Targeted Approach for Prevention and Therapy of Colorectal Cancer

描述（由申请人提供）：结直肠癌（CRC）是美国癌症发病率和死亡率的主要原因之一。从正常肠上皮组织到转移性肿瘤的多步骤进展是由于涉及调节增殖、分化、迁移和凋亡的正常模式的关键信号通路的多种调节机制的损伤。其中，Wnt和RAS信号通路在控制肠细胞增殖中起着至关重要的作用，并且是最经常受到干扰的 在结肠直肠癌中。尽管有这些知识，但很少有治疗策略被开发出来专门针对这些特定途径的成分，并且没有一种获得FDA的批准。我们小组已经确认了Kr ppel样因子5（KLF 5）是肠上皮细胞增殖的重要调节因子，在肠肿瘤发生过程中经常过表达。最近，我们将KLF 5与结直肠癌发生中的RAS和Wnt信号通路联系起来。我们的研究小组还观察到，KLF 5表达的减少导致肿瘤抑制基因APC（Wnt途径的重要组成部分）或APC和KRAS联合突变的小鼠肠道肿瘤形成减少。使用超高通量筛选（uHTS）方法通过靶向KLF 5表达来鉴定具有潜在治疗益处的新型先导化合物，然后对所得命中物进行结构-活性研究，我们鉴定了一种新型小分子ML 264，其有效且选择性地阻断结直肠癌细胞系中的KLF 5表达并降低其增殖。我们建议进一步表征ML 264抑制KLF 5表达的机制，并评估其作为结直肠癌治疗剂的疗效。本研究提案的长期目标是开发和表征用于预防和/或治疗结直肠癌的新型治疗药物。基于我们的研究结果，我们提出了中心假设，即化合物ML 264通过降低体内KLF 5表达来预防结直肠癌的发展和进展。为了验证这一假设，我们提出了三个具体目的：1）研究ML 264调节CRC细胞中KLF 5表达的机制; 2）评价化合物ML 264在结肠直肠癌小鼠模型中预防结肠癌形成的临床前疗效; 3）生成具有完全适当药代动力学特性的ML 264优化类似物用于抗癌治疗。本申请中提出的实验将提供ML 264及其优化类似物的结构和功能的明确细化。这项工作的目的是获得耐受性好，寿命长的生物可利用的化合物，适用于治疗结直肠癌。

DESCRIPTION (provided by applicant): Colorectal cancer (CRC) is one of the leading causes of cancer morbidity and mortality in the United States. The multistep progression from normal intestinal epithelial tissue to metastatic neoplasm results from impairment of multiple regulatory mechanisms involving critical signaling pathways that regulate normal patterns of proliferation, differentiation, migration, and apoptosis. Among these, the Wnt and RAS signaling pathways play crucial roles in governing intestinal cell proliferation and are the most frequently perturbed in colorectal cancer. Despite this knowledge, few therapeutic strategies have been developed to specifically target components of these particular pathways, and none have gained FDA approval. Our group has identified Kr¿ppel-like factor 5 (KLF5) as an important regulator of intestinal epithelial cell proliferation that is frequently overexpressed during intestinal tumorigenesis. Recently, we have linked KLF5 to both the RAS and Wnt signaling pathways in colorectal carcinogenesis. Our group has also observed that reduction in KLF5 expression leads to reduced intestinal tumor formation in mice harboring a germline mutation in the tumor suppressor gene, APC, a crucial component of the Wnt pathway, or combined APC and KRAS mutations. Using an ultrahigh-throughput screening (uHTS) approach to identify novel lead compounds with potential therapeutic benefits by targeting KLF5 expression, followed by structure-activity studies on the resultant hits, we identified a novel small molecule, ML264, which potently and selectively blocks KLF5 expression in and decreases proliferation of colorectal cancer cell lines. We propose to further characterize the mechanisms by which ML264 inhibits KLF5 expression and evaluate its efficacy as a therapeutic agent for colorectal cancer. The Long-Term Goal of this research proposal is to develop and characterize novel therapeutic agents for the prevention and/or treatment of colorectal cancer. Based on our results we propose the Central Hypothesis that the compound ML264 prevents colorectal cancer development and progression by decreasing KLF5 expression in vivo. To test this hypothesis we propose three Specific Aims: 1) To investigate the mechanism by which ML264 regulates KLF5 expression in CRC cells; 2) To evaluate the preclinical efficacy of compound ML264 in preventing colon cancer formation in mouse models of colorectal cancer; and 3) To generate optimized analogs of ML264 with fully appropriate pharmacokinetic properties for anticancer therapy. The experiments proposed in this application will provide a definitive refinement of the structure and function of ML264 and its optimized analogs. The intent of this effort is to obtain well-tolerated, long-lived bioavailable compounds suitable for therapeutic use in colorectal cancer.