Role of NFAT and NFAT-Induced Genes in Carcinoma

描述（由申请人提供）：本申请的目的是确定NFAT转录因子促进乳腺癌细胞侵袭性迁移的机制。具体来说，我们将重点关注NFAT诱导的基因刺激的信号通路，并促进侵袭性迁移。先前资助期的研究表明，NFAT是癌细胞中一个关键的转录因子，因为它既促进癌细胞的运动，又促进癌细胞的侵袭。我们发现1624整合素是导致NFAT激活的一个重要的上游调控机制，并发表了Akt/PKB和GSK-3在NFAT调控中的作用。然而，关于NFAT诱导的基因阵列，以及这些基因如何反过来控制侵袭性迁移，我们知之甚少。最近发表的研究和初步研究已经证明COX-2（环氧化酶-2）是一种促进肿瘤侵袭的nfat诱导基因。我们进一步确定了两个由NFAT诱导的细胞表面受体家族，趋化因子受体和glypicans（硫酸肝素蛋白多糖），研究表明它们促进侵袭性迁移。我们提出NFAT通过诱导旁分泌和自分泌信号通路促进侵袭性迁移的假设，其中趋化因子配体、趋化因子受体和glypicans都是这种表型的关键调节剂。关于NFAT在癌症中诱导的基因性质的知识几乎完全缺乏，我们的研究采用基于发现的方法来识别、表征和详细研究NFAT诱导的转录反应调节癌细胞信号的分子机制。我们的总体假设将在两个特定的目标中进行验证：在AIM 1中，我们将测试乳腺癌细胞中NFAT诱导的趋化因子受体和趋化因子的贡献。我们将确定趋化因子受体包括CXCR-2、CCR-2、XCR-1和CXCR4及其配体在nfat介导的侵袭中的作用，以及旁分泌和自分泌信号的作用。在AIM 2中，我们将确定NFAT诱导glypican-6 （GPC6）表达的机制。我们将确定NFAT和GPC6如何在体外和体内促进侵袭性迁移，并研究GPC6与Wnt信号传导合作的机制。这些研究结果将为NFAT通过诱导关键靶基因调节癌细胞侵袭性迁移的机制提供重要的新见解。我们预计，我们的NFAT研究的继续将在该领域提供重要的新信息，因为它们将突出调节癌症进展的新机制。我们的研究结果也有可能为肿瘤进展的治疗干预的未来发展提供帮助。公共卫生相关性：NFAT是一种细胞蛋白，在介导癌细胞运动导致远端器官转移中起关键作用。关于NFAT调节乳腺癌细胞迁移和侵袭能力的机制，我们所知的信息相对较少，而这两个特征对人类乳腺肿瘤的转移至关重要。该应用程序的总体目标是剖析NFAT在调节乳腺癌进展，导致转移的功能，这是目前有效治疗癌症的主要障碍。期望对乳腺癌细胞侵袭的更深入了解有助于设计更有效的抗癌药物。

DESCRIPTION (provided by applicant): The objective of this application is to define the mechanisms by which the NFAT transcription factor promotes breast cancer cell invasive migration. Specifically, we will focus on the signaling pathways stimulated by genes induced by NFAT and which promote invasive migration. Studies in the previous funding period showed that NFAT is a critical transcription factor in cancer cells as it promotes both the motility and invasion of carcinoma cells. We showed that the 1624 integrin is one important upstream regulatory mechanism leading to NFAT activation, and also published the role of Akt/PKB and GSK-3 in NFAT regulation. Little is known, however, concerning the array of genes induced by NFAT, and how in turn these genes control invasive migration. Recent published and preliminary studies have provided evidence that COX-2 (cyclooxygenase-2) is an NFAT-induced gene which promotes carcinoma invasion. We have further identified two families of cell surface receptors, chemokine receptors and glypicans (heparan sulfate proteoglycans) which are induced by NFAT, and studies show that they promote invasive migration. We propose the hypothesis that NFAT promotes invasive migration by inducing paracrine and autocrine signaling pathways whereby both chemokine ligands, chemokine receptors and glypicans are critical modulators of this phenotype. There is near complete paucity of knowledge concerning the nature of genes induced by NFAT in cancer, and our studies take a discovery-based approach to identify, characterize and investigate in detail the molecular mechanisms by which transcriptional responses induced by NFAT modulate cancer cell signaling. Our overall hypothesis will be tested in 2 specific Aims: In AIM 1 we will test the contribution chemokine receptors and chemokines induced by NFAT in breast cancer cells. We will determine the contribution of chemokine receptors including CXCR-2, CCR-2, XCR-1 and CXCR4 and their ligands in NFAT-mediated invasion, and the role of paracrine and autocrine signaling. In AIM 2, we will determine the mechanism by which NFAT induces glypican-6 (GPC6) expression. We will determine how NFAT and GPC6 promote invasive migration in vitro and in vivo, and investigate the mechanisms by which GPC6 collaborates with Wnt signaling. The results of these studies will provide important new insights into the mechanisms by which NFAT modulates cancer cell invasive migration through induction of critical target genes. We anticipate that continuation of our NFAT studies will provide important new information in the field because they will highlight new mechanisms of modulation of cancer progression. There is also the potential that the outcome of our studies will provide for the future development of therapeutic interventions for tumor progression. PUBLIC HEALTH RELEVANCE: NFAT is a cellular protein which plays a key role in mediating the motility of cancer cells leading to metastasis to distant organs. Relatively little information is known regarding the mechanisms by which NFAT regulated the ability of breast cancer cells to migrate and become invasive, two features which are critical for the metastasis of breast tumors in humans. The overall goal of the application is to dissect the functions of NFAT in modulating breast cancer progression, leading to metastasis, which is a major impediment in the effective treatment of cancer in the present day. It is expected that a greater understanding of breast cancer cell invasion can contribute to the design of more effective anti-cancer drugs.