An EGFR/HER2-Bispecific and enediyne-energized fusion protein shows high efficacy against esophageal cancer

PLoS One. 2014 Mar 24;9(3):e92986. doi: 10.1371/journal.pone.0092986. eCollection 2014.

Abstract

Esophageal cancer is one of the most common cancers, and the 5-year survival rate is less than 10% due to lack of effective therapeutic agents. This study was to evaluate antitumor activity of Ec-LDP-Hr-AE, a recently developed bispecific enediyne-energized fusion protein targeting both epidermal growth factor receptor (EGFR) and epidermal growth factor receptor 2 (HER2), on esophageal cancer. The fusion protein Ec-LDP-Hr-AE consists of two oligopeptide ligands and an enediyne antibiotic lidamycin (LDM) for receptor binding and cell killing, respectively. The current study demonstrated that Ec-LDP-Hr had high affinity to bind to esophageal squamous cell carcinoma (ESCC) cells, and enediyne-energized fusion protein Ec-LDP-Hr-AE showed potent cytotoxicity to ESCC cells with differential expression of EGFR and HER2. Ec-LDP-Hr-AE could cause significant G2-M arrest in EC9706 and KYSE150 cells, and it also induced apoptosis in ESCC cells in a dosage-dependent manner. Western blot assays showed that Ec-LDP-Hr-AE promoted caspase-3 and caspase-7 activities as well as PARP cleavage. Moreover, Ec-LDP-Hr-AE inhibited cell proliferation via decreasing phosphorylation of EGFR and HER2, and further exerted inhibition of the activation of their downstream signaling molecules. In vivo, at a tolerated dose, Ec-LDP-Hr-AE inhibited tumor growth by 88% when it was administered to nude mice bearing human ESCC cell KYSE150 xenografts. These results indicated that Ec-LDP-Hr-AE exhibited potent anti-caner efficacy on ESCC, suggesting it could be a promising candidate for targeted therapy of esophageal cancer.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Caspase 2 / metabolism
  • Caspase 7 / metabolism
  • Cell Line, Tumor
  • Cysteine Endopeptidases / metabolism
  • Enediynes / chemistry*
  • ErbB Receptors / antagonists & inhibitors*
  • ErbB Receptors / metabolism
  • Esophageal Neoplasms / drug therapy*
  • Esophageal Neoplasms / metabolism
  • Esophageal Neoplasms / pathology
  • Female
  • G2 Phase Cell Cycle Checkpoints
  • Humans
  • M Phase Cell Cycle Checkpoints / drug effects
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Receptor, ErbB-2 / antagonists & inhibitors*
  • Receptor, ErbB-2 / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / pharmacology*
  • Xenograft Model Antitumor Assays

Substances

  • Antineoplastic Agents
  • Enediynes
  • Recombinant Fusion Proteins
  • EGFR protein, human
  • ERBB2 protein, human
  • ErbB Receptors
  • Receptor, ErbB-2
  • CASP2 protein, human
  • CASP7 protein, human
  • Caspase 2
  • Caspase 7
  • Cysteine Endopeptidases

Grants and funding

This work is supported in part by the Natural Science Research Project of the Education Department of Henan Province, China (No. 12B350004 to XFG), National Natural Science Foundation of China (No. 81202447 to XFG, http://www.nsfc.gov.cn/Portal0/default152.htm), and a grant from the USCACA (No. USCACA-TIGM-001 to WCY). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.