Nicotinic Receptor Ligands and Tobacco-induced Lung Cancer

描述（由申请人提供）：申请资金用于支持我们正在进行的研究，以确定烟草亚硝胺对呼吸细胞的致癌作用的分子机制，并开发使用尼古丁乙酰胆碱受体（nAChR）配体的新型抗癌疗法。初步研究发现，呼吸细胞细胞膜上表达的nAChRs的规范配体和非规范配体都具有抗肿瘤潜能。这些受体在药理学剂量的烟草衍生致癌物亚硝胺4-（甲基亚硝胺）-1-（3-吡啶基）-1-丁酮（NNK）引起的BEP2D细胞恶性转化中发挥作用。nnk转化的肺癌细胞对新型胆碱能肽SLURP-1（哺乳动物分泌的Ly-6/尿激酶纤溶酶原激活物受体[uPAR]相关蛋白）诱导的凋亡高度敏感。整合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测的生理机制，并可能导致烟草相关肺癌预防和治疗的新方法的发展。我们将对以下工作假设进行验证：1)SLURP-1在体外和体内可以阻止呼吸细胞依赖nnk的转化；2)细胞质捕获SLURP-1导致nnk转化的BEP2D细胞和肺癌细胞质膜上nAChRs的表达改变；3) SLURP-1作为竞争性nAChR拮抗剂，17个nAChR亚型介导了SLURP-1的大部分作用；4) SLURP-1干扰正常和恶性人呼吸细胞中NNK连接的nAChR亚型下游受体介导的信号。具体目的将是确定：1)SLURP-1在呼吸细胞免受NNK致癌性的生理保护中的作用；2) SLURP-1诱导恶性呼吸道细胞凋亡敏感性增高的分子机制；3)介导SLURP-1药理活性的nAChR亚型及其对呼吸细胞表达的nAChR的作用模式；4) SLURP-1和NNK连接的nachr下游的信号通路。

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.