Profilin as a target to suppress invasive breast cancer

描述（由申请人提供）：乳腺癌的死亡率是由于远处器官的转移性累及，很大程度上是由于侵袭性增加。先前的研究表明，在转移性乳腺癌细胞中，profilin（一种肌动蛋白结合蛋白，也具有肿瘤抑制作用）的表达下调。这与我们的初步数据表明，过度表达profilin或其突变体选择性地与肌动蛋白或富含脯氨酸的基序（PRM）蛋白结合受损，显著降低乳腺癌细胞的迁移，导致profilin的功能调节乳腺癌的侵袭和转移的假设（假设）。该项目的总体目标是确定如何利用侧位蛋白的扰动来抑制乳腺癌的侵袭和转移。为了验证这一假设，在Aim I中，我们将首先使用一系列分子结构来确定profilin功能的调节如何改变乳腺癌细胞的迁移。接下来，为了确定细胞迁移中依赖谱蛋白变化的分子基础，我们将研究谱蛋白的各种扰动如何改变细胞骨架结构和细胞的突出能力。在Aim II中，我们将首先采用光操纵技术来确定profilin的功能在迁移细胞中是否受到空间限制。接下来，我们将选择性地取消profilin与不同类型的PRM蛋白的相互作用，以确定乳腺癌细胞迁移中关键的PRM相互作用，然后利用荧光共振能量转移（FRET）技术研究这些相互作用在细胞迁移过程中的时空方面。在Aim III中，我们将首先确定在部分模拟肿瘤细胞-基质相互作用的体外环境中，profin的扰动如何改变乳腺癌细胞的侵袭。最后，我们将使用动物模型来测试profilin的扰动是否有效抑制乳腺癌转移。

DESCRIPTION (provided by applicant): Breast cancer mortality is due to metastatic involvement of distant organs driven in large part by increased invasiveness. Previous studies show downregulation in the expression of profilin (an actin-binding protein which also has a tumor-suppressive effect) in metastatic breast cancer cells. This, taken together with our preliminary data showing that overexpressing profilin or it's mutants that are selectively impaired in binding to either actin or proline-rich motif (PRM) proteins significantly decreases the migration of breast carcinoma cells, leads to a hypothesis that profilin's function regulates breast cancer invasion and metastasis (HYPOTHESIS). The overall goal of the project is determine how perturbations of profilin can be utilized to suppress breast cancer invasion and metastasis. To test the hypothesis, in Aim I, we will first use a series of molecular constructs to determine how modulations of profilin's function alter the migration of breast cancer cells. Next, in order to determine the molecular basis for profilin-dependent changes in cell migration, we will investigate how various perturbations of profilin alter the cytoskeletal structure and the protrusive ability of cells. In Aim II, we will first employ photomanipulative techniques to determine whether profilin's function is spatially restricted in migrating cells. Next, we will abolish profilin's interaction selectively with different classes of PRM proteins to identify the key PRM interactions in breast cancer cell migration, and then use fluorescence resonance energy transfer (FRET) technique to study the spatiotemporal aspects of these interactions during cell migration. In Aim III, we will first determine how perturbations of profiin alter breast cancer cell invasion in an in vitro milieu partially mimicking tumor cell-stromal interactions. Finally, using animal model we will test whether perturbations of profilin are effective in inhibiting breast cancer metastasis.