Nicotinic Receptor Ligands and Tobacco-induced Lung Cancer

描述（由申请人提供）：要求提供资金支持我们正在进行的研究，以确定烟草亚硝胺对呼吸道细胞的致癌作用的分子机制，并使用烟碱乙酰胆碱受体（nAChR）配体开发新型抗癌疗法。初步研究揭示了在呼吸细胞的细胞膜上表达的nAChR的典型和非典型配体两者的抗肿瘤潜力。这些受体在药理剂量的烟草衍生致癌亚硝胺4-（甲基亚硝胺）-1-（3-吡啶基）-1-丁酮（NNK）引起的BEP 2D细胞恶性转化中发挥作用。NNK转化细胞和肺癌细胞对新型胆碱能肽SLURP-1（分泌型哺乳动物Ly-6/尿激酶纤溶酶原激活物受体[uPAR]相关蛋白）诱导的细胞凋亡高度敏感。整合关于SLURP-1与NNK对呼吸细胞作用的结构和功能信息将有助于更好地理解肺部肿瘤监视的生理机制，并可能导致开发预防和治疗烟草相关肺癌的新方法。我们将测试以下工作假设：1）SLURP-1可以在体外和体内阻止呼吸道细胞的NNK依赖性转化; 2）SLURP-1的胞质捕获导致NNK转化的BEP 2D和肺癌细胞的质膜上nAChR的表达改变; 3）SLURP-1充当竞争性nAChR拮抗剂，其中17种nAChR亚型介导大部分SLURP-1效应;和4）SLURP-1干扰正常和恶性人呼吸道细胞中由NNK连接的nAChR亚型下游的受体介导的信号传导。具体目的将是确定：1）SLURP-1在呼吸道细胞免受NNK致癌性的生理保护中的作用; 2）恶性呼吸道细胞对SLURP-1诱导的细胞凋亡的敏感性增加的分子机制; 3）介导SLURP-1药理学活性的nAChR亚型及其对呼吸道细胞表达的nAChR的作用模式;和4）SLURP-1和NNK连接的nAChR下游的信号通路。 公共卫生相关性：该提案的重点是预防和治疗与烟草有关的肺癌的紧迫问题。它进一步发展了一个新的概念，受体介导的烟草致癌物和肿瘤促进剂的作用，将肺烟碱乙酰胆碱受体的病理生理循环的中心。长期的目标是发展肺癌的药物化学预防，在以前的吸烟者，并在人们暴露于环境烟草烟雾。预计的研究将最终建立SLURP-1的抗肿瘤活性的机制，SLURP-1是一种有效的，但以前未知的，肺烟碱受体的自分泌和旁分泌配体，能够防止烟草亚硝胺诱导的BEP 2D细胞恶性转化。

DESCRIPTION (provided by applicant): Funding is requested to support our ongoing studies toward identification of molecular mechanisms mediating oncogenic effects of tobacco nitrosamines on respiratory cells and development of novel anti-cancer therapies using nicotinic acetylcholine receptor (nAChR) ligands. Preliminary studies revealed an anti-tumor potential of both canonical and non-canonical ligands of the nAChRs expressed on the cell membrane of respiratory cells. These receptors play a role in the malignant transformation of BEP2D cells caused by pharmacologic doses of the tobacco-derived carcinogenic nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). The NNK-transformed and lung cancer cells are highly sensitive to apoptosis induced by the novel cholinergic peptide SLURP-1 (secreted mammalian Ly-6/urokinase plasminogen activator receptor [uPAR]-related protein). Integrating structural and functional information about SLURP-1 vs. NNK actions on respiratory cells will facilitate a better understanding of the physiologic mechanism of tumor surveillance in lungs, and may lead to the development of novel methods of prevention and treatments of tobacco-related lung cancer. We will test the following working hypotheses: 1) SLURP-1 can prevent NNK-dependent transformation of respiratory cells in vitro and in vivo; 2) cytoplasmic trapping of SLURP-1 results in altered expression of nAChRs on the plasma membrane of NNK-transformed BEP2D and lung cancer cells; 3) SLURP-1 acts as a competitive nAChR antagonist with the 17 nAChR subtype mediating most of SLURP-1 effects; and 4) SLURP-1 interferes with the receptor-mediated signaling downstream of the nAChR subtype(s) ligated by NNK in normal and malignant human respiratory cells. The Specific Aims will be to determine: 1) the role of SLURP-1 in the physiologic protection of respiratory cells from NNK carcinogenicity; 2) the molecular mechanism of increased sensitivity of malignant respiratory cells to the apoptosis induced by SLURP-1; 3) the nAChR subtype(s) mediating the pharmacologic activity of SLURP-1 and the mode of its action on the nAChRs expressed by respiratory cells; and 4) the signaling pathways downstream of the nAChRs ligated by SLURP-1 and NNK. PUBLIC HEALTH RELEVANCE: This proposal is focused on urgent problems of prevention and treatment of tobacco related lung cancer. It further develops a novel concept of receptor-mediated action of tobacco carcinogens and tumor promoters placing lung nicotinic acetylcholine receptors in the center of the pathophysiologic loop. The long-term objective is to develop pharmacologic chemoprevention of lung cancer in former smokers, and in people exposed to environmental tobacco smoke. The projected studies will ultimately establish the mechanism of anti-tumor activity of SLURP-1-an efficient, yet previously unknown, autocrine and paracrine ligand of lung nicotinic receptors capable of preventing tobacco nitrosamine-induced malignant transformation of BEP2D cells.