title: Specific antibodies elicited by a novel DNA vaccine targeting gastrin-releasing peptide inhibit murine melanoma growth in vivo.
abstract: The elevated expression and receptor binding of gastrin-releasing peptide (GRP) in various types of cancer, especially in malignant melanoma of the skin, suggest that GRP might be a putative target for immunotherapy in neoplastic diseases. We have therefore constructed a novel DNA vaccine coding for six tandem repeats of a fragment of GRP from amino acids 18 to 27 (GRP6) flanked by helper T-cell epitopes for increased immunogenicity, including HSP65, a tetanus toxoid fragment from amino acids 830 to 844 (T), pan-HLA-DR-binding epitope (PADRE) (P), and two repeats of a mycobacterial HSP70 fragment from amino acids 407 to 426 (M). The anti-GRP DNA vaccine (pCR3.1-VS-HSP65-TP-GRP6-M2) was constructed on a backbone of a pCR3.1 plasmid vector with eight 5'-GACGTT-3' CpG motifs and the VEGF183 signal peptide (VS). Intramuscular (IM) injections of anti-GRP vaccine in mice stimulated the production of high titers of specific antibodies against GRP and suppressed the growth of subcutaneous tumors of B16-F10 melanoma cells. Parallel results were obtained in vitro, showing inhibition of B16-F10 cell proliferation by GRP antisera. IM injections of the DNA vaccine also significantly attenuated tumor-induced angiogenesis associated with intradermal tumors of B16-F10 cells. In addition, lung invasion of intravenously injected cells was highly diminished, suggesting potent antimetastatic activity of the DNA vaccine. These findings support the highly immunogenic and potent antitumorigenic activity of specific anti-GRP antibodies elicited by the anti-GRP DNA vaccine.
authors.affiliation: Institute of Chemical Industry of Forest Products, CAF, Nanjing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Fang
authors.forename: Yong
authors.initials: Y
authors.lastname: Lu
authors.forename: Kedong
authors.initials: K
authors.lastname: Ouyang
authors.forename: Guojun
authors.initials: G
authors.lastname: Wu
authors.forename: Huiyong
authors.initials: H
authors.lastname: Zhang
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Liu
authors.forename: Yingying
authors.initials: Y
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Lin
authors.forename: Huaqian
authors.initials: H
authors.lastname: Wang
authors.forename: Liang
authors.initials: L
authors.lastname: Jin
authors.forename: Rongyue
authors.initials: R
authors.lastname: Cao
authors.forename: Rouel S
authors.initials: RS
authors.lastname: Roque
authors.forename: Li
authors.initials: L
authors.lastname: Zong
authors.forename: Jingjing
authors.initials: J
authors.lastname: Liu
authors.forename: Taiming
authors.initials: T
authors.lastname: Li
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology*; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology*; D002460:Cell Line; D018899:CpG Islands; D018984:Epitopes, T-Lymphocyte / Q000235:genetics / Q000276:immunology; D019886:Gastrin-Releasing Peptide / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000276:immunology*; D007273:Injections, Intramuscular; D008175:Lung Neoplasms / Q000276:immunology / Q000517:prevention & control; D008297:Male; D008545:Melanoma / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010957:Plasmids; D012878:Skin Neoplasms / Q000276:immunology / Q000517:prevention & control; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*
chemical_list: D000906:Antibodies; D019496:Cancer Vaccines; D018984:Epitopes, T-Lymphocyte; D019444:Vaccines, DNA; D019886:Gastrin-Releasing Peptide