NO-releasing ASA colorectal cancer, and NF-kappaB

说明书(申请人提供)：NO释放阿司匹林(NO-ASA)是一种很有前途的结肠癌化学预防药物，由传统的阿司匹林(ASA)分子组成，NO释放部分-NO2通过化学间隔分子共价连接到该分子上。NO-ASA通过抑制细胞增殖和增强细胞杀伤作用，比ASA更有效地抑制结肠癌细胞的生长。人们对癌细胞中导致这种效应的分子靶点知之甚少。我们的假设是，基于初步结果，核因子-kappaB是NO-ASA在结肠癌化学预防中作用的重要中介。因此，本研究的目的是阐明NO-ASA调节核因子-kappaB信号系统的分子机制，并确定这种调节是否对NO-ASA的结直肠癌化学预防作用起关键作用。 我们将追求3个具体目标。具体目标1：在人结肠癌细胞系中，评估NO-ASA对NF-kappaB激活的影响，并将这一事件与NO-ASA对细胞动力学的影响相关联。具体目标2：评估NO-ASA分子的哪一部分对其影响核因子-kappaB的激活起关键作用。将测试NO-ASA每个结构成分的单独贡献：ASA、ASA+Spacer(不带-NO2基团的NO-ASA)、间隔基(连接ASA和-NO2的NO-ASA部分)、去乙酰化的NO-ASA(NO-ASA减去乙酰基)。具体目标3：使用结肠癌临床前模型测试我们的体外研究结果的生物学相关性。我们将在用偶氮甲烷治疗的大鼠身上直接评估核因子-kappaB在结肠癌预防中的作用，并将测试体外研究的关键机制发现。证明NO-ASA可诱导恶性结肠细胞发生重要的分子变化，这可能与其在癌症中的药理作用有关，这将对结肠癌的预防具有重要意义。拟议的研究结果不仅具有机械学意义，还将揭示合理设计药物组合的机会，从而提高NO-ASA的效力和疗效。因此，我们的建议对癌症化学预防和控制的总体贡献预计将是直接和重大的。

DESCRIPTION (provided by applicant): NO-releasing aspirin (NO-ASA), a promising colon cancer chemopreventive agent, consists of a traditional aspirin (ASA) molecule to which -NO2, the NO-releasing moiety, is covalently attached via a chemical spacer molecule. NO-ASA inhibits colon cancer cell growth more potently than ASA by inhibiting cell proliferation and enhancing cell killing. Very little is known about the molecular targets in the cancer cell that are responsible for this effect. Our hypothesis, based on preliminary results, is that NF-kappaB is an important mediator of the effect of NO-ASA in colon cancer chemoprevention. Therefore, the goal of this study is to elucidate the molecular mechanisms by which NO-ASA modulates the NF-kappaB signaling system and to determine whether such modulation is critical for NO-ASA's chemopreventive effect against colorectal cancer. We will pursue 3 specific aims. Specific Aim 1: Assess, in human colon cancer cell lines, the effect of NO-ASA on NF-kappaB activation and correlate this event with the effect of NO-ASA on cell kinetics. Specific Aim 2: Evaluate which portion of the NO-ASA molecule is critical for its effect on NF-kappaB activation. The individual contribution of each structural component of NO-ASA will be tested: ASA, ASA+ Spacer (NO-ASA without the -NO2 group); spacer (the part of NO-ASA linking ASA to -NO2); deacetylated NO-ASA (NO-ASA minus the acetyl group). Specific Aim 3: Test the biological relevance of our in vitro findings using a preclinical model of colon cancer. We will evaluate directly in rats treated with azoxymethane, an established model of colon cancer, the role of NF-kappaB in colon cancer prevention and will test the key mechanistic findings from the in vitro study. Demonstrating that NO-ASA induces an important molecular change in the malignant colonocyte that may be relevant to its pharmacological actions in cancer would have important implications for colon cancer prevention. The results of the proposed studies not only will be of mechanistic interest but will also reveal opportunities for the rational design of drug combinations that will enhance the potency and efficacy of NO-ASA. Thus, the overall contribution of our proposal to cancer chemoprevention and control is expected to be both direct and significant.