Candidate DNA methylation drivers of acquired cisplatin resistance in ovarian cancer identified by methylome and expression profiling
Candidate DNA methylation drivers of acquired cisplatin resistance in ovarian cancer identified by methylome and expression profiling
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DOI：
10.1038/onc.2011.611
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发表时间：
2012-10-01
期刊：
影响因子：
8
通讯作者：
Brown, R.
中科院分区：
文献类型：
--
作者：
Zeller, C.;Dai, W.;Brown, R.
癌症甲基组中的多重DNA甲基化变化与耐药性的获得有关；然而，仍不确定有多少代表化学耐药的关键DNA甲基化驱动因素。我们使用等基因顺铂敏感/耐药卵巢癌细胞系，并使用去甲基化药物诱导重致敏，目的是确定与化疗耐药相关的一致的甲基化和表达变化。利用27 578个CpG位点的全基因组DNA甲基化分析，我们发现与亲本敏感的A2780细胞系相比，耐药A2780/cp70细胞系中4092个基因位点发生了高甲基化。基因启动子区域的高甲基化通常与转录沉默有关；然而，通过微阵列表达谱检测，只有245个高甲基化基因在A2780/cp70中表达下调。用去甲基化剂2-脱氧-5′-氮胞苷处理A2780/cp70可诱导顺铂重敏，41个下调基因重新表达。在进一步独立的顺铂耐药A2780细胞衍生物中，共有13/41个基因持续高甲基化。13个基因中的9个（ARHGDIB、ARMCX2、COL1A、FLNA、FLNC、MEST、MLH1、NTS和PSMB9）的CpG位点在化疗后复发的卵巢肿瘤或患者复发时衍生的化疗耐药细胞系中获得甲基化。此外，5/13个基因（ARMCX2、COL1A1、MDK、MEST和MLH1）在耐药卵巢癌维持（侧群体）细胞中获得甲基化。当重新导入体外细胞时，MLH1在赋予顺铂敏感性方面具有直接作用。这种结合基因组学的方法已经确定了进一步的化学耐药的潜在关键驱动因素，其表达被DNA甲基化沉默，应该进一步评估作为耐药的临床生物标志物。中华肿瘤杂志，2012,31 (3):467 - 476；doi: 10.1038 / onc.2011.611;2012年1月16日在线发布
Multiple DNA methylation changes in the cancer methylome are associated with the acquisition of drug resistance; however it remains uncertain how many represent critical DNA methylation drivers of chemoresistance. Using isogenic, cisplatin-sensitive/resistant ovarian cancer cell lines and inducing resensitizaton with demethylating agents, we aimed to identify consistent methylation and expression changes associated with chemoresistance. Using genome-wide DNA methylation profiling across 27 578 CpG sites, we identified loci at 4092 genes becoming hypermethylated in chemoresistant A2780/cp70 compared with the parental-sensitive A2780 cell line. Hypermethylation at gene promoter regions is often associated with transcriptional silencing; however, expression of only 245 of these hypermethylated genes becomes downregulated in A2780/cp70 as measured by microarray expression profiling. Treatment of A2780/cp70 with the demethylating agent 2-deoxy-5'-azacytidine induces resensitization to cisplatin and re-expression of 41 of the downregulated genes. A total of 13/41 genes were consistently hypermethylated in further independent cisplatin-resistant A2780 cell derivatives. CpG sites at 9 of the 13 genes (ARHGDIB, ARMCX2, COL1A, FLNA, FLNC, MEST, MLH1, NTS and PSMB9) acquired methylation in ovarian tumours at relapse following chemotherapy or chemoresistant cell lines derived at the time of patient relapse. Furthermore, 5/13 genes (ARMCX2, COL1A1, MDK, MEST and MLH1) acquired methylation in drug-resistant ovarian cancer-sustaining (side population) cells. MLH1 has a direct role in conferring cisplatin sensitivity when reintroduced into cells in vitro. This combined genomics approach has identified further potential key drivers of chemoresistance whose expression is silenced by DNA methylation that should be further evaluated as clinical biomarkers of drug resistance. Oncogene (2012) 31, 4567-4576; doi:10.1038/onc.2011.611; published online 16 January 2012