DNA 甲基化与有机阳离子转运蛋白 OCT1（SLC22A1）在人肝癌中的下调有关。
DNA methylation is associated with downregulation of the organic cation transporter OCT1 (SLC22A1) in human hepatocellular carcinoma.
机构信息
Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Auerbachstrasse 112, 70376 Stuttgart, Germany.
出版信息
Genome Med. 2011 Dec 23;3(12):82. doi: 10.1186/gm298.
BACKGROUND
Organic cation transporters (OCTs) determine not only physiological processes but are also involved in the cellular uptake of anticancer agents. Based on microarray analyses in hepatocellular carcinoma (HCC), SLC22A1/OCT1 mRNA seems to be downregulated, but systematic protein expression data are currently missing. Moreover, the underlying molecular mechanisms responsible for altered SLC22A1 expression in HCC are not fully understood. Therefore, we investigated the role of DNA methylation in the transcriptional regulation of the family members SLC22A1/OCT1, SLC22A2/OCT2 and SLC22A3/OCT3 in HCC.
METHODS
Semiquantitative immunohistochemistry of SLC22A1 protein expression was performed in paired HCC and histological normal adjacent liver tissues (n = 71) using tissue microarray analyses, and the results were correlated with clinicopathological features. DNA methylation, quantified by MALDI-TOF mass spectrometry and gene expression of SLC22A1, SLC22A2 and SLC22A3 were investigated using fresh-frozen HCC (n = 22) and non-tumor adjacent liver tissues as well as histologically normal liver samples (n = 120) from a large-scale liverbank.
RESULTS
Based on tissue microarray analyses, we observed a significant downregulation of SLC22A1 protein expression in HCC compared to normal adjacent tissue (P < 0.0001). SLC22A1 expression was significantly inverse correlated with expression of the proliferation marker MIB1/Ki-67 (rs = -0.464, P < 0.0001). DNA methylation of SLC22A1 was significantly higher in HCC compared with non-tumor adjacent liver tissue and was lowest in histologically normal liver tissue. Methylation levels for SLC22A1 in combination with RASSF1A resulted in a specificity of > 90% and a sensitivity of 82% for discriminating HCC and tumor-free liver tissue.
CONCLUSIONS
DNA methylation of SLC22A1 is associated with downregulation of SLC22A1 in HCC and might be a new biomarker for HCC diagnosis and prognosis. Moreover, targeting SLC22A1 methylation by demethylating agents may offer a novel strategy for anticancer therapy of HCC.
背景
有机阳离子转运体（OCTs）不仅决定了生理过程，还参与了抗癌药物的细胞摄取。基于肝细胞癌（HCC）的基因芯片分析，SLC22A1/OCT1mRNA 似乎下调，但目前缺乏系统的蛋白表达数据。此外，SLC22A1 在 HCC 中表达改变的潜在分子机制尚不完全清楚。因此，我们研究了 DNA 甲基化在 HCC 中家族成员 SLC22A1/OCT1、SLC22A2/OCT2 和 SLC22A3/OCT3 转录调控中的作用。
方法
使用组织微阵列分析对配对的 HCC 和组织学正常相邻肝组织（n=71）中的 SLC22A1 蛋白表达进行半定量免疫组织化学检测，并将结果与临床病理特征相关联。使用来自大型肝库的新鲜冷冻 HCC（n=22）和非肿瘤相邻肝组织以及组织学正常肝样本（n=120），通过 MALDI-TOF 质谱法定量 DNA 甲基化，并研究 SLC22A1、SLC22A2 和 SLC22A3 的基因表达。
结果
基于组织微阵列分析，我们观察到 HCC 中 SLC22A1 蛋白表达明显低于正常相邻组织（P<0.0001）。SLC22A1 表达与增殖标志物 MIB1/Ki-67 的表达呈显著负相关（rs=-0.464，P<0.0001）。与非肿瘤相邻肝组织相比，HCC 中 SLC22A1 的 DNA 甲基化水平显著升高，在组织学正常肝组织中最低。SLC22A1 的甲基化水平与 RASSF1A 相结合，用于区分 HCC 和无肿瘤肝组织的特异性>90%，敏感性 82%。
结论
SLC22A1 的 DNA 甲基化与 HCC 中 SLC22A1 的下调有关，可能是 HCC 诊断和预后的新生物标志物。此外，通过去甲基化剂靶向 SLC22A1 甲基化可能为 HCC 的抗癌治疗提供新策略。
Zotero 插件