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

<h3>Background</h3> 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. <h3>Methods</h3> 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<i> in vivo</i> 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. <h3>Results</h3> In this study, we showed that the m⁶A methyltransferase Wilms tumor 1-associating protein (WTAP) weakens oxaliplatin chemosensitivity in CRC <i>in vitro</i> and<i> in vivo</i>. 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. <h3>Conclusions</h3> 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.