cJun-N-terminal kinase activity and mitosis perturbation drive the 2-methoxyestradiol-mediated enhancement of viral oncolysis by Epizootic Hemorrhagic Disease Virus-Tel Aviv University.

Oncolytic viruses (OVs) are promising cancer therapies whose efficacy is restricted by tumor heterogeneity and monotherapy limitations. We investigated combining the oncolytic orbivirus Epizootic Hemorrhagic Disease Virus -Tel Aviv University (EHDV-TAU) with the microtubule-targeting agent (MTA) 2-methoxyestradiol (2ME2) for the oncolysis of bladder cancer (BC) cells (T24 or SW1710) or melanoma cells (SKMEL3). Sub-lethal 2ME2 concentrations perturbed the cell cycle and enhanced multiple parameters of EHDV-TAU oncolysis of T24 and SKMEL3 cells (semi-permissive to EHDV-TAU), minimally affected the successful oncolysis of SW1710 cells (EHDV-TAU-permissive), but failed to relieve the resistance of non-transformed human foreskin fibroblasts to infection. The enhancement was linked to amplified c-Jun N-terminal kinase (JNK) activity, which was required for increases in the expression of the pro-apoptotic factor NOXA, caspase activity, and calreticulin exposure, all in line with the induction of an immunogenic form of apoptosis in infected/treated cells. Cell cycle disruption by 2ME2 was essential, as cyclin-dependent kinase 1 (CDK1) inhibition mitigated its effects. The findings suggest that combining OVs with MTAs, specifically EHDV-TAU and 2ME2, may exploit the enhanced susceptibility of cell-cycle-perturbed cancer cells to viral infection and cell death pathways. Such combinations may improve virus-based therapies for BC and potentially other cancers.