Oncogenic Function of Ca2+ Channel Orai1 in Esophageal Carcinogenesis

描述（由申请方提供）：食管癌是全球第六大癌症死亡原因，超过90%的病例为食管鳞状细胞癌（ESCC）。在美国，这种疾病的总体5年生存率仅为13%，在所有癌症中排名第四。目前迫切需要鉴定有效的生物标志物用于食管癌的早期检测、预后分层以及新的治疗干预。Ca 2+信号转导的失调与许多人类疾病包括癌症有关。了解Ca 2+渗透通道的病理生理作用最近已成为癌症研究的一个令人兴奋的领域。我们已经获得了令人兴奋的初步数据表明，Orai 1，质膜钙离子通道，作为一个癌基因，有助于食管癌的进展，通过调节细胞内钙离子振荡。在ESCC患者切除的肿瘤中，我们检测到Orai 1表达升高，这与生存率低有关。在培养的人ESCC细胞中，我们发现了细胞内Ca 2+振荡的显著过度活跃，与非肿瘤细胞的静止性质形成鲜明对比。通过药理学或分子手段抑制Orai 1可以利用高钙振荡，这反过来又抑制ESCC细胞的细胞增殖和迁移。此外，我们的初步数据表明，抑制Orai 1可以防止异种移植裸鼠中的肿瘤生长。在这个项目中，我们假设Orai 1介导的Ca 2+振荡的过度活跃有助于食管上皮的致癌作用，靶向Orai 1功能是治疗食管癌的潜在手段。首先，我们将确定由Orai 1-SOCE升高引起的Ca 2+振荡过度活跃的分子机制。接下来，我们将确定Orai 1在体内食管癌发生过程中的致癌作用。最后，我们将靶向Orai 1-SOCE用于ESCC治疗。将使用多学科方法，包括活细胞成像、超微结构分析、细胞内Ca 2+测量、稳健的异种移植和致癌物诱导的食管癌动物模型。该项目的创新方面包括首次研究ESCC中Orai 1的异常表达和细胞内Ca 2+振荡的过度活跃，鉴定上皮细胞中介导内质网和质膜连接结构的第一个分子，一种新型的转基因小鼠模型，其中Orai 1的表达以可诱导和可逆的方式控制，特别是在食管上皮细胞中。该项目的结果将揭示Orai 1-SOCE-Ca 2+振荡在食管癌发生中的作用的细胞机制理解。这些研究将为靶向Orai 1通道活性的ESCC治疗方法提供原理验证数据。

DESCRIPTION (provided by applicant): Esophageal cancer is the 6th leading cause of cancer death worldwide with more than 90% of all cases being esophageal squamous cell carcinoma (ESCC). The overall 5-year survival rate for this disease is only 13% in US, which is the fourth worst among all cancers. There is an urgent need to identify effective biomarkers for early detection, prognostic stratification as well as novel therapeutic interventions for esophageal cancer. Dysregulation in Ca2+ signaling has been linked to many human diseases including cancers. Understanding the pathophysiological roles of Ca2+ permeable channels has recently emerged as an exciting area of cancer research. We have obtained exciting preliminary data suggesting that Orai1, a plasma membrane Ca2+ channel, acts as an oncogene that contributes to the progression of esophageal cancer through regulation of intracellular Ca2+ oscillations. In tumors removed from patients with ESCC, we detected elevated expression of Orai1 which was associated with poor survival rate. In cultured human ESCC cells, we identified a striking hyperactivity in intracellular Ca2+ oscillations, in sharp contrast to the quiescent nature in non-tumor cells. Inhibition of Orai1 by either pharmacological or molecular means could harness hyper Ca2+ oscillations, which in turn suppress cell proliferation and migration in ESCC cells. Moreover, our preliminary data showed that inhibition of Orai1 prevents tumor growth in xenograft nude mice. In this project, we hypothesize that hyperactivity of Orai1-mediated Ca2+ oscillations contributes to carcinogenesis in esophageal epithelia, and targeting Orai1 function represents a potential means for treatment of esophageal cancer. First, we will identify the molecular mechanisms underlying the hyperactivity of Ca2+ oscillations resulting from elevated Orai1-SOCE. Next, we will define the oncogenic role of Orai1 during esophageal carcinogenesis in vivo. Lastly, we will target Orai1-SOCE for ESCC therapy. A multidisciplinary approach will be used including live cell imaging, ultrastructure analysis, intracellular Ca2+ measurement, robust xenograft and carcinogen-induced esophageal cancer animal models. The innovative aspects of this project include the first study on abnormal Orai1 expression and hyperactivity of intracellular Ca2+ oscillations in ESCC, identification of the first molecule mediating endoplasmic reticulum and plasma membranes junctional structures in epithelial cells, a novel transgenic mouse model in which the expression of Orai1 is controlled in an inducible and reversible manner specifically in esophageal epithelial cells. The outcome of this project will reveal the cellular mechanistic understanding of the role of Orai1-SOCE-Ca2+ oscillations in esophageal carcinogenesis. These studies will provide proof-of-principle data on therapeutic approach for ESCC by targeting Orai1 channel activity.