ABSTRACT
Objective To explore the effects of cAMP response element binding protein ( CREB) on taxol-induced cell cycle arrest in HeLa cells .Methods MTT assay was used to determine the optimal concentration and treatment time . PCR method was used to construct the recombinant plasmid pCI neo /CREB( PN) and site-directed mutagenesis recombinant plasmid pCI neo/CREB-M(PM).Cell cycle was assayed by flow cytometry .Expressions of pCREB, CREB, cyclins and CDKs were assayed by Western blotting .Results The effective conditions of taxol treatment on HeLa cells were 0.1μmol/L for 24 hours.After cells were treated with 0.1μmol/L taxol, G2/M phase was arrested in a time-dependent manner , accomplished with the decrease of cyclin A , a significant increase of cyclin B1, D1 and phosphorylated CREB (pCREB) protein expression, whereas, no marked changes were observed in cyclin E , CDK1, CDK2, CDK4 and CREB expressions. However, combinantion of PM and taxol treatment significantly reduced taxol-induced G2/M phase arrest, and reversed the effect of taxol-decreased cyclin A, increased cyclin B1 and D1 expression.Conclusion Tanscription factor CREB-mediated specific cyclins play a pivotal role in taxol-induced G 2/M arrest in HeLa cells .
ABSTRACT
Objective To measure plasma microRNAs dysregulated in patients with pancreatic cancer and to assess the potential of these miRNAs as biomarkers for pancreatic cancer.Methods Thirty-seven patients with pancreatic cancer who underwent pancreatic resection between June 2010 to July 2011 were enrolled in the Lihuili Hospital,and ten healthy volunteers were used as control in this study.The expression levels of miR-190,miR-196a,miR-221 and miR-222 were analyzed using quantitative real time polymerase chain reaction (qRT-PCR).U6 was used as an internal control.The relationships between clinicopathoiogic characteristics of pancreatic cancer and microRNA expression levels were analyzed.Results The relative abundances of plasma microRNAs were significantly higher in pancreatic cancer patients than in the control group.The highly expressed plasma miR-190,miR-196a,miR-221,miR-222 levels did not correlate with clinicopathologic characteristics of patients such as sex,age,tumor maximal diameter,and level of serum CA199.The plasma miR-196a levels showed a positive correlation with TNM stage in pancreatic cancer patients.Conclusions The plasma levels ofmiR-190,miR-196a,miR-221 and miR-222 were highly upregulated in pancreatic cancer patients.These microRNAs in plasma may provide a new method in the early diagnosis of pancreatic cancer.