Effects of recombinant human growth hormone on vascular endothelial growth factor expression of human gastric carcinoma xenografts in nude mice / 中华临床营养杂志

ABSTRACT

@#Objective To investigate the effects of recombinant human growth hormone (rhGH) on tumor growth and vascular endothelial growth factor (VEGF) expression of human gastric carcinoma xenografts in nude mice with different expressions of growth hormone receptor (GHR). Methods Immunocytochemical method was used to pick out one GHR-positive and one GHR-negative cell line. Then the cells were subcutaneously injected into 24 nude mice separately. The nude mice bearing two different kinds of human gastric caicinoma were equalges of body weight and tumor volume of nude mice were recorded. Serum concentrations of VEGF in peripheral blood were analyzed by ELISA. VEGF protein and mRNA expression in tumor tissue were detected by immunohistochemistry and RT-PCR, respectively. Results We chose SGC-7901 as GHR positive group, and MKN-45 as the negative one. For nude mice bearing GHR + SGC-7901 xenografts, the tumor volumes were significantly larger in rhGH groups than in control group (P ＜ 0.05), and the high-dose rhGH group revealed greater effect (P ＜ 0. 05).Body weights were not significantly different among three groups (P ＞ 0. 05). Serum VEGF concentration was (252.94 ± 15.32) ng/L in the high-dose rhGH group, which was significantly higher than that in control group [(49.94 ± 5.73) ng/L] and low-dose rhGH group [(167.60 ± 9.54) ng/L] (P ＜ 0.05). Moderate positive staining with VEGF was observed in the control group, while VEGF staining was strong in rhGH administration groups. The relative expression of VEGF mRNA for the high-dose rhGH group was 0. 6470 ± 0. 0447, which was significantly higher than that in control group (0. 3230 ± 0. 0258)and low-dose rhGH group (0. 412 ± 0. 0351)(P ＜ 0.05). While for nude mice bearing GHR-MKN-45 xenografts, the body weights of the rhGH-administrated groups were significantly higher than that of control group (P ＜ 0.05), while tumor growth, serum VEGF concentration, and the expressions of VEGF mRNA and protein in tumor tissue were not significantly different (P ＞ 0.05).Conclusions rhGH can promote tumor growth and increase the expression of VEGF in the GHR-highly-expressed SGC-7901 xenograft tumor model. However, such effects do not exist in GHR-negatively-expressed MKN-45 xenograft tumor model. The existence of GHR may be a key target where rhGH influences the secretion of VEGF.