Delivery of a bacterial inhibitor of NF-kB to colon tumors

描述（由申请人提供）：结直肠癌是美国常见的癌症形式，每年在全球造成近百万人死亡。迫切需要改进的化学治疗剂和化学预防剂。活化B细胞核因子κ轻链增强子（NF-？B）转录因子复合物是细胞存活和肿瘤发生的关键启动子。NF-？B活化与结直肠癌的发展密切相关。NF-？B抑制剂是所需的，并且可能防止细胞进展为结肠癌。 我们已经发现了一种细菌蛋白，选择性地改变转录活性的NF-？肠细胞中的B。这种蛋白质，NleH 1，大肠杆菌O 157：H7表达，结合并抑制新鉴定的NF-？B，核糖体蛋白S3（RPS 3）。RPS 3通常指导NF-？B复合物与特异性基因启动子结合。NleH 1通过减少RPS 3的核丰度来抑制随后的宿主转录输出而发挥作用。RPS 3还在DNA修复和调节肿瘤转移中发挥重要作用。重要的是，RPS 3在结直肠癌中也上调。我们提出的研究细菌蛋白与天然的肠细胞向性，结合和抑制RPS 3和NF-？B可能在结直肠化疗药物的未来开发中具有重要的实用性。 我们的长期目标是表征NleH 1蛋白，并利用我们获得的信息来设计新的治疗结直肠癌的方法，其中NF-？B和RPS 3几乎普遍失调。该特定应用的目的是测试将NleH 1递送至结肠癌细胞系将抑制细胞增殖的假设。 具体目标是：1）定量NleH 1降低结肠癌细胞系中RPS 3的核丰度的程度，和2）定量NleH 1抑制RPS 3的转录活性和降低结肠癌细胞系的细胞增殖的程度。 这项研究具有重要意义和创新性，因为它将评估易位细菌效应蛋白在抑制与癌症发展相关的宿主转录活性中的效用。这些研究将有一个显着的积极影响，结肠癌的治疗，因为他们将形成的基础，为未来的机制研究，其中的具体目标NleH 1结肠癌细胞进行优化，也为功能解剖的区域NleH 1负责抑制RPS 3和NF-？B。 公共卫生相关性：激活NF-？B转录因子复合体与结直肠癌的发生密切相关。申请人已经发现了一种细菌蛋白，选择性地改变NF-？肠细胞中的B。这种细菌蛋白质，大肠杆菌NleH 1，提出的机制研究，很可能有效用，在指导结直肠化疗药物的发展。

DESCRIPTION (provided by applicant): Colorectal cancer is a common form of cancer in the United States and is responsible for nearly a million deaths each year worldwide. Improved chemotherapeutics and chemopreventive agents are urgently needed. The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-?B) transcription factor complex is a key promoter of cell survival and tumorigenesis. NF-?B activation is strongly correlated with the development of colorectal cancer. NF-?B inhibitors are desired and are likely to prevent cellular progression to colon cancer. We have discovered a bacterial protein that selectively alters the transcriptional activity of NF-?B in intestinal cells. This protein, NleH1, expressed by Escherichia coli O157:H7, binds to and inhibits the function of a newly identified subunit of NF-?B, the ribosomal protein S3 (RPS3). RPS3 normally guides the recruitment of the NF-?B complex to specific gene promoters. NleH1 functions by reducing the nuclear abundance of RPS3 to dampen subsequent host transcriptional outputs. RPS3 also plays an important role in DNA repair and regulates tumor metastases. Importantly, RPS3 is also up-regulated in colorectal cancers. Our proposed studies of a bacterial protein with a natural intestinal cell tropism that binds and inhibits the activities of both RPS3 and NF-?B are likely to have significant utility in the future development of colorectal chemotherapeutics. Our long-term goal is to characterize the NleH1 protein and use the information we obtain to design novel therapies for colorectal cancers, in which NF-?B and RPS3 are virtually universally misregulated. The objective of this particular application is to test the hypothesis that delivering NleH1 to colon cancer cell lines will inhibit cellular proliferation. The specific aims are to: 1) quantify the extent to which NleH1 reduces the nuclear abundance of RPS3 in colon cancer cell lines and 2) quantify the extent to which NleH1 inhibits the transcriptional activities of RPS3 and reduces cellular proliferation of colon cancer cell lines. The proposed research is significant and innovative because it will evaluate the utility of a translocated bacterial effector protein in inhibiting host transcriptional activities associated with cancer development. These studies will have a significant positive impact on colon cancer therapeutics, as they will form the basis both for future mechanistic studies in which the specific targeting of NleH1 to colon cancer cells is optimized and also for functional dissection of the region of NleH1 responsible for inhibiting RPS3 and NF-?B. PUBLIC HEALTH RELEVANCE: Activation of the NF-?B transcription factor complex is strongly correlated with the development of colorectal cancer. The applicant has discovered a bacterial protein that selectively alters the transcriptional activity of NF-?B in intestinal cells. The proposed mechanistic studies of this bacterial protein, Escherichia coli NleH1, are likely to have utility in guiding the development of colorectal chemotherapeutics.