DNMT3B drives neuroendocrine lineage plasticity and aggressive progression in prostate cancer

Neuroendocrine prostate cancer (NEPC) is an aggressive, treatment-resistant subtype of prostate cancer characterized by poor prognosis and limited therapeutic options. In this study, we identify de novo DNA methyltransferase 3B (DNMT3B) as a critical driver of NEPC growth and neuroendocrine differentiation. We demonstrate that DNMT3B expression is significantly upregulated during prostate cancer progression and is essential for NEPC cell proliferation, as its genetic inhibition via CRISPR-Cas9 and inducible shRNA systems impairs tumor growth and promotes apoptosis both in vitro and in vivo. Transcriptomic profiling reveals that DNMT3B loss disrupts cell cycle regulation and suppresses neuroendocrine lineage programs by downregulating key transcription factors such as FOXA2, NEUROD1, SOX2, and INSM1. Moreover, DNMT3B is required for both the initiation and maintenance of NEPC in a human genetically engineered prostate cancer model. Pharmacological inhibition of DNMT3B with Nanaomycin A selectively suppresses NEPC tumor growth and attenuates neuroendocrine marker expression without causing systemic toxicity. These findings establish DNMT3B as a central regulator of NEPC and support its potential as a therapeutic target for this lethal cancer subtype