Metastatic clear cell renal cell carcinoma (CCC) remains incurable despite advances in the development of anti-angiogenic targeted therapies and the emergence of immune checkpoint inhibitors. We have previously shown that the sonic hedgehog-Gli signaling pathway is oncogenic in CCC allowing us to identify the developmental Lim1 transcription factor as a Gli target and as a new oncogene in CCC regulating cell proliferation and apoptosis, and promoting tumor growth. In this previous study, preliminary in vitro results also suggested that Lim1 may be implicated in metastatic spread. Here we investigated the potential pro-metastatic role of Lim1 in advanced CCC (1) in vitro using a panel of CCC cell lines expressing or not the von Hippel-Lindau (VHL) tumor suppressor gene either naturally or by gene transfer and (2) ex vivo in 30 CCC metastatic tissues, including lymph nodes, lung, skin, bone, and adrenal metastases, and (3) in vivo, using a metastatic model by intravenous injection of siRNA-transfected cells into Balb/c nude. Our in vitro results reveal that Lim1 knockdown time-dependently decreased CCC cell motility, migration, invasion, and clonogenicity by up to 50% regardless of their VHL status. Investigating the molecular machinery involved in these processes, we identified a large panel of Lim1 targets known to be involved in cell adhesion (paxillin and fibronectin), epithelial-mesenchymal transition (Twist1/2 and snail), invasion (MMP1/2/3/8/9), and metastatic progression (CXCR4, SDF-1, and ANG-1). Importantly, Lim1 was found constitutively expressed in all metastatic tissues. The H-score in metastatic tissues being significantly superior to the score in the corresponding primary tumor tissues (P value = 0.009). Furthermore, we showed that Lim1 silencing decreases pulmonary metastasis development in terms of number and size in the in vivo metastatic model of human CCC. Taken together, these experiments strengthen the potential therapeutic value of Lim1 targeting as a promising novel approach for treating metastatic human CCC.

中文翻译：

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Lim1癌基因作为转移性人肾细胞癌的新治疗靶标。

尽管抗血管生成靶向疗法的发展和免疫检查点抑制剂的出现，转移性透明细胞肾细胞癌（CCC）仍无法治愈。先前我们已经表明，声波刺猬-Gli信号通路在CCC中是致癌的，这使我们能够将发育性Lim1转录因子识别为Gli靶点，并将其作为CCC中调节细胞增殖和凋亡并促进肿瘤生长的新致癌基因。在这项先前的研究中，初步的体外研究结果还表明，Lim1可能与转移扩散有关。在这里，我们使用一组表达或不表达von Hippel-Lindau（VHL）抑癌基因的CCC细胞系，通过自然或通过基因转移来研究Lim1在晚期CCC（1）中的潜在前转移作用，以及（2） （30）使用转移模型，通过将siRNA转染的细胞静脉内注射到Balb / c裸鼠体内，使用转移模型在30个CCC转移组织中进行离体，包括淋巴结，肺，皮肤，骨骼和肾上腺转移，以及（3）在体内。我们的体外研究结果表明，Lim1敲低时间依赖性地降低了CCC细胞的运动性，迁移，侵袭和克隆形成性，无论其VHL状态如何，最多可降低50％。调查了这些过程中涉及的分子机制，我们发现了一大批已知与细胞粘附有关的Lim1靶标（paxillin和纤连蛋白），上皮-间质转化（Twist1 / 2和蜗牛），侵袭（MMP1 / 2/3/8/9）和转移性进展（CXCR4，SDF-1和ANG-1）。重要的是，发现Lim1在所有转移组织中组成性表达。转移组织中的H评分显着优于相应原发肿瘤组织中的评分（P值= 0.009）。此外，我们显示，Lim1沉默可在人CCC体内转移模型中减少肺转移的发展，无论是数量还是大小。综上所述，这些实验增强了Lim1靶向治疗作为治疗转移性人类CCC的有前途的新方法的潜在治疗价值。转移组织中的H评分显着优于相应原发肿瘤组织中的评分（P值= 0.009）。此外，我们显示，Lim1沉默可在人CCC体内转移模型中减少肺转移的发展，无论是数量还是大小。综上所述，这些实验增强了Lim1靶向治疗作为治疗转移性人类CCC的有前途的新方法的潜在治疗价值。转移组织中的H评分显着优于相应原发肿瘤组织中的评分（P值= 0.009）。此外，我们显示，Lim1沉默可在人CCC体内转移模型中减少肺转移的发展，无论是数量还是大小。综上所述，这些实验增强了Lim1靶向治疗作为治疗转移性人类CCC的有前途的新方法的潜在治疗价值。