Department of Experimental Oncology and Molecular Medicine, Fondazione IRCSS Istituto Nazionale Tumori, Milan, Italy.
Biochem Pharmacol. 2010 Apr 15;79(8):1108-17. doi: 10.1016/j.bcp.2009.12.002. Epub 2009 Dec 31.
Pt compounds still represent the mainstay of the treatment of ovarian carcinoma. The aim of the present study was to investigate the molecular bases of resistance to Pt drugs using an oxaliplatin-resistant ovarian carcinoma cell model IGROV-1/OHP. These cells exhibited high levels of resistance to oxaliplatin, cross-resistance to cisplatin and topotecan and displayed a marked accumulation defect of Pt drugs. This feature was associated with increased expression and altered N-linked glycosylation of ATP binding cassette transporters MRP1 and MRP4. Pre-treatment with tunicamycin, which inhibits the biosynthesis of N-linked oligosaccharides, decreased the accumulation of Pt in sensitive cells exposed to oxaliplatin or cisplatin and increased the electrophoretic mobility of MRP1 and MRP4, reproducing the association between decreased glycosylation of MRP1 and MRP4 and decreased Pt accumulation observed in the resistant IGROV-1/OHP cells. The observed N-glycosylation defect of oxaliplatin-resistant cells was linked to reduced levels of N-acetylglucosamine-1-phosphotransferase (GNPTG) and mannosyl (alpha-1,6-)-glycoprotein beta-1,6-N-acetyl-glucosaminyltransferase (MGAT5). This feature, observed in IGROV-1/OHP cells, was associated with decreased retention of Pt drugs. In addition, the overexpression of fully glycosylated MRP1 or MRP4 in tumor cell line of ovarian origin was associated with resistance to oxaliplatin and cisplatin. Our findings, showing that development of resistance to oxaliplatin results in up-regulation of MRPs, support that patients with oxaliplatin-refractory ovarian carcinomas may benefit from non-Pt-based regimens which do not contain MRP1 and MRP4 substrates.
铂类化合物仍然是卵巢癌治疗的主要手段。本研究旨在利用奥沙利铂耐药卵巢癌细胞模型 IGROV-1/OHP 研究铂类耐药的分子基础。这些细胞对奥沙利铂表现出高水平的耐药性，对顺铂和拓扑替康交叉耐药，并表现出明显的铂类药物蓄积缺陷。这一特征与 ABC 转运蛋白 MRP1 和 MRP4 的表达增加和 N-连接糖基化改变有关。用 tunicamycin 预处理可抑制 N-连接寡糖的生物合成，减少敏感细胞暴露于奥沙利铂或顺铂时铂的蓄积，并增加 MRP1 和 MRP4 的电泳迁移率，重现耐药 IGROV-1/OHP 细胞中观察到的 MRP1 和 MRP4 糖基化减少与铂蓄积减少之间的关联。奥沙利铂耐药细胞观察到的 N-糖基化缺陷与 N-乙酰葡萄糖胺-1-磷酸转移酶 (GNPTG) 和甘露糖（α-1,6-)-糖蛋白β-1,6-N-乙酰-葡萄糖胺基转移酶 (MGAT5) 水平降低有关。IGROV-1/OHP 细胞中观察到的这种特征与铂类药物保留减少有关。此外，卵巢来源肿瘤细胞系中完全糖基化的 MRP1 或 MRP4 的过表达与奥沙利铂和顺铂耐药有关。我们的研究结果表明，对奥沙利铂耐药的发展导致 MRPs 的上调，支持奥沙利铂难治性卵巢癌患者可能受益于不含 MRP1 和 MRP4 底物的非铂类方案。
