Objective：To investigate the effects of small interfering RNA targeting human growth hormone receptor (hGHR) combined with 5-fluorouracil (5-FU) on liver metastasis of colon cancer.
Methods：Animal model of liver metastases with human colon cancer cell SW480 was established on BALB/c mouse and siRNA interfering plasmid targeting hGHR gene was constructed. The tumor-bearing mice were randomly divided into 6 groups that included saline control group, plasmid group, growth hormone (GH) group, 5-FU group, 5-FU+plasmid group and 5-FU+plasmid+GH group. The liver metastasis in each group was observed.
Results：Liver metastases were found in all the mice. siRNA interfering plasmid treatment significantly reduced the incidence of liver metastases compared with saline or GH group (2.67±1.37 vs. 10.17±1.94, 10.50±1.38, P＜0.05). The combined treatment of interfering plasmid and 5-FU slightly decreased the incidence of liver metastases compared with plasmid alone or 5-FU alone treatment (2.33±1.03 vs. 3.17±0.98, 2.67±1.37, P＞0.05),  but had no statistical significance. On the basis of the combination of interfering plasmid and 5-FU, the additional GH did not increase the incidence of liver metastases (P＞0.05), but improved the weight loss of the mice (P＜0.05) induced by inhibition of GHR and toxicity of 5-FU.
Conclusions：siRNA targeting hGHR can reduce the incidence of liver metastases of human colon cancer cell SW480 in mice. GHR may play an important role in tumor metastasis.