Disruption of NUAK2-Mediated RNA Splicing by Trilaciclib Reveals a Therapeutic Vulnerability in AR-Indifferent Prostate Cancer

Abstract

Prostate cancer remains a leading cause of cancer-related mortality in men, with aggressive, treatment-emergent androgen receptor (AR)-indifferent subtypes, including double-negative prostate cancer (DNPC) and neuroendocrine prostate cancer (NEPC), posing major clinical challenges due to limited therapeutic options. NUAK family kinase 2 (NUAK2), an AMPK-related kinase, has been implicated in tumor growth and metastatic progression; however, its functional significance and therapeutic potential in advanced prostate cancer remain largely unexplored. Here, we identify NUAK2 as a therapeutically actionable kinase dependency in AR-indifferent prostate cancer. Transcriptomic analyses across independent patient cohorts demonstrated progressive upregulation of NUAK2 with disease progression, with the highest expression in NEPC. Immunohistochemical analysis of clinical specimens further confirmed elevated NUAK2 protein expression in NEPC relative to prostate adenocarcinoma. Genetic loss- and gain-of-function studies established NUAK2 as a functional dependency that promotes tumor cell proliferation, clonogenic growth, and tumor growth in vivo. Mechanistically, integrated proteomic analyses revealed that NUAK2 associates with spliceosomal and RNA-processing machinery, while NUAK2 perturbation induced widespread alterations in pre-mRNA splicing programs involving genes linked to mitotic regulation and oncogenic signaling. Pharmacologic studies identified trilaciclib (G1T-28), a clinically approved CDK4/6 inhibitor, as a functionally relevant NUAK2 inhibitor that directly engages NUAK2, suppresses tumor growth, and enhances the efficacy of platinum-based chemotherapy across multiple preclinical models. Collectively, these findings uncover NUAK2 as a previously unrecognized regulator of RNA splicing and therapeutic vulnerability in AR-indifferent prostate cancer and provide a rationale for repurposing G1T-28 and developing NUAK2-directed therapeutic strategies for aggressive, treatment-refractory prostate cancer.