[Effect of NK4 gene transfection on tumor growth of human pancreatic cancer xenograft in nude mice].

Background & Objective: NK4 is not only an antagonist of hepatocyte growth factor but also an angiogenesis inhibitor. Studies have confirmed that NK4 can inhibit tumor growth and metastasis, but its effect on pancreatic cancer remains unknown. This study was designed to observe the effect of NK4 gene on human pancreatic cancer in nude mice and the possible mechanisms.

Methods: The nude mouse model of pancreatic cancer was established with human pancreatic cancer cell line SW1990. The eukaryotic expression vector of NK4 gene was constructed and transfected into the tumors. The mice weight, tumor size and volume were measured before and after transfection. The apoptotic cells, microvessel density (MVD), and the expression of proliferating cell nuclear antigen (PCNA) in the tumors were observed using immunohistochemistry and terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) technique.

Results: Four weeks after NK4 gene transfection, the tumor volume and weight was significantly smaller in NK4-transfected group than in PBS control group and empty vector group [(1.39+/-0.33) cm(3) vs. (2.06+/-0.55) cm(3) and (1.90+/-0.36) cm(3), P<0.01; (1.30+/-0.81) g vs. (3.45+/-1.88) g and (3.14+/-1.51) g, P<0.01]; the inhibition rate was 62.29%. The tumor cell apoptotic index was significantly higher in NK4-transfected group than in the rest 2 groups (9.34+/-0.91 vs. 4.13+/-0.79 and 3.94+/-1.03, P<0.001); the MVD was significantly lower in NK4-transfected group than in the rest 2 groups (12.24+/-4.63 vs. 20.13+/-7.00 and 19.70+/-6.15, P<0.05); the expression of PCNA in NK4-transfected group was not different from those of the rest 2 groups (53.88+/-4.30 vs. 56.24+/-4.03 and 54.33+/-5.41,P>0.05).

Conclusion: NK4 gene transfection may inhibit the growth of human pancreatic cancer in mouse model through suppressing angiogenesis and enhancing the apoptosis of pancreatic cancer cells.