Department of Gynecology, The First Affiliated Hospital of China Medical University, Shenyang, China.
Department of Biochemistry and Molecular Biology, College of Basic Medicine, China Medical University, Shenyang, China.
Cell Death Dis. 2017 Oct 12;8(10):e3118. doi: 10.1038/cddis.2017.486.
Highly upregulated in liver cancer (HULC) is a long noncoding RNA (lncRNA), which has recently been identified as a key regulator in the progression of hepatocellular carcinoma, gliomas and gastric cancer. However, its role in epithelial ovarian carcinoma (EOC) remains unknown. In this study, HULC expression was examined in EOC, borderline and benign ovarian tumors, and normal ovarian tissues by RT-PCR. Ovarian cancer cell phenotypes, as well as autophagy-associated proteins were examined after HULC overexpression or downregulation by plasmid or small interfering RNA (siRNA) transfection, respectively. LncRNA-protein interactions were examined by ribonucleoprotein immunoprecipitation (RIP) assays. We found that HULC expression levels were higher in EOC tissues than normal samples. HULC overexpression induced cell proliferation, migration, invasion, whereas reduced cell apoptosis in vitro and induced tumor growth in vivo. In contrast, downregulation of HULC by siRNA transfection reduced cell proliferation, migration and invasion, and induced cell apoptosis and autophagy. Our results showed that HULC overexpression reduced ATG7, LC3-II and LAMP1 expression, while inducing SQSTM1 (P62) and ITGB1 expression. HULC downregulation had the opposite effects. Furthermore, RIP indicated that ATG7 interacted with HULC; ATG7 downregulation also induced cell proliferation, reduced apoptosis and inhibited autophagy in vitro by reducing LC3-II and LAMP1 expression, while inducing SQSTM1 expression. Furthermore, ATG7 co-transfection with HULC reversed the oncogenic effects of HULC both in vitro and in vivo; however, downregulating ATG7 did not affect cell migration and invasive ability. We found that ITGB1 siRNA co-transfection with HULC reversed the function of HULC in inducing ovarian cancer cell migration and invasive ability. Taken together, our results show that HULC may promote ovarian carcinoma tumorigenesis by inhibiting ATG7 and inducing progression by regulating ITGB1.
肝癌中高度上调的 HULC 是一种长链非编码 RNA（lncRNA），最近被确定为肝细胞癌、神经胶质瘤和胃癌进展的关键调节因子。然而，其在卵巢上皮性癌（EOC）中的作用尚不清楚。在这项研究中，通过 RT-PCR 检测了 EOC、交界性和良性卵巢肿瘤以及正常卵巢组织中的 HULC 表达。通过质粒或小干扰 RNA（siRNA）转染分别上调或下调 HULC 后，检测卵巢癌细胞表型以及自噬相关蛋白。通过核糖核蛋白免疫沉淀（RIP）测定检测 lncRNA-蛋白相互作用。我们发现 HULC 在 EOC 组织中的表达水平高于正常样本。HULC 过表达诱导细胞增殖、迁移和侵袭，而体外降低细胞凋亡并诱导体内肿瘤生长。相反，siRNA 转染下调 HULC 减少细胞增殖、迁移和侵袭，诱导细胞凋亡和自噬。我们的结果表明，HULC 过表达降低了 ATG7、LC3-II 和 LAMP1 的表达，同时诱导了 SQSTM1（P62）和 ITGB1 的表达。HULC 下调则有相反的效果。此外，RIP 表明 ATG7 与 HULC 相互作用；ATG7 下调通过降低 LC3-II 和 LAMP1 的表达诱导细胞增殖，减少凋亡并抑制自噬，同时诱导 SQSTM1 表达。此外，ATG7 与 HULC 共转染在体外和体内逆转了 HULC 的致癌作用；然而，下调 ATG7 并不影响细胞迁移和侵袭能力。我们发现 HULC 与 ITGB1 siRNA 共转染逆转了 HULC 诱导卵巢癌细胞迁移和侵袭能力的功能。总之，我们的结果表明，HULC 可能通过抑制 ATG7 并通过调节 ITGB1 诱导进展来促进卵巢癌的肿瘤发生。
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