Hu Jianguo, Zhang Luo, Mei Zhiqiang, Jiang Yuan, Yi Yuan, Liu Li, Meng Ying, Zhou Lili, Zeng Jianhua, Wu Huan, Jiang Xingwei
Department of Obstetrics and Gynecology, Second Affiliated Hospital, Chongqing Medical University, Chongqing, China.
The Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, China.
Cell Physiol Biochem. 2018;47(2):654-666. doi: 10.1159/000490020. Epub 2018 May 22.
BACKGROUND/AIMS: Ubiquitin E3 ligase MARCH7 plays an important role in T cell proliferation and neuronal development. But its role in ovarian cancer remains unclear. This study aimed to investigate the role of Ubiquitin E3 ligase MARCH7 in ovarian cancer.
Real-time PCR, immunohistochemistry and western blotting analysis were performed to determine the expression of MARCH7, MALAT1 and ATG7 in ovarian cancer cell lines and clinical specimens. The role of MARCH7 in maintaining ovarian cancer malignant phenotype was examined by Wound healing assay, Matrigel invasion assays and Mouse orthotopic xenograft model. Luciferase reporter assay, western blot analysis and ChIP assay were used to determine whether MARCH7 activates TGF-β-smad2/3 pathway by interacting with TGFβR2.
MARCH7 interacted with MALAT1 by miR-200a (microRNA-200a). MARCH7 may function as a competing endogenous RNA (ceRNA) to regulate the expression of ATG7 by competing with miR-200a. MARCH7 regulated TGF-β-smad2/3 pathway by interacting with TGFβR2. Inhibition of TGF-β-smad2/3 pathway downregulated MARCH7, MALAT1 and ATG7. MiR-200a regulated TGF-β induced autophagy, invasion and metastasis of SKOV3 cells by targeting MARCH7. MARCH7 silencing inhibited autophagy invasion and metastasis of SKOV3 cells both in vitro and in vivo. In contrast, MARCH7 overexpression promoted TGF-β induced autophagy, invasion and metastasis of A2780 cells in vitro by depending on MALAT1 and ATG7. We also found that TGF-β-smad2/3 pathway regulated MARCH7 and ATG7 through MALAT1.
These findings suggested that TGFβR2-Smad2/3-MALAT1/MARCH7/ATG7 feedback loop mediated autophagy, migration and invasion in ovarian cancer.
背景/目的：泛素E3连接酶MARCH7在T细胞增殖和神经元发育中起重要作用。但其在卵巢癌中的作用仍不清楚。本研究旨在探讨泛素E3连接酶MARCH7在卵巢癌中的作用。
采用实时定量PCR、免疫组织化学和蛋白质印迹分析来确定MARCH7、MALAT1和ATG7在卵巢癌细胞系和临床标本中的表达。通过伤口愈合试验、基质胶侵袭试验和小鼠原位异种移植模型检测MARCH7在维持卵巢癌恶性表型中的作用。采用荧光素酶报告基因试验、蛋白质印迹分析和染色质免疫沉淀试验来确定MARCH7是否通过与TGFβR2相互作用激活TGF-β-smad2/3信号通路。
MARCH7通过miR-200a（微小RNA-200a）与MALAT1相互作用。MARCH7可能作为一种竞争性内源RNA（ceRNA），通过与miR-200a竞争来调节ATG7的表达。MARCH7通过与TGFβR2相互作用调节TGF-β-smad2/3信号通路。抑制TGF-β-smad2/3信号通路可下调MARCH7、MALAT1和ATG7。miR-200a通过靶向MARCH7调节TGF-β诱导的SKOV3细胞自噬、侵袭和转移。MARCH7沉默在体外和体内均抑制SKOV3细胞的自噬、侵袭和转移。相反，MARCH7过表达在体外依赖MALAT1和ATG7促进TGF-β诱导的A2780细胞自噬、侵袭和转移。我们还发现TGF-β-smad2/3信号通路通过MALAT1调节MARCH7和ATG7。
这些发现表明，TGFβR2-Smad2/3-MALAT1/MARCH7/ATG7反馈环介导卵巢癌中的自噬、迁移和侵袭。
