CALCIUM- AND INTEGRIN-BINDING PROTEIN 1 (CIB1) IN CANCER CELL INVASION

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 癌症是全人类死亡的主要原因之一。癌细胞不仅表现出不受控制的增殖，而且还发展出从其原始部位迁移到体内其他器官的能力。这一事件被称为转移，恶性肿瘤的标志。在转移过程中，癌细胞打破许多障碍，穿过身体的循环系统，侵入其他器官，形成继发性肿瘤。因此，了解癌症转移的潜在机制以找到癌症的治疗方法是重要的。整合素是细胞外基质蛋白的膜蛋白受体，与癌细胞的增殖和转移有关。此外，粘着斑（FAK）已被证明是细胞粘附和迁移的关键。然而，在整合素和FAK介导的信号通路中的效应分子的参与在很大程度上是未知的。我们的实验室最近发现了一种普遍表达的钙和整合素结合蛋白1（CIB 1），它与许多细胞蛋白相互作用，包括血小板特异性整合素<$IIb <$3。此外，CIB 1还与FAK在膜延伸处相互作用并共定位，并与细胞扩散和迁移有关。CIB 1在病理生理条件如癌症中的作用仍有待阐明。我们的初步研究结果表明，CIB 1的表达显着增加，在乳腺癌组织相比，正常乳腺组织。CIB 1在T47 D细胞，乳腺上皮细胞系中的过表达显示出增加的胶原基质上的细胞迁移，如通过跨孔迁移测定所确定的。当使用siRNA敲低T47 D细胞中的内源性CIB 1时，细胞迁移显著降低。与模拟转染的细胞相比，在CIB 1敲除的T47 D细胞中也观察到FAK的酪氨酸磷酸化降低，如通过蛋白质印迹分析所确定的，表明CIB 1可以通过增强FAK的磷酸化来介导癌细胞迁移。本研究的目的是更好地了解CIB 1在癌细胞侵袭导致转移中的作用。这将通过确定CIB 1表达与乳腺癌细胞体外和体内侵袭行为的关系，并通过阐明CIB 1调节以决定乳腺癌细胞侵袭行为的信号通路来实现。 我们相信我们的研究将更好地了解CIB 1在癌细胞侵袭中的作用。它还将确定一个新的细胞靶点，用于乳腺癌的治疗干预。此外，更清楚地了解这一过程将为开发针对乳腺癌这一最致命方面的有效疗法提供基础。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Cancer is one of the leading causes of death of all mankind. Cancer cells not only display uncontrolled proliferation, but also develop the ability to migrate from their original site to other organs in the body. This event is known as metastasis, the hallmark of malignant cancers. During metastasis, cancer cells break numerous barriers to travel through the body's circulatory system and invade other organs to form secondary tumors. Therefore, it is important to understand, the underlying mechanism of cancer metastasis to find a cure for cancer. Integrins, membrane protein receptors for extracellular matrix proteins, have been implicated in cancer cell proliferation and metastasis. In addition, focal adhesion kianse (FAK) has been shown to be pivotal for cell adhesion and migration. However, the involvement of effector molecules which lie in the integrin and FAK mediated signaling pathway is largely unknown. Our lab recently discovered an ubiquitously expressed calcium and integrin-binding protein 1 (CIB1) which interacts with a number of cellular proteins, including platelet specific integrin ¿IIb¿3. Further, CIB1 also interacts and co-localizes with FAK at the membraneous extensions and has been implicated in cell spreading and migration. The role of CIB1 in a pathophysiological condition such as cancer remains to be elucidated. Our preliminary results show that CIB1 expression is significantly increased in breast cancer tissue compared to normal breast tissue. Overexpression of CIB1 in T47D cells, breast epithelial cell line, showed increased cell migration on collagen matrix as determined by a trans-well migration assay. When endogenous CIB1 was knocked down in T47D cells using siRNA, cell migration was significantly decreased. A decreased tyrosine phosphorylation of FAK was also observed in CIB1 knocked down T47D cells compared to mock transfected cells as determined by Western blot analysis, demonstrating that CIB1 may mediate cancer cell migration by enhancing phosphorylation of FAK. The goal of the present study is to have better insights of CIB1's role in cancer cell invasion leading to metastasis. This will be achieved by determining the relationship of CIB1 expression and invasive behavior of the breast cancer cells in vitro and vivo and by elucidating the signaling pathways that CIB1 regulates in order to dictate the invasive behavior of breast cancer cells. We believe that our study will give a better understanding of the role of CIB1 in cancer cell invasion. It will also identify a novel cellular target for therapeutic intervention of breast cancer. Further, a clearer understanding of this process will provide a basis for developing effective therapies for this most lethal aspect of breast cancer.