Role of formulation composition in folate receptor-targeted liposomal doxorubicin delivery to acute myelogenous leukemia cells.

Targeted drug delivery has the potential to improve the efficacy of a therapeutic agent while reducing its side effects. The folate receptor type beta (FR-beta) is a cell surface marker selectively expressed in the leukemic cells of approximately 70% of acute myeloid leukemia (AML) patients. Upregulation of FR-beta may also be selectively induced in AML cells by treatment with all-trans-retinoic acid (ATRA). In this study, the role of formulation composition in FR-targeted liposomal doxorubicin (DOX) delivery to AML cells was investigated. Liposomal formulations with a variable percentage of folate-polyethylene glycol distearoyl phosphatidylethanolamine (f-PEG-DSPE) were synthesized and evaluated for FR-beta-targeted DOX delivery in MV4-11 AML cells in vitro and for their pharmacokinetic properties in vivo. The formulation containing 0.5 mol % f-PEG-DSPE exhibited the highest efficiency of cellular uptake and in vitro cytotoxicity, as well as a long systemic circulation time in mice. In MV4-11 cells, the binding and cytotoxicity of FR-targeted liposomal DOX based on this formulation was also enhanced by ATRA-induced FR-beta upregulation.