Preclin. model for prevention of NSCLC in former smokers

描述(由申请人提供) 这一应用的中心假设是，在人和小鼠肺泡型肺腺癌(PAC II)以及在人和仓鼠肺鳞癌(SGC)中表达的生长调节通路与在人和仓鼠Clara细胞型肺腺癌(PAC)中表达的生长调节通路是拮抗的。因此，适用于前吸烟者的化学预防研究需要使用代表这些不同调节的癌症类型的模型。需要开发非侵入性方法，允许监测这些通路在前吸烟者中的表达水平，以评估对治疗的反应，并确保个人接受有效的化学预防治疗，同时避免潜在的癌症促进剂。为了在临床前阶段实现这些目标，我们的具体目标如下： 1)我们将研究绿茶、茶碱、β-胡萝卜素、视黄醇、糖皮质激素β-阻滞剂、cAMP拮抗剂和环氧合酶-2(COX-2)或5-1环氧合酶(5-.LOX)抑制剂对来源于PAC II、PACC或QSQC的人肺癌细胞系以及非致瘤和致瘤的小鼠PAC II细胞系的影响。 2)我们将合成~(125)I和~(123)I标记的COX-2、cAMP依赖的PKA和5-LOX的抑制剂类似物，用于微光子发射断层扫描(Micro-SPECT)。我们将通过体外结合分析来验证这些类似物与其细胞靶点的结合，使用根据AIM 1描述的人肺癌细胞系，并通过体内生物分布研究，使用携带这些人肺癌细胞系的异种照片的小鼠。 3)利用A/J/小鼠PAC II型模型、仓鼠PACC模型和仓鼠SQC模型，研究Aim 1所选药物在生物测定中的化学预防作用。实验设计将模拟前吸烟者的化学预防，在肿瘤诱导治疗已经停止且动物出现癌前病变时开始化学预防治疗。数据评估将包括组织病理学，包括COX-2、PKA和5-LOX的免疫染色，以及通过Western blotts分析这些酶在诱导肿瘤起源的正常细胞、癌前病变和激光捕获显微镜下采集的肺癌细胞中的蛋白表达。 4)利用AIM 2中的碘-125-1标记类似物，对AIM 3中每组随机选择的5只动物在化疗前、化疗中和化疗后进行微量SPECT分析，并尝试对肺组织和肺肿瘤组织中COX-2、PKA和5-LOX的水平进行定量。

DESCRIPTION (provided by applicant) The central hypothesis of this application is that growth regulating pathways expressed in human and mouse alveolar type II cell pulmonary adenocarcinomas (PAC type II) and in human and hamster pulmonary squamous cell carcinomas (SQCs) are antagonistic to those expressed in human and hamster Clara cell type pulmonary adenocarcinomas (PACCs). Chemoprevention studies applicable to former smokers therefore need to use models representing these differently regulated cancer types. Non-invasive methods need to be developed that allow to monitor the expression levels of these pathways in former smokers to asses response to treatment and to ensure assignment of individuals to effective chemopreventive treatments while avoiding potentially cancer promoting agents. To achieve these goals in a preclinical setup, our specific aims are as follows: 1) We will characterize the effects of green tea, theophylline, beta-carotene, retinol, glucocorticoid beta- blockers, cAMP antaogonists, and inhibitors of cyclooxygenase-2 (COX-2) or 5-1ipooxygenase (5-.LOX) in human lung cancer cell lines derived from PAC type II, PACC or QSQC and in non-tumorigenic and tumorigenic mouse PAC type II cell lines. 2) We will synthesize iodine-125 and -123-labeled analogues of inhibitors of COX-2, cAMP-dependent PKA and 5-LOX for use in micro-photon emisssion tomography (micro-SPECT). We will verify the binding of these analogues to their cellular targets by in vitro binding assays, using human lung cancer cell lines characterized under aim 1 and by in vivo bio-distribution studies, using mice carrying xenographs of these human lung cancer cell lines. 3) We will study the chemopreventive effects of selected agents from aim 1 in bioassay experiments, using the A/J/mouse PAC type II model, the hamster PACC model and the hamster SQC model. The experimental designs will simulate chemoprevention in former smokers by starting the chemopreventive treatments at the time when tumor induction treatment has been discontinued and precancerous lesions are present in the animals. Evaluation of data will include histopathology, including immunostains for COX-2, PKA and 5-LOX as well as analysis of protein expression of these enzymes by Western blots in normal cells of origin of the induced tumors, premalignant lesions, and in lung cancers harvested by laser capture microscopy. 4) Using the iodine-125-1abeled analogues from aim 2, we will conduct micro-SPECT analysis of five randomly chosen animals per treatment group of aim 3 before, during and after completion of chemopreventive treatments and we will attempt to quantitate levels of COX-2, PKA, and 5-LOX in lung tissues and lung tumors.