REGULATION OF CYP1A1 IN HUMAN EPITHELIAL CELLS

申请人摘要：这项建议的重点是审查 细胞色素P450家族成员细胞色素P1A1的组织特异性调节 正常的人类皮肤。CYP1A1是一种多环卤代芳香族化合物 碳氢化合物诱导的单加氧酶。因为超过一半的癌症 发生在与环境有直接接触的上皮细胞中， 了解细胞色素P4501A1的内源性调控和表达 组织很重要。 对于正常人群中细胞色素P4受体A1的组织特异性调节知之甚少 人类复层鳞状上皮。然而，PAHs和HAHS依赖 细胞色素P4501A1的调控是由基本螺旋-环-螺旋转录介导的 含芳烃受体(AhR)的因子复合体及其 二聚体蛋白，AhR核转位蛋白(ARNT)。角色 AhR和Arnt在非小鼠皮肤组织特异性细胞色素P1A1调节中的作用 很好理解。此外，尚不清楚是否承诺 细胞色素P1A1在皮肤中的表达是否需要分化，如果 Any、CyP1A1、AhR和Arnt参与的终端分化计划 角质形成细胞，复层鳞状上皮的主要细胞类型。我们 最近发现CYPlA1基因的表达和酶的活性 是由细胞信号事件快速诱导的，由暂停 培养的人角质形成细胞在不含异物或其他物质的情况下 诱导分化的条件，如高水平的钙和 血清。我们怀疑类似的细胞信号事件导致了 CYP1A1在体内复层鳞状上皮细胞中的诱导。这部小说 CYP1A1的诱导机制应加深我们对哺乳动物的认识 复层鳞状上皮细胞色素P450基因调控 可能有助于鉴定内源诱导物和底物 对于细胞色素P1A1。到目前为止，我们所产生的结果使我们 假设细胞黏附的变化是细胞色素P1A1的重要调节因子 在正常的人类复层上皮细胞中。具体目标是：1) 鉴定细胞色素P1A1在角质形成细胞中的内源性表达，以及 不同时期AhR+/+和AhR-/-小鼠角质形成细胞 体外分化和原位分化。2)分子生物学研究 细胞角质形成细胞丧失后细胞色素P1A1的诱导机制 和细胞-底物接触，以及3)识别特定的细胞-细胞或 细胞-底物相互作用，当被破坏时，导致快速诱导 角质形成细胞CYP1A1与AhR/Arnt信号转导通路的关系 用AhR-/-小鼠角质形成细胞黏附介导的细胞色素P1A1的诱导。

APPLICANT'S ABSTRACT: The focus of this proposal is to examine the tissue-specific regulation of a cytochrome P450 family member, CYP1A1, in normal human skin. CYP1A1 is a polycyclic and halogenated aromatic hydrocarbon-inducible monooxygenase. Since more than half of all cancers arise in epithelia having direct contact with the environment, an understanding of the endogenous regulation and expression of CYP1A1 in these tissues is important. Little is known about the tissue-specific regulation of CYPlA1 in normal human stratified squamous epithelia. However, PAHs and HAHs-dependent regulation of CYP1A1 is mediated by a basic helix-loop-helix transcription factor complex containing the aryl hydrocarbon receptor (AhR) and its dimerization partner, AhR nuclear translocator protein (Arnt). The role that AhR and Arnt play in tissue-specific CYP1A1 regulation in skin in not well understood. Furthermore, it is unknown if commitment to differentiation is necessary for CYP1A1 expression in skin or what role, if any, CYP1A1, AhR, and Arnt play in the terminal differentiation program of keratinocytes, the major cell type of stratified squamous epithelia. We have recently found that expression of the CYPlAl gene and enzyme activity is rapidly induced by cellular signaling events initiated by suspension of cultured human keratinocytes in the absence of xenobiotics or other differentiation-inducing conditions, such as high levels of calcium and serum. We suspect that similar cellular signaling events contribute to the induction of CYP1A1 in stratified squamous epithelia in vivo. This novel mechanism of CYP1A1 induction should enhance our understanding of mammalian cytochrome P450 gene regulation in stratified squamous epithelia and potentially aid in the identification of endogenous inducers and substrates for CYP1A1. The results we have generated thus far have led us to hypothesize that changes in cell adhesion are important regulators of CYP1A1 in normal human stratified epithelia. The specific aims are: 1) Characterize the endogenous expression of CYP1A1 in human keratinocytes, and in AhR+/+ and AhR-/- mouse keratinocytes at different stages of differentiation in vitro and in situ., 2) Investigate the molecular mechanism of CYP1A1 induction in keratinocytes following loss of cell-cell and cell-substratum contact, and 3) Identify specific cell-cell or cell-substratum interaction that, when disrupted, cause rapid induction of keratinocyte CYP1A1 and investigate the role of the AhR/Arnt signaling in adhesion-mediated CYP1A1 induction using AhR-/- mouse keratinocytes.