Role of NFAT and NFAT-Induced Genes in Carcinoma

说明（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，我们将专注于NFAT诱导的基因刺激的信号通路，并促进侵入性迁移。上一个资助期的研究表明，NFAT是癌细胞中的关键转录因子，因为它促进癌细胞的运动和侵袭。我们发现1624整合素是导致NFAT活化的一个重要上游调节机制，并且还公开了Akt/PKB和GSK-3在NFAT调节中的作用。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入侵性迁移，我们知之甚少。最近发表的和初步的研究提供了证据，考克斯-2（环氧合酶-2）是NFAT诱导的基因，促进肿瘤的侵袭。我们已经进一步鉴定了两个家族的细胞表面受体，趋化因子受体和磷脂酰肌醇蛋白聚糖（硫酸乙酰肝素蛋白聚糖），它们是由NFAT诱导的，并且研究表明它们促进侵入性迁移。我们提出的假设，NFAT促进侵入性迁移诱导旁分泌和自分泌信号通路，其中两个趋化因子配体，趋化因子受体和磷脂酰肌醇蛋白聚糖是这种表型的关键调节剂。关于NFAT在癌症中诱导的基因的性质的知识几乎完全缺乏，我们的研究采取了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传导的分子机制。我们的总体假设将在2个特定目标中进行测试：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CXCR 4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诱导磷脂酰肌醇蛋白聚糖-6（GPC 6）表达的机制。我们将确定NFAT和GPC 6如何在体外和体内促进侵袭性迁移，并研究GPC 6与Wnt信号传导合作的机制。这些研究的结果将为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，因为它们将突出癌症进展调节的新机制。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，其在介导癌细胞的运动性中起关键作用，从而导致向远处器官的转移。关于NFAT调节乳腺癌细胞迁移和侵袭能力的机制，相对较少的信息是已知的，这两个特征对于人类乳腺肿瘤的转移至关重要。该申请的总体目标是剖析NFAT在调节乳腺癌进展中的功能，导致转移，这是当今有效治疗癌症的主要障碍。人们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.