title: Liposome promotion of tumor growth is associated with angiogenesis and inhibition of antitumor immune responses.
abstract: Liposomes have tremendous potential as drug carriers in the treatment of cancer. However, despite enhanced tumor drug delivery and decreased toxicity, patient survival rates have not improved significantly compared to corresponding free drug treatments. Importantly, we found that a liposomal nanoparticle currently used as a drug carrier in cancer patients enhanced tumor growth in an immune competent murine model of cancer. This was associated with increased tumor angiogenesis and suppression of antitumor immune responses as indicated by decreased cytokine production by tumor macrophages and cytotoxic T cells, diminished tumor infiltration of tumor-specific T cells, and decreased number of dendritic cells in tumor draining lymph nodes. These results suggest that carrier-induced immunosuppression and angiogenesis have the potential to reduce the antitumor effects of drugs loaded within. These findings may have significant implications for the current use and future development of anticancer nanoparticles and further investigations are urgently needed.
  
  
  BACKGROUND
  This study discusses important implications of nanoliposome-based drug delivery systems in cancer therapy, and demonstrates that nanoliposomes may have immunosuppressive and angiogenetic properties, directly counterbalancing their anti-cancer activity, which may also have important clinical implications related to more widespread applications of such systems.
authors.affiliation: Department of Immunotherapeutics and Biotechnology, Texas Tech University Health Sciences Center School of Pharmacy, Abilene, TX, USA.
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Sabnani
authors.affiliation: Department of Immunotherapeutics and Biotechnology, Texas Tech University Health Sciences Center School of Pharmacy, Abilene, TX, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Rajan
authors.affiliation: Department of Immunotherapeutics and Biotechnology, Texas Tech University Health Sciences Center School of Pharmacy, Abilene, TX, USA.
authors.forename: Bradley
authors.initials: B
authors.lastname: Rowland
authors.affiliation: Department of Immunotherapeutics and Biotechnology, Texas Tech University Health Sciences Center School of Pharmacy, Abilene, TX, USA.
authors.forename: Vikram
authors.initials: V
authors.lastname: Mavinkurve
authors.affiliation: Department of Immunotherapeutics and Biotechnology, Texas Tech University Health Sciences Center School of Pharmacy, Abilene, TX, USA.
authors.forename: Laurence M
authors.initials: LM
authors.lastname: Wood
authors.affiliation: Laboratory of Experimental Oncology, Shaare Zedek Medical Center and Hebrew University, Jerusalem, Israel.
authors.forename: Alberto A
authors.initials: AA
authors.lastname: Gabizon
authors.affiliation: Department of Immunotherapeutics and Biotechnology, Texas Tech University Health Sciences Center School of Pharmacy, Abilene, TX, USA. Electronic address: irene.la-beck@ttuhsc.edu.
authors.forename: Ninh M
authors.initials: NM
authors.lastname: La-Beck
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects*; D004337:Drug Carriers / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008081:Liposomes / Q000008:administration & dosage / Q000009:adverse effects*; D051379:Mice; D053758:Nanoparticles / Q000008:administration & dosage / Q000009:adverse effects; D009389:Neovascularization, Pathologic / Q000139:chemically induced / Q000473:pathology
chemical_list: D004337:Drug Carriers; D008081:Liposomes
keywords: Angiogenesis; Immunosuppression; Liposome; Nanoparticle; Tumor growth