title: A novel recombinant immuno-tBid with a furin site effectively suppresses the growth of HER2-positive osteosarcoma cells in vitro.
abstract: Immunotherapy is a promising strategy for the treatment of human epidermal growth factor receptor 2 (HER2)-positive tumors. Previously, we constructed an immuno-carboxy terminal fragment of Bid (immuno-tBid) and reported its specific and effective destruction of HER2-positive tumor cells. In this study, in order to further reduce the immunogenicity of the previous immuno-proapoptotic protein, we constructed a novel immuno-tBid by replacing domain II of Pseudomonas exotoxin A with a short furin cleavage sequence from the diphtheria toxin. In order to explore the possible application of this novel immuno-tBid in the treatment of osteosarcoma, we first examined the expression of the HER2 protein in a subclone of a human osteosarcoma cell line with relatively high metastatic potential (SOSP-9607-E10), as well as in clinical specimens of osteosarcoma. Quantitative real-time PCR and Western blot analysis revealed that the expression of HER2 was up-regulated in the SOSP-9607-E10 cells, while immunohistochemical analysis revealed that HER2 was overexpressed in 37% of the tissue specimens examined. Both HER2-positive SOSP-9607-E10 and SKBR-3 cells, as well as HER2-negative HeLa cells were transiently transfected with the novel immuno-tBid in order to study its specific pro-apoptotic effect. We demonstrate here that this novel immuno-tBid induces the specific destruction of HER2-overexpressing SOSP-9607-E10 cells through the release of cytochrome C. These results suggest that the novel immuno-tBid with a minimized exogenous fragment could represent a competitive approach for the treatment of HER2-positive osteosarcoma.
authors.affiliation: Department of Orthopaedic Surgery, Tangdu hospital, Fourth Military Medical University, Xi'an, PR China.
authors.forename: Le-Qun
authors.initials: LQ
authors.lastname: Shan
authors.forename: Sai
authors.initials: S
authors.lastname: Ma
authors.forename: Xiu-Chun
authors.initials: XC
authors.lastname: Qiu
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Shi-Bin
authors.initials: SB
authors.lastname: Yu
authors.forename: Bao-An
authors.initials: BA
authors.lastname: Ma
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhou
authors.forename: Qing-Yu
authors.initials: QY
authors.lastname: Fan
authors.forename: An-Gang
authors.initials: AG
authors.lastname: Yang
mesh_terms: D051023:BH3 Interacting Domain Death Agonist Protein / Q000737:chemistry / Q000494:pharmacology*; D001665:Binding Sites; D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D049109:Cell Proliferation / Q000187:drug effects*; D015536:Down-Regulation / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D045683:Furin / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D018796:Immunoconjugates / Q000737:chemistry / Q000494:pharmacology; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D017434:Protein Structure, Tertiary / Q000502:physiology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000494:pharmacology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D051023:BH3 Interacting Domain Death Agonist Protein; D045683:Furin; D018796:Immunoconjugates; D010446:Peptide Fragments; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; C508053:ERBB2 protein, human