PO.ET03.02 · 实验与分子治疗
TKI耐药RCC中EZH2-AR非经典轴的激活：lenvatinib与cabozantinib的差异性效应
EZH2-AR non-canonical axis activation in TKI-resistant RCC: Differential effects of lenvatinib and cabozantinib
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
酪氨酸激酶抑制剂（TKI）对肾细胞癌（RCC）的治疗至关重要。然而，复发和转移性RCC常对TKI产生耐药，限制了治疗选择。理解这种耐药背后的分子机制对改善患者结局至关重要。我们此前的研究已确定EZH2和雄激素受体（AR）是获得性TKI耐药的关键调控因子。抑制EZH2或AR可在体外和体内恢复对sunitinib的敏感性，凸显这些分子作为可能在各TKI间共有的治疗靶点。为研究EZH2和AR之间的相互作用，我们将sunitinib耐药的786-0细胞（786-0 RS）与过表达AR的未接触药物的786-0细胞（786-0 AR）进行比较。染色质免疫沉淀测序显示，AR和EZH2仅在耐药细胞中共同占据基因组位点。sunitinib处理诱导786-0 AR中AR的核转位，AR结合于EZH2占据的位点。质谱进一步显示，786-0 RS中AR在S81和S213处高度磷酸化（配体非依赖性激活的标志），而786-0 AR中不存在。786-0 RS细胞通过一种可能的非经典机制经历EZH2依赖性的酪氨酸激酶组重编程。磷酸模拟EZH2突变体（S21D）与AR共表达可促进sunitinib耐药，而野生型或磷酸缺失型（S21A）EZH2则不能。扩展的磷酸化蛋白质组学分析揭示了sunitinib耐药细胞中丝氨酸/苏氨酸信号网络的广泛重塑，包括EGFR驱动的MAPK和AKT通路的富集。有趣的是，初步数据表明cabozantinib不像其他TKI（如lenvatinib）那样诱导AR和EZH2上调。此外，cabozantinib似乎能阻止由lenvatinib触发的代偿性通路激活，提示其具有独特的耐药特征。与此一致，在对sunitinib、dovitinib和lenvatinib耐药的RCC细胞系中观察到AR表达，但cabozantinib治疗时则没有。正在进行的磷酸化蛋白质组学分析将剖析各TKI药物之间的差异。总体而言，我们的发现提示EZH2依赖性激酶重编程驱动AR磷酸化和激活，促成对选择性TKI的药物耐药。cabozantinib绕过AR/EZH2上调的独特能力凸显了探索替代耐药通路的必要性。
查看英文原文 English abstract
Tyrosine kinase inhibitors (TKIs) are critical to the treatment of renal cell carcinoma (RCC). However, recurrent and metastatic RCC frequently develop resistance to TKIs, limiting therapeutic options. Understanding the molecular mechanisms underlying this resistance is crucial for improving patient outcomes. Our previous studies have identified EZH2 and the androgen receptor (AR) as key regulators of acquired resistance to the TKI . Inhibiting EZH2 or AR restores sunitinib sensitivity in vitro and in vivo, highlighting these molecules as therapeutic targets potentially shared across TKIs .To investigate the interplay between EZH2 and AR, we compared sunitinib-resistant 786-0 cells (786-0 RS ) with drug-naive 786-0 cells overexpressing AR (786-0 AR ). Chromatin immunoprecipitation sequencing revealed that AR and EZH2 co-occupy genomic loci exclusively in resistant cells. Sunitinib treatment induced nuclear translocation of AR in 786-0 AR , with AR binding at EZH2-occupied sites. Mass spectrometry further showed high phosphorylation of AR at S81 and S213, markers of ligand-independent activation, in 786-0 RS , which was absent in 786-0 AR .786-0 RS cells undergo EZH2-dependent reprogramming of the tyrosine kinome via a likely non-canonical mechanism. Co-expression of a phosphomimetic EZH2 mutant (S21D) with AR promoted sunitinib resistance, whereas wild-type or phosphonull (S21A) EZH2 did not. Expanded phosphoproteomic analyses revealed extensive rewiring of serine/threonine signaling networks in sunitinib resistant cells, including enrichment of EGFR-driven MAPK and AKT pathways. Interestingly, preliminary data indicate that cabozantinib does not induce AR and EZH2 upregulation like other TKIs such as lenvatinib. Moreover, cabozantinib appears to prevent compensatory pathway activation triggered by lenvantinib, suggesting a distinct resistance profile. Consistently, AR expression is observed in RCC lines resistant to sunitinib, dovitinib, and lenvatinib, but not with cabozantinib treatment. Ongoing phosphoproteomic analysis will dissect the difference across the TKIsdrugs. Overall, our findings suggest that EZH2-dependent kinase reprogramming drives AR phosphorylation and activation, contributing to drug resistance to selective TKIs. Cabozantinibunique ability to bypass AR/EZH2 upregulation underscores the need to explore alternative resistance pathways.
利益披露 Disclosure
C. Migliarese,
Hologic Inc. Other, Curricular Practical Training.