ObjectiveTo investigate the inhibitory effect of short hairpin RNA (shRNA) mediated contactin-1 (CNTN1) gene silencing on growth of human breast cancer cell line MDA-MB-468 transplanted tumors in nude mice.MethodsEighteen nude mice (4-week-old male BALB/c) were randomly equally divided into three groups: blank control group, empty vector group, and silencing group. The MDA-MB-468 cells (blank control group), MDA-MB-468 cells transfected by nonsense shRNA (empty vector group), and MDA-MB-468 cells transfected by shRNA (silencing group) were collected in the logarithmic growth period, respectively. The subcutaneous tumor models of nude mice were prepared by the subcutaneous injection of the different group cells. The tumor growth was observed and the expressions of CNTN1 and Ki-67 proteins in the transplanted tumor were detected by the immunohistochemistry.ResultsThe xenograft models of human breast cancer cells were established successfully. The tumor growth in the silencing group was significantly slower than that of the other two groups at every 3 d point (P<0.05). The tumor volume and the tumor weight in the silencing group were significantly smaller or slighter than those of the other two groups at day 18 (P<0.05). The positive rates of CNTN1 and Ki-67 protein expressions in the tumor tissues of the silencing group were lower than those of the other two groups (P<0.05), respectively.ConclusionSilencing expression of CNTN1 gene might inhibit growth of breast cancer cell line MDA-MB-468 transplanted tumors in mude mice.
ObjectiveTo determine the expressions of Lgr5 protein and Ki-67 protein in gastric cancer tissues, and to analyze the possible function in the carcinogenesis and development of gastric cancer.MethodsThe SABC immunohistochemical method was adopted to examine the expressions of Lgr5 protein and Ki-67 protein in the 69 paraffin slices of gastric cancer from the patients, with the adjacent normal gastric tissue as the control group. The statistical relationship between the expressions of these two kinds of proteins and clinicopathologic features of gastric cancer was examined respectively.ResultsIn the gastric cancer tissue group, the expressions of Lgr5 protein and Ki-67 protein upregulated in comparison to the adjacent normal gastric tissue group [Lgr5 protein: 87.0% (60/69) versus 16.7% (5/30), χ2=45.81, P<0.001; Ki-67 protein: 79.7% (55/69) versus 36.7% (11/30), χ2=17.43, P<0.001]. The expressions of Lgr5 protein and Ki-67 protein all upregulated in the N1–N3 stage groups, lowly differentiated+undifferentiated groups and positive Helicobacter pylori (HP) groups. The expression of Lgr5 protein upregulated in the T3+T4 stage groups in comparison to T1+T2 stage groups, while, no significant relationship was found in the expression of Ki-67 protein and tumor T staging. No significant relationship was found between the gender or metastasis and the expression of these two proteins. There was a positive correlation between the Lgr5 protein expression and the Ki-67 protein expression in the gastric cancer (rs=0.340, P=0.004).ConclusionsIn the development progress of gastric cancer, the Lgr5 protein might get involved in the mechanism of tumor invasion, lymph nodal metastasis, and low differentiation. Ki-67 protein might get involved in the mechanism of lymph nodal metastasis and low differentiation. The two proteins, together with the HP infection, might play a synergistic role in tumorigenesis and development.