NUSAP1 mediates enzalutamide resistance in prostate cancer via Wnt/β-catenin signalling-dependent regulation of AR and AR-V7.

BACKGROUND: Castration-resistant prostate cancer (CRPC) demonstrates significant resistance to androgen deprivation therapy (ADT), presenting a substantial therapeutic challenge. Although the reactivation of androgen receptor (AR) signalling is a key driver of this resistance, the specific regulatory mechanisms involved remain unclear. Nucleolar and spindle-associated protein 1 (NUSAP1) is overexpressed in various malignancies; however, its function in mediating resistance to enzalutamide (ENZ) has yet to be elucidated. This study aims to clarify the influence of NUSAP1 on ENZ resistance in prostate cancer. METHODS: Bioinformatics analyses were conducted on three GEO datasets (GSE3325, GSE27616, and GSE35988) to identify potential genes linked to metastatic CRPC. Subsequent functional experiments, such as CCK-8, colony formation, Wound-healing, and Transwell assays, were carried out to assess the impact of knockdown NUSAP1 on proliferation, migration, and invasion in ENZ-resistant prostate cancer cells (MDVR and 22Rv1). Western blot and RT-qPCR analyses were employed to explore underlying molecular mechanisms. Pharmacological interventions and rescue experiments utilizing R1881, Laduviglusib, and DK419 were executed to investigate pathway interactions. Additionally, a xenograft mouse model was established to validate the observed in vivo effects. RESULTS: Bioinformatics analysis revealed NUSAP1 as a pivotal prognostic gene significantly linked to overall survival (OS, P = 0.02) and disease-free survival (DFS, P = 0.0018) in prostate cancer. Elevated NUSAP1 expression was observed in ENZ-resistant prostate cancer cells. Knockdown of NUSAP1 markedly impeded cell proliferation, migration, and invasion, while increasing the cells' sensitivity to ENZ both in vitro and in vivo. Subsequent investigations illustrated that NUSAP1 promotes β-Catenin translocation to the nucleus and increased Wnt/β-Catenin signalling activity, and then amplifies downstream AR signalling. CONCLUSIONS: The results indicate that NUSAP1 enhanced prostate cancer ENZ resistance through activation of the Wnt/β-Catenin-AR/AR-V7 signalling pathway. Targeting NUSAP1 could offer a potential therapeutic approach to address ENZ resistance in CRPC.