Expression and biological function of N-myc down-regulated gene 1 in human cervical cancer

The expression of N-myc down-regulated gene 1 (NDRG1) has previously been reported to be involved in the proliferation, differentiation, invasion and metastasis of cancer cells, but its role in cervical cancer is still unclear. This study aimed to investigate the expression of NDRG1gene in human cervical cancer and its effect on aggressive tumor behaviors. The NDRG1 expression in cervical tissues and cells was detected by RT-PCR. Specific expression plasmid pEGFP-N1-NDRG1-GFP was used to enhance the expression of NDRG1 in human cervical cancer cell lines. The mRNA and protein level of NDRG1 was assessed by RT-PCR and Western blotting, respectively. Its effects on cell proliferation, migration, invasion, cell cycle and apoptosis were detected by MTT, transwell migration assay and flow cytometry (FCM), respectively. The results showed that the expression of NDRG1 in cervical cancer tissues and cells was significantly lower than in normal cervical tissues (P<0.001). After transfection with pEGFP-N1-NDRG1-GFP, the mRNA and protein expression of NDRG1 was up-regulated in Siha cells, which suppressed cell proliferation (P<0.001), induced cell cycle arrest (P<0.05), reduced invasion and migration of Siha cells (P<0.05), but caused no cell apoptosis. Moreover, vascular endothelial growth factor (VEGF), a tumor-induced angiogenesis factor, was markedly reduced and E-cadherin, a cell adhesion molecule, was increased in the cells transfected with pEGFP-N1-NDRG1-GFP. It was concluded that up-regulated NDRG1 may play a role in the suppression of malignant cell growth, invasion and metastasis of human cervical cancer.