title: Vesicular stomatitis virus expressing a chimeric Sindbis glycoprotein containing an Fc antibody binding domain targets to Her2/neu overexpressing breast cancer cells.
abstract: Vesicular stomatitis virus (VSV) is a candidate for development for cancer therapy. It is an oncolytic virus that is safe in humans. Recombinant virus can be made directly from plasmid components. We attempted to create a virus that targeted specifically to breast cancer cells. Nonreplicating and replicating pseudotype VSV were created whose only surface glycoprotein (gp) was a Sindbis gp, called Sindbis-ZZ, modified to severely reduce its native binding function and to contain the Fc-binding domain of Staphylococcus aureus protein A. When titered on Her2/neu overexpressing SKBR3 human breast cancer cells, pseudotype VSV coated with Sindbis-ZZ had <1% the titer of pseudotype VSV coated with wild-type Sindbis gp. Titer was increased 50-fold when the Sindbis-ZZ pseudotype was conjugated with 4D5, a mouse monoclonal antibody directed against the Her2/neu receptor. Titers of antibody-conjugated virus were increased 36-fold on a second human breast cancer cell line, MCF7/H2, which expressed lower concentrations of Her2/neu receptor on the cell surface. At multiple concentrations of antibody, titers on SKBR3 cells were significantly greater when the virus was incubated with Herceptin, an antibody with a human Fc, than with 4D5, a mouse antibody, reflecting the known higher affinity of the protein A Fc-binding domain for human Fc. Analysis of the protein composition of the pseudotype VSV found low expression of the modified Sindbis gp on the virus accounting, in part, for a viral titer that did not exceed 1.2 x 10(5)/ml. This work demonstrates the ability to easily create, directly from plasmid components, an oncolytic replicating VSV with a restricted host cell range.
authors.affiliation: Departments of Pediatric, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA. ira.bergman@chp.edu
authors.forename: Ira
authors.initials: I
authors.lastname: Bergman
authors.forename: Patricia
authors.initials: P
authors.lastname: Whitaker-Dowling
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Gao
authors.forename: Judith A
authors.initials: JA
authors.lastname: Griffin
authors.forename: Simon C
authors.initials: SC
authors.lastname: Watkins
mesh_terms: D000911:Antibodies, Monoclonal / Q000235:genetics*; D001665:Binding Sites; D001943:Breast Neoplasms / Q000628:therapy*; D045744:Cell Line, Tumor; D005260:Female; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007141:Immunoglobulin Fc Fragments / Q000235:genetics*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011993:Recombinant Fusion Proteins / Q000235:genetics*; D013205:Staphylococcal Protein A / Q000235:genetics; D014721:Vesicular stomatitis Indiana virus / Q000235:genetics*; D014759:Viral Envelope Proteins / Q000235:genetics*
chemical_list: D000911:Antibodies, Monoclonal; D007141:Immunoglobulin Fc Fragments; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D013205:Staphylococcal Protein A; D014759:Viral Envelope Proteins; C064950:glycoprotein E2, Sindbis virus