Mechanism of ATF5 addition in breast cancer

ATF5添加在乳腺癌中的作用机制

• 批准号: 9230231
• 负责人: David X Liu
• 金额: $ 34.17万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-01 至 2019-05-16
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9230231
• 关键词: Area; Breast Cancer Cell; Breast Cancer Model; Breast Epithelial Cells; Breast cancer metastasis; Cancer Burden; Cancer Etiology; Cell Death; Cell Proliferation; Cell Survival; Cells; Complex; Data; Development; Dimerization; Doctor of Pharmacy; Feedback; Genetic Transcription; Goals; Grant; Health; Heterodimerization; Human; ITAM; Interruption; Lead; Malignant Neoplasms; Medicine; Molecular; Mus; Neoplasm Metastasis; Pathway interactions; Phosphorylation; Regulation; Research; SRC gene; Science; Signal Transduction; Site; Students; Testing; Therapeutic; Tumorigenicity; Work; activating transcription factor; base; breast cancer survival; cancer cell; cancer therapy; cancer type; cell transformation; cell type; design; dimer; hands on research; innovation; killings; laboratory curriculum; malignant breast neoplasm; mouse model; novel; transcription factor; tumorigenic; undergraduate student

Project Summary ATF5 is required for the survival of breast cancer cells but is dispensable in their non-transformed counterparts. The reason for ATF5 to have such transformation-dependent pro-survival function is completely unknown. Understanding how ATF5 is uniquely required for the survival of breast cancer cells will new vulnerabilities of cancer cells and help design strategies for their selective construction. Our studies show that ATF5, when phosphorylated by Src and complexed with NFkB, activates the transcription of ATF5, NFkB, and c-Src. Consequently, we hypothesize that 1) NFkB is an obligatory partner for an ATF5-NFkB heterodimer transcription factor, which is responsible for the transcription of ATF5, NFkB, and c-Src; 2) c-Src activates ATF5 by phosphorylating the immunoreceptor tyrosine-based activation motif (ITAM) on ATF5, which creates an auto-stimulatory feedback mechanism sustaining elevated ATF5 and Src activity, perpetuating Src-Ras signaling; and 3) Due to aberrant Src activation in transformed cells, ATF5 is ITAM-phosphorylated, i.e., activated, only in transformed cells. The interdependence between activation of ATF5 and elevated Src-Ras signaling, which promotes cell survival and proliferation of transformed cells, renders ATF5 “addicted” in cancer cells. We will further test the ideas that disruption of ATF5-NFkB interaction or blocking ATF5 ITAM phosphorylation abrogate Ras signaling in transformed cells and cause cell death. Our long-term goal is to determine the molecular mechanism that underlies the transformation-dependent pro-survival function of ATF5 and to develop new strategies to selectively kill breast cancer cells. Here, we propose the two Specific Aims: Aim 1: Determine the mechanism by which ATF5 activates Ras signaling in breast cancer cells. Specifically, we will a) determine how ATF5 and NFkB cooperate to regulate the transcription of the ATF5, NFkB, and c-Src genes in breast cancer cells; b) determine the effect of ATF5 ITAM phosphorylation on ATF5-dependent gene transcription of ATF5, NFkB, and c-Src in breast cancer cells. Aim 2: Selectively destroy breast cancer cells by targeting the ATF5/Ras pathway. Specifically, we will a) determine whether interrupting ATF5-NFkB interaction effectively blocks Ras signaling and induce cell death in transformed HBECs but not in non-transformed HBECs; b) determine whether blocking ATF5 ITAM phosphorylation selectively induces cell death in breast cancer cells and inhibit breast cancer development in mouse models. Completion of these aims will reveal the mechanism that underlies the transformation-dependent pro-survival function of ATF5 and find new strategies for cancer therapy that can selectively destroy breast cancer cells. This research will provide undergraduate students and PharmD students with research opportunities in science and medicine, alleviating a situation in our area—the Inland Northwest—where most of these students have no access to research other than undergraduate laboratory courses.

项目摘要 ATF5是乳腺癌细胞生存所必需的，但在未转化的乳腺癌细胞中是必不可少的 对口单位。ATF5具有这种依赖于转化的促生存功能的原因完全是 未知。了解ATF5是如何对乳腺癌细胞的生存起着独特的作用将是新的 这一技术有助于研究癌细胞的脆弱性，并有助于为其选择性构建设计策略。我们的研究表明 当ATF5被Src磷酸化并与NFkB络合时，激活ATF5、NFkB和 C-源因此，我们假设1)NFkB是ATF5-NFkB杂二聚体的必备伙伴 转录因子，负责转录ATF5、NFkB和c-Src；2)c-Src被激活 通过磷酸化ATF5上的基于免疫受体酪氨酸的激活基序(ITAM)，从而产生 维持ATF5和Src活性升高，使Src-RAS永久化的自动刺激反馈机制 3)由于转化细胞中Src的异常激活，ATF5被ITAM磷酸化，即， 激活，仅在转化的细胞中。ATF5激活与Src-RAS升高之间的相互依赖关系 促进转化细胞存活和增殖的信号转导，使ATF5成瘾。 癌细胞。我们将进一步测试中断ATF5-NFkB相互作用或阻止ATF5 ITAM的想法 磷酸化抑制转化细胞中的RAS信号，导致细胞死亡。我们的长期目标是 确定ATF5依赖转化的促生存功能的分子机制 并开发选择性杀死乳腺癌细胞的新策略。在此，我们提出了两个具体目标： 目的1：确定ATF5激活乳腺癌细胞RAS信号的机制。具体来说， 我们将a)确定ATF5和NFkB如何协同调节ATF5、NFkB和c-Src的转录 乳腺癌细胞中的基因；b)确定ATF5 ITAM磷酸化对ATF5依赖基因的影响 乳腺癌细胞中ATF5、NFkB和c-Src的转录目标2：通过以下方式选择性地摧毁乳腺癌细胞 靶向ATF5/RAS通路。具体地说，我们将a)确定中断ATF5-NFkB交互 在转化的HBECs中有效地阻断RAS信号并诱导细胞死亡，但在未转化的HBECs中不能 HBECs；b)确定阻断ATF5 ITAM磷酸化是否选择性地诱导乳腺细胞死亡 并在小鼠模型中抑制乳腺癌的发展。完成这些目标将揭示 ATF5依赖转化的促生存功能的机制和寻找新的策略 用于癌症治疗，可以选择性地摧毁乳腺癌细胞。这项研究将为本科生提供 为学生和药学博士学生提供科学和医学研究机会，缓解 我们的地区-内陆西北部-在那里，大多数学生除了学习之外，没有其他研究的机会 本科实验室课程。