Novel Mechanisms of Carcinoma Cell Migration

描述（由申请人提供）：肿瘤侵袭和转移仍然夺去大多数癌症患者的生命。尽管在癌症检测和预防方面已经取得了很大的进步，但对癌症转移的更有效治疗的需求仍然是一个中心问题。值得注意的是，控制细胞极化和定向迁移的空间信号传导的分子通过其提高转移的第一步的效率的能力而有助于癌症的致死性。RhoA在定向细胞运动期间有助于细胞极化，但 RhoA在空间上是如何控制的仍不清楚。我们建议，整合素信号通过cAMP/PKA是有助于空间信号的RhoA和细胞极化。重要的是，我们以前的工作表明，？1整联蛋白控制PKA活性梯度的产生在迁移癌细胞的前沿，在那里它控制RhoA功能。我们提供了令人信服的证据表明，这些PKA活性梯度存在于乳腺癌患者样本和三维乳腺癌培养物中，这证明了这些梯度在人类乳腺癌中的意义。整合素？？六个？4在晚期乳腺癌中上调，其中它与基底样乳腺癌最密切相关。重要的是，整合素？六个？4通过我们提出的逆转PKA作用的机制促进RhoA的活化。因此，我们认为这些整合素对RhoA的反向调控模式允许RhoA的有效区室化，从而促进乳腺癌的运动性、侵袭性和转移。因此，本申请的中心假设是，合作信令之间？1整合素和整合素？六个？4促进RhoA活性的空间分布，以促进层状结构的形成和定向迁移。我们小组的长期目标是确定整合素是如何促进肿瘤侵袭的，以便它们最终可以被适当地靶向用于治疗干预，特别强调整合素？六个？4.我们将通过完成以下目标来验证我们的中心假设并实现我们的长期目标：1）定义耦合的大分子复合物？1）整合素对PKA的活化从而限制RhoA活性的前沿，2）确定整合素如何？六个？4）导致RhoA的活化，和3）阐明RhoA功能如何改变以促进Lamb形成。我们是唯一适合执行这些研究，由于我们强大的合作;我们的良好特征的模型？六个？4整合素和RhoA依赖的侵袭和迁移;我们在整合素生物学和Rho信号传导方面的专业知识，以及我们支持该项目的坚实的初步数据。从这项研究中获得的结果将是重要的，因为它们将深入研究整合素如何协调空间信号以实现极化，层形成，定向细胞迁移和最终入侵。最终，我们的研究将具有重要意义，因为它将产生对控制前沿动态的信号通路的更坚定的理解，这些动态将产生成功的方法来治疗转移的早期步骤。

DESCRIPTION (provided by applicant): Tumor invasion and metastasis still claim the majority of cancer patients' lives. Although great strides have been made in cancer detection and prevention, the need for a more effective treatment for cancer metastasis remains a central problem. Notably, molecules that control spatial signaling for cell polarization and directed migration contribute to the lethality of cancer through their ability to improve the efficiency of he first steps of metastasis. RhoA contributes to cell polarization during directed cell motility, yet how RhoA is spatially controlled remains unclear. We propose that integrin signaling through cAMP/PKA is instrumental for spatial signaling of RhoA and cell polarization. Importantly, our previous work has shown that ?1 integrins control the generation of PKA activity gradients at the leading edge of migrating carcinoma cells where it controls RhoA function. We provide compelling evidence that these PKA activity gradients exist in breast carcinoma patient samples and in three-dimensional breast carcinoma cultures, which attest to the significance of these gradients in human breast cancer. Integrin??6?4 is upregulated in advanced breast cancers where it is most closely associated with basal-like breast cancers. Importantly, integrin ??6?4 promotes the activation of RhoA by a mechanism that we propose reverses the effect of PKA. Therefore, we suggest that the counter-opposing modes of regulation these integrins have on RhoA permit efficient compartmentalization of RhoA that facilitates breast carcinoma motility, invasion and metastasis. Accordingly, the central hypothesis of this application is that cooperative signaling between ?1 integrins and integrin ?6?4 facilitates the spatial distribution of RhoA activity to promote lamellae formation and directed migration. The long-term goal of our group is to determine how integrins contribute to tumor invasion so that they may be eventually targeted appropriately for therapeutic intervention, with special emphasis on integrin ?6?4. We will test our central hypothesis and achieve our long- term goal through the completion of the following aims: 1) Define the macromolecular complex that couples ?1 integrins to PKA activation thereby limiting RhoA activity at the leading edge, 2) Determine how integrin ?6?4 leads to the activation of RhoA, and 3) Elucidate how RhoA function is altered to promote lamellae formation. We are uniquely suited to perform these studies due to our strong collaborations; our well-characterized models of ?6?4 integrin- and RhoA-dependent invasion and migration; our expertise in integrin biology and Rho signaling, and our solid preliminary data supporting this project. The results obtained from this study will be important as they will go int mechanistic depth regarding how integrins coordinate spatial signaling to achieve polarization, lamellae formation, directed cell migration and, finally, invasion. Ultimately, our study will be significant as it will generate a firmer understanding of signaling pathways that govern leading edge dynamics that will produce successful methods to therapeutically target the early steps in metastasis.