Development of resistance to chemotherapy is a hallmark of many advanced human cancers. The molecular basis of clinical resistance is not well understood. Over the past 15 years, a number of different molecular mechanisms of resistance to anticancer drugs have been identified in many cell lines. One mechanism involves the increased expression of the plasma membrane P-glycoprotein (Pgp), which i...

Pgp (P-glycoprotein) (ABCB1) is an ATP-powered efflux pump which can transport hundreds of structurally unrelated hydrophobic amphipathic compounds, including therapeutic drugs, peptides and lipid-like compounds. This 170 kDa polypeptide plays a crucial physiological role in protecting tissues from toxic xenobiotics and endogenous metabolites, and also affects the uptake and distribution of man...

Ever since Juliano and Ling first described P-glycoprotein (P-gp) in 1975, it has become an important focus of research. P-gp is a member of the ATP-binding cassette (ABC) superfamily of proteins that is highly conserved in distantly related species (from simple eukaryotes to vertebrates). These similarities across species suggest that P-gp plays an important role in physiological processes in ...