CDX2 gene overexpression and its inhibition on malignant progress of human colorectal cancer cell line

Objective: To investigate the effect of human caudal-related homeobox 2 (CDX2) gene expression on human colorectal cancer cell line Lovo and explore CDX2's role in the pathogenesis and development of colorectal cancer. Methods: Human colon gene CDX2 was cloned and the pEGFP-C1-CDX2 eukayotic expression plasmid was constructed by DNA recombinant method. Lovo cells were divided into three groups, transfected with pEGFP-C1-CDX2, transfected with pEGFP-C1, and non-transfected. We transfected pEGFP-C1-CDX2 and pEGFP-C1 plasmid into Lovo cells separately with lipofectamine 2000. CDX2 gene expression in Lovo cells was detected by Western blotting. The effects of CDX2 overexpression on the proliferation, apoptosis and cycle of Lovo cells were assessed by MTT and flow cytometry. The effects on the matrix metalloproteinase-2 (MMP-2) expression were detected by ELISA method. Results: pEGFP-C1-CDX2 eukayotic expression plasmid was constructed successfully and there was a higher expression of CDX2 protein in Lovo cells which had transient transfection of pEGFP-C1-CDX2 plasmid for 48 hours. Compared with that of the cells transfected with empty vector or non-transfected cells, the growth of cells transfected with pEGFP-C1-CDX2 was not inhibited obviously after 72 hours (P>0.05). The proportion of G ₁ and S phases of cell cycle progression did not change obviously (P>0.05). Apoptosis rate was not increased obviously, either (P>0.05). However, the secretion of MMP-2 was reduced obviously (P<0.05). Conclusion: The overexpression of CDX2 gene has no obvious effect on the proliferation, apoptosis or cycle of Lovo cells, but it can significantly weaken the invasiveness and migration of Lovo cells; therefore, it may play an important role in inhibiting the invasion and metastasis of colorectal cancer.