NO-releasing ASA colorectal cancer, and NF-kappaB

描述（由申请人提供）：NO释放阿司匹林（NO-ASA）是一种有前途的结肠癌化学预防剂，由传统的阿司匹林（阿萨）分子组成，NO释放部分-NO2通过化学间隔分子共价连接。NO-ASA通过抑制细胞增殖和增强细胞杀伤，比阿萨更有效地抑制结肠癌细胞生长。对癌细胞中负责这种效应的分子靶点知之甚少。基于初步结果，我们的假设是NF-κ B是NO-ASA在结肠癌化学预防中作用的重要介质。因此，本研究的目的是阐明NO-ASA调节NF-κ B信号系统的分子机制，并确定这种调节是否是NO-ASA对结直肠癌的化学预防作用的关键。 我们将实现三个具体目标。具体目标1：在人结肠癌细胞系中评估NO-ASA对NF-κ B活化的影响，并将该事件与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对NF-κ B活化的影响至关重要。将测试NO-ASA每个结构组分的单独贡献：阿萨、阿萨+间隔基（不含-NO2基团的NO-ASA）;间隔基（NO-ASA中连接阿萨与-NO2的部分）;脱乙酰基NO-ASA（NO-ASA减去乙酰基）。具体目标3：使用结肠癌的临床前模型测试我们的体外发现的生物学相关性。我们将直接在用氧化偶氮甲烷（一种已建立的结肠癌模型）治疗的大鼠中评估NF-κ B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在恶性结肠细胞中诱导可能与其在癌症中的药理作用相关的重要分子变化，将对结肠癌预防具有重要意义。所提出的研究结果不仅具有机理上的意义，而且还将揭示合理设计药物组合的机会，这将提高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是直接和重要的。

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.