN signaling pathway prevent the establishment of an effective antiviral state (Shmulevitz et al., 2005, Journal of Virology). This combination creates a unique therapeutic window for oncolytic viruses, such as Pelareorep (Reovirus), which can selectively replicate within and lyse these tumor cells while sparing healthy tissue. Beyond direct oncolysis, the destruction of these cells releases tumor-associated antigens and pro-inflammatory cytokines, which can overcome local immunosuppression and prime the systemic immune system to recognize and attack the remaining tumor burden (Gong et al., 2016, Frontiers in Oncology). This approach is particularly relevant for treating 'cold' tumors that are otherwise resistant to traditional immunotherapies.

Other names

RAS-transformed cellsIFN-deficient tumor cellsOncolytic virus-susceptible tumor cellsRAS-MAPK activated tumor cells

Selective oncolysis through exploitation of impaired PKR-mediated viral inhibition in RAS-active cells and deficient Type I Interferon antiviral signaling, leading to direct cell lysis and induction of systemic anti-tumor immunity.