Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
Pharm Res. 2010 Mar;27(3):510-6. doi: 10.1007/s11095-010-0064-3. Epub 2010 Feb 4.
Multispecific organic anion transporter, OATP1B3/SLCO1B3, is expressed in several cancer cell lines as well as tumor tissues, and its expression sensitizes the cells to some anti-cancer agents. The present study was aimed to characterize the DNA methylation profiles around the transcriptional start site (TSS) of OATP1B3 and correlate them with the mRNA expression in cancer and immortalized cell lines.
The mRNA expression and DNA methylation profiles of OATP1B3 were determined by RT-PCR and bisulfite sequencing, respectively.
The expression of OATP1B3 mRNA was detected in DLD-1, TFK-1, PK-8, and PK-45P cells, but below the limit of detection in HepG2, Caco-2, and HEK293 cells. Bisulfite sequencing demonstrated that CpG dinucleotides around the TSS are differentially methylated among cell lines and partly associated with the mRNA expression profile of OATP1B3. Furthermore, treatment with 5-aza-2'-deoxycytidine, an inhibitor of DNA methyltransferase, significantly increased the mRNA expression of OATP1B3 in HepG2 and Caco-2 cells by 18- and 14-fold, respectively, but not in DLD-1 and TFK-1 cells.
DNA methylation-dependent gene silencing is at least partly involved in the regulation of OATP1B3 expression in cancer/immortalized cell lines.
多特异性有机阴离子转运体 OATP1B3/SLCO1B3 在几种癌细胞系和肿瘤组织中表达，其表达使细胞对一些抗癌药物敏感。本研究旨在描述 OATP1B3 转录起始位点（TSS）周围的 DNA 甲基化谱，并将其与癌细胞和永生化细胞系中的 mRNA 表达相关联。
通过 RT-PCR 和亚硫酸氢盐测序分别测定 OATP1B3 的 mRNA 表达和 DNA 甲基化谱。
在 DLD-1、TFK-1、PK-8 和 PK-45P 细胞中检测到 OATP1B3 mRNA 的表达，但在 HepG2、Caco-2 和 HEK293 细胞中低于检测限。亚硫酸氢盐测序表明，TSS 周围的 CpG 二核苷酸在细胞系之间存在差异甲基化，部分与 OATP1B3 的 mRNA 表达谱相关。此外，用 DNA 甲基转移酶抑制剂 5-氮杂-2'-脱氧胞苷处理 HepG2 和 Caco-2 细胞，可分别使 OATP1B3 的 mRNA 表达增加 18 倍和 14 倍，但在 DLD-1 和 TFK-1 细胞中没有增加。
DNA 甲基化依赖性基因沉默至少部分参与了 OATP1B3 在癌细胞/永生化细胞系中的表达调控。
