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Molecular Cytogenetics of Solid Tumors

实体瘤的分子细胞遗传学

基本信息

批准号：
8348954
负责人：
NICOLAE POPESCU
金额：
$ 107.86万
依托单位：
DIVISION OF BASIC SCIENCES - NCI
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/8348954
关键词：
16q22 16q24 ANXA2 gene Affect Anchorage-Independent Growth Annexins Annual Reports Area Attenuated Binding Binding Sites Biological Assay Breast Cancer Cell Breast Carcinoma Cancer Prognosis Cell Aging Cell Line Cell Surface Receptors Cells Cervix carcinoma Chromosome Transfer Chromosomes, Human, Pair 16 Chromosomes, Human, Pair 6 DLC1 gene DLEC1 gene Data Development Diagnosis Dose Down-Regulation Epigenetic Process Esophageal Event Frequencies Gene Mutation Genes Genomics Goals Hepatocarcinogenesis Human In Vitro Inflammatory Laboratories Large Intestine Carcinoma Link Malignant Epithelial Cell Malignant Neoplasms Malignant neoplasm of liver Malignant neoplasm of lung Mammary Neoplasms Maps Metastasis Suppressor Genes Methylation Molecular Molecular Biology Molecular Cytogenetics Neoplasm Metastasis Plasmin Plasminogen Primary Neoplasm Process Protein Isoforms Proteins Proteolysis Rattus Recurrence Research Role S100 family protein p11 S100A2 gene Screening procedure Signal Pathway Signal Transduction Solid Neoplasm Stomach Structure Therapeutic Therapeutic Intervention Tumor Cell Invasion Tumor Suppressor Genes Tumor Suppressor Proteins Ubiquitin Work YAC Clone Yeasts cancer cell cancer therapy carcinogenesis cell motility design insight interest lung Carcinoma neoplastic cell novel ovarian neoplasm programs promoter rho GTP-Binding Proteins senescence tumor tumor progression yeast two hybrid system

项目摘要

Over the past few years, DLC1 gained the status of a major tumor suppressor gene and is increasingly recognized as a metastasis suppressor gene. In the last two years our work focused in protein interaction, a new area of our research program designed to gain insights into the function of DLC1 gene. A yeast two hybrid screening identified several binding partners of DLC1 that were confirmed in human cells and thus enabling us to examine the consequences of their interactions on DLC1 function. Our previous studies underlined the importance to DLC1 interaction with proteins other than Rho GTPases and their therapeutic implication. We characterized a new DLC1 interaction with S100A10 an inflammatory protein and a key cell surface receptor for plasminogen that regulates pericellular proteolysis and tumor cell invasion. DLC1 and Annexin A2 shear the same binding site at the C-terminus of S110A10. DLC1 binding displaced annexin 2 thus making it accessible to ubiquitin dependent degradation that in turn resulted in a dose dependent down regulation of S100A2 expression. This process attenuated plasminogen activation and was accompanied by inhibition of in vitro cell migration, invasion, colony formation, and anchorage independent growth of aggressive lung cancer cells. DLC1 binding to S100A10 did not affect DLC1 RhoGAP activity. Thus, this study unraveled a novel GAP-independent mechanism that contributes to the tumor suppressive activity of DLC1 and most importantly provides a plausible mechanism for DLC1 anti metastatic function through which conversion of plasminogen to plasmin diminish tumor cell capacity for invasion and metastasis in the tumor microenvironment. Currently, DLC1 is considered as a metastasis suppressor gene and its involvement in the process of metastasis through interaction with S100A10 protein provides a valid target for therapeutic intervention in the most harmful event in cancer progression. In the last year annual report we described the isolation and characterization of novel DLC1 isoform 4 (DLC1i4) that is significantly downregulated by promoter methylation in a high number of nasopharyngeal, esophageal, gastric, breast, colorectal, cervical and lung carcinoma cell lines as well as in primary tumors and has potent tumor suppressor activity. Inadvertently, the results shoving a high frequency of deregulation DLC1i4 in liver cancer were omitted. Human liver cancer is of central interest in our laboratory and frequent epigenetic downregulation of the new DLC1 isoform together with similar data generated with another isoform underlined the complexity of DLC1 activity in hepatocarcinogenesis. In a previous collaborative study it has been demonstrated that the introduction of an intact chromosome 16 or of fragments corresponding to 16q22-qter or 16q23-qter into breast cancer cells revealed the presence of a cell senescence gene at region 16q24. This year using a similar approach, a novel senescence gene locus, on chromosome transfer into immortal ovarian tumor cells identified 6 designated SEN6A. To refine the gene locus, intact chromosome 6 or 6q were transferred into rat ovarian tumor cells and a panel of immortal revertant clones of senescent cells was generated. The analysis of these revertant cells indicated the presence of a senescence gene confined to the region 6q16.3. Using a functional assay, it was demonstrated that transfer of a YAC clone that maps at 6q16.3 restores senescence in both rat and human ovarian and breast tumor cells.

