Kobayashi Kazuhiro, Ito Kousei, Takada Tappei, Sugiyama Yuichi, Suzuki Hiroshi
Department of Pharmacy, The University of Tokyo Hospital, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
Pharmacogenet Genomics. 2008 Sep;18(9):823-33. doi: 10.1097/FPC.0b013e328306e9ae.
The multidrug resistance-associated protein 3/ATP-binding cassette transmembrane transporter subfamily C member 3 (MRP3/ABCC3) plays an important role in exporting endogenous and xenobiotic anionic substrates, including glucuronide conjugates of xenobiotics, from hepatocytes into the blood circulation. This excretory function of ABCC3 becomes very apparent particularly under cholestatic conditions, since ABCC3 is induced when the biliary excretion pathway is impaired. In this study, we analyzed the functional properties of 11 nonsynonymous single nucleotide polymorphisms (SNPs) in the ABCC3 gene found in the public SNP database.
HeLa and Sf9 insect cells were used to analyze the protein expression and transport function, respectively.
After transient transfection of cDNA into HeLa cells, it was found that R1381S ABCC3 exhibits intracellular accumulation of immature protein, the localization of which was mostly merged with a marker for the endoplasmic reticulum. Two kinds of SNPs type ABCC3 (S346F and S607N) lost their transport activity for [H]estradiol-17beta-D-glucuronide in membrane vesicles from Sf9 cells infected with the recombinant baculoviruses, although the band length and the amount of protein expression remained normal. In contrast, the cellular localization, protein expression and function of other eight kinds of SNPs type ABCC3 (G11D, R99Q, V765L, P920S, R923Q, R1286G, R1348C, and Q1365R ABCC3) remained normal.
The results of this study suggest that the possession of R1381S, S346F, and S607N types of ABCC3 sequences may be a possible risk factor for the acquisition of hepatotoxicity, due to their poor ability to transport toxic compounds across the sinusoidal membrane.
多药耐药相关蛋白3/ATP结合盒转运体C亚家族成员3（MRP3/ABCC3）在将内源性和外源性阴离子底物（包括外源性物质的葡糖醛酸共轭物）从肝细胞转运至血液循环中发挥重要作用。ABCC3的这种排泄功能在胆汁淤积条件下尤为明显，因为当胆汁排泄途径受损时ABCC3会被诱导。在本研究中，我们分析了公共SNP数据库中ABCC3基因的11个非同义单核苷酸多态性（SNP）的功能特性。
分别使用HeLa细胞和Sf9昆虫细胞分析蛋白表达和转运功能。
将cDNA瞬时转染到HeLa细胞后，发现R1381S型ABCC3表现出未成熟蛋白的细胞内积累，其定位大多与内质网标记物重叠。两种SNP类型的ABCC3（S346F和S607N）在感染重组杆状病毒的Sf9细胞的膜泡中丧失了对[H]雌二醇-17β-D-葡糖醛酸的转运活性，尽管条带长度和蛋白表达量保持正常。相比之下，其他八种SNP类型的ABCC3（G11D、R99Q、V765L、P920S、R923Q、R1286G、R1348C和Q1365R ABCC3）的细胞定位、蛋白表达和功能保持正常。
本研究结果表明，拥有R1381S、S346F和S607N类型的ABCC3序列可能是获得肝毒性的一个潜在危险因素，因为它们跨窦状膜转运有毒化合物的能力较差。
