Profilin as a target to suppress invasive breast cancer

乳腺癌死亡率是由于远处器官的转移所致，这在很大程度上是由 侵犯性。先前的研究表明Profilin(一种肌动蛋白结合蛋白)的表达下调 其在转移性乳腺癌细胞中也具有肿瘤抑制作用)。这一点与我们的 初步数据显示，过度表达的Profilin或其突变体在结合时选择性受损 肌动蛋白或富含脯氨酸基序(PRM)蛋白均可显著减少乳腺癌的转移 细胞，导致一种假说，即Profilin的功能调节乳腺癌的侵袭和转移 (假设)。该项目的总体目标是确定如何利用Profilin的扰动来 抑制乳腺癌的侵袭和转移。为了检验这一假设，在目标I中，我们将首先使用一系列 决定Profilin功能调节如何改变乳腺癌转移的分子结构 细胞。接下来，为了确定细胞迁移中依赖于Profilin的变化的分子基础，我们将 研究Profilin的各种扰动如何改变细胞骨架结构和突起能力 细胞。在AIM II中，我们将首先使用光模拟技术来确定Profilin的功能是否 在空间上受限于迁移的细胞。接下来，我们将有选择地取消Profilin与不同的 确定乳腺癌细胞迁移中关键的PRM相互作用，然后使用 荧光共振能量转移(FRET)技术研究这些 细胞迁移过程中的相互作用。在目标III中，我们将首先确定Profiin的扰动如何改变乳房 癌细胞在体外环境中的侵袭部分模拟了肿瘤细胞-间质的相互作用。最后，使用 动物模型，我们将测试Profilin的扰动是否有效地抑制乳腺癌的转移。

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'smutants 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 constructsto 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 cancermetastasis.