The Effects Of MiR-23a On On The Development Of Pancreatic Cancer

Background:Pancreatic cancer is one of the most aggressive types of cancer worldwide.Although tremendous efforts have been made to heighten early diagnosisand clinical outcomes of patients with PC,the overall prognosis is still very poor andthe survival rate is approximately about 8%(4).Therefore,it is urgent toprovide novel biomarkers and elucidatemultiple signaling networks for pancreatic cancer early diagnosis and therapy.microRNAs is a hotspot in the research of the tumor molecular biology.Although some studies suggest that miR-23afunctions as a oncogenic regulator in pancreatic cancer,the underlying molecular mechanism remains poorly understand.Our preliminary experiments showed that miR-23a suppressed pancreatic cancer cell MIA-PaCa-2 proliferation,PLK-1 overexpressed in various tumors and strongly correlated with a wide spectrum of human cancers withpoor prognosis.ManymiRNAssuppressed the development of tumor cell via inhibiting PLK-1 expression.Target gene prediction software showedtat miR-23 a and PLK-1 May be a direct of miR23 a.Considering the important roles of miRNAs and PLK-1,it is necessary to screen novel target miRNA of PLK-1 for PC treatment.Objective:1?To study the expression of miR-23a and PLK-1 in pancreatic cancer tissues and pancreatic cancer cell lines,and to explore the correlation of expression between miR-23a and PLK-1.2?To study the effect of miR-23a on cell proliferation,migration,invasion and apoptosis in human pancreatic cell lines.3?To explore the underlying mechanism of altered expression of miR23a on affecting PLK-1 expression in pancreatic cell lines.Methods:1?The expression of miR-23a and PLK-1 in 20 primary pancreatic cancer tissues,adjacent tissues,one pancreatic duct endothelial cells and three types of pancreatic cell lines by using quantitative RT-PCR.MiR-23a and PLK-1 over-expression/RNA interference plasmids vectors were constructed and the proof of relationship between PLK-1 and miR-23a was assessed by luciferase reporter system.2?miR-23a over-expression/RNA transduced into pancreatic cancer cells MIA-PaCa-2 and Panc-1.CCK8 assay were performed to investigate cell proliferation after transfection.Transwell assay was performed to measurement cell migration and invasion ability after transfection and flow cytometry apoptosis assay was used to analyze cell apoptosis in pancreatic cancer cells after transfected cells.Finally,xenograft experiment was conducted to investigate the impact of miR-23a on pancreatic tumor growth in vivo.3?miR-23a and PLK-1 plasmids vectors were transduced respectively or co-transduced into pancreatic cancer cells MIA-PaCa-2.Transwell assay was performed to measurement cell migration and invasion ability.after transfection,flow cytometry apoptosis assay was used to analyze cell apoptosis in pancreatic cancer cells after transfected,RT-PCR assay was used to detect the impact of miR-23a on PLK-1 protein expression in vivo,and western blot assay was performed to measurement the protein expression of PLK-1 and its downstream signals of Bax?Bcl2?cyclinB1,E-cadherin andVimentin in pancreatic cancer cells after transfection.Results:1?Significantly higher levels of PLK-1 in 11 cases the cancer tissues and miR-23a in 19(95%)cases cancer tissuesamong 20 pairs of pancreatic cancer patient tissue samples were showed than in the adjacent tissues.The remarkableup-regulation of miR-23a and PLK-lwere observed in three types of pancreatic cell lines andmiR-23a showsnegativelycorrelated with PLK-1.Luciferase Reporter Assaysuggest that miR-23 a is a direct regulator of PLK-1 in PC cells.2?Compared with the control groups,miR-23a over-expression inhibited MIA-PaCa-2 cell proliferation,migration,invasion andimproved cell apoptosis.However,the results of Panc-1 cell assay is in contrast to the MIA-PaCa-2 cells.The tumor masses distinctly diminished in group of MIA-PaCa-2 cells transfected with miR-23a compared to control and negative control groups.3?Compared with the control groups,PLK-1 over-expression improved MIA-PaCa-2 cell proliferation,migration,invasion and inhibited cell apoptosis.However,the results of co-transduced group is similar with control groups.Furthermore,Western Blot showed miR-23a transfection could also inhibit PLK-1 and its downstream signals of Bcl-2,Cyclin B1 and Vimentin expression,while promote Bax and E-cadherin expression.However,these genes alter expression was reversed in PLK-1 treated group,while,the results of co-transduced group is similar with control groups.Finally,RT-PCR assay showed that PLK-1 expression was significantly suppressed when miR-23a was overexpressed in vivo.Conclusion:1?Expression of miR-23 a was up-regulated Significantly in pancreatic cancer tissues and in three types of pancreatic cell lines.miR-23a expression was negatively correlated with PLK-1 expression in pancreatic cancer cell lines.PLK-1 was a direct target of miR23a in pancreatic cancer cells.2?MiR-23a overexpression suppressed MIA-PaCa-2 cell proliferation,inhibited cell migrationand invasion,and promoted cell apoptosis,and the results of Panc-1 cell assay is in contrast to the MIA-PaCa-2 cells.3?miR-23 a overexpression suppressed cell proliferation,inhibited cell migrationand invasion,and promoted cell apoptosis via inhibiting PLK-1 expression.