ABSTRACT
OBJECTIVE@#To explore the role of nasopharyngeal carinoma associated gene 6 (NGX6) in Wnt/β-catenin signaling pathway and to identify whether there is feedback regulation between NGX6 and Wnt signal pathway once the Wnt signal is blocked.@*METHODS@#pCMV-myc-NGX6 and pCMV-myc were transfected to colon cancer cell line SW62O and the expression of downstream target molecules of Wnt/β-catenin signaling pathway such as c-myc, cyclinD1, and c-jun were detected by Western blot. The eukaryotic expression vector pcDNA3.1 (+)-LEF1(DN) (without N-terminal β-catenin binding domain) was constructed to inhibit Wnt signaling pathway, and the effect was confirmed by Western blot and TCF-4 luciferase report system. The mRNA expression of NGX6 in SW620 was detected by RT-PCR after pcDNA3.1(+)-LEF1(DN) transient transfection.@*RESULTS@#The expression of above molecules were obviously down-regulated by NGX6 transient transfection in SW620. The eukaryotic expression vector pcDNA3.1(+)-LEF1(DN) showed an inhibitory effect on Wnt/β-catenin signaling pathway. The mRNA expression of NGX6 in SW620 was up-regulated after pcDNA3.1(+)-LEF1(DN) transient transfection.@*CONCLUSION@#NGX6 could inhibit the expression of Wnt signaling downstream target genes, which maybe related to the potential feedback regulation between NGX6 and Wnt signal pathway.
Subject(s)
Female , Humans , Male , Base Sequence , Cell Line, Tumor , Colonic Neoplasms , Genetics , Metabolism , Pathology , Cyclin D1 , Genetics , Down-Regulation , Gene Expression Regulation, Neoplastic , Membrane Proteins , Genetics , Metabolism , Molecular Sequence Data , Proto-Oncogene Proteins c-myc , Genetics , RNA, Messenger , Genetics , Metabolism , Transfection , Tumor Suppressor Proteins , Genetics , Metabolism , Wnt Signaling Pathway , GeneticsABSTRACT
Objective NAG6, NAG 7 and BRD7 genes were novel tumor related genes identified recently. This study was designed to examine the expression of these genes in gastric cancer and matched paracancerous tissues and to investigate their roles in the occurrence and development of gastric carcinoma. Methods The expression levels of NAG6, NAG 7 and BRD7 in 34 cases of human gastric cancer and matched paracancerous tissues were analyzed by RT PCR, Northern blot analysis and Dot hybridization. Results The expression of NAG6 was absent in 61.8% gastric cancer tissues(21/34). The expression of NAG6 was significantly down regulated in gastric cancer tissues compared with that in paracancerous tissues ( P 0.05 ). The expression rates of NAG 7 in gastric cancer and paracancerous tissues were 88.2% (30/34) and 82.3% (28/34) respectively. BRD7 was expressed in all gastric cancers and matched paracancerous tissues. The results of RT PCR, Northern blot analysis and Dot hybridization all showed that the expressions of NAG 7 and BRD7 did not display any difference between gastric cancer and matched paracancerous tissues. Meanwhile, Dot hybridization also confirmed that NAG6 was significantly down expressed in gastric cancer. Conclusions NAG6 gene was significantly down regulated in gastric cancer tissues. The down regulation of this gene may play a key role in occurrence and development of gastric cancer, however it may be not associated with lymph node or distance metastasis. The expression levels of NAG 7 and BRD7 were not altered in gastric cancer. It seems that NAG 7 and BRD7 gene may not contribute to the occurrence and development of gastric carcinoma.
ABSTRACT
Objective To explore the mechanism of the decreased expression of connexin gene (Cx) 43 in human gastric cancer. Methods Detections on mutation of Cx43 coding region in 30 cases of human gastric cancer and control normal tissues were undertaken by means of reverse transcription-polymerase chain reaction-single strand conformation polymorphism (RT-PCR-SSCP). Results [WTBZ]No point mutation of Cx43 was found in 30 cases with human gastric cancer. Conclusion The decreased expression of Cx43 was not related to the mutation of coding region, but to the non-coding sequence, especially the 5' regulation sequence. The results were helpful for the further studying of the relationship between gastric cancer and connexin gene. The RT-PCR-SSCP is effective, fast, inexpensive and radiationless for mutation detection, which may be a means of gene diagnosis for gastric cancer.
ABSTRACT
Objective To study the expression of connexin (Cx) genes and the effects of a variety of inducers on the expression changes of Cx and mutations of Cx coding sequences in human gastric cancer. Methods Northern Blot, RT PCR and PCR single strand conformational polymorphism were used. Results 1.There were regular expression patterns of Cx genes in human normal gastric epithelium, paracancerous tissues and gastric cancers. 2.RA and DMSO can induce the expression of Cx43 in gastric cancer and decrease of Cx46 expression by RA and TPA induction. 3.There was no any mutation in Cx43 coding sequences. Conclusion 1.Cx32 gene may be a specific gene in genome of gastric epithelium constructing gap junctional intercellular communication. 2.Cx43 is a inducible gene in gastric cancer cells. 3.The down regulation of Cx43 expression is not caused by mutation of Cx coding sequences in human gastric cancers. 4.The authors proposed a hypothesis on the variation of expression of Cx genes in human gastric cancer.