title: Palmitoyl ascorbate liposomes and free ascorbic acid: comparison of anticancer therapeutic effects upon parenteral administration.
abstract: OBJECTIVE
  To evaluate and compare anticancer therapeutic effect of palmitoyl ascorbate liposomes (PAL) and free ascorbic acid (AA).
  
  
  METHODS
  Liposomes incorporating palmitoyl ascorbate (PA) were prepared and evaluated for PA content by HPLC. To elucidate mechanism of action of cell death in vitro, effect of various H(2)O(2) scavengers and metal chelators on PA-mediated cytotoxicity was studied. Effect of various combinations of PAL and free AA on in vitro cytotoxicity was evaluated on 4T1 cells. In vivo, PAL formulation was modified with polyethylene glycol; effect of PEGylation on in vitro cytotoxicity was evaluated. Biodistribution of PEG-PAL formulation was investigated in female Balb/c mice bearing murine mammary carcinoma (4T1 cells). In vivo anticancer activity of PEG-PAL (PEG-PAL equivalent to 20 mg/kg of PA injected intravenously on alternate days) was compared with free AA therapy in same model.
  
  
  RESULTS
  PEG-PAL treatment was significantly more effective than free AA treatment in slowing tumor growth.
  
  
  CONCLUSIONS
  Nanoparticle formulations incorporating PA can kill cancer cells in vitro. The mechanism of PA cytotoxicity is based on production of extracellular reactive oxygen species and involves intracellular transition metals.
authors.affiliation: Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Mugar Building, Room 312, 360 Huntington Avenue, Boston, Massachusetts 02115, USA.
authors.forename: Rupa R
authors.initials: RR
authors.lastname: Sawant
authors.forename: Onkar S
authors.initials: OS
authors.lastname: Vaze
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Gerard G M
authors.initials: GG
authors.lastname: D'Souza
authors.forename: Karen
authors.initials: K
authors.lastname: Rockwell
authors.forename: Keyur
authors.initials: K
authors.lastname: Gada
authors.forename: Ban-An
authors.initials: BA
authors.lastname: Khaw
authors.forename: Vladimir P
authors.initials: VP
authors.lastname: Torchilin
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage* / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D001940:Breast / Q000187:drug effects / Q000473:pathology; D045744:Cell Line, Tumor; D005260:Female; D008081:Liposomes; D054878:Lipoylation; D015674:Mammary Neoplasms, Animal / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C
chemical_list: D000975:Antioxidants; D008081:Liposomes; D001205:Ascorbic Acid; C031226:6-O-palmitoylascorbic acid