DNA methylation profiles of organic anion transporting polypeptide 1B3 in cancer cell lines.
OBJECTIVE
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.


METHODS
The mRNA expression and DNA methylation profiles of OATP1B3 were determined by RT-PCR and bisulfite sequencing, respectively.


RESULTS
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.


CONCLUSIONS
DNA methylation-dependent gene silencing is at least partly involved in the regulation of OATP1B3 expression in cancer/immortalized cell lines.
Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
Sayaka
S
Ichihara
Ryota
R
Kikuchi
Hiroyuki
H
Kusuhara
Satoki
S
Imai
Kazuya
K
Maeda
Yuichi
Y
Sugiyama
D045744:Cell Line, Tumor; D018899:CpG Islands; D019175:DNA Methylation; D003841:Deoxycytidine / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009369:Neoplasms / Q000235:genetics*; D029362:Organic Anion Transporters, Sodium-Independent / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D000074542:Solute Carrier Organic Anion Transporter Family Member 1B3; D014157:Transcription Factors / Q000235:genetics; D015533:Transcriptional Activation
D029362:Organic Anion Transporters, Sodium-Independent; D012333:RNA, Messenger; C421209:SLCO1B3 protein, human; D000074542:Solute Carrier Organic Anion Transporter Family Member 1B3; D014157:Transcription Factors; D003841:Deoxycytidine