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Open Access Research

Gene therapy for colorectal cancer by an oncolytic adenovirus that targets loss of the insulin-like growth factor 2 imprinting system

Zhen-Lin Nie1, Yu-Qin Pan1, Bang-Shun He1, Ling Gu2, Li-Ping Chen2, Rui Li2, Ye-Qiong Xu1, Tian-Yi Gao1, Guo-Qi Song1, Andrew R Hoffman3, Shu-Kui Wang1* and Ji-Fan Hu34*

Author Affiliations

1 Central Laboratory, Nanjing First Hospital, Nanjing Medical University, Nanjing, 210006, Jiangsu Province, China

2 Department of Life Sciences, Nanjing Normal University, Nanjing, 210046, Jiangsu Province, China

3 Department of Medicine, Stanford University Medical School, Palo Alto, CA, 94304, USA

4 Department of Medicine, PAIRE, VA Palo Alto Health Care System, Palo Alto, CA, 94304, USA

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Molecular Cancer 2012, 11:86  doi:10.1186/1476-4598-11-86

Published: 21 November 2012

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.

Keywords:
Genomic imprinting; IGF2; Oncolytic adenovirus; Colorectal cancer; Targeted therapy