Effect of overexpression of Smad7 gene on cell proliferation / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the effect of overexpression of Smad7 gene on cell proliferation in human bronchial epithelial cell lines.</p><p><b>METHODS</b>Human bronchial epithelial cell lines, BEP2D and BERP35T2 cells, were cotransfected with the mammalian expression vectors PCISmad7.neo and pMyc-SEAP, the latter was ac-myc cis-acting enhancer element fused with alkaline phosphatase (SEAP) reporter gene. Expression of c-myc, p15 and p21 mRNA was detected by RT-PCR before and after stable transfection of Smad7 into BEP2D and BERP35T2 cells in order to study the regulation of TGF-beta-mediated growth inhibition.</p><p><b>RESULTS</b>After BEP2D and BERP35T2 cells transfected with Smad7, the transcriptional activity of c-myc was significantly increased. Smad7 overexpressing cells showed upregulation of c-myc expression and downregulation of p15 and p21 expression, which contributed to the loss of TGF-beta responses in these cells.</p><p><b>CONCLUSION</b>Overexpression of Smad7 may facilitate cell proliferation by antagonizing TGF-beta-mediated antiproliferative gene responses.</p>

Expression of DNA-PK in hepato- and cholangio-neoplasms and its significance / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To characterize DNA-PKcs and Ku70 expressions in hepato- and cholangio-neoplastic tissues and the association with the degree of malignancy and invasiveness of the tumors.</p><p><b>METHODS</b>The expression of DNA-PKcs and Ku70 was examined in 47 cases of hepato- or cholangio-neoplasm by immunohistochemistry.</p><p><b>RESULTS</b>Ku70 was expressed in all of the neoplastic tissues examined and with a little variation in levels. The highest expression was observed in adenocarcinomas and adenomas. There was no statistically significant association between Ku70 expression level and the degree of their malignancy extent or invasiveness. In contrast to Ku 70, a wide variation in expression levels of DNA-Pkcs was observed among different types of neoplastic tissues. The highest ratio of positive expressing cells was detected in hepatocellular carcinomas (92.1%), which was significantly higher than that in cholangioadeno carcinomas (65.3%) and biliary cystadenocarcinomas (51.9%). Low or no expression level was detected in papillary adenoma cases. DNA-PKcs expression of invasive adenomas and adeno-carcinomas (61.2%) was significantly higher than that of non-invasive adenomas and adeno-carcinomas (30.4%). There was no expression observed in the normal tissues adjacent to the tumors.</p><p><b>CONCLUSION</b>DNA-PKcs is expressed in hepato- and cholangio-neoplasms and its variable level of expression is associated with the types of the tumor and their degree of malignancy and invasiveness. DNA-PKcs could be recognized as a new biomarker for liver neoplasm.</p>