The molecular mechanism underlying the induction of hepatic MRP3 expression and function by omeprazole

Impact of liver diseases and pharmacological interactions on the transportome involved in hepatic drug disposition

The liver plays a pivotal role in drug disposition owing to the expression of transporters accounting for the uptake at the sinusoidal membrane and the efflux across the basolateral and canalicular membranes of hepatocytes of many different compounds. Moreover, intracellular mechanisms of phases I and II biotransformation generate, in general, inactive compounds that are more polar and easier to eliminate into bile or refluxed back toward the blood for their elimination by the kidneys, which becomes crucial when the biliary route is hampered. The set of transporters expressed at a given time, i.e., the so-called transportome, is encoded by genes belonging to two gene superfamilies named Solute Carriers (SLC) and ATP-Binding Cassette (ABC), which account mainly, but not exclusively, for the uptake and efflux of endogenous substances and xenobiotics, which include many different drugs. Besides the existence of genetic variants, which determines a marked interindividual heterogeneity regarding liver drug disposition among patients, prevalent diseases, such as cirrhosis, non-alcoholic steatohepatitis, primary sclerosing cholangitis, primary biliary cirrhosis, viral hepatitis, hepatocellular carcinoma, cholangiocarcinoma, and several cholestatic liver diseases, can alter the transportome and hence affect the pharmacokinetics of drugs used to treat these patients. Moreover, hepatic drug transporters are involved in many drug-drug interactions (DDI) that challenge the safety of using a combination of agents handled by these proteins. Updated information on these questions has been organized in this article by superfamilies and families of members of the transportome involved in hepatic drug disposition.

Use of omeprazole, the proton pump inhibitor, as a potential therapy for the capecitabine-induced hand-foot syndrome

Hand-foot syndrome (HFS), also known as palmar-plantar erythrodysesthesia (PPE), is a major side effect of capecitabine. Although the pathogenesis of HFS remains unknown, some studies suggested a potential involvement of inflammation in its pathogenesis. Proton pump inhibitors (PPIs) have been reported to have anti-inflammatory effects. In this study, we investigated the ameliorative effects of omeprazole, a PPI on capecitabine-related HFS in mice model, and a real-world database. Repeated administration of capecitabine (200 mg/kg, p.o., five times a week for 3 weeks) increased fluid content, redness, and tumor necrosis factor (TNF)-α substance of the mice hind paw. Co-administration of omeprazole (20 mg/kg, p.o., at the same schedule) significantly inhibited these changes induced by capecitabine. Moreover, based on the clinical database analysis of the Food and Drug Administration Adverse Event Reporting System, the group that has used any PPIs had a lower reporting rate of capecitabine-related PPE than the group that has not used any PPIs. (6.25% vs. 8.31%, p < 0.0001, reporting odds ratio (ROR) 0.74, 95% confidence interval (CI) 0.65-0.83). Our results suggest that omeprazole may be a potential prophylactic agent for capecitabine-induced HFS.

Modulation of Hepatic MRP3/ABCC3 by Xenobiotics and Pathophysiological Conditions: Role in Drug Pharmacokinetics

Liver transporters play an important role in the pharmacokinetics and disposition of pharmaceuticals, environmental contaminants, and endogenous compounds. Among them, the family of ATP-Binding Cassette (ABC) transporters is the most important due to its role in the transport of endo- and xenobiotics. The ABCC sub-family is the largest one, consisting of 13 members that include the cystic fibrosis conductance regulator (CFTR/ABCC7); the sulfonylurea receptors (SUR1/ABCC8 and SUR2/ABCC9) and the multidrug resistanceassociated proteins (MRPs). The MRP-related proteins can collectively confer resistance to natural, synthetic drugs and their conjugated metabolites, including platinum-containing compounds, folate anti-metabolites, nucleoside and nucleotide analogs, among others. MRPs can be also catalogued into "long" (MRP1/ABCC1, -2/C2, -3/C3, -6/C6, and -7/C10) and "short" (MRP4/C4, -5/C5, -8/C11, -9/C12, and -10/C13) categories. While MRP2/ABCC2 is expressed in the canalicular pole of hepatocytes, all others are located in the basolateral membrane. In this review, we summarize information from studies examining the changes in expression and regulation of the basolateral hepatic transporter MPR3/ABCC3 by xenobiotics and during various pathophysiological conditions. We also focus, primarily, on the consequences of such changes in the pharmacokinetic, pharmacodynamic and/or toxicity of different drugs of clinical use transported by MRP3.