去势抵抗性前列腺癌 (CRPC) 是男性前列腺癌 (PCa) 相关死亡的主要原因，发生在雄激素剥夺疗法 (ADT) 失败后。 PIWI 相互作用 RNA (piRNA) 是许多人类癌症的重要调节因子，但它们在 CRPC 中的表达模式和作用仍然未知。在这项研究中，我们使用来自同一患者的 10 个良性前列腺组织和 9 配对的激素敏感 PCa (HSPCa) 和 CRPC 组织进行小 RNA 测序，以探索 CRPC 相关的 piRNA。与HSPCa和良性组相比，PiRNA-4447944（piR-4447944）被发现在CRPC组中高表达。功能分析显示，piR-4447944过表达赋予PCa细胞体外和体内去势抵抗能力，而使用反义RNA敲低piR-4447944可抑制CRPC细胞的增殖、迁移和侵袭。此外，强制表达piR-4447944可促进PCa细胞的体外迁移和侵袭，并减少细胞凋亡。从机制上讲，piR-4447944 与 PIWIL2 结合形成 piR-4447944/PIWIL2 复合物，并通过转录后水平的直接相互作用抑制肿瘤抑制因子 NEFH。总的来说，我们的研究表明 piR-4447944 对于前列腺肿瘤增殖细胞至关重要，并介导 PCa 的雄激素非依赖性生长，这扩展了目前对癌症生物学中 piRNA 的理解，并为 CRPC 治疗提供了潜在的方法。© 作者。

Castration-resistant prostate cancer (CRPC) is the leading cause of prostate cancer (PCa)-related death in males, which occurs after the failure of androgen deprivation therapy (ADT). PIWI-interacting RNAs (piRNAs) are crucial regulators in many human cancers, but their expression patterns and roles in CRPC remain unknown. In this study, we performed small RNA sequencing to explore CRPC-associated piRNAs using 10 benign prostate tissues, and 9 paired hormone-sensitive PCa (HSPCa) and CRPC tissues from the same patients. PiRNA-4447944 (piR-4447944) was discovered to be highly expressed in CRPC group compared with HSPCa and benign groups. Functional analyses revealed that piR-4447944 overexpression endowed PCa cells with castration resistance ability in vitro and in vivo, whereas knockdown of piR-4447944 using anti-sense RNA suppressed the proliferation, migration and invasion of CRPC cells. Additionally, enforced piR-4447944 expression promoted in vitro migration and invasion of PCa cells, and reduced cell apoptosis. Mechanistically, piR-4447944 bound to PIWIL2 to form a piR-4447944/PIWIL2 complex and inhibited tumor suppressor NEFH through direct interaction at the post-transcriptional level. Collectively, our study indicates that piR-4447944 is essential for prostate tumor-propagating cells and mediates androgen-independent growth of PCa, which extends current understanding of piRNAs in cancer biology and provides a potential approach for CRPC treatment.© The author(s).