Role of Inflammation in the Development and Progression of Pancreatic Cancer

我们首先检验MIF促进胰腺癌侵袭性并预测切除病例的疾病结局的假设，从而开始我们的研究。与我们的假设一致，我们发现肿瘤中MIF mRNA表达升高与PDAC切除病例的不良结局显著相关。这一观察结果使我们验证了MIF在上皮细胞向间充质细胞转化（EMT）表型的获得中起作用，从而增强胰腺癌细胞恶性潜能的假设。机制分析显示，MIF过表达降低了胰腺癌细胞系中的E-钙粘蛋白，增加了波形蛋白mRNA和蛋白水平，与EMT的分子特征一致。此外，MIF过表达显著增加胰腺癌细胞中ZEB 1/2的表达并降低miR-200 b的表达，而MIF的shRNA介导的抑制增加E-cadherin和miR-200 b的表达，并降低ZEB 1/2的表达。在MIF过表达细胞中重新表达miR-200 b恢复了上皮特征，如E-cadherin的增加和ZEB 1/2和波形蛋白表达的减少所示。表明恶性潜能增加，MIF过表达细胞显示其体外侵袭能力显著增加，并且在原位异种移植小鼠模型中肿瘤生长和转移显著增加。这些结果清楚地支持MIF在疾病侵袭性中的作用，表明其作为候选治疗靶标用于设计具有改善结果的治疗胰腺癌的新策略的潜在有用性（Funamizu et.例如，Int J Cancer，Epub，2012年7月23日）。我们正在进一步扩展我们的研究：a）检查MIF诱导的EMT的最接近的效应; B）检查具有不同水平的MIF的原代胰腺癌细胞的转移潜力。

We started our investigation by first testing the hypothesis that MIF contributes to pancreatic cancer aggressiveness and predicts disease outcome in resected cases. Consistent with our hypothesis we found that an elevated MIF mRNA expression in tumors was significantly associated with poor outcome in resected cases of PDAC. This observation led us to test the hypothesis that MIF plays a role in the acquisition of epithelial-to-mesenchymal transition (EMT) phenotype and thereby enhancing malignant potential of pancreatic cancer cells. Mechanistic analyses revealed that MIF overexpression decreased E-cadherin and increased vimentin mRNA and protein levels in pancreatic cancer cell lines, consistent with molecular features of EMT. Furthermore, MIF-overexpression significantly increased ZEB1/2 and decreased miR-200b expression, while shRNA-mediated inhibition of MIF increased E-cadherin and miR-200b expression, and reduced the expression of ZEB1/2 in Pancreatic cancer cells. Re-expression of miR-200b in MIF overexpressing cells restored the epithelial characteristics, as indicated by an increase in E-cadherin and decrease in ZEB1/2 and vimentin expression. Indicative of an increased malignant potential, MIF over-expressing cells showed significant increase in their invasion ability in vitro, and tumor growth and metastasis in an orthotopic xenograft mouse model. These results clearly support a role of MIF in disease aggressiveness, indicating its potential usefulness as a candidate therapeutic target for designing novel strategies for treatment of pancreatic cancer with improved outcome (Funamizu et. al., Int J Cancer, Epub, July 23, 2012). We are further extending our investigation to: a) Examine the most proximate effectors of MIF-induced EMT; b) Examine the metastatic potential of the primary pancreatic cancer cells with different levels of MIF.