title: An enediyne-energized single-domain antibody-containing fusion protein shows potent antitumor activity.
abstract: Single-domain antibodies are attractive as tumor-targeting vehicles because of their much smaller size than intact antibody molecules. Lidamycin is a macromolecular antitumor antibiotic, which consists of a labile enediyne chromophore (AE) and a noncovalently bound apoprotein (LDP). An enediyne-energized fusion protein VH-LDP-AE composed of single-domain antibody directed against type IV collagenase and lidamycin was prepared by a novel two-step method including DNA recombination and molecular reconstitution. VH-LDP-AE demonstrated extremely potent cytotoxicity to cancer cells and marked antiangiogenic activity in vitro. In the mouse hepatoma 22 model, drugs were administered intravenously as a single dose on day 1 with maximal tolerated doses. VH-LDP-AE (0.25 mg/kg) suppressed the tumor growth by 95.9%, whereas lidamycin (0.05 mg/kg) and mitomycin (1 mg/kg) by 79.6 and 51.1%, respectively. In the HT-1080 xenograft model in nude mice, drugs were given intravenously as a single dose on day 4 after tumor implantation. VH-LDP-AE at 0.25 mg/kg suppressed tumor growth by 76% (P<0.05) compared with that of lidamycin at 0.05 mg/kg (53%) on day 18. No obvious toxic effects were observed in all groups during treatments. The results showed that energized fusion protein VH-LDP-AE was more effective than lidamycin and mitomycin. These properties, together with its much smaller size than conventional antibody-based agents, suggested that VH-LDP-AE would be a promising candidate for cancer-targeting therapy. In addition, the two-step approach could serve as a new technology platform for making a series of highly potent engineered antibody-based drugs for a variety of cancers.
authors.affiliation: Department of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, #1 Tiantan Xili, Beijing 100050, PRC.
authors.forename: Qing-fang
authors.initials: QF
authors.lastname: Miao
authors.forename: Xiao-yun
authors.initials: XY
authors.lastname: Liu
authors.forename: Bo-yang
authors.initials: BY
authors.lastname: Shang
authors.forename: Zhi-gang
authors.initials: ZG
authors.lastname: Ouyang
authors.forename: Yong-su
authors.initials: YS
authors.lastname: Zhen
mesh_terms: D000482:Allantois / Q000737:chemistry / Q000187:drug effects; D000595:Amino Acid Sequence; D020533:Angiogenesis Inhibitors / Q000138:chemical synthesis / Q000494:pharmacology; D000818:Animals; D000906:Antibodies / Q000737:chemistry* / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002642:Chick Embryo; D017364:Collagenases / Q000737:chemistry / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005822:Genetic Vectors; D007202:Indicators and Reagents; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D008870:Microtubules; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology
chemical_list: D020533:Angiogenesis Inhibitors; D000906:Antibodies; D000970:Antineoplastic Agents; D007202:Indicators and Reagents; D011993:Recombinant Fusion Proteins; D017364:Collagenases