OATP8 - A membrane transport protein responsible for cancer drug uptake

Mon, 07/20/2015 - 14:21

Human hepatocytes express important transport proteins that are responsible for the uptake and removal of organic anions from the blood. These proteins are members of the organic anion-transporting polypeptide (OATP) family and are essential for proper liver function. OATPs are encoded by the SLC21 gene family and contain 12 transmembrane alpha-helices and are primarily expressed in the liver. The OATP family transports endogenous substrates like bile salts and steroid hormones as well as exogenous molecules like anticancer drugs and imaging agents. This broad specificity makes OATPs an important research topic for understanding basic liver biology and for designing therapeutic and diagnostic strategies. Of particular importance is OATP8. Early studies of OATP8 used immunofluorescent staining with OATP8 antibodies to demonstrate basolateral localization in human hepatocytes (1). Additionally immunoblotting with OATP8 antibodies indicated heavy glycosylation of this important membrane protein. Additional work by the Keppler group showed the usefulness of OATP8 antibodies as markers in hepatocellular carcinoma (2). They generated monoclonal OATP8 antibodies and demonstrated hepatocellular carcinomas express OATP8 without exception while liver tumor metastases derived from other tissues were negative. However a recent study performed immunohistochemistry with OATP8 antibodies did show expression in pancreatic cancer cells (3). While more research is needed to determine the utility of OATP8 antibodies in cancer diagnostics, this study indicates OATP8 may be a potential target in treating pancreatic adenocarcinoma. In addition to diagnostic purposes, OATP8 is also of importance for its role in the hepatic uptake of the cancer drug paclitaxel (4). Research on OATP8 uptake of paclitaxel indicates a potential role in differences in drug reactions between individuals and could prove important for selecting successful personalized drug regimens.

Novus Biologicals offers OATP8 reagents for your research needs including:

1. 10779507
2. 12695556
3. 21552413
4. 16210916

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