Preclinical evaluation of NOS inhibitors for the treatment of pancreatic cancer

描述(申请人提供)：胰腺癌是一种毁灭性的疾病，在美国估计每年导致33,370人死亡，五年存活率仅为5%。这种癌症的分子标志是小GTP酶KRAS的激活突变，众所周知，这种突变促进了肿瘤的发生。不幸的是，很难从药物上抑制KRAS，这促使我们寻找KRAS致癌所需的可用药蛋白。我们发现致癌的KRAS通过激活AKT，刺激内皮型一氧化氮合酶(ENOS)。此外，在人类胰腺癌细胞系中敲除eNOS或在小鼠中遗传去除eNOS基因可以延缓致癌RAS驱动的肿瘤生长。小分子量一氧化氮合酶抑制剂已经在败血症和心源性休克的I-III期临床试验中进行了测试。利用一氧化氮合酶抑制剂用于治疗其他疾病的开发，我们测试并发现一氧化氮合酶抑制剂L-NAME阻碍了人胰腺癌细胞系的肿瘤生长。我们建议现在测试两种最常用的一氧化氮合酶抑制剂，L-NAME和L-NMMA，用于抗肿瘤活性。这两种药物都非常容易服用，可以口服，并且已经在老鼠、大型哺乳动物和人类身上进行了研究。我们将使用两个成熟的胰腺癌小鼠模型来测试这两种一氧化氮合酶抑制剂的抗肿瘤活性：人胰腺癌异种移植(AIM 1)，因为这类细胞来自人类癌症，这是一个重要的考虑因素，因为致癌RAS信号在人和啮齿动物细胞之间可能不同；以及胰腺表达致癌KRAS转基因小鼠(AIM 2)，它更好地反映了胰腺癌在正确器官中的建立。结合起来，这两个非常不同的模型将使我们能够确定L-NMMA和L-NMMA在多大程度上以及在什么条件下阻碍胰腺肿瘤的发生。反过来，这些研究应该为潜在的临床试验奠定临床前基础。公共卫生相关性：胰腺癌是最致命的癌症之一，几乎没有治疗选择。我们发现内皮型一氧化氮合酶是胰腺肿瘤生长所必需的，并且可以用现有的小分子量抑制剂进行药物抑制。因此，测试一氧化氮合酶抑制剂的抗肿瘤活性的研究对人类健康具有重要意义，特别是作为可能的胰腺癌新的治疗方式。

DESCRIPTION (provided by applicant): Pancreatic cancer is a devastating disease, causing an estimated 33,370 deaths per year in the USA with a five-year survival rate of only 5%. The molecular hallmark of this cancer is an activating mutation in the small GTPase KRas, which is well known to promote tumorigenesis. Unfortunately, it has been difficult to pharmacologically inhibit KRas, prompting us to identify druggable proteins required for KRas oncogenesis. We found that oncogenic KRas, through activation of AKT, stimulates the enzyme endothelial Nitric Oxide Synthase (eNOS). Moreover, knockdown of eNOS in human pancreatic cancer cell lines or genetic ablation of the eNOS gene in mice retarded oncogenic Ras-driven tumor growth. Small molecular weight inhibitors of NOS enzymes have been tested in phase I to III clinical trials of septic and cardiogenic shock. Capitalizing on the development of NOS inhibitors for the treatment of other diseases, we tested and found that the NOS inhibitor L-NAME impeded tumor growth of human pancreatic cancer cell lines. We propose to now test the two most developed general NOS inhibitors, L- NAME and L-NMMA, for anti-tumor activity. Both these drugs are very easy to administer, being orally available, and have been studied in mice, large mammals and humans. We will use two well established mouse models of pancreatic cancer to test the anti-tumor activity of these two NOS inhibitors: human pancreatic cancer xenografts (aim 1) as such cells are derived from human cancers, an important consideration as oncogenic Ras signaling can differ between human and rodent cells; and pancreatic expressed-oncogenic KRAS transgenic mice (aim 2), which better reflect the establishment of pancreatic cancer in the correct organ. Together, these two very different models will allow us to determine how broadly and under what conditions L- NAME and L-NMMA impede pancreatic tumorigenesis. These studies should, in turn, lay the preclinical groundwork for a potential clinical trial. PUBLIC HEALTH RELEVANCE: Pancreatic cancer is one of the most deadliest cancers with very few therapeutic options. We discovered the enzyme eNOS is required for pancreatic tumor growth and can be pharmacologically inhibited with available small molecular weight inhibitors. The studies proposed to test NOS inhibitors for anti-tumor activity thus have important relevance to human health, specifically as possible new treatment modalities for pancreatic cancer.