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 detect the expression of contactin-1 (CNTN1) gene in the breast cancer tissues and explore the relation between the expression and prognosis of patients with breast cancer. MethodsThe clinicopathologic data of 35 patients with breast cancer who met the inclusion criteria from January to June in 2015 in the Shaanxi Provincial Cancer Hospital were retrospectively collected. The Western blot and immunohistochemistry methods were used to detect the CNTN1 protein expressions in the 35 breast cancer tissues and their corresponding tissues adjacent to cancer and the reverse transcriptase-PCR method was used to detect the CNTN1 mRNA expression. The relation between the CNTN1 protein expression and 5-year overall survival (OS) was analyzed. ResultsThe positive rate and expression level of CNTN1 protein in the breast cancer tissues were higher than those in the tissues adjacent to cancer [65.7% (23/35) vs. 45.7% (16/35), χ2=8.235, P=0.003; 0.825±0.221 vs. 0.412±0.117, t=12.556, P<0.001], and the expression level of CNTN1 mRNA in the breast cancer tissue was also higher than that in the corresponding tissues adjacent to cancer (0.763±0.218 vs. 0.353±0.135, t=11.162, P<0.001). The positive rates of CNTN1 protein were higher in the patients with larger tumor diameter (>2 cm), lower differentiation, later TNM stage (stage Ⅲ+Ⅳ) and axillary lymph node metastasis (P<0.05). The median OS of 35 patients with breast cancer was 47.3 months, which was 36.2 months and 52.5 months in the patients with high CNTN1 expression and low CNTN1 expression (median expression of CNTN1 protein was 0.785 as critical value) respectively (χ2=4.052, P=0.049). ConclusionPreliminary results of this study suggest that overexpression of CNTN1 gene might play an important role in occurrence and progression of primary breast cancer and is related to prognosis of survival.