Colonic responses to vitamin D and aspirin in African- and European-Americans

项目总结/摘要 非裔美国人（AA）在美国结直肠癌（CRC）的负担最大， 造成这种差异的原因仍然不完全清楚。宿主与环境的相互作用 已知包括化学预防治疗在内的因素可改变CRC风险， AA和欧洲美国人（EA）之间治疗效果的差异， 化学预防剂维生素D和阿司匹林我们的主要目标是建模和理解如何在 治疗反应的种族差异可能导致CRC差异。我们的实验室优化了 干细胞衍生的人类类器官培养物，以研究尚未被 使用传统的模式是可行的。在这个提议中，我们使用结肠类器官来测试中心假设， 转录、染色质可及性和细胞对维生素D和/或阿司匹林的反应在AA和AA之间不同。 这些种族间差异可能影响CRC风险和临床治疗反应。 我们先前用活性维生素D（1，25 D）和维生素E（1，25 D）处理来自AA和EA的离体原代结肠组织。 发现了几个具有种族间反应差异的基因。成功地找到种族间基因 反应差异为将我们的全基因组方法扩展到1，25 D，阿司匹林和 在更大样本量的结肠类器官（80 AA和80 EA）中进行组合治疗，以实现更大的功效 以确定转录网络以及染色质可及性的种族间差异。我们将 在一个独立的类器官队列中重复观察到的差异以及癌症相关细胞的检测 在经处理的类器官的子集中的处理表型（50 AA和50 EA）（目标1）。此外，使用RNA-seq数据 在目标1中获得，我们将测试个体之间反应差异的遗传贡献， 使用等位基因特异性表达来区分种族。将对识别的应答基因和SNP进行检测， 来自NIH资助的CRC GWAS和化学预防试验的基因和SNP之间的富集， 使用功能测定进行机械测试（Aim 2）。 我们的创新研究成果将：i）阐明潜在的生物学和遗传结构， 结肠中对维生素D和阿司匹林的反应以及它们如何因种族而异，ii）连接细胞反应 与CRC风险和对化学预防的反应有关，以及iii）鉴定用于机制研究的基因和SNP， 以及作为个性化CRC预防的新生物标志物的可能发展，最终， 减少CRC差异。

PROJECT SUMMARY/ABSTRACT African Americans (AA) have the greatest burden of colorectal cancer (CRC) in the US, and biological reasons for this disparity remain incompletely understood. Interactions between host and environmental factors, including chemopreventive treatments, are known to modify CRC risk, and there is emerging evidence of differences in treatment effects between AA and European Americans (EA) for the two most promising chemopreventive agents, vitamin D and aspirin. Our broad objective is to model and understand how inter- ethnic differences in treatment responses could contribute to CRC disparities. Our laboratory has optimized stem cell-derived human organoid cultures to study cellular responses between individuals that have not been feasible using traditional models. In this proposal, we use colonic organoids to test the central hypothesis that transcriptional, chromatin accessibility and cellular responses to vitamin D and/or aspirin differ between AA and EA, and that these inter-ethnic differences could impact CRC risk and clinical treatment response. We previously treated ex vivo primary colon tissue from AA and EA with active vitamin D (1,25D) and identified several genes with inter-ethnic response differences. The success of finding genes with inter-ethnic response differences provides rationale for extending our genome-wide approach to 1,25D, aspirin and combination treatments in a larger sample size of colonic organoids (80 AA & 80 EA) to achieve greater power to identify inter-ethnic differences in transcriptional networks as well as chromatin accessibility. We will replicate observed differences in an independent cohort of organoids as well as test for cancer-relevant cellular treatment phenotypes in a subset of treated organoids (50 AA & 50 EA) (Aim 1). Further, using RNA-seq data obtained in Aim 1, we will test for a genetic contribution to response differences between individuals and ethnicities using allele specific expression. The response genes and SNPs identified will be tested for enrichment among genes and SNPs from NIH-funded CRC GWAS and chemoprevention trials as well as tested mechanistically using functional assays (Aim 2). The outcomes of our innovative study will: i) elucidate underlying biology and genetic architecture of responses to vitamin D and aspirin in the colon and how they differ by ethnicity, ii) connect cellular response with CRC risk and response to chemoprevention, and iii) identify genes and SNPs for mechanistic studies as well as for possible development as novel biomarkers for personalized CRC prevention in order to, ultimately, reduce CRC disparities.