POLYAMINES AND EPITHELIAL TUMORIGENESIS

多胺与上皮肿瘤发生

• 批准号: 6376251
• 负责人: Susan K. Gilmour
• 金额: $ 28.12万
• 依托单位: LANKENAU INSTITUTE FOR MEDICAL RESEARCH
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-05 至 2004-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6376251
• 关键词: angiogenesis; athymic mouse; carcinogenesis; cell differentiation; connective tissue cells; enzyme activity; epithelioma; gene induction /repression; genetically modified animals; guanine nucleotide binding protein; guanine nucleotide exchange factors; keratinization; keratinocyte; microarray technology; mitogen activated protein kinase; neoplasm /cancer genetics; neoplasm /cancer invasiveness; oncoprotein p21; ornithine decarboxylase; phosphatidylinositol 3 kinase; polyamines; representational difference analysis; skin neoplasms; wound healing

Ornithine decarboxylase (ODC) is a key regulatory enzyme in the biosynthesis of polyamines which are essential for normal cell growth and differentiation. The applicants have demonstrated that elevated levels of ODC and polyamines cooperate with a mutated Ha-ras gene to promote epithelial tumor formation and invasion. The applicant's hypothesis is that elevated levels of ODC and polyamines "activate" keratinocytes and dermal stromal cells to produce a phenotype similar to that in wounded skin, which is characterized by increased proliferation and migration, neoangiogenesis, altered differentiation, and increased expression of proteases. A corollary is that conditions (or oncogenes) that sustain this polyamine-induced activation of cells will result in the development of a tumor. The overall goal of this project is to identify downstream effectors that play a key role in mediating ODC-promoted tumorigenesis in skin. The objective is complicated when tumors arise as a consequence of a mutated ras (as is generally found in initiated skin) since multiple effector pathways contribute to Ras-mediated transformation of cells. Therefore, in order to achieve these goals, the applicant plans to dissect out the downstream effectors of polyamines as well as the downstream effectors of an activated ras that cooperate with ODC and polyamines to drive epithelial tumorigenesis. To this end, Dr, Gilmour proposes the following specific aims: 1. To determine if elevated levels of ODC and polyamines activate keratinocytes and dermal stromal cells in a manner similar to that in wounded skin, ODC will be expressed in both normal quiescent adult epidermis (using an inducible ODC transgenic mouse model), and in proliferative activated epidermis (abrading K6/ODC transgenic mouse skin). By controlling expression of ODC in either sedentary or activated keratinocytes, the applicants will evaluate this noninitiated (i.e. no mutated ras gene) skin for the induction of: A. a wound healing phenotype, and B. the formation of benign skin tumors dependent upon sustained ODC-induced activation of cells. 2. Using the inducible ODC transgenic mouse model, mRNA from ODC overexpressing skin will be compared with that from normal skin using representational difference analysis (RDA) and microarray approaches. Genes that are upregulated or downregulated by ODC will be evaluated for their role in mediating the tumorigenic and invasive effects of ODC when expressed with a mutated H-ras. 3. Dr. Gilmour will determine which downstream effectors of an activated Ha-Ras can cooperate with elevated levels of ODC and polyamines to convert epidermal cells to a malignant invasive phenotype. In particular, she plans to investigate possible cooperation between ODC and various partial function effector mutants of an activate Ha-Ras that specifically induce either the raf-1/ERK, RalGDS, or phosphoinostitie 3-OH kinase pathway.

鸟氨酸脱羧酶（ODC）是一种关键调节酶 多胺的生物合成对于正常细胞生长和 分化。申请人证明了ODC水平升高 多胺与突变的HA-RAS基因合作以促进上皮肿瘤 形成和入侵。申请人的假设是 ODC和多胺“激活”角质形成细胞和真皮基质细胞产生 与受伤皮肤类似的表型，其特征是 增加的增殖和迁移，新血管生成，改变了 分化和蛋白酶表达增加。推论是 维持这种多胺诱导的激活的条件（或致癌基因） 细胞将导致肿瘤的发展。总体目标 项目是确定在调解中起关键作用的下游效应子 ODC促进的皮肤肿瘤发生。当肿瘤时，目标很复杂 由于突变的Ras而产生（正如始于开始的 皮肤）由于多个效应途径有助于RAS介导 细胞的转化。因此，为了实现这些目标 申请人计划也剖析多胺的下游效应子 作为与ODC合作的激活RA的下游效应子 多胺驱动上皮肿瘤发生。为此，吉尔穆尔博士提出了 以下具体目的：1。确定ODC和ODC水平是否升高 多胺以类似的方式激活角质形成细胞和皮肤基质细胞 在受伤的皮肤中，ODC将在两个正常静止的成年人中表达 表皮（使用诱导型ODC转基因小鼠模型）和增生性 活化的表皮（磨损K6/ODC转基因小鼠皮肤）。通过控制 ODC在久坐或活化角质形成细胞中的表达， 申请人将评估这种非导致的（即没有突变的RAS基因）皮肤的皮肤 诱导：A。伤口愈合表型和B.良性的形成 皮肤肿瘤取决于ODC诱导的细胞激活。 2。使用 诱导的ODC转基因小鼠模型，来自ODC过表达的MRNA 将使用代表性差异将其与正常皮肤的比较 分析（RDA）和微阵列方法。上调或 被ODC下调的将评估其在中介中的作用 用突变的H-RAS表达ODC的致瘤和侵入性作用。 3。 Gilmour博士将确定激活HA-RAS的下游效应子 可以与升高的ODC和多胺合作以转化表皮 细胞为恶性侵入性表型。她特别计划 调查ODC与各种部分功能之间的可能合作 激活HA-RA的效应子突变体，该突变体特异性地诱导了 RAF-1/ERK，RALGDS或磷酸磷酸3-OH激酶途径。