Nicotinic Receptor Ligands and Tobacco-induced Lung Cancer

描述(申请人提供)：申请资助，以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，并利用烟碱型乙酰胆碱受体(NAChR)配体开发新的抗癌疗法。初步研究表明，表达在呼吸道细胞细胞膜上的nAChRs的典型和非典型配体均具有抗肿瘤作用。这些受体在烟草致癌亚硝胺4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone(NNK)的药理剂量引起的BEP2D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多肽slurp-1(分泌型哺乳动物Ly-6/尿激酶型纤溶酶原激活剂受体相关蛋白)诱导的细胞凋亡高度敏感。整合Surp-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，并可能导致烟草相关肺癌预防和治疗新方法的发展。我们将检验以下工作假设：1)slurp-1可以在体外和体内阻止NNK依赖性的呼吸细胞转化；2)细胞质捕获slurp-1导致NNK转化的BEP2D和肺癌细胞质膜上nAChRs表达的改变；3)slurp-1作为竞争性nAChR拮抗剂，17个nAChR亚型介导大部分slurp-1的作用；4)slurp-1干扰由NNK连接的nAChR亚型(S)下游的受体介导的信号传导。其具体目的将确定：1)slurp-1在NNK致癌中的生理保护作用；2)恶性呼吸道细胞对slurp-1诱导的凋亡敏感性增加的分子机制；3)介导slurp-1药理活性的nAChR亚型(S)及其对呼吸细胞表达的nAChRs的作用方式；以及4)由slurp-1和NNK连接的nAChRs下游的信号通路。 公共卫生相关性：该提案侧重于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，即烟草致癌物和肿瘤促进剂的受体介导的作用，将肺烟碱型乙酰胆碱受体置于病理生理环路的中心。长期目标是开发药物化学预防肺癌的前吸烟者和暴露在环境烟草烟雾中的人。计划中的研究将最终确定slurp-1的抗肿瘤活性机制-一种先前未知的有效的肺尼古丁受体的自分泌和旁分泌配体，能够防止烟草亚硝胺诱导的BEP2D细胞的恶性转化。

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.