Growth/differentiation control of keratinocytes by ROR alpha

描述（由申请人提供）：分化与上皮性肿瘤的发展呈负相关。我们最近发现叉头转录因子FOXN1和Notch1信号通路在功能上与抑制恶性皮肤肿瘤的形成有关。我们的工作假设是，类维生素a相关的核孤儿受体ROR1是角化细胞前分化网络的关键组成部分，作为FOXN1/Notch1基因和参与脂质代谢或体内平衡的酶的上游调节剂。ROR1先前涉及许多过程，包括发育、炎症和昼夜节律。我们的初步结果表明ROR1在角化细胞生长/分化和肿瘤发展中起关键作用。对于我们未来的工作，我们将解决以下具体目标：1)我们将评估ROR1是否在控制角化细胞分化中发挥重要作用，FOXN1和Notch1基因作为下游效应物。我们将通过对常规和3D器官型培养物中的原代人角质形成细胞（HKCs）以及ROR1基因破坏的小鼠进行综合分析来验证这一假设。2)我们将评估ROR1是否控制脂质代谢相关酶的表达。我们将测试ROR1的代谢功能通过ALOXE3影响生长/分化控制和肿瘤发生的更一般方面的可能性，ALOXE3是一种脂肪加氧酶，密切参与角质细胞分化。3)我们将评估ROR1是否在角化细胞肿瘤形成的控制中发挥重要作用。这一假设将通过双重遗传学和药理学方法进行检验。检测ROR1基因杂合突变小鼠对dba - tpa诱导的皮肤癌的敏感性，检测ras癌基因表达加/负ROR1敲低的HKCs的异种移植物是否形成肿瘤。药理学上，我们将测试用ROR1特异性激动剂（CGP 52608）治疗是否能影响化学诱导和/或异种移植肿瘤的形成。

DESCRIPTION (provided by applicant): Differentiation is inversely related to development of epithelial tumors. We recently showed that the forkhead transcription factor FOXN1 and the Notch1 signaling pathways are functionally linked to suppression of malignant skin tumor formation. Our working hypothesis is that the retinoid-related nuclear orphan receptor ROR1 is a key integral element of the pro-differentiation network in keratinocytes, functioning as an upstream regulator of FOXN1/Notch1 genes and enzymes involved in lipid metabolism or homeostasis. ROR1 has been previously implicated in a number of processes, including development, inflammation and circadian rhythm. Our preliminary results point to a key role of ROR1 in keratinocyte growth/differentiation and tumor development. For our future work we will address the following specific aims: 1) We will assess whether ROR1 plays an important role in control of keratinocyte differentiation with the FOXN1 and Notch1 genes as downstream effectors. We will test this hypothesis by a combined analysis of primary human keratinocytes (HKCs) in conventional and 3D organotypic cultures, and mice with disruption of the ROR1 gene. 2) We will assess whether ROR1 controls the expression of enzymes involved in lipid metabolism. We will test the possibility that the metabolic function of ROR1 impinges on more general aspects of growth/differentiation control and tumorigenesis via ALOXE3, a lipoxygenase that is intensively involved in keratinocyte differentiation. 3) We will assess whether ROR1 plays an important role in control of keratinocyte tumor formation. This hypothesis will be tested by a dual genetic and pharmacological approach. Mice with heterozygous ROR1 gene mutation will be tested for their sensitivity to DMBA-TPA-induced skin carcinogenesis, and xenografts of HKCs with ras oncogene expression plus/minus ROR1 knockdown will be tested for tumor formation. Pharmacologically, we will test whether treatment with a ROR1 specific agonist (CGP 52608) can affect chemical- induced and/or xenograft tumor formation. ) PUBLIC HEALTH RELEVANCE: Epidermal differentiation is regulated by orchestrated gene expression. ROR1 is a transcription factor with a critical role in differentiation and development. Our working hypothesis is that ROR1 plays a key role in control of epidermal differentiation through an interconnection with the Notch1 and FOXN1 genes and with specific lipid metabolism related genes.)