Micucci Carla, Matacchione Giulia, Valli Debora, Orciari Silvia, Catalano Alfonso
Department of Clinical and Molecular Sciences, Polytechnic University of Marche, School of Medicine, Via Tronto 10/A, 60100 Ancona, Italy.
Br J Cancer. 2015 Oct 20;113(8):1178-85. doi: 10.1038/bjc.2015.338. Epub 2015 Oct 6.
Hypoxia and the subsequent activation of hypoxia-inducible factor-2α (HIF2α) contribute to the progression of a variety of cancers. However, their role in the generation of renal cell carcinoma-derived stem cells has not been fully addressed.
A sphere formation assay, cell proliferation, RT-PCR, western blot, FACS, immunohistochemistry and tumour xenograft were used to study the role of HIF2α.
Propagation of four renal cell carcinoma (RCC) cell lines (Caki-1, Caki-2, 786-O, 769-P) in anchorage-independent floating spheres led to the expansion of cells bearing the CXCR4 (CD184) surface marker. Inhibition of the CXCR4 pathway reduced sphere expansion. The enhanced self-renewal activity of the CXCR4-positive spheres was preceded by the upregulation of HIF2α. Knockdown of HIF2α abrogated CXCR4 expression and sphere formation. Finally, RCC-derived spheres showed an undifferentiated phenotype in vivo and formed subcutaneous tumours that highly expressed HIF2α and CXCR4. Inhibition of HIF2α abolished tumour growth in animal models.
These results suggest that the generation of RCC-derived CSCs involves the activation of HIF2α and may provide a foundation for the development of new strategies to prevent the induction of CSCs in RCC.
缺氧及随后缺氧诱导因子-2α（HIF2α）的激活促进多种癌症的进展。然而，它们在肾细胞癌衍生干细胞产生中的作用尚未完全阐明。
采用成球实验、细胞增殖实验、RT-PCR、蛋白质免疫印迹、流式细胞术、免疫组织化学和肿瘤异种移植实验来研究HIF2α的作用。
四种肾细胞癌（RCC）细胞系（Caki-1、Caki-2、786-O、769-P）在非贴壁依赖性悬浮球体中增殖导致携带CXCR4（CD184）表面标志物的细胞扩增。CXCR4通路的抑制减少了球体扩增。在CXCR4阳性球体增强的自我更新活性之前，HIF2α表达上调。敲低HIF2α消除了CXCR4表达和成球能力。最后，RCC衍生的球体在体内表现出未分化表型，并形成高表达HIF2α和CXCR4的皮下肿瘤。抑制HIF2α消除了动物模型中的肿瘤生长。
这些结果表明，RCC衍生的癌症干细胞的产生涉及HIF2α的激活，并可能为开发预防RCC中癌症干细胞诱导的新策略提供基础。
