HMG-CoA Reductase and Polyamine Inhibitors for Prevention of Colorectal Cancer

摘要 该提案的总体目标是制定有效的化学预防策略， 了解他汀类药物（3- 羟基-3甲基戊二酰辅酶A还原酶（HMG-R）抑制剂）和多胺抑制剂，DFMO 对抗结肠癌结直肠癌是男性和女性最常见的恶性肿瘤之一。 美国的女人。在制定翻译策略时，最好的方法是针对多个 选择性地促进肿瘤生长的信号通路，因此它提供了一种 协同/加和功效。结肠肿瘤细胞产生高水平的多胺内源性通过 鸟氨酸脱羧酶（ODC）的活化。DFMO选择性抑制ODC活性，从而 内源性多胺合成和结肠肿瘤生长。多胺转运的新见解 通过小窝蛋白-1（cav-1）和SLC 3A 2介导的途径在肿瘤细胞中的表达表明， 需要有效的多胺调节肿瘤细胞。尽管DFMO抑制了 内源性多胺合成，肿瘤细胞仍然可以通过cav-1摄取细胞外多胺 依赖性内吞机制。此外，Cav-1在一氧化氮的产生中起重要作用 (NO)以及AKT和Rho信号传导的激活，导致增强的肿瘤细胞增殖和侵袭。 我们的初步研究结果表明，瑞舒伐他汀与低剂量DFMO联合使用可抑制 氧化偶氮甲烷（AOM）诱导的结肠异常隐窝灶（ACF）和异常隐窝细胞增殖。我们 体外和体内结果表明，CAV-1在结肠癌中起重要作用，他汀类药物表现出 结肠肿瘤抑制部分通过调节CAV-1实现。因此，我们希望开发一种他汀类药物的组合， 和DFMO用于结肠癌预防/治疗，并了解cav-1在结肠癌中的作用及其 miRNAs的可能调控。具体目的是：1）确定瑞舒伐他汀的体内疗效 （Crestor）在F344大鼠结肠癌发生模型中的作用（最大耐受/最佳剂量选择;剂量- 反应效果;以及促进/进展阶段的有效性（早期/晚期干预）。 2)确定阿托伐他汀/瑞舒伐他汀和DFMO联合治疗对 结肠ACF（起始后/早期）或腺瘤（进展/晚期）至结肠腺癌 在大鼠中形成。我们还想确定他汀类药物和DFMO对cav-1水平的影响， 多胺、ODC活性、NO（iNOS和eNOS活性）、SLC 3A 2、AKT和Rho信号传导蛋白， 结肠粘膜和肿瘤组织中的miRNA修饰及其与结肠肿瘤的相关性 抑制作用3)利用cav-1基因敲除小鼠模型明确cav-1在结肠癌发生中的作用， 确定他汀类药物与或不与DFMO对cav中致癌物诱导的结肠肿瘤形成的影响。 1-/-和cav-1+/+小鼠。此外，拟议的研究将阐明选择性miRNAs在细胞凋亡中的作用。 cav-1在结肠癌细胞中的调节，并评估他汀类药物和DFMO对结肠癌细胞中cav-1的可能调节作用。 cav-1 miRNA调控。

Abstract The overall goal of this proposal is to develop effective chemopreventive strategies and understand the molecular mechanism of colon tumor inhibition by a combination of statins (3- hydroxy-3methyl glutaryl CoA reductase (HMG-R) inhibitors) and polyamine inhibitor, DFMO against colon cancer. Colorectal cancer is one of the most common malignancies in both men and women in the US. In developing translational strategies, a preferable approach is to target multiple signaling pathways that selectively contribute towards tumor growth, so that it provides a synergistic/additive efficacy. Colon tumor cells produce high levels of polyamines endogenously through the activation of ornithine decarboxylase (ODC). DFMO selectively inhibits ODC activity and thereby endogenous polyamine synthesis and colon tumor growth. New insights into the transport of polyamines in tumor cells by caveolin-1 (cav-1) and SLC3A2 mediated pathways suggest that new approaches are needed for effective polyamine regulation in tumor cells. In spite of the fact that DFMO inhibits endogenous polyamine synthesis, tumor cells can still uptake extracellular polyamines through a cav-1 dependent endocytic mechanism. Further, Cav-1 plays an important role in the generation of nitric oxide (NO) and activation of AKT and Rho-signaling, leading to enhanced tumor cell proliferation and invasion. Our preliminary results suggest, that a combination of rosuvastatin with low-dose DFMO suppresses azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF), and aberrant crypt cell proliferation. Our in vitro and in vivo results suggest that cav-1 plays an important role in colon cancer, and statins exhibit colon tumor inhibition in part by modulating cav-1. Therefore, we want to develop a combination of statin and DFMO for colon cancer prevention/treatment and understand the role of cav-1 in colon cancer and its possible regulation by miRNAs. Specific aims are 1) Determine the in vivo efficacy of Rosuvastatin (Crestor) in a F344 rat colon carcinogenesis model (maximum tolerated/optimal dose selection; dose- response effects; and effectiveness during promotion/progression stages (early/late interventions). 2) Determine the combinational efficacy of atorvastatin/rosuvastatin and DFMO on the progression of colonic ACF (post-initiation/early stage) or adenoma (progression/late stage) to colon adenocarcinoma formation in rats. We also want to determine the effect of statins and DFMO on the levels of cav-1, polyamines, ODC activity, NO (iNOS and eNOS activities), SLC3A2, AKT and Rho signaling proteins, miRNA modifications in colonic mucosa and tumor tissues and correlate these results with colon tumor inhibition. 3) Define the role of cav-1 in colon carcinogenesis using cav-1-/- knockout mouse model and determine the effect of statins with or without DFMO on carcinogen induced colon tumor formation in cav- 1-/- and cav-1+/+ mice. In addition, proposed research will elucidate the role of selective miRNAs on the regulation of cav-1 in colon cancer cells, and assess the possible modulatory role of statins and DFMO on cav-1 miRNA regulation.