Impact of Genetic Diversity on Human Xenograft Tumor Growth

项目总结/摘要 患者来源的异种移植物（PDX）小鼠模型是研究癌症生物学、生物标志物和肿瘤标志物的重要工具。 开发、药物筛选和个性化医疗策略的临床前评估， 癌症的类型。然而，即使在免疫功能低下的宿主中，由于宿主排斥导致的异种移植物失败率也很低。 约20%至100%，取决于肿瘤类型。这样的失败通常导致样品丢失和样品丢失。 获得该患者或肿瘤类型的临床相关数据的机会。新出现的证据表明 宿主遗传背景是异种移植物建立以及肿瘤中这种变异性的基础 对药物的反应。为了提高PDX模型系统的临床相关性，一种创新的替代方案是 利用宿主PDX小鼠的遗传多样性作为工具来显著改善肿瘤移植。的 协作杂交（CC）和多样性远交（DO）是重组近交的互补组， 菌株，其分别衍生自八个亲本近交系，并且联合收割机结合了高遗传多样性， 平衡的种群结构是遗传性状作图的理想选择。CC近交系提供了高度的 遗传变异性和潜在的遗传上易于处理的平台，用于持续和可重现的体内PDX 问题研究DO在远交基因组中提供了最大的遗传变异性，具有类似于 对人类群体，是理想的表征宿主遗传的全部潜在影响， 肿瘤细胞扩增的背景变化。为了建立PDX小鼠，宿主免疫系统必须是 抑制异种移植物接受。拟议研究的挑战是抑制免疫系统， 系统在具有不同遗传背景的个体免疫活性小鼠中的应用。目标1：免疫 使用新型CRISPR-Cas9敲除Rag 1基因将抑制CC小鼠中的系统 基础编辑系统在目标2中，免疫系统将在遗传独特的DO小鼠中被抑制 使用一种新型的口服免疫抑制剂。这项研究意义重大，因为它将提供基因 任何类型的肿瘤生长所必需的多样性，扩展PDX平台以维持癌症， 以前是不可能异种移植的。这项研究在概念上是创新的，因为它将介绍 遗传多样性的PDX平台。这项研究在技术上是创新的，因为它将损害 通过最先进CRISPR-Cas9碱基编辑器技术在多个遗传多样性小鼠中的免疫系统 (Aim 1）或在饮用水中使用新型化学免疫抑制剂（目标2）。最先进的基地 目标1中的编辑器系统将在所有小鼠中产生相同的突变，几乎没有或没有附带的遗传改变。 这些新平台的开发具有风险，这些风险将随着PDX植入的产生而得到回报。 “困难的”肿瘤，使癌症生物学和新的治疗方法的发展有了更好的理解。 .

PROJECT SUMMARY/ABSTRACT Patient derived xenograft (PDX) mouse models are an essential tool for the study of cancer biology, biomarker development, drug screening, and the preclinical evaluation of personalized medicine strategies for many types of cancers. However, xenograft failure rates due to host rejection, even in immunocompromised hosts, is between ~20% and 100% depending on tumor type. Such failure often results in a lost sample and a lost opportunity to obtain clinically relevant data for that patient or tumor type. Emerging evidence suggests that host genetic background underlies much of this variability in xenograft establishment as well as tumor response to drugs. To advance the clinical relevance of the PDX model system, an innovative alternative is to utilize genetic diversity of the host PDX mice as a tool to substantially improve tumor engraftment. The Collaborative Cross (CC) and Diversity Outbred (DO) are complementary sets of recombinant inbred and strains, respectively, that derive from eight parental inbred strains, and combine high genetic diversity with balanced population structures ideal for genetic trait mapping. The CC inbred strains provide a high degree of genetic variability and potentially a genetically tractable platform for sustained and reproducible in vivo PDX studies. DO provides the most genetic variability in outbred genomes with high levels of heterozygosity similar to the human population, and is ideal for characterizing the full range of potential effects of host genetic background variation on tumor cell expansion. To establish a PDX mouse, the host immune system must be suppressed for xenograft acceptance. The challenge in the proposed studies is to suppress the immune system in individual immunocompetent mice with different genetic backgrounds. In Aim 1, the immune system will be suppressed in CC mice by knocking out the Rag1 gene using a novel CRISPR-Cas9 base editing system. In Aim 2, the immune system will be suppressed in genetically unique DO mice using a novel oral immunosuppressant drug. This study is significant because it will provide the genetic diversity necessary for the growth of any type of tumor, expanding the PDX platform to sustain cancers that have previously been impossible to xenograft. This study is conceptually innovative because it will introduce genetic diversity into the PDX platform. This study is technically innovative because it will compromise the immune system in multiple genetically diverse mice by state-of-the-art CRISPR-Cas9 Base Editor technology (Aim 1) or using a novel chemical immunosuppressant in the drinking water (Aim 2). The state-of-the-art Base Editor system in Aim 1 will produce identical mutations in all mice with little or no collateral genetic alterations. Development of these novel platforms has risks that will be rewarded with the generation of PDX engraftment of “difficult” tumors, enabling a greater understanding of cancer biology and development of novel therapeutics. .