Spatial control of cAMP/PKA by integrin receptors

描述(由申请人提供)：细胞运动是肿瘤细胞侵袭和转移的一个基本且不可或缺的方面。因此，不受控制的肿瘤细胞运动是绝大多数癌症死亡的直接原因，因此是治疗干预的极佳靶点。为了更好地了解细胞运动，这项研究将探索来自整合素的信号，整合素是细胞外基质的受体，传递对细胞运动至关重要的信号。近年来，整合素被证明通过不同的整合素受体亚群介导cAMP的合成和降解来调节蛋白激酶A(PKA)。重要的是，由于PKA参与了Rac和Rho GTP酶的不同调控，因此这种对PKA的调控对细胞运动至关重要。然而，整合素调节cAMP/PKA的机制以及这种调节如何促进细胞运动尚不清楚。该项目的长期目标是了解整合素及其对cAMP代谢的控制如何促进癌细胞侵袭。本研究的目的是了解整合素在乳腺癌细胞趋化迁移过程中如何调节cAMP/PKA的空间分布。在我们的第一个目标中，我们将使用荧光共振能量转移(FRET)技术来定义在化学诱导剂刺激的细胞中使用的激活的PKA的分布，并评估α6β4和β1整合素对这种分布的贡献。在我们的第二个目标中，我们将通过鉴定在我们的细胞系统中表达的腺苷环化酶异构体并使用小干扰RNA(SiRNAs)来降低它们的表达，从而确定Beta1整合素如何向PKA发出信号。使用最先进的技术和我们理想的模型系统，我们预计这些方法将识别在细胞迁移过程中影响细胞极性的cAMP/PKA活性梯度，并开始阐明它们是如何形成的。这些研究将具有重要意义，因为它们将为我们提供信息，使我们能够智能地将PKA作为晚期癌症治疗干预的靶点。这是一种令人兴奋的可能性，因为目前正在开发针对cAMP的药物来治疗炎症，这种药物也有可能降低癌症患者的发病率和死亡率。

DESCRIPTION (provided by applicant): Cell motility is a fundamental and indispensable aspect of both tumor cell invasion and metastasis. As such, uncontrolled tumor cell motility is directly responsible for the vast majority of cancer deaths and, therefore, represents an excellent target for therapeutic intervention. To better understand cell motility, this study will explore signaling from integrins, which are receptors for the extracellular matrix that transduce signals that are critical for cell motility. Recently, integrins were shown to regulate Protein Kinase A (PKA) through the synthesis and degradation of cAMP mediated by different subsets of integrin receptors. Importantly, this regulation of PKA is critical for cell motility due to the involvement of PKA in the differential regulation of Rac and Rho GTPases. However, the mechanisms of integrin regulation of cAMP/PKA and how this regulation promotes cell motility are unclear. The long-term goal of this project is to understand how integrins and their control of cAMP metabolism promote carcinoma cell invasion. The objective of this proposal is to understand how integrins regulate the spatial distribution of cAMP/PKA during the chemotactic migration of breast carcinoma cells. In our first aim, we will define the distribution of activated PKA using in chemoattractant-stimulated cells using fluorescence resonance energy transfer (FRET) technique and assess the contributions of alpha6beta4 and beta1 integrins to this distribution. In our second aim, we will determine how beta1 integrins signal to PKA by identifying the adenyl cyclase isoforms expressed in our cell system and reducing their expression using small interfering RNAs (siRNAs). Using state-of-the-art technologies and our ideal model system, we expect that these approaches will identify cAMP/PKA activity gradients that influence cell polarity during cell migration and begin elucidating how they form. These studies will be significant because they will give us information that will permit us to intelligently target PKA as a target for therapeutic intervention of late-stage cancer. This is an exciting possibility since drugs targeting cAMP are currently being developed for treating inflammation that also have the potential to decrease cancer patient morbidity and mortality.