ABSTRACT
Hypermethylation of the promoter region is an important mean for the transcriptional repression of a number of cancer-associated genes, and over-expression and/or increased activity of DNA methyltransferase are considered to be the main cause of promoter hypermethylation. In order to further explore the epigenetic mechanism of tumor suppressor gene RASSF1A inactivation,5-aza-2'-deoxycytidine (5-Aza-CdR), a DNA methyltransferase inhibitor, was used to treat the human biliary tract carcinoma cell line QBC-939 at the concentration of 5 μmol/L for 24 h in this study. After the chemical intervention with 5-Aza-CdR, the methylation status in the promoter region of RASSF1A gene was detected by methylation specific PCR (MS-PCR), and the expression alteration of RASSF1A mRNA and protein were observed by RT-PCR and Western Blot respectively. Following the treatment with 5-Aza-CdR, methylaiton status in the promoter region of RASSF1A gene was reversed from methylation to unmethylation. A 280 bp DNA band which represented RASS1FA expression at transcriptional level and a 40 kDa (1kDa=0.9921 ku) protein band which represented RASSF1A expression at protein level were detected by RT-PCR and Western Blot respectively in the experimental group cells and there were no corresponding bands in the control group cells. The experimental results suggest that 5-Aza-CdR can induce demethylation in the promoter region of RASSF1A. It can also reverse epigenetic transcriptional silencing caused by DNA methylation and induce the re-expression of RASSF1A in QBC-939. This study also suggest that the mechanism of RASSF1A inactivation is very closely related to the methylation of the promoter region, which may provide a new epigenetic understanding for tumor related gene inactivation and the pathogenesis of biliary tract carcinoma.
ABSTRACT
0.05). Conclusion:The excessive expression of Survivin in gallbladder cancer indicates that Survivin could be not only correlated with the occurrence of carcinoma but an early and common event in gallbladder carcinogenesis. Surviv in will promisingly become a novel tumor marker and can be applied in the clinic al practice for helping the early diagnosis as well as targeting gene therapy fo r gallbladder cancer.
ABSTRACT
Objective To evaluate the relationship between the clinicopathological factors, prognosis and the expression of p16 and c erbB 2 protein in primary breast cancer. Methods The expression of p16 and c erbB 2 by immunohistochemical method was observed in 50 patients with primary breast cancer and the detection of p16 by polymerase chain reaction(PCR) and the point mutation of p16 by PCR single strand conformational polymorphism(SSCP) were detected in 20 patients with breast cancer. Results Among the cancers, positive expression of p16 protein was found in 17(34.00%) cases, c erbB 2 protein positive expression in 24(48.00%) cases. No homozygous deletion in p16 gene was found. However, exon2 point mutation of p16 gene was found in 1 of 20 breast cancer. The results showed no relationship between p16 expression and clinicopathological factor or prognosis. Positive expressions of c erbB 2 protein were often found in breast cancer with lymph node metastasis(P=0.0237) with a poor 5 year survivalrate(P=0.0169). There was no consistent relationship between the expression of p16 and c erbB 2 protein. Neither p16 nor c erbB 2 protein expression could be as an independent prognostic factor. Conclusions The patients with breast cancer of positive expression of c erbB 2 protein has a high lymph node metastasis rate and a poor survival rate. The point mutation rate of p16 gene is lower in primary breast cancer, and it can be a molecular events in advanced primary breast cancer.
ABSTRACT
AIMTo investigate the effect of morp hine on purine nucleotides catabolism and its possible mechanisms. METHO DSRats were administered with morphine by intraperitoneal injection with increasing dose to develop ad diction model. The determination of uric acid concentration in plasma and the ac tivities of xanthine oxidase (XO) in the plasma and the small intestine were per formed. RT-PCR was used to examine the expressing level of key enzyme of purine nucleotides catabolism,XO mRNA. ?-actin was used as control gene in RT-PCR s tudy. RESULTSThe concentration of uric acid in plasma was sign ificantly increased in morphine-pretreated rats compared with control(P