title: Antitumor effects of an engineered and energized fusion protein consisting of an anti-CD20 scFv fragment and lidamycin.
abstract: Antibody-based fusion proteins are the next generation of antibody therapies for cancer and other diseases. CD20 antigen, which is overexpressed on cell membranes in nearly 95% of cases of B-cell Non-Hodgkin's Lymphoma, is an attractive target for the therapy of B-lymphoid malignancies. Lidamycin (LDM) is a potent enediyne-containing antitumor antibiotic that now has entered phase II clinical trials. In this study, we prepared an engineered fusion protein, scFv-LDP, consisting of an anti-CD20 scFv fragment and the apoprotein LDP of LDM using DNA recombination. After purification and refolding, scFv-LDP was found to bind specifically to CD20-positive lymphoma cells using ELISA and indirect immunofluorescent cytochemical staining assays. The energized fusion protein scFv-LDP-AE was obtained using molecular reconstitution of the active chromophore AE of LDM and scFv-LDP. MTT assay revealed potent cytotoxicity of scFv-LDP-AE to CD20-positive Raji and Daudi cells, with IC(50) values of 1.21×10(-11) and 6.24×10(-11) mol L(-1), respectively. An in vivo subcutaneous xenograft model of CD20-positive B cell lymphoma in BALB/c (nu/nu) mice was also utilized. Drugs were given intravenously on day 14 and 21 after tumor transplantation. In terms of maximal tolerated doses, scFv-LDP-AE at 0.3 mg kg(-1) suppressed tumor growth by 79.3%, and LDM at 0.05 mg kg(-1) by 68.6% (P<0.05). Results suggested scFv-LDP-AE could be a potential candidate for tumor-targeting therapy.
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Fang
authors.forename: Qingfang
authors.initials: Q
authors.lastname: Miao
authors.forename: Shenghua
authors.initials: S
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Cheng
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Xiong
authors.forename: Yongsu
authors.initials: Y
authors.lastname: Zhen
mesh_terms: D000617:Aminoglycosides / Q000235:genetics / Q000494:pharmacology*; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D018951:Antigens, CD20 / Q000276:immunology*; D045744:Cell Line, Tumor / Q000187:drug effects; D053281:Enediynes / Q000494:pharmacology*; D005260:Female; D016393:Lymphoma, B-Cell / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D015202:Protein Engineering; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000494:pharmacology / Q000627:therapeutic use*; D057127:Single-Chain Antibodies / Q000235:genetics / Q000276:immunology / Q000494:pharmacology / Q000627:therapeutic use*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000617:Aminoglycosides; D000903:Antibiotics, Antineoplastic; D018951:Antigens, CD20; D053281:Enediynes; D011993:Recombinant Fusion Proteins; D057127:Single-Chain Antibodies; C058024:C 1027