Comparative Molecular Field Analysis of Multidrug Resistance Modifiers

Abstract

Pharmacol. modulation of multidrug resistance (MDR) in tumor cells relates to the application of drugs able to block the function of the membrane-integrated P-glycoprotein (P-gp). P-gp may transport the antitumor agent out of the cells by an ATP-dependent efflux, decreasing in this manner its intracellular concn. and the cytotoxic effect. In general, the MDR modulators are considered to interact with the same binding sites as the antitumor agents. Different binding sites as well as more than one interaction site have been suggested in order to explain the extraordinary structural variety of the P-gp substrates and inhibitors. The absence of information about the binding sites requires identification of common space determinants of structurally different MDR reversing compds., and thus this was investigated. The results outline the role of hydrophobicity as a structural characteristic of importance for the activity studied. They point to hydrophobicity as a space directed mol. property for explaining the differences in MDR modulating activity of the investigated compds. [on SciFinder(R)]