title: Targeted delivery of transferrin-conjugated liposomes to an orthotopic model of lung cancer in nude rats.
abstract: BACKGROUND
  Lung cancer is the leading cause of cancer death worldwide. Pulmonary anticancer therapy might offer several advantages over systemic delivery, leading to an increased exposure of the lung tumor to the drug, while minimizing side effects, due to regional containment. Here, we studied if a combination of inhalation therapy and drug targeting holds potential as an even more efficient lung cancer therapy.
  
  
  METHODS
  Transferrin (Tf )-conjugated PEG liposomes loaded with doxorubicin (DOX) were administered using an intracorporeal nebulizing catheter to an orthotopic lung cancer model established in athymic Rowett nude rats. Different DOX formulations and doses (0.2 and 0.4 mg/kg) were tested and the influence on tumor progression and life span of rats was evaluated in comparison with the i.v. administration of Tf-PEG-liposomes loaded with DOX at a therapeutic dose of 2 mg/kg.
  
  
  RESULTS
  Rats in the untreated control group showed significant weight loss 2 weeks after tumor induction and died between days 19 and 29. Lungs of these animals showed multiple foci of neoplastic deposits, ranging up to 20 mm replacing the entire lobe. Empty Tf-liposomes showed a significant effect on survival time. This might be caused by the secondary cytotoxicity via stimulation of pulmonary macrophages. All animal treated intravenously also perished before the end of the study. No significant (p<0.05) improvement in survival was observed between the groups treated with aerosols of free drug, DOX encapsulated in plain and in Tf-modified liposomes. However, more animals survived in the Tf-liposome groups than in the other treatment regimes, and their lung tissue generally had fewer and smaller tumors. Nevertheless, the size of the groups, and the duration of the trial render it impossible to come to a definite conclusion.
  
  
  CONCLUSIONS
  Drug targeting demonstrated potential for improving the aerosol treatment of lung cancer.
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin, Ireland.
authors.forename: Maria Manuela
authors.initials: MM
authors.lastname: Gaspar
authors.forename: Anna
authors.initials: A
authors.lastname: Radomska
authors.forename: Oliviero L
authors.initials: OL
authors.lastname: Gobbo
authors.forename: Udo
authors.initials: U
authors.lastname: Bakowsky
authors.forename: Marek W
authors.initials: MW
authors.lastname: Radomski
authors.forename: Carsten
authors.initials: C
authors.lastname: Ehrhardt
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D004337:Drug Carriers / Q000737:chemistry; D016503:Drug Delivery Systems; D005260:Female; D006801:Humans; D008081:Liposomes; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000473:pathology; D009330:Nebulizers and Vaporizers; D011092:Polyethylene Glycols / Q000737:chemistry; D051381:Rats; D011923:Rats, Nude; D015996:Survival Rate; D014168:Transferrin / Q000737:chemistry
chemical_list: D000336:Aerosols; D000903:Antibiotics, Antineoplastic; D004337:Drug Carriers; D008081:Liposomes; D014168:Transferrin; D011092:Polyethylene Glycols; D004317:Doxorubicin