Tyrosine kinase inhibitors as modulators of ABC transporter-mediated drug resistance

Tyrosine kinases (TKs) are involved in key signaling events/pathways that regulate cancer cell proliferation, apoptosis, angiogenesis and metastasis. Deregulated activity of TKs has been implicated in several types of cancers. In recent years, tyrosine kinase inhibitors (TKIs) have been developed to inhibit specific kinases whose constitutive activity results in specific cancer types. These TKIs have been found to demonstrate effective anticancer activity and some of them have been approved by the Food and Drug Administration for clinical use or are in clinical trials. However, these targeted therapeutic agents are also transported by ATP-binding cassette (ABC) transporters, resulting in altered pharmacokinetics or development of resistance to these drugs in cancer patients. This review covers the recent findings on the interactions of clinically important TKIs with ABC drug transporters. Future research efforts in the development of novel TKIs with specific targets, seeking improved activity, should consider these underlying causes of resistance to TKIs in cancer cells.