title: Genetically engineered endostatin-lidamycin fusion proteins effectively inhibit tumor growth and metastasis.
abstract: BACKGROUND
  Endostatin (ES) inhibits endothelial cell proliferation, migration, invasion, and tube formation. It also shows antiangiogenesis and antitumor activities in several animal models. Endostatin specifically targets tumor vasculature to block tumor growth. Lidamycin (LDM), which consists of an active enediyne chromophore (AE) and a non-covalently bound apo-protein (LDP), is a member of chromoprotein family of antitumor antibiotics with extremely potent cytotoxicity to cancer cells. Therefore, we reasoned that endostatin-lidamycin (ES-LDM) fusion proteins upon energizing with enediyne chromophore may obtain the combined capability targeting tumor vasculature and tumor cell by respective ES and LDM moiety.
  
  
  METHODS
  In this study, we designed and obtained two new endostatin-based fusion proteins, endostatin-LDP (ES-LDP) and LDP-endostatin (LDP-ES). In vitro, the antiangiogenic effect of fusion proteins was determined by the wound healing assay and tube formation assay and the cytotoxicity of their enediyne-energized analogs was evaluated by CCK-8 assay. Tissue microarray was used to analyze the binding affinity of LDP, ES or ES-LDP with specimens of human lung tissue and lung tumor. The in vivo efficacy of the fusion proteins was evaluated with human lung carcinoma PG-BE1 xenograft and the experimental metastasis model of 4T1-luc breast cancer.
  
  
  RESULTS
  ES-LDP and LDP-ES disrupted the formation of endothelial tube structures and inhibited endothelial cell migration. Evidently, ES-LDP accumulated in the tumor and suppressed tumor growth and metastasis. ES-LDP and ES show higher binding capability than LDP to lung carcinoma; in addition, ES-LDP and ES share similar binding capability. Furthermore, the enediyne-energized fusion protein ES-LDP-AE demonstrated significant efficacy against lung carcinoma xenograft in athymic mice.
  
  
  CONCLUSIONS
  The ES-based fusion protein therapy provides some fundamental information for further drug development. Targeting both tumor vasculature and tumor cells by endostatin-based fusion proteins and their enediyne-energized analogs probably provides a promising modality in cancer therapy.
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P, R, China. yluo@tsinghua.edu.cn.
authors.forename: Wen-guo
authors.initials: WG
authors.lastname: Jiang
authors.forename: Xin-an
authors.initials: XA
authors.lastname: Lu
authors.forename: Bo-yang
authors.initials: BY
authors.lastname: Shang
authors.forename: Yan
authors.initials: Y
authors.lastname: Fu
authors.forename: Sheng-hua
authors.initials: SH
authors.lastname: Zhang
authors.forename: Daifu
authors.initials: D
authors.lastname: Zhou
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Yongzhang
authors.initials: Y
authors.lastname: Luo
authors.forename: Yong-su
authors.initials: YS
authors.lastname: Zhen
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D043169:Endostatins / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D042783:Endothelial Cells / Q000187:drug effects / Q000502:physiology; D005260:Female; D006801:Humans; D008168:Lung / Q000378:metabolism; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000556:secondary; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D011993:Recombinant Fusion Proteins / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D046888:Tissue Array Analysis; D014018:Tissue Distribution; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D043169:Endostatins; C587180:LDP-endostatin N-terminal fusion protein; D011993:Recombinant Fusion Proteins; C587179:endostatin-LDP C-terminal fusion protein