ADT-induced stress elevates CDKN2AIP to promote neuroendocrine prostate cancer

Approximately 80-90% of prostate cancers (PC) initially depend on androgen signaling for growth, making androgen deprivation therapy (ADT) the standard first-line treatment. However, chronic ADT imposes metabolic and oxidative stress that drives therapeutic resistance and progression to castration-resistant prostate cancer (CRPC). A subset of CRPC tumors further acquires a neuroendocrine (NE) phenotype, leading to the development of neuroendocrine prostate cancer (NEPC), an aggressive, therapy-refractory disease with no effective treatment options. Understanding the molecular mechanisms and identifying key drivers of this phenotypic transition are therefore critical. Analysis of NEPC patient datasets revealed elevated expression of CARF (CDKN2AIP), a stress-responsive RNA regulatory factor whose role in lineage plasticity is unknown. Using an ADT-conditioned LNCaP model, we observed upregulation of CARF together with NEPC-associated regulators SIRT1, CHGA, SYP, and c-MYC, as shown by immunostaining, immunoblotting, and RT-qPCR. Silencing CARF via shRNA significantly reduced the expression of these NE markers, indicating that CARF is required to sustain their induction under ADT. Mechanistically, exposure to H₂O₂-induced oxidative stress increased CARF and SIRT1 expression, suggesting that ADT-associated oxidative stress upregulates CARF and contributes to NEPC development. We further found that ADT increased the expression of the splicing regulator SRSF3, while CARF knockdown suppressed SRSF3, implicating CARF in an alternative splicing pathway that facilitates NE lineage reprogramming.Overall, these findings identify a CARF-SRSF3 signaling axis that integrates oxidative stress and RNA regulation to promote neuroendocrine differentiation in prostate cancer. This pathway represents a potential therapeutic target for preventing or reversing NE transdifferentiation and treatment resistance in advanced disease.