Abstract 96: A novel virus-drug combination to enhance oncolysis in colorectal cancer (crc)

• Published in: Cancer research (Chicago, Ill.) Ill.), 2022-06, Vol.82 (12_Supplement), p.96-96
• Main Authors: Chavez, Valery A., Bustamante, Floritza, Murray, Abner, Saluja, Ashok, Merchan, Jaime
• Format: Article
• Language: English
• ISSN: 1538-7445; 1538-7445
• DOI: 10.1158/1538-7445.AM2022-96

Background: While advances in immune and targeted therapies improve outcomes in selected cancers, only a minority of colorectal cancer (CRC) patients benefit from them. Oncolytic viruses (OVs) represent novel cancer biotherapies, and among them, the oncolytic measles virus (MV) has demonstrated safety and antitumor activity in early clinical studies. MV alone does is not associated with cancer cures. Triptolide, a diterpenoid epoxide extracted from the thunder god vine (Tripterygium wilfordii), has been reported to have potent antitumor effects via multiple mechanisms, including anti-proliferative, pro-apoptotic, antiangiogenic, and induction of ER stress. The effects of triptolide on viral colon cancer oncolysis have not been previously investigated. Objectives: To characterize the in vitro and in vivo mechanisms of novel stromal retargeted oncolytic MVs and improve efficacy by combining MVs with triptolide. Methods: The in vitro effects of triptolide alone, MV-GFP (Edmonston strain of Measles virus expressing eGFP, for human cancer cells), MV-m-uPA (MV retargeted against the murine uPA receptor, for murine cancer cells), or virus-triptolide combinations on tumor cell cytotoxicity were assessed by cell count (Vi cell counter) or xCelligence assays, on HT-29, HCT116, SW620, CT26, and MC38 cells. Molecular and mechanistic characterization of Triptolide’s effects alone and combination with MV in HT29 cells will be analyzed by the (Reverse Phase Protein Array (RPPA) and validated by western blot analysis (experiment undergoing). In vivo effects (tumor progression and survival) of minnelide (M) (water-soluble version of Triptolide) alone and in combination with Measles Virus were assessed in Balb/C mice bearing CT26. Results: While MV and T had dose-dependent cytotoxic activity as single agents, significant augmentation of MV oncolysis was induced by co-treatment with triptolide. In vivo experiments showed similar effects observed in vitro, with potent antitumor activity of triptolide and enhanced in vivo antitumor activity when minnelide was combined with MV vectors. Conclusions: our results strongly suggest that triptolide or minnelide enhances measles virus oncolysis in vitro and in vivo models of colorectal cancer. In vitro and in vivo mechanistic studies are underway to characterize the molecular mechanisms by which triptolide enhances MV oncolysis and will be presented at the meeting. Citation Format: Valery A. Chavez, Floritza Bustamante, Abner Murray,