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

吸烟与肺癌和心血管疾病的发病密切相关。约60%的 非小细胞肺癌(NSCLC)是吸烟的结果。尼古丁与结构相关 烟草致癌物质，如(4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone和N‘-NitrosonorNicotine 已发现(NNN)可诱导肺癌细胞系的增殖。此外，这些 药物在体外和体内都能诱导血管生成，并具有抗细胞凋亡的作用。这些事件是 通过激活烟碱型乙酰胆碱受体(NAChRs)，nAChRs已被 在各种非神经细胞中检测到。尼古丁本身并不会导致肿瘤发生，但基于 它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生长， 非小细胞肺癌的进展和转移。我们最近的研究结果表明，脚手架 蛋白？-arrestin-1在nAChRs的增殖信号中起主要作用，是 NAChR刺激后Src的激活。此外，尼古丁对A549细胞的刺激导致了 上皮-间充质转化相关基因的表达。最近的研究表明， β-arrestin-1在结直肠癌的转移中起重要作用。鉴于这一背景，我们将 评估β-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。已有报道称β-arrestin-1在G蛋白的作用下移位到细胞核 偶联受体信号并激活多个启动子；我们在 尼古丁刺激。我们的初步结果表明，nAChR对非小细胞肺癌的刺激 细胞导致参与增殖和EMT的启动子的转录激活；我们将评估 ？-arrestin-1在这一过程中的贡献。根据我们的发现，尼古丁可以促进非 在小鼠小细胞肺癌中，我们将检查尼古丁是否促进肿瘤的进展和转移 三种不同的鼠标模型。促进这些进程的基本机制将被阐明，包括 α-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小区 肺癌与吸烟有关，这些研究将揭示肺癌的分子机制。 尼古丁影响肺癌生长和进展的机制。吸烟与肺癌的发病密切相关。尽管它是 烟草致癌物引发肿瘤形成的直接影响，暴露于 尼古丁可能会促进已经形成的肿瘤的生长和发展。这是 尤其重要的是，许多吸烟者使用尼古丁补充剂来戒烟。这个 在这项申请中提出的研究将阐明尼古丁 诱导细胞增殖，肿瘤生长和扩散，以及形成新的血液 船只。这些研究有望导致新型制剂的发展，以 与癌症抗争。

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. Expsoure 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 faciliate 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.