Palmitoyl Ascorbate-Loaded Polymeric Micelles: Cancer Cell Targeting and Cytotoxicity

To evaluate the potential of palmitoyl ascorbate (PA)-loaded micelles for ascorbate-mediated cancer cell targeting and cytotoxicity. PA was incorporated in polyethylene glycol-phosphatidyl ethanolamine micelles at varying concentrations. The formulations were evaluated for PA content by RP-HPLC. A stable formulation was selected based on size and zeta potential measurements. A co-culture of cancer cells and GFP-expressing non-cancer cells was used to determine the specificity of PA micelle binding. In vitro cytotoxicity of the micellar formulations towards various cancer cell lines was investigated using a cell viability assay. To elucidate the mechanism of action of cell death in vitro, the effect of various H2O2 scavengers and metal chelators on PA-mediated cytotoxicity was studied. The in vivo anti-cancer activity of PA micelles was studied in female Balb/c mice bearing a murine mammary carcinoma (4T1 cells). PA micelles associated preferentially with various cancer cells compared to non-cancer cells in co-culture. PA micelles exhibited anti-cancer activity in cancer cell lines both in vitro and in vivo. The mechanism of cell death was due primarily to generation of reactive oxygen species (ROS). The anti-cancer activity of PA micelles associated with its enhanced cancer cell binding and subsequent generation of ROS.