Role of Beta-arrestin-1 and Src in nAChR Signaling and Lung Caancer

描述（申请人提供）：吸烟与肺癌和心血管疾病的发病密切相关。大约60%的非小细胞肺癌（nsclc）是由吸烟引起的。尼古丁和烟草结构相关致癌物如4-（甲基亚硝胺）-1-（3-吡啶基）-1-丁酮（NNK）和N'-亚硝基索诺尼古丁（NNN）已被发现可诱导肺癌细胞系的增殖。此外，这些药物还能在体外和体内诱导血管生成，并赋予细胞凋亡抗性。这些事件是通过尼古丁乙酰胆碱受体（nAChRs）的激活介导的，nAChRs已在多种非神经元细胞中被检测到。目前还不知道尼古丁本身会致癌；但基于其诱导肿瘤生长和血管生成的能力，我们建议研究尼古丁如何影响非小细胞肺癌的生长、进展和转移。我们最近的研究结果表明，支架蛋白¿-arrestin-1在介导nAChR的增殖信号中起主要作用，并且是响应nAChR刺激激活Src所必需的。此外，尼古丁刺激A549细胞导致参与上皮-间质转化（EMT）的基因表达发生变化。最近的研究表明，¿-arrestin-1在结直肠癌的转移中起着重要作用。在此背景下，我们将评估¿-arrestin-1和Src在尼古丁诱导的细胞增殖、肿瘤细胞侵袭、转移和血管生成中的作用。据报道，¿-arrestin-1响应g蛋白偶联受体信号易位到细胞核并激活多个启动子；我们在尼古丁刺激下发现了类似的核易位。我们的初步结果表明，nAChR刺激非小细胞肺癌细胞导致参与增殖和EMT的启动子的转录激活；我们将评估逮捕对这一进程的贡献。基于我们发现尼古丁可以促进小鼠非小细胞肺肿瘤的生长，我们将在三种不同的小鼠模型中研究尼古丁是否促进肿瘤的进展和转移。促进这些过程的潜在机制将被阐明，包括¿-arrestin-1和Src在尼古丁诱导的肿瘤转移中的作用。由于大多数非小细胞肺癌与接触烟草烟雾有关，这些研究将阐明尼古丁影响肺癌生长和进展的分子机制。公共卫生相关性：接触烟草烟雾与肺癌发病高度相关。虽然是烟草致癌物的直接作用引发肿瘤的形成，但接触尼古丁可能会促进已经形成的肿瘤的生长和进展。这一点尤其重要，因为许多吸烟者使用尼古丁补充剂来戒烟。本研究将阐明尼古丁诱导细胞增殖、肿瘤生长和扩散以及新血管形成的机制。这些研究有望导致新型抗癌药物的开发。

DESCRIPTION (provided by applicant): Cigarette smoking is strongly correlated with onset of lung cancer and cardiovascular diseases. About 60% of non-small cell lung carcinomas (NSCLCs) arise as a result of smoking. Nicotine and structurally related tobacco carcinogens like 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) have been found to induce the proliferation of cell lines derived from lung cancers. In addition, these agents could induce angiogenesis in vitro and in vivo and confer resistance to apoptosis. These events are mediated through the activation of the nicotinic acetylcholine receptors (nAChRs), and nAChRs have been detected in a variety of non-neuronal cells. Nicotine by itself is not known to induce oncogenesis; but based on its ability to induce tumor growth and angiogenesis, we propose to study how nicotine affects the growth, progression and metastasis of non-small cell lung carcinomas. Our recent results show that the scaffolding protein ¿-arrestin-1 plays a major role in mediating the proliferative signals of nAChRs and was necessary for activation of Src in response to nAChR stimulation. Further, nicotine stimulation of A549 cells led to changes in the expression of genes involved in epithelial-mesenchymal transition (EMT). Recent studies have shown that ¿-arrestin-1 plays a significant role in the metastasis of colorectal cancers. Given this background, we will assess the role of ¿-arrestin-1 and Src in nicotine-induced cell proliferation, tumor cell invasion, metastasis and angiogenesis. It has been reported that ¿-arrestin-1 translocates to the nucleus in response to G-protein coupled receptor signaling and activates multiple promoters; we find a similar nuclear translocation upon nicotine stimulation. Our preliminary results show that nAChR stimulation of non-small cell lung carcinoma cells leads to transcriptional activation of promoters involved in proliferation and EMT; we will assess the contribution of ¿-arrestin-1 to this process. Based on our finding that nicotine can promote the growth of non-small cell lung tumors in mice, we will examine whether nicotine promotes tumor progression and metastasis in three different mouse models. Underlying mechanisms facilitating these processes will be elucidated, including the contribution of ¿-arrestin-1 and Src in nicotine-induced tumor metastasis. Since a majority of non-small cell lung carcinomas correlate with exposure to tobacco smoke, these studies will throw light on the molecular mechanisms by which nicotine affects the growth and progression of lung cancers. PUBLIC HEALTH RELEVANCE: Exposure to tobacco smoke is highly correlated with onset of lung cancer. Though it is the direct effect of tobacco carcinogens that initiate tumor formation, exposure to nicotine might facilitate the growth and progression of tumors already formed. This is especially relevant since many smokers use nicotine supplements to quit smoking. The studies proposed in this application will elucidate the mechanisms by which nicotine induces cell proliferation, tumor growth and spread, as well as formation of new blood vessels. These studies can be expected to lead to the development of novel agents to combat cancer.