在过去的几年中，DLC1获得了主要肿瘤抑制基因的地位，并且越来越多地被认为是一种转移抑制基因。在过去两年中，我们的工作重点是蛋白质相互作用，这是我们研究计划的一个新领域，旨在深入了解 DLC1 基因的功能。酵母两种杂交筛选鉴定了 DLC1 的几种结合伴侣，这些结合伴侣在人类细胞中得到了证实，从而使我们能够检查它们相互作用对 DLC1 功能的影响。我们之前的研究强调了 DLC1 与 Rho GTPases 以外的蛋白质相互作用的重要性及其治疗意义。我们表征了 DLC1 与 S100A10 的新相互作用，S100A10 是一种炎症蛋白和纤溶酶原的关键细胞表面受体，可调节细胞周蛋白水解和肿瘤细胞侵袭。 DLC1 和膜联蛋白 A2 在 S110A10 的 C 末端剪切相同的结合位点。 DLC1 结合取代了膜联蛋白 2，从而使其容易发生泛素依赖性降解，进而导致 S100A2 表达的剂量依赖性下调。这一过程减弱了纤溶酶原的激活，并伴随着抑制体外细胞迁移、侵袭、集落形成和侵袭性肺癌细胞的贴壁独立生长。 DLC1 与 S100A10 的结合不影响 DLC1 RhoGAP 活性。因此，这项研究揭示了一种新的GAP独立机制，该机制有助于DLC1的肿瘤抑制活性，最重要的是，为DLC1抗转移功能提供了一种合理的机制，通过纤溶酶原转化为纤溶酶，降低了肿瘤细胞在肿瘤微环境中侵袭和转移的能力。目前，DLC1被认为是一种转移抑制基因，它通过与S100A10蛋白相互作用参与转移过程，为癌症进展中最有害事件的治疗干预提供了有效的靶点。在去年的年度报告中，我们描述了新型 DLC1 异构体 4 (DLC1i4) 的分离和表征，该异构体在大量鼻咽癌、食管癌、胃癌、乳腺癌、结直肠癌、宫颈癌和肺癌细胞系以及原发性肿瘤中通过启动子甲基化显着下调，并具有有效的肿瘤抑制活性。无意中，忽略了 DLC1i4 在肝癌中高频率失调的结果。人类肝癌是我们实验室的核心关注点，新的 DLC1 同工型的频繁表观遗传下调以及另一种同工型产生的类似数据强调了 DLC1 活性在肝癌发生中的复杂性。在之前的一项合作研究中，已经证明，将完整的 16 号染色体或对应于 16q22-qter 或 16q23-qter 的片段引入乳腺癌细胞，揭示了 16q24 区域存在细胞衰老基因。今年采用类似的方法，将一个新的衰老基因位点，通过染色体转移到永生卵巢肿瘤细胞中，鉴定出6个命名为SEN6A的细胞。为了精炼基因位点，将完整的 6 号或 6q 染色体转移到大鼠卵巢肿瘤细胞中，并生成了一组衰老细胞的永生回复克隆。对这些回复体细胞的分析表明存在仅限于 6q16.3 区域的衰老基因。使用功能测定，证明转移位于 6q16.3 的 YAC 克隆可以恢复大鼠和人类卵巢和乳腺肿瘤细胞的衰老。