Uptake Carriers and Oncology Drug Safety

Abstract

Members of the solute carrier (SLC) family of transporters are responsible for the cellular influx of a broad range of endogenous compounds and xenobiotics in multiple tissues. Many of these transporters are highly expressed in the gastrointestinal tract, liver, and kidney and are considered to be of particular importance in governing drug absorption, elimination, and cellular sensitivity of specific organs to a wide variety of oncology drugs. Although the majority of studies on the interaction of oncology drugs with SLC have been restricted to the use of exploratory in vitro model systems, emerging evidence suggests that several SLCs, including OCT2 and OATP1B1, contribute to clinically important phenotypes associated with those agents. Recent literature has indicated that modulation of SLC activity may result in drug-drug interactions, and genetic polymorphisms in SLC genes have been described that can affect the handling of substrates. Alteration of SLC function by either of these mechanisms has been demonstrated to contribute to interindividual variability in the pharmacokinetics and toxicity associated with several oncology drugs. In this report, we provide an update on this rapidly emerging field.

What would be the observable consequences if phospholipid bilayer diffusion of drugs into cells is negligible?

“…Finally, drugs (and metabolites and nutrients) that share the same transporter will compete with each other for it [49,50], and the covariation of their uptake between tissues will tend in part to follow the covariation of transporter expression.…”

Mitigation of acute kidney injury by cell-cycle inhibitors that suppress both CDK4/6 and OCT2 functions

“…cation transporters, Oct1 and Oct2, together fulfill a role equivalent to that of a single organic cation transporter, OCT2, in human kidneys. These transporters are highly expressed on the basolateral membrane of renal tubular cells, and their pharmacological or genetic inhibition reduces cisplatin nephrotoxicity (57).…”

Insights into solute carriers: physiological functions and implications in disease and pharmacokinetics

“…76 Another approach would be to develop SLC-specific inhibitors, like the TKI imatinib, a noncompetitive inhibitor of OCT2, which protects patients from cisplatin-induced nephrotoxicity by preventing platinum accumulation in the kidney. 71 Conscious drug design toward SLCs seems to be a promising avenue that should bring about significant advances in the treatment of several pathologies, including cardiovascular disorders, CNS diseases, and cancer.…”

“…70 Imatinib (a tyrosine kinase inhibitor) is an inhibitor of OCT2 and seems to prevent cisplatin-induced nephrotoxicity by preventing platinum accumulation in the kidney. 71 Both diclofenac and its major metabolite acyl-β-Dglucuronide are renally excreted and have been studied as substrates of different human drug transporters in vitro. Diclofenac and its metabolite were identified as substrates of OATs, 72 and are an example where drug substrates and metabolites can competitively use the same transporters.…”