Sphingomyelin content conditions insertion of daunorubicin within phosphatidylcholine monolayers

Cell death induced by the chemotherapeutic drug daunorubicin (DNR) implicates an apoptotic pathway originating at the plasma membrane and characterized by sphingomyelin (SM) hydrolysis and ceramide generation. The mechanisms by which such a drug (hypothetically passively diffusing across a structural membrane) can trigger SM hydrolysis is unknown, but raises the question of the precise interaction between DNR and membrane lipid constituents. In this initial study, using alternative current polarography together with voltammetry, we report that after a first step of adsorption, insertion of DNR within a condensed phosphatidylcholine monolayer was significantly facilitated by SM content.