[Glutoxime--an inhibitor of multiple drug resistance phenotype associated with Pgp expression]

Interaction of Glutoxime with P-glucoprotein (Pgp), a multiple drug resistance marker, as well as the Glutoxime impact on doxorubicin intracellular accumulation were investigated. It was shown that the Glutoxime effect on the Pgp expressing tumor cells resulted in a decrease of the cell specific fluorescence intensity, conditioned by binding of the monoclonal antibodies to the transport protein. That was evident of Glutoxime competition with the monoclonal antibodies for binding to Pgp and indicative of the modificator interaction with the transport protein. The effect was proved with the use of two cultures of human tumor cells of different histogenesis, i.e., the cells of Jurkat T-cellular leukemia and nonsmall cell lung cancer A549. Inhibition of the Pgp functional activity by Glutoxime was also demonstrateds. The authors suggested that it could be caused by direct competition of the modificator with the antitumor agent for binding to the precipitation sites on Pgp. Glutoxime could be considered as an inhibitor of multiple drug resistance associated with the Pgp function.