ADT and activation of HGF and WNT axes in double-null prostate cancer.

Prostate cancer remains the most frequently diagnosed malignancy in men worldwide. Most primary prostate cancer cells express the androgen receptor (AR) and rely on androgens for oncogenic growth and progression. Thus, androgen deprivation therapy (ADT) that directly targets AR-expressing prostate cancer cells has been the frontline treatment for advanced prostate cancer. However, ADT inevitably fails in most patients, resulting in castration-resistant prostate cancer development. To inhibit reactivation of AR-promoted tumour progression via residual androgens and altered AR activation, next-generation AR antagonists and inhibitors of androgen biosynthesis were developed to improve clinical outcomes. However, these therapeutic advances also induce heterogeneous resistance phenotypes. Among them, double-null prostate cancer, featuring AR-null and neuroendocrine-null cell properties, occurs in patients treated with abiraterone and enzalutamide. Emerging clinical and experimental evidence demonstrates that current ADT induces HGF and canonical WNT signalling activation, which further elevates nuclear exporting and ribosomal biogenesis to foster tumour lineage plasticity and promote diverse castration-resistant prostate cancer phenotypes and double-null prostate cancer development. These mechanistic insights remain under active investigation, but they provide therapeutic prospects for co-targeting nuclear exporting, ribosomal biosynthesis and other oncogenic pathways in combination with current ADT to forestall the lethal disease.