Department of Hepatobiliary Surgery, Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
Department of Gastroenterology, Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
Exp Cell Res. 2019 Dec 1;385(1):111649. doi: 10.1016/j.yexcr.2019.111649. Epub 2019 Sep 25.
Exosomes are present within the local hypoxic tumor microenvironment, where they are able to transfer microRNAs between cells, thereby, effectively mediating cell-cell communication. Hypoxia plays a pivotal role in the progression of many tumor types such as hepatocellular carcinoma (HCC), but how hypoxia-induced exosomes in HCC affect HCC cells remains uncertain. In the present study, we found that hypoxic conditions induced increased exosomal production by HCC cells, and these exosomes, in turn, enhanced the proliferation, migration, and invasiveness in addition to epithelial-to-mesenchymal transition (EMT) in HCC cells under normoxic conditions. When we analyzed these exosomes, we found that miR-1273f were present at higher levels under hypoxic conditions, and we determined that this miRNA was responsible for directly replicating the effects of hypoxic exosomes within HCC cells, in addition to activating the Wnt/β-catenin signaling. We finally identified LHX6, which is a known inhibitor of the Wnt/β-catenin pathway, to be a miR-1273f target. These results, thus, provide evidence that hypoxic conditions can lead HCC cells to express increased exosomes that facilitate miR-1273f expression in normoxic cells, thereby enhancing their malignant phenotype at least in part by targeting LHX6 for downregulation.
外泌体存在于局部缺氧的肿瘤微环境中,它们能够在细胞之间传递 microRNAs,从而有效地介导细胞间通讯。缺氧在许多肿瘤类型的进展中起着关键作用,如肝细胞癌(HCC),但 HCC 中缺氧诱导的外泌体如何影响 HCC 细胞尚不清楚。在本研究中,我们发现缺氧条件诱导 HCC 细胞产生更多的外泌体,这些外泌体反过来又增强了 HCC 细胞在常氧条件下的增殖、迁移和侵袭能力,以及上皮-间充质转化(EMT)。当我们分析这些外泌体时,我们发现 miR-1273f 在缺氧条件下的表达水平更高,我们确定这种 miRNA 负责直接复制缺氧外泌体在 HCC 细胞中的作用,同时激活 Wnt/β-catenin 信号通路。我们最终确定 LHX6 是 Wnt/β-catenin 通路的已知抑制剂,是 miR-1273f 的靶标。这些结果表明,缺氧条件可导致 HCC 细胞表达更多的外泌体,促进常氧细胞中 miR-1273f 的表达,从而至少部分通过下调 LHX6 来增强其恶性表型。