Signaling Dynamics of Leukocyte-Tumor Cell Interactions

描述(由申请人提供)：成功的癌症免疫治疗将取决于了解免疫细胞与其肿瘤靶点之间的复杂关系。中性粒细胞是抗体依赖型宿主对癌症抵抗的关键参与者，而T细胞在抗体非依赖性抗肿瘤机制中起关键作用。然而，对抗原应答的跨膜信号的性质以及效应器和靶点之间的化学通信仍然知之甚少。这项NCI计划建立了这个实验室独有的高速显微镜技术；通过使用非常短的快门速度，细胞内的化学信号没有足够的时间移动，从而保留了大量的时空信息。引人注目的是，这些研究揭示了化学信号在细胞内和细胞之间的路径，从而为研究信号转导提供了一种全新的方式。现在，我们将利用这一新工具，以前所未有的详细程度研究免疫细胞和肿瘤细胞之间的相互作用。我们将确定化学信息，如钙和氧化剂波，如何在中性粒细胞和抗体调理靶点之间传播，包括多细胞肿瘤球体。特别是，我们将使用生物物理、生化和计算工具解决如何在两个或更多细胞之间快速传递信号，以及这些事件如何导致肿瘤细胞凋亡。初步研究表明，至少有四种钙波与细胞毒性T淋巴细胞(CTL)介导的肿瘤细胞杀伤有关。这些信号将使用生化、生物物理和遗传工具进行系统分析。特别是，我们将探索T细胞信号处理的动态机制。例如，我们将探索不同的多肽抗原如何与MHC-I类分子结合在CTL中引发不同的信号和功能。将研究CTL诱导肿瘤细胞死亡的机制，包括穿孔素在肿瘤细胞内异常钙信号中的潜在作用。通过使用新的成像、计算和免疫细胞工具的融合，我们的研究将在一个新的细胞复杂性水平上揭示和表征白细胞介导的肿瘤细胞破坏的机制。这些新的见解可能会导致癌症免疫疗法的进步。

DESCRIPTION (provided by applicant): The successful immunotherapy of cancer will depend upon understanding the complex relationships between immune cells and their tumor targets. Neutrophils are key participants in antibody-dependent host resistance to cancer whereas T cells are crucial in antibody-independent anti-tumor mechanisms. However, the nature of transmembrane signaling in response to antigens and the chemical communication between effectors and targets remain poorly understood. This NCI program has established the technique of high speed microscopy, which is unique to this laboratory; by using very brief shutter speeds, chemical signals within cells do not have enough time to move, which thereby retains a great deal of spatiotemporal information. Strikingly, these studies have revealed the routes chemical signals follow within and among cells, thus providing a completely new way of studying signal transduction. We will now exploit this new tool to study the interactions among immune and tumor cells in unprecedented detail. We will determine how chemical information, such as calcium and oxidant waves, travel among neutrophils and antibody-opsonized targets, including multi-cellular tumor spheroids. In particular, we will address how rapid signals travel among two or more cells and how these events lead to tumor cell apoptosis using biophysical, biochemical and computational tools. Preliminary studies have revealed at least four calcium waves associated with cytotoxic T lymphocyte (CTL)-mediated tumor cell killing. These signals will be systematically dissected using biochemical, biophysical, and genetic tools. In particular, we will explore the dynamic mechanism of signal processing by T cells. For example, we will explore how different peptide antigens bound to MHC class I molecules elicit different signals and functions in CTLs. The mechanism of CTL-induced tumor cell death will be studied, including the potential role of perforin in aberrant calcium signaling in tumor cells. By using a confluence of new imaging, computational, and immune cell tools, our studies will reveal and characterize mechanisms of leukocyte-mediated tumor cell destruction at a novel level of cellular complexity. These new insights are likely to lead to advances in immunotherapy of cancer.