title: Molecular determinants in the transport of a bile acid-derived diagnostic agent in tumoral and nontumoral cell lines of human liver.
abstract: Contrast-enhanced magnetic resonance imaging (CE-MRI) is a valuable technique for the diagnosis of liver diseases. As gadocoletic acid trisodium salt (B22956/1), a new contrast agent showing high biliary excretion, may be potentially advantageous in hepatobiliary imaging, the aim of the study was to investigate the molecular mechanisms of hepatic transport of the B22956 ion in a cellular model of hepatic tumor. B22956 ion uptake was measured in tumoral (HepG2) and nontumoral (Chang liver) hepatic cell lines. Absolute quantitative real-time reverse transcriptase (RT)-polymerase chain reaction (PCR) analyses, using cloned PCR products as standards, were performed on total RNA of both cell lines and normal liver to evaluate the transcription of 12 transport genes: SLCO1A2, SLCO2B1, SLCO1B1, SLCO3A1, SLCO4A1, SLCO1B3, SLC22A7, SLC22A8, SLC22A1, SLC10A1, SLC15A1, and SLC15A2. B22956 transport was more efficient in Chang liver than in HepG2 cells and was inhibited by cholecystokinin-8, a specific substrate of OATP1B3. Real-time RT-PCR analyses revealed different transcription profiles in the tumoral and nontumoral cell lines. Compared with normal liver, the expression of SLCO1B1, SLCO3A1, and SLCO1B3 was greatly repressed in HepG2 cells, whereas SLCO2B1, SLC22A7, and SLC22A8 expression was either maintained or increased. On the contrary, in Chang liver cells, SLC22A7 and SLC22A8 genes were undetectable, whereas the expression of SLCO3A1, SLCO4A1, and SLCO1B3 was similar to normal liver. Transport studies and gene expression analyses indicated that B22956 ion is a good substrate to the liver-specific OATP1B3, reported to be poorly expressed or absent in human liver tumors. Therefore, B22956 may be helpful in detecting hepatic neoplastic lesions by CE-MRI.
authors.affiliation: Centro Studi Fegato, Bldg. Q, AREA Science Park Basovizza, SS 14 Km 163.5, 34012 Trieste, Italy.
authors.forename: Antonin
authors.initials: A
authors.lastname: Libra
authors.forename: Cristina
authors.initials: C
authors.lastname: Fernetti
authors.forename: Vito
authors.initials: V
authors.lastname: Lorusso
authors.forename: Massimo
authors.initials: M
authors.lastname: Visigalli
authors.forename: Pier Lucio
authors.initials: PL
authors.lastname: Anelli
authors.forename: Frantisek
authors.initials: F
authors.lastname: Staud
authors.forename: Claudio
authors.initials: C
authors.lastname: Tiribelli
authors.forename: Lorella
authors.initials: L
authors.lastname: Pascolo
mesh_terms: D001692:Biological Transport; D015153:Blotting, Western; D002460:Cell Line; D003287:Contrast Media / Q000493:pharmacokinetics*; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism; D029362:Organic Anion Transporters, Sodium-Independent / Q000032:analysis; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000074542:Solute Carrier Organic Anion Transporter Family Member 1B3; D013656:Taurocholic Acid / Q000493:pharmacokinetics
chemical_list: C440468:B-22956-1; D003287:Contrast Media; D029362:Organic Anion Transporters, Sodium-Independent; D009942:Organometallic Compounds; C421209:SLCO1B3 protein, human; D000074542:Solute Carrier Organic Anion Transporter Family Member 1B3; D013656:Taurocholic Acid