Targeted CDX2 expression inhibits aggressive phenotypes of colon cancer cells in vitro and in vivo

Loss of caudal type homeobox 2 (CDX2) is associated with the development of human colorectal cancer, while human telomerase reverse transcriptase (hTERT) frequently occurs in variety of human cancers. We investigated the effects of restoration of CDX2 expression using a hypoxia-inducible hTERT promoter-driven vector (pLVX-5HRE-hTERTp-CDX2-3FLAG) on colon cancer cell viability, cell cycle distribution, apoptosis, colony formation, invasion ability and xenograft tumor growth in nude mice. CDX2 overexpression significantly inhibited viability, colony formation, and the invasion and migration ability of LoVo cells, and induced cell cycle arrest and apoptosis in vitro, especially under hypoxic culture conditions. Overexpression of CDX2 under normoxic conditions significantly suppressed the expression of TGF-β, cyclin D1, uPA, MMP-9, MMP-2, and Bcl-2, and stimulated the expression of collagen IV, laminin-1, and Bax. Overexpression of CDX2 reduced colon cancer xenograft tumor formation in nude mice which was associated with downregulation of Ki-67. In conclusion, overexpression of CDX2 using a hypoxia-inducible hTERT promoter-driven vector suppressed malignant progression of colon cancer cells in vitro and in vivo. These results suggest that pLVX-5HRE-hTERTp-CDX2-3FLAG gene therapy may be a promising novel approach to treat colon cancer.