Investigation of molecular mechanisms of TIMP-1-induced metastasis via shRNA technology

金属蛋白酶组织抑制剂-1（TIMP-1）是一种天然的广谱金属蛋白酶抑制剂，与肿瘤患者预后差、生存期短有关。在前两个资助期，我们可以证明，升高的全身TIMP-1水平不仅增加了肿瘤细胞内在的转移潜力，而且还诱导了肝脏中转移前小生境的形成，其中中性粒细胞（NG）作为肝转移增加的功能介质。我们未发表的数据表明，TIMP-1不仅影响肝脏中的NG稳态，而且还导致外周血中NG计数增加。这是令人感兴趣的，因为高血液NG被描述为促进特别是肝转移。此外，NG可以通过分泌细胞因子或蛋白酶来促进转移的局部微环境。因此，在最后一个资助期，我们希望澄清血液中NG数量的增加是否有助于TIMP-1诱导的肝转移，以及TIMP-1在什么水平上影响血液和肝脏中的NG稳态。主要问题有：1. TIMP-1诱导血NG升高的机制是什么？2. NG在肝脏中TIMP-1诱导的转移前小生境中的促转移作用是什么？3. 肿瘤细胞与血液中NG的相互作用是否有助于TIMP-1诱导的肝转移？从这些结果中，我们期望对局部组织稳态、免疫区室和肿瘤细胞的相互作用有更深入的了解。这将解释炎症和癌症进展背景下有关TIMP-1的临床观察结果。

Tissue inhibitor of metalloproteinases-1 (TIMP-1), a natural broad spectrum inhibitor of metalloproteinases, is associated with poor prognosis and short survival of cancer patients. In the previous two funding periods we could show that elevated systemic TIMP-1 levels not only increase the tumor cell-intrinsic metastatic potential, but also induce the formation of a pre-metastatic niche in the liver, where neutrophil granulocytes (NGs) act as functional mediators of increased liver metastasis. Our un-published data indicate that TIMP-1 affects NG homeostasis not only in the liver, but also leads to increased NG counts in peripheral blood. This is interesting as high blood NGs are described to promote particularly liver metastasis. Furthermore, NGs can contribute to a pro-metastatic local microenvironment by secreting cytokines or proteases.In the last funding period we would therefore like to clarify whether the increase of NG numbers in the blood contributes to TIMP-1-induced liver metastasis, and at what level TIMP-1 impacts on NG homeostasis in the blood as well as in the liver. The main questions are:1. What is the mechanism of TIMP-1-induced increase of blood NGs?2. What are the pro-metastatic effects of NGs in the TIMP-1-induced pre-metastatic niche in the liver?3. Does interaction of tumor cells with NGs in the blood contribute to TIMP-1-induced liver metastasis?From the results we expect a deeper understanding of the interplay of local tissue homeostasis, the immune compartment, and tumor cells. This will explain clinical observations concerning TIMP-1 in the context of inflammation and cancer progression.