Cao Ya-Lei, Zhuang Ting, Xing Bao-Heng, Li Na, Li Qin
Department of Gynaecology and Obstetrics, Cangzhou Center Hospital, Cangzhou, China.
Research Center for Immunology, School of Laboratory Medicine, Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, Xinxiang Medical University, Xinxiang, Henan Province, China.
Cell Biochem Funct. 2017 Aug;35(6):296-303. doi: 10.1002/cbf.3276. Epub 2017 Aug 8.
Ovarian cancer is the most common malignancy in women. Owing to late syndromic presentation and lack of efficient early detection, most cases are diagnosed at advanced stages. Surgery and platinum-based chemotherapy are still the standard care currently. However, resistance invoked often compromises the clinical value of the latter. Expression of DNA methyltransferase 1 (DNMT1) was analysed by gene array. Protein was determined by immunoblotting. Exosome was isolated with commercial kit. Cell proliferation was measured by CCK8 method. Annexin V-PI double staining was performed for apoptosis evaluation. Xenograft model was established and administrated with exosome. Tumour growth and overall survival were monitored. We demonstrated the upregulation of DNMT1 in both tumour and derived cell line. DNMT1 transcripts were highly enriched in exosomes from conditioned medium of ovarian cells. Co-incubation with exosomes stimulated endogenous expression and rendered host cell the resistance to cytotoxicity of cisplatin. In vivo administration of DNMT1-containing exosomes exacerbated xenograft progression and reduced overall survival significantly. Moreover, treatment with exosome inhibitor GW4869 almost completely restored sensitivity in resistant cells. Our data elucidated an unappreciated mechanism of exosomal DNMT1 in cisplatin resistance in ovarian cancer, also indicating the potential of the combination of exosome inhibitor with cisplatin in resistant patients.
卵巢癌是女性中最常见的恶性肿瘤。由于症状出现较晚且缺乏有效的早期检测方法，大多数病例在晚期才被诊断出来。手术和铂类化疗仍是目前的标准治疗方法。然而，常常引发的耐药性会损害后者的临床价值。通过基因阵列分析DNA甲基转移酶1（DNMT1）的表达。通过免疫印迹法测定蛋白质。使用商业试剂盒分离外泌体。通过CCK8法测量细胞增殖。进行Annexin V-PI双染色以评估细胞凋亡。建立异种移植模型并给予外泌体。监测肿瘤生长和总生存期。我们证明了DNMT1在肿瘤及其衍生细胞系中均上调。DNMT1转录本在卵巢细胞条件培养基中的外泌体中高度富集。与外泌体共同孵育刺激内源性表达并使宿主细胞对顺铂的细胞毒性产生抗性。在体内给予含DNMT1的外泌体会加剧异种移植进展并显著降低总生存期。此外，用外泌体抑制剂GW4869治疗几乎完全恢复了耐药细胞的敏感性。我们的数据阐明了外泌体DNMT1在卵巢癌顺铂耐药中的一种未被认识的机制，也表明外泌体抑制剂与顺铂联合应用于耐药患者的潜力。
