Primary Study Of The Role Of NDRG2 In Tumor Cells By ShRNA-mediated RNA Interference

Human NDRG2(N-myc downstream regulated gene 2) was first discovered by FMMU of China, which was registrated in Genbank with No. AFI59092. NDRG2 is expressed widely in normal tissues and differently between normal and tumor tissues through in-site hybridization. But the mechanism and process of the gene in regulation on cells is still not clear.RNA interference is a phenomenon that long double strand RNA is processed to 21nt duplexes, small interfering RNA, which silence special genes through a mRNA degradation pathway. It has the characteristics of sequence specificity, high efficiency and permanence. So it is a good tool for suppressing the expression of specific gene and studying its function.We have constructed a plasmid containg DNA templates for the shRNA targeted against NDRG2 to suppress the expression of NDRG2 in HHCC cell and SGC-7901 cell, and a plasmid containing NDRG2 cDNA to improve the expression of NDRG2. Our purpose was to test the cells properties after improving or reducing the NDRG2 content. To suppress the expression of NDRG2, a human U6 snRNA promoter was amplified from human genomic DNA by PCR and ligased with a 29 bp DNA template for a shRNA targeted against NDRG2 sequence and plasmid pSNAV. The recombinant pSNAV-shRNA. plasmid was transfected into HHCC cell lines and SGC-7901 cell lines to detect the effects of NDRG2 expression separately. The analysed results indicated that pSNAV-shRNA can suppressed the NDRG2 expression successfully and slower the growth of both the cell lines and caused G1 phase arrested. The transfected cells had less ability of colony formation and tumor formation on nude mice in vivo, than the control ones.Cells did not show characteristics of apoptosis. In contrast, when cells were transfected with plasmids containing NDRG2, the expression of NDRG2 was enhanced and the cells showed opposite changes.At last, we drew the conclusion that the suppression of NDRG2 can suppress the growth and proliferation of HHCC and SGC-7901 cells, NDRG2 probably play the role of oncogene.