Down-regulation of OGT promotes cisplatin resistance by inducing autophagy in ovarian cancer
Down-regulation of OGT promotes cisplatin resistance by inducing autophagy in ovarian cancer
复制标题
OGT 下调通过诱导卵巢癌自噬促进顺铂耐药
DOI：
10.7150/thno.27806
复制
发表时间：
2018-01-01
期刊：
影响因子：
12.4
通讯作者：
Chen, Biliang
中科院分区：
文献类型：
--
作者：
Zhou, Fuxing;Yang, Xiaoshan;Chen, Biliang
顺铂耐药严重影响卵巢癌患者的生存率。然而，卵巢癌顺铂耐药的主要机制仍不清楚。方法：采用免疫组织化学方法检测OGT、OGA和O-GlcNAc在化疗耐药和化疗敏感的卵巢癌组织中的表达。功能分析(体外和体内)证实OGT在顺铂耐药中的作用。免疫印迹法检测自噬相关蛋白。用透射电子显微镜和MRFP-GFP-LC3腺病毒报告基因进行自噬通量分析。免疫沉淀法检测蛋白质之间的相互作用。结果：化疗耐药卵巢癌组织中O-GlcNAc和O-GlcNAc转移酶(OGT)水平明显低于化疗敏感组织，而O-GlcNAc酶(OGA)水平无明显差异。OGT的下调增加了卵巢癌细胞对顺铂的耐药性，但不影响紫杉醇的疗效。在小鼠异种移植瘤模型中，OGT的下调改善了肿瘤对顺铂的耐药性。OGT基因敲除增强了顺铂诱导的自噬，从而减少了顺铂诱导的细胞死亡，并促进了自溶酶体的形成。OGT下调导致O-GlcN酰化SNAP-29水平降低，促进了SNARE复合体和自噬通量的形成。结论：OGT表达下调可通过SNAP-29增强顺铂诱导的自噬，导致卵巢癌顺铂耐药。OGT可能是克服卵巢癌顺铂耐药的新靶点。
Cisplatin resistance significantly affects the survival rate of patients with ovarian cancer. However, the main mechanism underlying cisplatin resistance in ovarian cancer remains unclear. Methods: Immunohistochemistry was used to determine the expression of OGT, OGA and O-GlcNAc in chemoresistant and chemosensitive ovarian cancer tissues. Functional analyses (in vitro and in vivo) were performed to confirm the role of OGT in cisplatin resistance. Autophagy-related proteins were tested by western blot. Transmission electron microscopy and mRFP-GFP-LC3 adenovirus reporter were used for autophagy flux analysis. Immunoprecipitation assay was utilized to detect protein-protein interactions. Results: We found that O-GlcNAc and O-GlcNAc transferase (OGT) levels were significantly lower in chemoresistant ovarian cancer tissues than in chemosensitive tissues, whereas O-GlcNAcase (OGA) levels did not differ. The down-regulation of OGT increased cisplatin resistance in ovarian cancer cells but had no effect on the efficacy of paclitaxel. The down-regulation of OGT improved tumor resistance to cisplatin in a mouse xenograft tumor model. OGT knockdown enhanced cisplatin-induced autophagy, which reduced apoptotic cell death induced by cisplatin, and promoted autolysosome formation. A reduction in O-GlcNAcylated SNAP-29 levels caused by the down-regulation of OGT promoted the formation of the SNARE complex and autophagic flux. Conclusion: Our findings suggest that down-regulation of OGT enhances cisplatin-induced autophagy via SNAP-29, resulting in cisplatin-resistant ovarian cancer. OGT may represent a novel target for overcoming cisplatin resistance in ovarian cancer.