Abstract
Abstract Oncolytic vaccinia virus has several advantages over other OV platforms, including an efficient life cycle, multiple mechanisms of viral spread, large genome, allowing acceptance of foreign therapeutic DNA inserts, and proven safety in humans, due to its use as smallpox vaccine. JX-594 (Pexavec, SillaJen) is an attenuated (TKdeactivated ) oncolytic vaccinia VV, engineered to express GM-CSF and to selectively target tumor over non-tumor tissues. It is currently being investigated as a novel therapeutic option in patients with advanced Renal Cell Carcinoma (RCC, NCT03294083). The present study was undertaken to investigate the effects of JX-954 in a panel of clear and non-clear cell RCC cell lines and characterize the potential mechanisms of JX-594 oncolysis in vitro. We evaluated the oncolytic potency of JX-594 in human clear cell RCCs (VHL mutant 786-0, A498, VHL wild type Caki-1), non-clear cell RCC (ACHN, papillary RCC, and UOK-262, an FH deficient papillary RCC cell) and murine renal cancer cells (RENCA). Potent and persistent cytotoxic effects were induced by JX-594 in all human RCC cells, regardless of the histological subtype, and by mJX-594 (a Western Reserve strain of vaccinia virus expressing murine GMCSF) in RENCA cells. Moreover, we observed efficient viral replication in human (786-0, ACHN) and murine (RENCA) cells, confirming RCC permissiveness to viral infection. Functional proteomics analysis of JX-594 treated 786-0 cells was performed by reverse phase protein array (RPPA) to gain knowledge on potential mechanisms of viral oncolysis. JX-594 treatment had significant effects on the expression levels of proteins related to inducing cell cycle, apoptosis, necrosis, Akt signaling, MAPK signaling, autophagy and stress induction. In particular, the proteins related to cell cycle (Wee1, Cdc25c, CHK1/2, and Cyclin B1) and Akt signaling (PI3K, mTOR, Rictor and FOXO), MAPK signaling (JAK2, PAK1, FAK and MEK1) were down regulated, while proteins involved in apoptosis and necrosis were upregulated. In summary, our studies show that human and murine renal cancer cells are permissive to infection and replication by JX-594 and mJX-594, which induce potent oncolytic effects in clear and non-clear cell RCC, effects associated with significant modulation of RCC pathways associated with cell cycle, proliferation, and survival and stress responses. Citation Format: Yuqi Jing, F Bustamante Guerrero, Jaime Merchan. In vitro cellular and molecular effects of oncolytic vaccinia virus in clear and non-clear cell renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3293.