Tung S-L, Huang W-C, Hsu F-C, Yang Z-P, Jang T-H, Chang J-W, Chuang C-M, Lai C-R, Wang L-H
Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan.
Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan.
Oncogenesis. 2017 May 1;6(5):e326. doi: 10.1038/oncsis.2017.25.
Epithelial ovarian cancer is the most lethal gynecological cancer mainly due to late diagnosis, easy spreading and rapid development of chemoresistance. Cancer stem cells are considered to be one of the main mechanisms for chemoresistance, as well as metastasis and recurrent disease. To explore the stemness characteristics of ovarian cancer stem cells, we successfully enriched ovarian cancer stem-like cells from an established ovarian cancer cell line (SKOV-I6) and a fresh ovarian tumor-derived cell line (OVS1). These ovarian cancer stem-like cells possess important cancer stemness characteristics including sphere-forming and self-renewing abilities, expressing important ovarian cancer stem cell and epithelial-mesenchymal transition markers, as well as increased drug resistance and potent tumorigenicity. Microarray analysis of OVS1-derived sphere cells revealed increased expression of amphiregulin (AREG) and decreased expression of its conserved regulatory microRNA, miR-34c-5p, when compared with the OVS1 parental cells. Overexpression of AREG and decreased miR-34c-5p expression in SKOV-I6 and OVS1 sphere cells were confirmed by quantitative real-time PCR analysis. Luciferase reporter assay and mutant analysis confirmed that AREG is a direct target of miR-34c-5p. Furthermore, AREG-mediated increase of sphere formation, drug resistance toward docetaxel and carboplatin, as well as tumorigenicity of SKOV-I6 and OVS1 cells could be abrogated by miR-34c-5p. We further demonstrated that miR-34c-5p inhibited ovarian cancer stemness through downregulation of the AREG-EGFR-ERK pathway. Overexpression of AREG was found to be correlated with advanced ovarian cancer stages and poor prognosis. Taken together, our data suggest that AREG promotes ovarian cancer stemness and drug resistance via the AREG-EGFR-ERK pathway and this is inhibited by miR-34c-5p. Targeting AREG, miR-34c-5p could be a potential strategy for anti-cancer-stem cell therapy in ovarian cancer.
上皮性卵巢癌是最致命的妇科癌症，主要原因是诊断较晚、易于扩散以及化疗耐药性迅速发展。癌症干细胞被认为是化疗耐药性以及转移和疾病复发的主要机制之一。为了探索卵巢癌干细胞的干性特征，我们成功地从已建立的卵巢癌细胞系（SKOV-I6）和新鲜的卵巢肿瘤衍生细胞系（OVS1）中富集了卵巢癌干细胞样细胞。这些卵巢癌干细胞样细胞具有重要的癌症干性特征，包括成球和自我更新能力，表达重要的卵巢癌干细胞和上皮-间质转化标志物，以及增加的耐药性和强大的致瘤性。与OVS1亲代细胞相比，对OVS1衍生的球细胞进行微阵列分析显示双调蛋白（AREG）表达增加，其保守调控微小RNA miR-34c-5p表达降低。通过定量实时PCR分析证实了SKOV-I6和OVS1球细胞中AREG的过表达和miR-34c-5p表达的降低。荧光素酶报告基因测定和突变分析证实AREG是miR-34c-5p的直接靶标。此外，miR-34c-5p可以消除AREG介导的SKOV-I6和OVS1细胞的成球增加、对多西他赛和顺铂的耐药性以及致瘤性。我们进一步证明，miR-34c-5p通过下调AREG-EGFR-ERK途径抑制卵巢癌干性。发现AREG的过表达与晚期卵巢癌阶段和不良预后相关。综上所述,我们的数据表明,AREG通过AREG-EGFR-ERK途径促进卵巢癌干性和耐药性,而这被miR-34c-5p抑制。靶向AREG，miR-34c-5p可能是卵巢癌抗癌干细胞治疗的潜在策略。
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