Role of prolactin in adipocyte-breast cancer cell crosstalk

项目总结/摘要 我们对脂肪细胞分泌的催乳素（PRL）和乳腺癌细胞分泌的催乳素之间的关系的理解存在差距。 丝氨酸/苏氨酸PAK 1连接以协调调节人乳腺癌（BC）的进展， 脂肪细胞-乳腺癌细胞串扰。这项研究的长期目标是建立PAK 1，由 脂肪细胞分泌的PRL作为BC细胞转移潜能的新诊断工具，并提供所需的 深入了解潜在的机制。本申请的总体目标是建立一个 研究脂肪细胞分泌的PRL对乳腺癌细胞和脂肪细胞-乳腺癌的影响的实验系统 癌细胞相互干扰，并进一步建立PRL激活的PAK 1有助于 乳腺癌核心假设是脂肪细胞产生的催乳素增强了侵袭性， 乳腺癌细胞的致瘤性和转移潜力通过激活PAK 1激酶和pTyr- PAK 1是预测这些乳腺癌细胞转移潜力的生物标志物。建议的理由 研究表明，乳腺脂肪细胞分泌包括PRL在内的脂肪细胞因子，可能影响乳腺肿瘤的发生 行为PRL促进乳腺癌细胞中JAK 2活化和PAK 1的酪氨酰磷酸化。的 中心假设将通过追求以下具体目标来检验：具体目标1将检验我们的工作 脂肪细胞源性PRL激活PAK 1增强乳腺癌细胞侵袭力和细胞增殖的假说 运动通过Tec激酶和脂肪细胞-乳腺癌细胞串扰诱导MMP-11分泌 脂肪细胞和乳腺癌细胞的MMP-1。具体目标2将测试我们的工作假设，PAK 1 脂肪细胞源性催乳素激活对乳腺癌细胞体内致瘤性和转移潜能的影响 pTyr-PAK 1可作为预测乳腺癌转移的生物标志物。在次级目标下， 将使用表征的PAK 1磷酸化特异性抗体来评估细胞在200 μ g/ml时的转移潜力。 BC早期这一提议在概念上具有创新性，因为它有望纵向推进， 扩大我们对肥胖如何通过脂肪细胞分泌的PRL影响BC的理解， PRL激活的PAK 1在这个过程中。这项建议在技术上也是创新的，因为它将采用 独特的PAK 1磷酸化特异性抗体。这项研究是有意义的，因为阐明 PRL/PAK 1介导的细胞内信号转导通路将有助于我们对PRL/PAK 1介导的细胞内信号转导机制的理解。 参与BC的调节，并将导致开发基于PAK 1的BC诊断工具。

Project Summary/Abstract There is a gap in our understanding of how hormone prolactin (PRL), secreted by adipocytes, and the serine/threonine PAK1 connect to coordinately regulate progression of human breast cancer (BC) and adipocyte-breast cancer cell crosstalk. The long-term goal of this research is to establish PAK1, activated by adipocyte-secreted PRL, as a new diagnostic tool for the metastatic potential of BC cells and provide needed insight into the underlying mechanisms. The overall objective of the current application is to establish an experimental system to study effects of adipocyte-secreted PRL on breast cancer cells and adipocyte-breast cancer cells crosstalk and further establish the mechanisms by which PRL-activated PAK1 contributes to breast cancer. The central hypothesis is that that adipocyte-produced prolactin enhances invasiveness, tumorigenicity and metastatic potential of breast cancer cells through activation of PAK1 kinase and pTyr- PAK1 is a biomarker to predict metastatic potential of these breast cancer cells. The rational for the proposed research is that breast adipocytes secret adipocytokines including PRL, which may influence breast tumor behavior. PRL promotes JAK2 activation and tyrosyl phosphorylation of PAK1 in breast cancer cells. The central hypothesis will be tested by pursuing the following specific aims: Specific Aim 1 will test our working hypothesis that PAK1 activated by adipocyte-derived PRL enhances breast cancer cell invasiveness and cell motility via Tec kinase and that adipocyte-breast cancer cells crosstalk induces secretion of MMP-11 by adipocytes and MMP-1 by breast cancer cells. Specific Aim 2 will test our working hypothesis that PAK1 activated by adipocyte-derived PRL affects tumorigenicity and metastatic potential of breast cancer cells in vivo and that pTyr-PAK1 can serve as a biomarker to predict breast tumor metastasis. Under the sub-aim, characterized PAK1 phospho-specific antibodies will be used to evaluate metastatic potential of the cells at an early stage of BC. This proposal is conceptually innovative because it is expected to vertically advance and expand our understanding of how obesity through adipocyte-secreted PRL influences BC and the unique role of PRL-activated PAK1 in this process. This proposal is technically innovative as well because it will employ unique PAK1 phospho-specific antibodies. The proposed research is significant because the elucidation of PRL/PAK1 mediated intracellular signaling pathways will enhance our understanding of the mechanisms involved in regulation of BC and will lead to development of PAK1-based tools for BC diagnosis.