Prevention of Lung Cancer Growth by Angiotensin-(1-7)

描述（由申请人提供）： 肺癌是男性和女性死亡的主要原因，每年在美国造成约 160,000 人死亡，全球新增肺癌病例超过 1,000,000 例。尽管许多临床试验测试了各种化合物作为化学预防剂，但没有一个能够有效降低肺癌风险。然而，使用血管紧张素转换酶（ACE）抑制剂治疗高血压患者可以降低患癌症，尤其是肺癌的风险。抑制 ACE 活性会降低血管紧张素 II (Ang II) 并增加缓激肽和血管紧张素-(1-7) [Ang-(1-7)] 的水平。我们发现 Ang-(1-7) 在体外可减少血管生长，在体内可防止新内膜形成。更重要的是，我们的初步研究表明Ang-(1-7)显着抑制人肺癌细胞的生长，减少体内肿瘤的生长。因此，我们认为 Ang-(1-7) 的抗增殖反应超出了其对血管细胞的作用，并且 Ang-(1-7) 抑制癌细胞的生长。本申请中概述的研究旨在确定 Ang-(1-7) 是否抑制人肺癌细胞的增殖，并确定参与这种调节的分子机制。在用不同剂量的 Ang-(1-7) 处理后，将检查已建立的人肺癌细胞系的生长抑制情况。通过将 3 H-胸苷掺入增殖细胞、使用改良的 MTT 测定减少细胞数量以及通过流式细胞术进行细胞周期分析来评估细胞生长的减弱。 Ang-(1-7) 抗增殖反应的特异性将使用其他血管紧张素肽和受体拮抗剂来确定。将在患有化学诱导肺肿瘤的小鼠中检查 Ang-(1-7) 对肺癌细胞生长的减弱作用，以证明 Ang-(1-7) 在体内预防或减少肺肿瘤形成。基因阵列分析确定了人肺癌细胞受丝裂原刺激后受 Ang-(1-7) 调节的候选基因，包括编码肿瘤抑制因子和细胞死亡信号的基因的上调以及编码刺激细胞生长的信号通路的基因的下调。将通过逆转录酶聚合酶链式反应 (RT-PCR) 测定和蛋白质印迹杂交来评估 Ang-(1-7) 对特定基因和蛋白质的调节，以确定它们在 Ang-(1-7) 介导的肺癌细胞生长抑制中的作用。这些研究的结果将确定 Ang-(1-7) 是否能有效减弱人肺癌细胞的增殖，并确定参与抑制反应的细胞途径。这项工作的最终目标是确定给予 Ang-(1-7) 或增加循环 Ang-(1-7) 的药物是否是肺癌的有效化学预防治疗。

DESCRIPTION (provided by applicant): Lung cancer is a leading cause of death in both men and women, accounting for approximately 160,000 deaths annually in the United States with over 1,000,000 new cases of lung cancer worldwide. Despite a number of clinical trials testing various compounds as chemopreventive agents, none were effective in reducing the risk of lung cancer. However, treatment of hypertensive patients with angiotensin converting enzyme (ACE) inhibitors reduced the risk of cancer, especially lung cancer. Inhibition of ACE activity decreases angiotensin II (Ang II) and increases the levels of both bradykinin and angiotensin-(1-7) [Ang-(1-7)]. We showed that Ang-(1-7) reduces vascular growth in vitro and prevents neointimal formation in vivo. More importantly, our preliminary studies showed that Ang-(1-7) markedly inhibits the growth of human lung cancer cells and reduces tumor growth in vivo. Thus, we propose that the antiproliferative response to Ang-(1-7) extends beyond its effects on vascular cells and that Ang-(1-7) inhibits the growth of cancer cells. The studies outlined in this application are designed to determine whether Ang-(1-7) inhibits the proliferation of human lung cancer cells and identify the molecular mechanisms involved in this regulation. Established cell lines of human lung carcinomas will be examined for growth inhibition following treatment with various doses of Ang-(1-7). Attenuation of cell growth will be assessed by 3H-thymidine incorporation into proliferating cells, reductions in cell number using the modified MTT assay, and cell cycle analysis by flow cytometry. The specificity of the antiproliferative response to Ang-(1-7) will be determined using other angiotensin peptides and receptor antagonists. The attenuation of lung cancer cell growth by Ang-(1-7) will be examined in mice with chemically-induced lung tumors, to demonstrate that Ang-(1-7) prevents or reduces lung tumor formation in vivo. Gene array analysis identified candidate genes regulated by Ang-(1-7) following mitogen stimulation of human lung cancer cells, including up-regulation of genes encoding tumor suppressors and cell death signals and downregulation of genes encoding signaling pathways stimulating cell growth. Regulation of specific genes and proteins by Ang-(1-7) will be assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) assays and Western blot hybridization, to determine their role in Ang-(1-7)-mediated lung cancer cell growth inhibition. The results of these studies will determine whether Ang-(1-7) effectively attenuates the proliferation of human lung cancer cells and identify the cellular pathways involved in the inhibitory response. The ultimate goal of this work is to determine whether administration of Ang-(1-7) or agents, which increase circulating Ang-(1-7) is an effective chemopreventive treatment for lung cancers.