N-Myc down-regulated gene 1 mediates proliferation, invasion, and apoptosis of hepatocellular carcinoma cells.

The over-expression of N-myc down-regulated gene 1 (NDRG1) in hepatocellular carcinoma (HCC) was previously reported to correlate with vascular invasion and patient survival. Our current study aims to elucidate its functions in HCC. We found that it lacked the tumorigenic ability to promote soft agar colony formation or serum-independent growth of NIH3T3 cells. We used specific small interfering RNA (siRNA) oligos to suppress the expression of NDRG1 in human HCC (Hep3B and HepG2) cell lines, and found that this significantly reduced cell proliferation and invasion, and induced apoptosis. Additionally, NDRG1-specific siRNA inhibited the HepG2 xenograft growth in nude mice. These results are consistent with our earlier clinical observations that NDRG1 is associated with more aggressive tumor behavior, and suggest that NDRG1 may be a potential therapeutic target for HCC.