Expression Of Drosha In Pancreatic Cancer And The Regulated Mechanism Of GSK3β On Microrna Biogenesis

PART ONE EXPRESSION OF DROSHA AND ITSCLINICOPATHOLOGICAL SIGNIFICANCE INPANCREATIC CANCER TISSUESObjective: To investigate the expression of Drosha and itsclinicopathological significance in pancreatic cancer tissues.Methods: H&E staining and immunohistochemical stainingtechnology were used to detect the expression of Drosha, and its correlationwith clinicopathological characteristics was studied. And the RT-PCR wasperformed to detect the gene expression level of Drosha.Results: The positive rates of Drosha were76.5%(65/85) inpancreatic cancer tissues and100%(53/53) in adjacent non-cancer tissues,and the difference was statistically significant (P <0.05); the expression ofDrosha had a significantly positive correlation with the tumor stage(Chi-Square=19.2, P=0.0003), grade (Chi-Square=10.8, P=0.013) andlymph node metastasis (Chi-Square=23.6, P=0.00003). The gene expression of Drosha was down-regulated in these paired53pancreaticcancer patients compared to those adjacent pancreatic tissues（P=0.000）.Conclusion: Drosha is low expressed in pancreatic cancer tissues, andmay play important roles in pancreatic cancer biogenesis and progress. PART TWO GLYCOGEN SYNTHASE KINASE3BETAINHIBITS MICRORNA-183-96-182CLUSTER VIA THEβ-CATENIN/TCF/LEF-1PATHWAY IN GASTRIC CANCERCELLSObjective: To study the inhibited mechanism of GSK3βonmicroRNA-183-96-182cluster via β-Catenin/TCF/LEF-1pathway ingastric cancer cells.Method: Western Blot and IHC were determined to detect theexpression of GSk3β and β-Catenin in cells and gastric cancer tissues.QRT-PCR was used to detect the expression of microRNA-183,96, and182. Luciferase assay was explored to detect the promoter activity, andCHIP assay was used to transcriptional binding sites.Results: GSk3β can not only decrease the expression of β-Catenin, but also suppress its translation into the nucleus. Overexpression of GSk3βcan decrease the expression of microRNA-183,96, and182, whileoverexpression of β-Catenin increases their expression. GSk3β proteinlevel decreased in human gastric cancer patients with increases ofβ-Catenin, microRNA-183,96, and182compared to the paired adjacentgastric tissues. In addition, β-Catenin/TCF/LEF-1binds to the promoter ofmiR-183-96-182cluster gene and thereby activates the transcription of thecluster.Conclusion: GSk3β can inhibit microRNA-183-96-182cluster via theβ-Catenin/TCF/LEF-1pathway in gastric cancer cells.