WTAP stabilized by USP7 contributes to enzalutamide resistance in prostate cancer via mediating AKT m6A-modification

Abstract

Castration-resistant prostate cancer (CRPC) is one of the most prevalent cancers in men. The new generation androgen receptor (AR) inhibitor enzalutamide can improve the therapeutic effectiveness of patients with CRPC. However, these patients eventually develop acquired enzalutamide resistance (ENZR), and the mechanisms underlying resistance are not well understood. Wilms’ tumor 1-associating protein (WTAP) plays an important role in m6A modification and has been reported as an oncogene in various cancers. Here, we utilized a tissue microarray and collected tissues from prostate cancer (PCa) patients to detect WTAP expression, and found that WTAP is upregulated in PCa. Meanwhile, WTAP overexpression promotes cell proliferation and accelerates tumor growth through colony formation assays and the establishment of a subcutaneous xenograft model in vivo. These findings establish the tumor promoter role of WTAP in prostatic tumorigenesis. Furthermore, we verified that WTAP is a novel responsive gene of AR via promoter activity and chromatin immunoprecipitation (ChIP) assays. Importantly, we uncovered that WTAP is upregulated in ENZR cells, and WTAP knockdown inhibited the proliferation of ENZR cells. Mechanistically, ubiquitin-specific protease (USP7) enhanced the stability of WTAP by the ubiquitin-proteasome pathway in ENZR cells, thereby WTAP increases promote AKT signaling through an m6A-mediated way, and an AKT inhibitor can abolish the pro-resistance phenotype mediated by WTAP. Together, these findings suggest that WTAP plays a key role in ENZR development of PCa cells, and WTAP may be a potential treatment target for ENZR tumors.