title: MicroRNAs miR-125b and miR-100 suppress metastasis of hepatocellular carcinoma by disrupting the formation of vessels that encapsulate tumour clusters.
abstract: We have previously shown that vessels that encapsulated tumour cluster (VETC), a prevalent vascular pattern in hepatocellular carcinoma (HCC), facilitates the entry of the whole tumour cluster into the bloodstream in an invasion-independent manner, and that angiopoietin 2 (Angpt2), the levels of which are increased in HCC cells, is essential for VETC formation. However, the mechanisms underlying VETC formation remains unclear. Herein, we characterized miR-125b and miR-100 as novel VETC suppressors by using human HCC specimens, and cell and animal models. We showed that reduced expression of either miR-125b or miR-100 in human HCC tissues was significantly associated with the presence of VETC, venous invasion of tumour cells, and the occurrence of endothelium-coated microemboli. To confirm the role of miR-125b and miR-100 in VETC formation and HCC metastasis, cell lines with stable miR-125b and miR-100 expression were established by using human VETC-2 cells and mouse Hepa1-6 cells, the hepatoma cells that developed xenografts with VETC patterns. Our results showed that expression of miR-125b or miR-100 in VETC-2 and Hepa1-6 cells dramatically reduced VETC formation in xenografts, and consequently inhibited in vivo metastasis, suggesting that miR-125b and miR-100 may attenuate metastasis by repressing VETC formation. Further investigation revealed that miR-125b directly suppressed the expression of Angpt2 by binding to its 3'-untranslated region, whereas miR-100 reduced the protein level of Angpt2 by targeting mechanistic target of rapamycin (MTOR) and blocking the MTOR-p70S6K signalling pathway. Moreover, the suppressive effect of miR-125b and miR-100 on VETC formation was abrogated by injecting Angpt2-expressing viruses into xenografts. Taken together, our findings imply that miR-125b and miR-100 negatively regulate Angpt2 expression through different mechanisms, in turn inhibit VETC formation, and consequently abrogate the VETC-dependent metastasis of hepatoma cells. This study uncovers new regulatory mechanisms of VETC formation, identifies novel functions of miR-125b and miR-100, and provides new targets for antimetastasis therapy of HCC. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
authors: Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, PR China.
authors: Hui-Chao
authors: HC
authors: Zhou
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, Collaborative Innovation Centre for Cancer Medicine, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
authors: Jian-Hong
authors: JH
authors: Fang
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, Collaborative Innovation Centre for Cancer Medicine, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
authors: Li-Ru
authors: LR
authors: Shang
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, Collaborative Innovation Centre for Cancer Medicine, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
authors: Zi-Jun
authors: ZJ
authors: Zhang
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, Collaborative Innovation Centre for Cancer Medicine, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
authors: Ye
authors: Y
authors: Sang
authors: State Key Laboratory of Oncology in South China, Cancer Centre, Sun Yat-sen University, Guangzhou, PR China.|Department of Hepatobiliary Oncology, Cancer Centre, Sun Yat-sen University, Guangzhou, PR China.
authors: Li
authors: L
authors: Xu
authors: State Key Laboratory of Oncology in South China, Cancer Centre, Sun Yat-sen University, Guangzhou, PR China.|Department of Hepatobiliary Oncology, Cancer Centre, Sun Yat-sen University, Guangzhou, PR China.
authors: Yunfei
authors: Y
authors: Yuan
authors: State Key Laboratory of Oncology in South China, Cancer Centre, Sun Yat-sen University, Guangzhou, PR China.|Department of Hepatobiliary Oncology, Cancer Centre, Sun Yat-sen University, Guangzhou, PR China.
authors: Min-Shan
authors: MS
authors: Chen
authors: State Key Laboratory of Oncology in South China, Cancer Centre, Sun Yat-sen University, Guangzhou, PR China.
authors: Limin
authors: L
authors: Zheng
authors: State Key Laboratory of Oncology in South China, Cancer Centre, Sun Yat-sen University, Guangzhou, PR China.|Department of Hepatobiliary Oncology, Cancer Centre, Sun Yat-sen University, Guangzhou, PR China.
authors: Yaojun
authors: Y
authors: Zhang
authors: Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, PR China.|Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, Collaborative Innovation Centre for Cancer Medicine, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
authors: Shi-Mei
authors: SM
authors: Zhuang
mesh_terms: D042702:Angiopoietin-2 / Q000378:metabolism; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology / Q000556:secondary*; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D064593:Heterografts; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics / Q000502:physiology*; D009363:Neoplasm Proteins / Q000378:metabolism; D009368:Neoplasm Transplantation; D009360:Neoplastic Cells, Circulating / Q000473:pathology; D014407:Tumor Cells, Cultured
chemical_list: C586513:ANGPT2 protein, human; D042702:Angiopoietin-2; C544266:MIRN100 microRNA, human; C531888:MIRN125 microRNA, human; D035683:MicroRNAs; D009363:Neoplasm Proteins
keywords: Angpt2; VETC; angiopoietin-2; miRNA-100; miRNA-125b; non-coding RNA