ABSTRACT
Objective To explore the relationship of the methylation levels of tissue inhibitor of metalloproteinases 3 (TIMP-3) gene promoter CpG islands with the invasiveness and prognosis in cardia carcinoma. Methods The tumors tissues were collected from 65 patients with cardia carcinoma. The methylation levels of the promoter of TIMP-3 gene were detected by methylation-specific PCR (MSP), the mRNA expression levels of TIMP-3 gene were detected by RT-PCR. The relationship of TIMP-3 gene ectopic methylation with invasiveness and prognosis of the cardia carcinoma patients was analyzed. Results The positive expression rates of TIMP-3 mRNA in gastric cancer and normal gastric tissues were 53.8 % (35/65) and 96.9 % (63/65), respectively. The difference was not statistically significant(Fisher exact test, P=0.912). The positive rate of TIMP-3 mRNA was negatively correlated with the depth of tumor invasion and lymph node metastasis [mucosa and muscular vs. serosa and mucosa outside of the serosa and muscula: 83.3 % (10/12) vs. 45.3 % (24/53); with lymph node metastasis vs. without lymph node metastasis: 73.9 % (17/23) vs. 40.5 %(17/42)] (both P<0.05). There was a negative correlation between TIMP-3 gene promoter methylation and TIMP-3 mRNA expression (r=-0.276, P=0.026). The size of tumor and TIMP-3 gene promoter methylation were both the independent influencial factors of prognosis in cardia carcinoma (both P<0.05). Conclusion The methylation of promoter region in CpG islands plays an important role in the invasion and metastasis of cardia carcinoma, and it can be used as an independent predictor of biological behavior and prognosis.
ABSTRACT
Objective To explore the relations among the promoter methylation of tissue inhibitor of metalloproteinase-3 (TIMP-3) gene and its protein expression, and the clinicopathological features in the gastric cardia carcinoma. Methods The tumor tissues and the adjacent normal mucosal tissues were collected from 65 patients with cardia carcinoma. The promoter methylation levels and the protein expression of TIMP-3 gene were detected by methylation-specific PCR (MSP) and immunohistochemistry respectively. Results The TIMP-3 methylation rates was 78.5 % (51/65) in the tumor tissues and 13.8 % (9/65) in the incisal edge of normal tissues, the methylation rates of TIMP-3 had positive correlation with the size of tumor, invasion depth, lymphatic metastasis and the stage of tumor. The protein expression of TIMP-3 was 26.2 %(17/65) in the tumor tissues and 95.4 % (62/65) in the incisal edge of normal tissues (P = 0.016), the protein expression of TIMP-3 was negatively correlated with the size of tumor, invasion depth, lymphatic metastasis and the stage of tumor. Conclusion The methylation of promoter region in CpG islands is a main mechanism of reduced and loss expression of TIMP-3 gene, which may play an important role in the invasion and metastasis of cardia carcinoma.
ABSTRACT
AIM:To explore the mechanism by which over-expression of enhancer of zeste homolog 2 (EZH2) in a panel of gastric cancer cell lines is involved in tumorigenesis of gastric cancer .METHODS: Real-time PCR and Western blot were employed to examine the mRNA and protein levels of EZH 2, respectively.MTS assay, cell migration and soft agar assay were performed to investigate the role of EZH 2 in the regulation of stomach cancer behaviors .The effect of EZH2 on NF-κB target gene expression was determined by Luciferase reporter and real-time PCR.Co-immunoprecipitati-on was used to analyze the interaction of EZH 2 and p65 in HEK293T cells.RESULTS: The expression levels of EZH2 were significantly increased in the gastric cancer cells compared with normal gastric epithelial cells .Pharmacological inhibi-tion by DZNep or knockdown of EZH2 significantly compromised AGS and SNU-16 cell activity , cell migration and anchor-age-independent cell growth.Moreover, siRNA knockdown of EZH2 impaired NF-κB downstream targets, such as IL-8, CXCL5 and CCL20.In addition, the interaction of EZH2 and p65 was detected.CONCLUSION: EZH2 mediates the growth of gastric cancer cells through the regulation of NF-κB downstream gene expression .