Identification of critical cellular pathways triggered by mitomycins interstrand crosslinks

该提案的目的是确定由DNA链间存在引发的关键细胞途径 丝裂霉素产生的交联（ICL），并确定丝裂霉素ICL的结构如何决定 在没有功能性p53的情况下导致细胞死亡/细胞周期停滞的细胞信号传导。本研究 包括丝裂霉素C（MC），一种目前在临床上使用的抗癌药物， (DMC)本实验室合成了丝裂霉素衍生物MC-Lex。 这些化合物形成具有共同结构特征的高细胞毒性链间交联（ICL）。 MC与DNA形成α-ICL，DMC形成β-ICL，MC-Lex形成γ-ICL。的代表性构象 三个ICL表明，每个ICL诱导的DNA扰动水平按α<β<γ的顺序增加， α-ICL诱导的DNA扰动最小，γ-ICL显示显著的DNA扭曲和加宽 小沟的边缘先前的研究表明，三种药物（MC，DMC，MC-Lex）在以下方面也存在差异： 它们的细胞毒性和p53信号传导。由于ICL是主要负责细胞毒性的病变， 丝裂霉素，这表明三种ICL可以触发非常不同的生化细胞机制， 由癌细胞中存在的特定突变介导，这是现代癌症治疗的标志。拟议 研究将确定ICL如何作为生物信号触发不同的细胞死亡/细胞周期停滞 途径。了解丝裂霉素对局部DNA结构修饰的差异 与它们的细胞毒性相关对于理解临床使用的药物的作用至关重要。因此 对这三种结构不同的ICL（α/β/γ ICL）的研究为鉴定结构不同的ICL提供了理想的模型， 特征在于在功能性p53通路存在或不存在的情况下确定细胞信号传导结果。 由于p53肿瘤抑制基因在超过50%的人类癌症中发生突变，因此需要鉴定细胞的 不依赖于p53而诱导细胞死亡或细胞周期停滞的途径值得大量关注。这 有可能确定针对p53基因突变癌细胞的治疗方法， 基于肿瘤的遗传组成进行个性化治疗考虑。关联ICL结构 在取得显著成果后，我们会致力达致以下目标： 具体目标#1：使用仿生方法合成MC、DMC和MC-Lex ICL（α、β、γ-ICL）。 具体目标#2：确定p53依赖性和非依赖性DNA加合物（ICL）反应 使用定量标记的蛋白质组学和生物信息学的机制 具体目标#3：MC/DMC和α/β-ICL触发CHK 1介导的细胞周期阻滞机制 预期结果：本研究将确定决定细胞信号转导结果的ICL结构特征 在存在或不存在功能性p53通路的情况下，对于p53通路的特异性表达是一个特别感兴趣的特征。 个性化抗癌治疗的发展。

This proposal’s objective is to identify critical cellular pathways triggered by the presence of DNA interstrand crosslinks (ICLs) produced by mitomycins, and to identify how the structure of mitomycins ICLs determines the cellular signaling leading to cell death/cell cycle arrest in the absence of a functioning p53. This study includes mitomycin C (MC), an anti-cancer drug currently used in the clinics, decarbamoyl mitomycin C (DMC), a derivative of mitomycinc (MC) and a novel MC-derivative, MC-Lex, synthesized in our laboratory. These compounds form highly cytotoxic interstrand crosslinks (ICLs) that share common structural features. MC forms the α-ICL with DNA, DMC the β-ICL and MC-Lex the γ-ICL. Representative conformations of the three ICLs indicate that the level of DNA perturbation induced by each ICL increases in the order α<β<γ, with the α-ICL inducing minimal DNA perturbation and the γ-ICL shows significant DNA distortion and widening of the minor groove. Previous research has shown that the three drugs (MC, DMC, MC-Lex) also differ in their cytotoxicity and p53 signaling. Since ICLs are the lesions primarily responsible for the cytotoxicity of mitomycins, this indicates that the three ICLs could trigger very diverse biochemical cellular mechanisms, mediated by specific mutations present in cancer cells, a hallmark of modern cancer therapy. The proposed research will establish how the ICLs behave as biological signals to trigger different cell death/cell cycle arrest pathways. Knowledge of how differences in the modification of the local DNA structure by mitomycins correlates with their cytotoxicity is crucial for understanding the action of clinically used drugs. Therefore, the study of these three structurally different ICLs (α/β/γ ICLs) provides an ideal model for identifying structural features determining the cell-signaling outcome in the presence or the absence of a functioning p53 pathway. Since p53 tumor suppressor is mutated in more than 50% of human cancers, the need to identify cellular pathways that induce cell death or cell cycle arrest independently of p53 deserves substantial attention. This has the potential to identify treatments that could be tailored to cancer cells with mutations in the p53 gene for personalized treatment consideration based on the genetic makeup of a tumor. To correlate ICL structures with signaling outcome, we will be pursue the following aims: Specific aim #1: Synthesis of MC, DMC and MC-Lex ICLs (α,β,γ-ICLs) using biomimetic methods. Specific aim #2: Determination of p53-dependent and independent DNA adducts (ICLs) response mechanisms using quantitative label free proteomics and bioinformatics Specific aim #3: Mechanistic of CHK1 mediated cell cycle arrest triggered by MC/DMC and α/β-ICL Expected outcomes: This study will identify structural ICL features that determine the cell signaling outcome in the presence or the absence of a functioning p53 pathway, a feature of particular interest for the development of personalized anticancer therapy.