Epigenetic Modifications Causing Sex-Specificity of Fatal TIMP-1 Expression in Pancreatic Cancer

死于胰腺癌的风险极高，其原因是胰腺癌向肝脏的有效转移形成。最近，我们发现男性的这种风险甚至比女性更高，肿瘤来源的分泌因子TIMP-1(金属蛋白酶组织抑制因子-1)是这种癌症实体肝转移的性别差异的原因，这种差异与生活方式无关。在胰腺癌中，TIMP-1的表达是男性特有的，而女性的TIMP-1水平保持不变。调节X染色体上TIMP-1基因表达的这种性别特异性的机制完全未知。在这个项目中，我们跟踪了最初的数据，表明TIMP-1在疾病发展的早期阶段已经分别由恶性肿瘤细胞及其前体细胞表达增加，因此这些细胞的表观遗传重新编程似乎发挥了中心调节作用。事实上，根据最近的研究，表观遗传重编程被归类为胰腺癌启动过程中新的中心“使能特征”。然而，到目前为止，这些研究还没有考虑到可能的性别差异。我们将研究TIMP-1在成熟的体外系统(人胰腺癌细胞系)和体外系统(来自胰腺癌小鼠胰腺组织的有机化合物)以及已经收集和储存的分别从女性和男性患者和小鼠身上分离的胰腺肿瘤组织样本中TIMP-1表达特异性增加的分子机制基础。我们通过ATAC-SEQ研究TIMP-1启动子和TIMP-1基因远端调控元件的性别可及性，并通过芯片-聚合酶链式反应分析TIMP-1基因特定的局部表观遗传状态(组蛋白修饰)。组蛋白和DNA修饰的表观遗传酶TIMP-1表达的因果相关性将通过遗传操作(通过shRNA技术敲除，通过逆转录病毒基因转移过量表达)和临床相关抑制剂的药物抑制来研究。我们期待着对胰腺癌进展过程中表观遗传调控的性别差异的中心洞察，这可能有助于在患者中更有针对性地应用表观遗传活性药物(例如HAT或HDAC抑制剂)。

The exceptionally high risk to die from pancreatic cancer decisively arises from its efficient metastasis formation to the liver. Recently we found that this risk is even higher in men than in women and that the tumor-derived secreted factor TIMP-1 (Tissue Inhibitor of Metalloproteinases-1) is responsible for the sex difference in liver metastasis in this cancer entity in a life style-independent manner. In pancreatic cancer, TIMP-1 expression is male-specifically increased, while the levels remain constant in women. The mechanism regulating this sex-specificity of expression of the X-chromosomally located TIMP-1 gene is completely unknown. In this project we follow initial data showing that TIMP-1 is increasingly expressed already at early stages of the progression of this disease by malignant tumor cells and their progenitor cells, respectively, and that epigenetic reprogramming of these cells thereby seems to play a central regulatory role. In fact, based on recent studies, epigenetic reprogramming was classified as novel central ‘enabling characteristic’ during initiation of pancreatic cancer. However, possible sex differences so far have not been considered in those studies. We will investigate the molecular-mechanistic basis for sex-specific increase of TIMP-1 expression in well-established in vitro- (human pancreatic cancer cell lines) and ex vivo- (organoids derived from pancreas tissue from pancreatic cancer-bearing mice) systems, as well as already collected and stored pancreas tumor tissue samples which had been isolated from female and male patients and mice, respectively. We focus on sex-dependent accessibility of the TIMP-1 promoter as well as distal regulatory elements of the TIMP-1 gene via ATAC-seq and determination of the specific local epigenetic status (histone modification) of the TIMP-1 gene by ChIP-PCR analysis. Causal dependencies of TIMP-1 expression from histone- and DNA-modifying epigenetic enzymes will be investigated by genetic manipulation (knockdown by shRNA-technology, overexpression by retroviral gene transfer) and by pharmacological inhibition with clinically relevant inhibitors. We expect central insight into epigenetically regulated sex differences during progression of pancreatic cancer, which may contribute to more targeted therapeutic application of epigenetically active drugs (e.g. HAT- or HDAC-inhibitors) in patients.