Goujon Marine, Woszczyk Justine, Gaudelot Kelly, Swierczewski Thomas, Fellah Sandy, Gibier Jean-Baptiste, Van Seuningen Isabelle, Larrue Romain, Cauffiez Christelle, Gnemmi Viviane, Aubert Sébastien, Pottier Nicolas, Perrais Michaël
Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France.
CHU Lille, Service d'Anatomo-Pathologie, F-59000 Lille, France.
Cancers (Basel). 2022 Feb 4;14(3):795. doi: 10.3390/cancers14030795.
Clear cell renal cell carcinoma (ccRCC) is the main histotype of kidney cancer, which is typically highly resistant to conventional therapies and known for abnormal lipid accumulation. In this context, we focused our attention on miR-21, an oncogenic miRNA overexpressed in ccRCC, and peroxysome proliferator-activated receptor-α (PPAR- α), one master regulator of lipid metabolism targeted by miR-21. First, in a cohort of 52 primary ccRCC samples, using RT-qPCR and immunohistochemistry, we showed that miR-21 overexpression was correlated with PPAR-α downregulation. Then, in ACHN and 786-O cells, using RT-qPCR, the luciferase reporter gene, chromatin immunoprecipitation, and Western blotting, we showed that PPAR-α overexpression (i) decreased miR-21 expression, AP-1 and NF-κB transcriptional activity, and the binding of AP-1 and NF-κB to the miR-21 promoter and (ii) increased PTEN and PDCD4 expressions. In contrast, using pre-miR-21 transfection, miR-21 overexpression decreased PPAR-α expression and transcriptional activity mediated by PPAR-α, whereas the anti-miR-21 (LNA-21) strategy increased PPAR-α expression, but also the expression of its targets involved in fatty acid oxidation. In this study, we showed a double-negative feedback interaction between miR-21 and PPAR-α. In ccRCC, miR-21 silencing could be therapeutically exploited to restore PPAR-α expression and consequently inhibit the oncogenic events mediated by the aberrant lipid metabolism of ccRCC.
透明细胞肾细胞癌（ccRCC）是肾癌的主要组织学类型，通常对传统疗法具有高度抗性，并且以脂质异常蓄积而闻名。在此背景下，我们将注意力集中在miR-21（一种在ccRCC中过表达的致癌性微小RNA）和过氧化物酶体增殖物激活受体-α（PPAR-α，miR-21靶向的脂质代谢主要调节因子）上。首先，在一组52例原发性ccRCC样本中，我们通过逆转录定量聚合酶链反应（RT-qPCR）和免疫组织化学方法表明，miR-21过表达与PPAR-α下调相关。然后，在ACHN和786-O细胞中，我们通过RT-qPCR、荧光素酶报告基因、染色质免疫沉淀和蛋白质免疫印迹法表明，PPAR-α过表达（i）降低了miR-21表达、激活蛋白-1（AP-1）和核因子κB（NF-κB）的转录活性，以及AP-1和NF-κB与miR-21启动子的结合，并且（ii）增加了第10号染色体缺失的磷酸酶及张力蛋白同源物（PTEN）和程序性细胞死亡蛋白4（PDCD4）的表达。相反，使用pre-miR-21转染，miR-21过表达降低了PPAR-α表达及其介导的转录活性，而抗miR-21（锁核酸-21，LNA-21）策略增加了PPAR-α表达，同时也增加了其参与脂肪酸氧化的靶标的表达。在本研究中，我们展示了miR-21与PPAR-α之间的双负反馈相互作用。在ccRCC中，miR-21沉默可用于治疗，以恢复PPAR-α表达，从而抑制由ccRCC异常脂质代谢介导的致癌事件。
