title: Gene therapy for colorectal cancer by an oncolytic adenovirus that targets loss of the insulin-like growth factor 2 imprinting system.
abstract: BACKGROUND
  Colorectal cancer is one of the most common malignant tumors worldwide. Loss of imprinting (LOI) of the insulin-like growth factor 2 (IGF2) gene is an epigenetic abnormality observed in human colorectal neoplasms. Our aim was to investigate the feasibility of using the IGF2 imprinting system for targeted gene therapy of colorectal cancer.
  
  
  RESULTS
  We constructed a novel oncolytic adenovirus, Ad315-E1A, and a replication-deficient recombinant adenovirus, Ad315-EGFP, driven by the IGF2 imprinting system by inserting the H19 promoter, CCCTC binding factor, enhancer, human adenovirus early region 1A (E1A) and enhanced green fluorescent protein (EGFP) reporter gene into a pDC-315 shuttle plasmid. Cell lines with IGF2 LOI (HCT-8 and HT-29), which were infected with Ad315-EGFP, produced EGFP. However, no EGFP was produced in cell lines with maintenance of imprinting (HCT116 and GES-1). We found that Ad315-E1A significantly decreased cell viability and induced apoptosis only in LOI cell lines in vitro. In addition, mice bearing HCT-8-xenografted tumors, which received intratumoral administration of the oncolytic adenovirus, showed significantly reduced tumor growth and enhanced survival.
  
  
  CONCLUSIONS
  Our recombinant oncolytic virus targeting the IGF2 LOI system inhibits LOI cell growth in vitro and in vivo, and provides a novel approach for targeted gene therapy.
authors.affiliation: Central Laboratory, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, Jiangsu Province, China.
authors.forename: Zhen-Lin
authors.initials: ZL
authors.lastname: Nie
authors.forename: Yu-Qin
authors.initials: YQ
authors.lastname: Pan
authors.forename: Bang-Shun
authors.initials: BS
authors.lastname: He
authors.forename: Ling
authors.initials: L
authors.lastname: Gu
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Chen
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.forename: Ye-Qiong
authors.initials: YQ
authors.lastname: Xu
authors.forename: Tian-Yi
authors.initials: TY
authors.lastname: Gao
authors.forename: Guo-Qi
authors.initials: GQ
authors.lastname: Song
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Hoffman
authors.forename: Shu-Kui
authors.initials: SK
authors.lastname: Wang
authors.forename: Ji-Fan
authors.initials: JF
authors.lastname: Hu
mesh_terms: D017500:Adenovirus E1A Proteins / Q000235:genetics; D000818:Animals; D000970:Antineoplastic Agents; D017209:Apoptosis / Q000235:genetics; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics; D003001:Cloning, Molecular; D015179:Colorectal Neoplasms / Q000235:genetics / Q000628:therapy* / Q000821:virology; D005260:Female; D015316:Genetic Therapy / Q000379:methods*; D018392:Genomic Imprinting / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D019073:HT29 Cells; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D053208:Kaplan-Meier Estimate; D051379:Mice; D008819:Mice, Nude; D050130:Oncolytic Virotherapy / Q000379:methods*; D014162:Transfection; D023041:Xenograft Model Antitumor Assays
chemical_list: D017500:Adenovirus E1A Proteins; D000970:Antineoplastic Agents; D049452:Green Fluorescent Proteins; D007335:Insulin-Like Growth Factor II