Background and purpose: Pancreatic intraepithelial neoplasia (PanIN) is thought to be a precursor lesion of infiltrating pancreatic ductal adenocarcinoma. The mutation of the phenotypic impact of K-ras G12D alone, silencing of p53 and p16 could promote this process. The role of Smad4 in this progression was poorly understood. In the present study, we investigated the role of Smad4 in the development of pancreatic tumor, based on PanIN cell line from mice with K-ras G12D mutation in order to investigate the effect of Smad4 silencing on PanIN cells in the development and malignant transformation in nude mice. Methods: Smad4 knock-down PanIN cells (PanIN-S) were established by stable transfeetion with lentiviral-mediated Smad4 RNA interference (RNAi). In xenograft model experiments, BALB/c nude mice were randomly divided into 2 groups (5 mice per group) implanted with PanIN or PanlN-S cells subcutaneously. Two weeks after tumor cells inoculation, tumor volume and weight were estimated. PCNA staining was used to evaluate cell proliferation and CD31 polyclonal antibody was used to assess micro-vessel density (MVD) in tumors. Results: Effect of siRNA of Smad4 gene in PanlN cells was confirmed by RT-PCR and Western blot. Compared with PanlN groups, there was a dramatic increase in tumor volume and weight in PanIN-S groups (P<0.05). Furthermore, immunohistochemical analysis of the harvested tumors suggested that Smad4 silencing was associated with 'increased tumor cell proliferation (PCNA reactivity) and angiogenesis (micro-vessel density, MVD). The percentage of PCNA-positive cells in the PanlN-S groups were significantly increased than PanIN groups (P<0.05). CD31 staining revealed a significant increase in the PanlN-S groups compared to the PanlN groups (P<0.05). Conclusion: Silencing of Smad4 in PanlN cells with endogenous expression of K-ras G12D, enhanced progression to invasive adenocarcinomas. Cell proliferation and vascularization may be its important mechanisms.

This work was aimed to establish a quality control method for evaluating the effects on glucose and lipids of the fruiting body of Isaria cicadae Miquel from strain Ic-17-7 (Ic-17-7fb) using a rat model of type 2 diabetes (T2DM). Random amplified polymorphic DNA, sequence-characterized amplified region, and high-performance liquid chromatography (HPLC) were used for the quality control of Ic-17-7fb. The pharmacological effects on streptozocin (STZ)-induced high fat diet (HFD)-fed Albino Wistar rats were evaluated. The rats underwent the following treatments: control, metformin, Ic-17-7fb (0.166 and 0.5 g·kg
Animals ; Blood Glucose ; Cordyceps ; Diabetes Mellitus, Type 2/drug therapy* ; Metformin ; Quality Control ; Rats ; Rats, Wistar