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HORMONAL REGULATION OF C-HA-RAS AND ROLE IN METASTASIS

C-HA-RAS 的激素调节及其在转移中的作用

基本信息

批准号：
2700517
负责人：
Malathy PV Shekhar
金额：
$ 10.43万
依托单位：
WAYNE STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1994
资助国家：
美国
起止时间：
1994-05-01 至 1999-12-31
项目状态：
已结题

项目摘要

Oncogenes and suppressor genes that can affect tumor progression may control important points in the regulation of genes that are ultimately responsible for alteration seen in highly metastatic cells. Hence, understanding of the mechanisms regulating expression of the genes capable of influencing tumor development and progression is crucial for providing insights leading to more effective prognosis or therapy. The long term goal of this project is to identify and characterize genes that re involved in mammary tumor development and tumor progression. Elevated levels of nonmutated c-Ha-ras proteins have been reported to play a crucial role in tumorigenesis in the mammary tissue. We have shown a direct correlation between endogenous c-Ha-ras protein levels and metastatic behavior of mouse mammary tumor subpopulations, and have identified an novel hormone responsive transcriptional regulatory element in the intron-1 of the mouse Ha-ras gene. The enhancer activity of intron-1 element in the intron-1 element is induced strongly by glucocorticoids (edamethasone, Dx), and progesterone (Pg) in nonmetastatic sublines. IN metastatic mammary sublines it is moderately induce by Dx, Pg, and E2. Two specific complexes , A1 and A2, are formed when nuclear extract s form metastatic and nonmetastatic cells are incubated with the intron-1 element. Complex B is formed only when the intron-1 element is reacted with nuclear proteins of metastatic cells. We show significant differences in c-Has-ras protein levels, complex formation with intron-1 element, and hormonal responsiveness of the ras intron-1 element between metastatic and nonmetastatic mammary sublines used in our study. The hypothesis to be tested is that in the mouse mammary system tumor progression and expression of metastatic behavior is linked to the mechanisms regulating/deregulating Ha-ras gene expression. Our specific aims are: 1) To determine if hormonal responsiveness of ras expression is related to a mammary tumor phenotype; i.e., do cells with low p21ras levels exhibit greater hormone mapping whether there are other regulatory sites in intron-1 of the mouse Ha-ras gene and how they and regulatory sites 5-of intron-1 interact with the intron-1 of the mouse Ha-ras gene and how they and regulatory since similar motifs containing the ERE-and GRE-half sites are present in intron-1 element, since exon-1 of mouse, rat and human c-Ha-ras genes. 3) To define and characterize the transacting factors interacting with the ras intron-1 element in metastatic and nonmetastatic cells. 4) To determine whether the intron-1 element can confer hormonal responsiveness in in vitro transcription systems. 5) To determine whether E3 and glucocorticoid regulates c-Has- ras levels in the mouse mammary sublines primarily a the transcriptional levels or also by altering the stability of the proteins. Completion of these studies in a well-defined mouse metastasis a model system will provide valuable information on the mechanisms mediating transcriptions regulation of the Ha-ras gene in mammary tumor cells. Once characterized, trans-acting factor(s) specific to metastatic mammary cells will be of use in functional assays to more completely define the role of ras in metastasis.

可能影响肿瘤进展的癌基因和抑制基因可能控制着基因调控的关键点，在高转移性细胞中观察到的改变。因此，我们认为，了解调控基因表达的机制能够影响肿瘤的发展和进展，从而提供导致更有效的预后或治疗的见解。的该项目的长期目标是识别和表征基因，参与乳腺肿瘤的发生和发展。升高据报道，非突变的c-Ha-ras蛋白水平在在乳腺组织的肿瘤发生中起关键作用。我们展示了一个内源性c-Ha-ras蛋白水平与小鼠乳腺肿瘤亚群的转移行为，鉴定了一种新的激素应答转录调控元件在小鼠Ha-ras基因的内含子1中。增强子活性内含子-1元件中的内含子-1元件被强烈诱导，糖皮质激素（edlutamine，Dx）和孕酮（Pg），非转移性亚系。在转移性乳腺亚系中，由Dx、Pg和E2诱导。形成两种特定的复合物A1和A2，当细胞核提取物形成转移性和非转移性细胞时，与内含子-1元件一起孵育。复合物B仅在以下情况下形成：内含子-1元件与转移细胞的核蛋白反应。我们发现c-Has-ras蛋白水平，复合物 ras基因内含子-1元件的形成和ras的激素反应性转移性和非转移性乳腺亚系之间内含子-1元件在我们的研究中使用。有待检验的假设是，乳腺系统肿瘤进展和转移行为的表达与Ha-ras基因调控/去调控机制有关表情我们的具体目标是：1）确定ras的激素反应性，表达与乳腺肿瘤表型有关;即，做细胞与低p21 ras水平显示更大的激素定位，小鼠Ha-ras基因内含子-1中的调控位点，以及它们和内含子-1的5-调控位点与小鼠的内含子-1相互作用 Ha-ras基因以及它们如何与调控自相似的基序含有 ERE-和GRE-半位点存在于内含子1元件中，因为外显子1 小鼠、大鼠和人类c-Ha-ras基因的表达。3)为了定义和描述与ras内含子-1元件相互作用的反式调节因子转移性和非转移性细胞。 4)为了确定内含子1是否元件可以在体外转录中赋予激素反应性系统. 5)为了确定E3和糖皮质激素是否调节c-Has，小鼠乳腺亚系中的ras水平主要是转录或者通过改变蛋白质的稳定性。在明确定义的小鼠转移模型中完成这些研究系统将提供有关调解机制的宝贵信息， Ha-ras基因在乳腺肿瘤细胞中的转录调控。一旦表征，转移性乳腺癌特异性反式作用因子细胞将用于功能测定，以更完整地定义 ras在肿瘤转移中的作用

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Transcriptional activation of functional endogenous estrogen receptor gene expression in MCF10AT cells: a model for early breast cancer.

DOI：
10.3892/ijo.13.5.907
发表时间：
1998-11
期刊：
International journal of oncology
影响因子：
5.2
作者：
P. Shekhar;M. L. Chen;J. Werdell;G. Heppner;F. Miller;J. Christman
通讯作者：
P. Shekhar;M. L. Chen;J. Werdell;G. Heppner;F. Miller;J. Christman

Breast stroma plays a dominant regulatory role in breast epithelial growth and differentiation: implications for tumor development and progression.

DOI：
发表时间：
2001-02
期刊：
Cancer research
影响因子：
11.2
作者：
M. Shekhar;J. Werdell;S. Santner;R. Pauley;L. Tait
通讯作者：
M. Shekhar;J. Werdell;S. Santner;R. Pauley;L. Tait

Direct action of estrogen on sequence of progression of human preneoplastic breast disease.

DOI：
发表时间：
1998-05
期刊：
The American journal of pathology
影响因子：
0
作者：
M. Shekhar;P. Nangia-Makker;S. R. Wolman;Larry Tait;Gloria H. Heppner;Daniel W. Visscher
通讯作者：
M. Shekhar;P. Nangia-Makker;S. R. Wolman;Larry Tait;Gloria H. Heppner;Daniel W. Visscher

Correlation of differences in modulation of ras expression with metastatic competence of mouse mammary tumor subpopulations.

ras表达调节差异与小鼠乳腺肿瘤亚群转移能力的相关性。