| BackgroundThe prevalence of pancreatic cancer has shown an increased tendencies in recent years. Prognosis of the cancer is poor because of its high malignancy, low early diagnosis rate and inefficiency of current clinical treatment. So it is pressing to find some new technique in diagnosis and treatment of the cancer. With development of molecular biology theory and technology, investigating the pathogenesis and exploring means of diagnosis and treatment of the cancer in this field becomes a new research point. This paper discusses expression and pathogenesis function of MicroRNA in pancreatic cancer.Objectives1. To describe miRNA profile in cell line ASPC-1, malignant and benign pancreatic tissues, and to screen abnormal miRNA in pancreatic carcinoma cell line and tissue.2. To investigate the effect of abnormal expressed miRNAs in pancreatic cancer in growth and apoptosis of the cancer.3. To explore the role of miRNAs with significant effect on cell growth or apoptosis in molecular pathogenesis of the cancer.4. In summary, this study hopes to find new molecular target in treatment of pancreatic cancer, And Complements new contents in study of pathogenesis of the cancer.Methods 1. miRNA Microarray was used to determine abnormal expressed miRNA in pancreatic cancer cell line ASPC-1 and malignant pancreatic tissues compared with benign pancreatic tissues.2. according to the measuring results of miRNA profile. Some differential expressed miRNA (miR-21, 24, 191, 221) was down-regulated by transfect or co-transfect by lipofectamine with their antisense oligonucleotide inhibitors. after transfection. Fluorescent dyes FAM linked at the oligonucleotide was observed by fluorescence microscope and Real-time PCR of mir-21 was chosen to observe the changes of miRNA expression, MTT was tested to evaluate changes in Cell growth. apoptosis was observed by assessment of FITC-Annexin V/PI two-color flow cytometry flow cytometry and caspase-3 analysis . Cell cycle was observed by assessment of flow cytometry PI staining before and after transfection .3. according to the effects of miRNA on growth and apoptosis of the cancer, miR-21 which have most obvious effects was choose for further study. First,the gene targets of miR-21 were predicted by bioinformatics analysis, and one of the target, PTEN, was choose to be tested before and after transfection of miR-21 inhibitor. Then Real-time PCR technology was used to detected change of PTEN RNA, and Western blot was used to detected change of PTEN protein.Results1. among 416 human miRNAs tested by miRNA Microarray, 40 miRNAs were found to be down-regulated and 127 up-regulated in pancreatic cancer tissues and cell lines.2. observation of fluorescent dyes FAM in cells and Real-time PCR of mir-21 after transfection confirmed the efficiency of transfection and activity of antisense oligonucleotide inhibitors. Some of these miRNAs involve in cell growth and apoptosis of pancreatic cancer. in details, down-regulation of mir-21 individually would increase apoptosis and reduce cell activity of the cancer. down-regulated of mir-221 individually would change the cell cycle by reduce the proliferating phase cells and increase G0G1 phase cells, but with no significant effect on apoptosis and cell activity of the cells. When mir-221 and mir-21 were combined to be down-regulated . apoptosis and cell activity of the cells were further decreased than down-regulation of mir-21 individually.3. PTEN RNA have no obvious change but PTEN protein significantly increased after mir-21 was down-regulated.Conclusion1. there exists a lot of abnormal expressed miRNAs molecules in Pancreatic cancer tissue and cell lines.2. Only part of abnormal expressed miRNA in pancreatic cancer effect on cell growth , apoptosis or cell cycles of the cancer. Co-transfection of some miRNA inhibitors may have more profoundly effect than simple transfection .3. miR-21 may impact on the signaling pathways of pathogenesis of panctetic cancer by prevent the translation of PTEN protein.
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