IDDF2024-ABS-0159 WTAP weakens oxaliplatin chemosensitivity of colorectal cancer by preventing PANoptosis

Background Oxaliplatin-based chemotherapy is recognized by multiple clinical guidelines for patients with unresectable colorectal cancer (CRC) due to its effective and broad-spectrum anti-tumor activity. Chemosensitivity is intimately linked with N6-methyladenosine (m6A), the most abundant post-transcriptional modification in eukaryotes, and PANoptosis, a promising strategy for addressing various challenges in cancer therapy. However, the specific role and potential mechanism of m6A methylation in PANoptosis remain unclear. This project investigated the specific effects of m6A methylation in PANoptosis on oxaliplatin-based chemosensitivity in CRC. Methods The effects of oxaliplatin on the RNA m6A modification of CRC cells were investigated using m6A dot blot, m6A quantification, q-PCR, immunoblotting, cell viability assay, LDH release assay, and fluorescence microscope. We also investigated the role of WTAP inhibition in tumorigenesis and chemotherapy sensitivity in vivo utilizing subcutaneous and patient-derived xenograft (PDX) tumor models. Then, the specific mechanism by which WTAP deficiency triggers PANoptosis during oxaliplatin treatment was elucidated through MeRIP sequencing, q-PCR, immunoblotting, cell viability assay, LDH release assay, Live/dead fluorescence assay, apoptosis assay, ROS, and lipid ROS assay, GSH/GSSG-Glo™ assay. We further explored the clinical relevance of WTAP in patients with CRC through immunohistochemistry (IHC) in our CRC cohort. Results In this study, we showed that the m6A methyltransferase Wilms tumor 1-associating protein (WTAP) weakens oxaliplatin chemosensitivity in CRC in vitro and in vivo. Mechanistically, oxaliplatin treatment upregulated WTAP expression, thus preventing PANoptosis by increasing intracellular oxidative stress through maintaining the expression of nuclear factor erythroid-2-related factor 2 (NRF2), a major antioxidant response element, in an m6A-dependent manner. Additionally, high WTAP expression in CRC patients correlates with a poor prognosis and reduced benefit from standard chemotherapy. Conclusions Our finding emphasizes the significance of WTAP as a prognostic indicator and a promising therapeutic target for CRC. Inhibiting WTAP through developing targeted inhibitors, which will be the focus of future investigations, holds potential as a therapeutic strategy to enhance the antitumor efficacy of oxaliplatin-based chemotherapy in CRC treatment.