Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany and University of Tuebingen, Auerbachstr. 112, 70376 Stuttgart, Germany.
German Cancer Consortium (DKTK) and German Cancer Research Center (DKFZ), Heidelberg, Germany.
Sci Rep. 2016 Jul 20;6:29930. doi: 10.1038/srep29930.
Current therapies for metastatic clear cell renal cell carcinoma (ccRCC) show limited efficacy. Drug efficacy, typically investigated in preclinical cell line models during drug development, is influenced by pharmacogenes involved in targeting and disposition of drugs. Here we show through genome-wide DNA methylation profiling, that methylation patterns are concordant between primary ccRCC and macro-metastases irrespective of metastatic sites (rs ≥ 0.92). However, 195,038 (41%) of all investigated CpG sites, including sites within pharmacogenes, were differentially methylated (adjusted P < 0.05) in five established RCC cell lines compared to primary tumors, resulting in altered transcriptional expression. Exemplarily, gene-specific analyses of DNA methylation, mRNA and protein expression demonstrate lack of expression of the clinically important drug transporter OCT2 (encoded by SLC22A2) in cell lines due to hypermethylation compared to tumors or metastases. Our findings provide evidence that RCC cell lines are of limited benefit for prediction of drug effects due to epigenetic alterations. Similar epigenetic landscape of ccRCC-metastases and tumors opens new avenue for future therapeutic strategies.
目前转移性透明细胞肾细胞癌 (ccRCC) 的治疗方法疗效有限。药物疗效通常在药物开发过程中的临床前细胞系模型中进行研究,受到参与药物靶向和处置的药物相关基因的影响。在这里,我们通过全基因组 DNA 甲基化分析表明,原发性 ccRCC 和巨转移灶之间的甲基化模式一致,无论转移部位如何(rs ≥ 0.92)。然而,在与原发性肿瘤相比,在五个已建立的 RCC 细胞系中,包括药物相关基因内的 CpG 位点,有 195,038 个(41%)被差异化甲基化(调整后的 P < 0.05),导致转录表达改变。通过基因特异性的 DNA 甲基化、mRNA 和蛋白质表达分析表明,与肿瘤或转移灶相比,由于超甲基化,临床重要的药物转运蛋白 OCT2(由 SLC22A2 编码)在细胞系中缺乏表达。我们的研究结果表明,由于表观遗传改变,RCC 细胞系对预测药物效果的作用有限。ccRCC 转移灶和肿瘤之间相似的表观遗传景观为未来的治疗策略开辟了新的途径。