Curing of pancreatic cancer by DUSPG/MKP-3

为阐明DUSP6/MKP-3在胰腺癌发生发展中的作用，本研究开展了以下研究1。利用含有20K基因的芯片对外源过表达DUSP6的胰腺癌细胞进行表达谱分析，发现81个上调基因和78个下调基因。上调基因包括5组基因（8组转运基因、7组受体活性基因、6组细胞增殖基因、4组转录调控基因、4组信号转导基因）、34组其他功能基因和18组功能未知基因。下调基因包括3组基因（细胞周期和有丝分裂相关基因17组，DNA复制相关基因7组，受体信号通路相关基因5组），其他功能基因28组，功能未知基因21组。外源性过表达DUSPG的细胞中与凋亡相关的蛋白分析发现bh3结构域蛋白的改变和caspases的修饰。通过将携带DUSP6的腺病毒载体注射到人胰腺癌细胞接种的裸鼠肿瘤中，采用DUSPG进行体内基因治疗，有几种肿瘤的体积明显减少，但总体疗效差异无统计学意义。对DUSP6候选基因表达控制区的分析发现，DUSP6缺失的癌细胞和原发癌组织中，DUSP6内含子1中CpG岛的高甲基化与后者的低分化表型显著相关。组蛋白修饰在废除中也发挥了重要作用。研究了在浸润性导管癌或导管内乳头状粘液瘤（IPMN）胰腺组织前体病变中DUSPG的废除。DUSP6在胰腺上皮内瘤变中表达均匀，但在浸润性癌中表达缺失，表明其缺失与浸润性表型密切相关。一小部分IPMN显示废除，表明其与IPMN的起始有关。少

To elucidate roles of DUSP6/MKP-3 in development and progression of pancreatic cancer, following investigations were carried out in this research.1.Expressional profiling of pancreatic cancer cells exogenously overexpressing DUSP6 by using microarray containing 20K genes uncovered 81 upregulated genes and 78 downregulated genes. The upregulated genes comprised five groups of genes (eight in transport seven in receptor activity, six in cell proliferation, four in regulation of transcription, and four in signal transduction) as well as 34 genes with other functions and 18 with unknown function. The downregulated genes comprised three groups of genes (17 in cell cycle and mitosis, seven in DNA replication, and five in receptor signaling pathway) as well as 28 genes with other functions and 21 with unknown function.2.Analysis of proteins pertaining to apoptosis in cells exogenously overexpressing DUSPG uncovered alterations of BH3-domain proteins and modification of Caspases.3.Experimental … More in vivo gene therapy employing DUSPG by means of injection of the adenovirus vector harboring DUSP6 into inoculated tumors of human pancreatic cancer cells in nude mice revealed remarkable reductions of volumes of several tumors but no statistically significant difference in efficacy overall.4.Analysis of candidate gene-expression controlling regions of DUSP6 uncovered hypermethylation of CpG islands in intron 1 of DUSP6 in DUSP6-abrogated cancer cells and primary cancer tissues, which was significantly associated with the poorly differentiated phenotype of the latter. Histon modification was found to play an important role in the abrogation as well.5.Abrogation of DUSPG in precursor lesions in pancreatic tissues with invasive ductal carcinoma or intraductal papillary-mucinous neoplasm (IPMN) was investigated. DUSP6 was fairly expressed in pancreatic intraepithelial neoplasia but lost in invasive carcinoma, indicating strong association of the abrogation with invasive phenotype. A small fraction of IPMN revealed the abrogation, suggesting its association with initiation of IPMN. Less