PO.MCB11.02 · 分子与细胞生物学
PLK1介导的CHAF1A磷酸化促进前列腺癌中AR驱动的enzalutamide耐药
CHAF1A phosphorylation by PLK1 promotes AR-driven enzalutamide resistance in prostate cancer
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
前列腺癌(PCa)仍然是全球一项重大健康挑战,是男性中第二常见的诊断恶性肿瘤,也是癌症相关死亡的第五大原因。尽管雄激素剥夺疗法和新一代雄激素受体(AR)通路抑制剂(如enzalutamide)已改善临床结局,但去势抵抗性前列腺癌(CRPC)和治疗耐药的不可避免出现,凸显了阐明其潜在分子机制的必要性。Polo样激酶1(PLK1)是一种对有丝分裂至关重要的保守丝氨酸/苏氨酸激酶,已被认为参与促进enzalutamide耐药;然而,这一现象的机制基础仍未得到充分理解。在本研究中,我们鉴定出染色质组装因子1亚基A(CHAF1A)是一个此前未被认识的AR信号调节因子,也是enzalutamide耐药的关键促成因素。临床数据库分析显示,与良性前列腺组织相比,CHAF1A在PCa中显著过表达,且CHAF1A水平升高与患者预后不良相关。功能实验证明,在C4-2和22Rv1细胞中敲低CHAF1A可抑制细胞增殖、降低PSA表达并恢复对enzalutamide的敏感性。相反,在C4-2和LNCaP细胞中过表达CHAF1A可增强增殖并上调AR下游效应分子。机制研究揭示,CHAF1A是PLK1的潜在底物,并在苏氨酸591(T591)位点发生磷酸化。将磷酸化缺陷突变体CHAF1A-T591A导入C4-2细胞后,减弱了AR信号并显著提高了其对enzalutamide的响应性。RNA测序进一步证明,与野生型对照相比,表达CHAF1A-T591A的细胞中AR信号显著下调。使用ChIP-qPCR,我们发现CHAF1A增强了AR与关键下游靶点启动子区域的结合,从而提高了AR的转录活性。重要的是,T591A突变显著降低了AR的染色质占据,表明PLK1介导的T591位点磷酸化是CHAF1A依赖的AR激活所必需的。总之,这些发现确认CHAF1A是一个新的AR染色质结合和转录输出的增强因子,其作用通过PLK1依赖的磷酸化机制实现。我们提出,CHAF1A表达升高通过维持AR通路激活来驱动enzalutamide耐药,而破坏PLK1介导的CHAF1A磷酸化代表了一种克服CRPC耐药的有前景的治疗策略。
查看英文原文 English abstract
Prostate cancer (PCa) remains a major global health challenge, ranking as the second most frequently diagnosed malignancy and the fifth leading cause of cancer-related mortality among men. Although androgen deprivation therapy and next-generation androgen receptor (AR) pathway inhibitors, such as enzalutamide, have improved clinical outcomes, the inevitable emergence of castration-resistant prostate cancer (CRPC) and treatment resistance underscores the need to elucidate the underlying molecular mechanisms. Polo-like kinase 1 (PLK1), a conserved serine/threonine kinase essential for mitosis, has been implicated in promoting enzalutamide resistance; however, the mechanistic basis of this phenomenon remains insufficiently understood. In this study, we identify Chromatin Assembly Factor 1 subunit A (CHAF1A) as a previously unrecognized modulator of AR signaling and a critical contributor to enzalutamide resistance. Analysis of the clinical database revealed that CHAF1A is significantly overexpressed in PCa compared with benign prostate tissues, and elevated CHAF1A levels correlate with poor patient prognosis. Functional assays demonstrated that CHAF1A knockdown in C4-2 and 22Rv1 cells suppresses cell proliferation, decreases PSA expression, and restores sensitivity to enzalutamide. Conversely, CHAF1A overexpression in C4-2 and LNCaP cells enhances proliferation and upregulates AR downstream effectors. Mechanistic studies revealed that CHAF1A is a potential substrate of PLK1 and undergoes phosphorylation at threonine 591 (T591). Introduction of a phosphorylation-deficient mutant, CHAF1A-T591A, into C4-2 cells attenuated AR signaling and significantly increased their responsiveness to enzalutamide. RNA sequencing further demonstrated pronounced downregulation of AR signaling in CHAF1A-T591A-expressing cells compared with wild-type controls. Using ChIP-qPCR, we show that CHAF1A enhances AR binding to promoter regions of key downstream targets, thereby elevating AR transcriptional activity. Importantly, the T591A mutation markedly diminished AR chromatin occupancy, indicating that PLK1-mediated phosphorylation at T591 is required for CHAF1A-dependent AR activation. Collectively, these findings identify CHAF1A as a novel enhancer of AR chromatin binding and transcriptional output, acting through a PLK1-dependent phosphorylation mechanism. We propose that elevated CHAF1A expression drives enzalutamide resistance by sustaining AR pathway activation, and that disruption of PLK1-mediated CHAF1A phosphorylation represents a promising therapeutic strategy to overcome resistance in CRPC.
利益披露 Disclosure
S. Wu, None..
C. Li, None..
J. Peng, None.