MicroRNA regulation of glucocorticoid-induced autophagy and progression of pancreatic ductal adenocarcinoma

胰腺导管腺癌（Pancreatic ductal adenocarcinoma，PDA）是恶性肿瘤中最具侵袭性、预后差的一种。糖皮质激素（GC），如地塞米松（DEX），作为共同治疗，以限制副作用和姑息治疗的原因。越来越多的证据表明，GC诱导涉及PDA的上皮肿瘤细胞的进展和治疗抗性。这类似于其他类固醇激素，如雌激素或雄激素，其受体在乳腺癌和前列腺癌中因治疗原因而被阻断。2003年，我们的研究小组首次在体内报告了药理剂量的DEX在肺癌和宫颈癌细胞系中诱导化疗耐药性。与此同时，这些数据得到了其他几位研究人员的证实，并得到了患者研究的支持。我们最新的研究结果表明，糖皮质激素受体和激酶的信号转导激活TGFβ，从而介导PDA的治疗抵抗和上皮-间质转化（EMT）。我们未发表的结果表明，自噬和GC诱导的microRNA（miRNA）信号也参与其中。通过miRNA阵列分析、生物信息学评价和计算机模拟预测，我们确定miR-132、miR-378 a-3 p、miR-10 b-5 p及其靶基因TGFβ、ATG 12、RAS/ERK和JNK/AP-1为关键参与者。验证最重要的miRNAs及其靶基因，并检查GC诱导的EMT和自噬在恶性进展中的功能。我们将检查（1）是否不仅DEX，而且其他通常处方的GC药物也诱导PDA进展，（2）在维普莱OP之前的GC前驱用药影响候选miRNA及其靶基因在患者组织中的表达，（3）候选miRNA及其靶基因在功能上参与DEX诱导的自噬和EMT，（4）DEX诱导的自噬和EMT是交叉调节的，（5）最强的候选miRNA及其靶基因在肿瘤异种移植模型中是有效的。该项目有助于更好地了解复杂的分子机制，GC药物介导PDA的有益但也有害的影响。通常处方的GC药物的参与和患者组织的检查强调了转化特征和临床相关性。考虑到GC是经常使用的，严重的压力，慢性胰腺炎，抑郁症，富含蛋白质的食物，和急性吸烟提高内源性GC水平，预期的结果也可能有助于了解胰腺癌的发展，但也有其他上皮肿瘤实体。

Pancreatic ductal adenocarcinoma (PDA) is one of the most aggressive malignancies with poor prognosis. Glucocorticoids (GCs), such as dexamethasone (DEX), are administered as co-treatment to limit side effects and for palliative reasons. Accumulating evidence indicates that GCs induce progression and therapy resistance of epithelial tumor cells involving PDA. This is similar to other steroid hormones, such as estrogen or androgen, whose receptors are blocked for therapeutic reasons in breast and prostate cancer. The first in vivo report about the induction of chemotherapy resistance by pharmacological doses of DEX in a lung and cervical cancer cell line came from our group in 2003. Meanwhile these data were confirmed by several other researchers and are supported by patient studies. Our latest data demonstrate that signaling by glucocorticoid receptor and kinases activate TGFβ, which mediates therapy resistance and epithelial-mesenchymal transition (EMT) in PDA. Our unpublished results indicate that autophagy and GC-induced microRNA (miRNA) signaling are also involved. By miRNA array analysis, bioinformatic evaluation and in silico computational prediction we identified miR-132, miR-378a-3p, miR-10b-5p, and their target genes TGFβ, ATG12, RAS/ERK and JNK/AP-1 as key players.The aim of the requested project is the molecular analysis of GC-induced miRNA signaling, the verification of the most significant miRNAs with their target genes and to examine the function of GC-induced EMT and autophagy in malignant progression. We will examine whether (1) not only DEX, but also other commonly prescribed GC medicaments induce PDA progression, (2) GC pre-medication prior to Whipple OP influences the expression of candidate miRNAs and their target genes in patient tissue, (3) the miRNA candidates and their target genes are functionally involved in DEX-induced autophagy and EMT, (4) DEX-induced autophagy and EMT are cross-regulated, and (5) the strongest miRNA candidate and it´s target gene are effective in vivo using tumorxenograft models. This project contributes to a better understanding of the complex molecular mechanisms, by which GC medicaments mediate beneficial but also harmful effects in PDA. The involvement of commonly prescribed GC medicaments and the examination of patient tissues underline the translational character and the clinical relevance. Considering that GCs are frequently used and that severe stress, chronic pancreatitis, depression, protein-rich meals, and acute smoking raise endogenous GC levels, the expected results may also contribute to understand the development of pancreatic cancer, but also of other epithelial tumor entities.