ABSTRACT
Various methods have been explored to enhance antibody-based cancer therapy. The use of multivalent antibodies or fragments against tumor antigens has generated a great deal of interest, as various cellular signals, including induction of apoptosis, inhibition of cell growth/survival, or internalization of the surface molecules, can be triggered or enhanced on extensive cross-linking of the target/antibody complex by the multivalent form of the antibody. The goal of the studies reported here was to develop multivalent antibody constructs via grafting of antibody molecules onto liposome membranes to enhance antibody activity. Using trastuzumab and rituximab as examples, up to a 25-fold increase in the antibody potency in cell viability assay was observed when the antibodies were presented in the multivalent liposome formulation. Key cell survival signaling molecules, such as phosphorylated Akt and phosphorylated p65 nuclear factor-kappaB, were down-regulated on treatment with multivalent liposomal trastuzumab and liposomal rituximab, respectively. Potent in vivo antitumor activity was shown for liposomal trastuzumab. The data presented here showed the potential of liposome technology to enhance the therapeutic effect of antibodies via a mechanism that modulates cell survival through clustering of the target/antibody complex.
Subject(s)
Antibodies, Monoclonal/administration & dosage , Antineoplastic Agents/administration & dosage , Breast Neoplasms/therapy , Animals , Antibodies, Monoclonal, Humanized , Antibodies, Monoclonal, Murine-Derived , Antibodies, Neoplasm , Antigens, CD20/immunology , Antigens, Neoplasm/immunology , Blotting, Western , Breast Neoplasms/immunology , Breast Neoplasms/pathology , Cell Survival , DNA-Binding Proteins/genetics , DNA-Binding Proteins/physiology , Down-Regulation , Female , Flow Cytometry , Genes, erbB-2/genetics , Genes, erbB-2/immunology , Humans , Liposomes , Mice , Mice, Knockout , Phosphorylation , Proto-Oncogene Proteins c-akt/metabolism , Receptor, ErbB-2/immunology , Rituximab , Signal Transduction , Transcription Factor RelA/metabolism , TrastuzumabABSTRACT
The therapeutic potential of selected peptides and proteins is enormous, with applications ranging from use as therapeutic vaccines, as modulators of intracellular signaling pathways and as highly selective agents capable of recognizing unique extracellular targets. We have been pursuing development of hybrid lipid-based carrier formulations designed to take advantage of the therapeutic benefits of peptides selected for their ability to act in a complementary fashion with the carrier system. In this regard, it is critical to have simple and versatile methods to promote and control the binding of diverse peptides to a broad range of carrier formulations. As demonstrated here, recombinant proteins and synthetic peptides containing poly-histidine residues (4 to 10) can be specifically bound to liposomes containing a metal-ion-chelating lipid, DOGS-NTA-Ni. The potential of this approach is demonstrated using two functional peptides, AntpHD-Cw3 (applications for vaccine production) and AHNP (specificity for Her-2 expressing cells).
