The role of the senescent microenvironment on cancer initiating cells in the colon.

衰老微环境对结肠癌起始细胞的作用。

• 批准号: 10638374
• 负责人: William Mallory Grady
• 金额: $ 6.94万
• 依托单位: FRED HUTCHINSON CANCER CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-30 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10638374
• 关键词: role; senescent; microenvironment; cancer; initiating

PROJECT SUMMARY/ABSTRACT Advanced age is the single most significant risk factor for cancer. Although there are many plausible age-related mechanisms that mediate the increased risk for cancer in the elderly, functional evidence is lacking for the majority of these mechanisms. This proposal will focus on the role of the aged microenvironment, particularly senescence, in promoting the formation of colorectal cancer (CRC), which is a common age-related cancer in the U.S. It is well established that the majority of CRCs arise through the serial accumulation of mutations and epigenetic alterations in oncogenes and tumor suppressor genes in colon epithelial stem cells. However, our group and others have found cells with cancer-causing DNA alterations (e.g. oncogenic KRAS and TP53) in the histologically normal colon mucosa of people, which suggests that the DNA alterations alone are not sufficient to drive the complete CRC formation process. Our group has recently shown that a senescent normal colon tissue microenvironment can promote the neoplastic behavior of colon epithelial cells ex vivo. We found increased senescent fibroblasts in the colons of the elderly and of people at high risk for CRC. We found that certain senescence associated secretory phenotype (SASP) factors produced by senescent fibroblasts can induce cancer hallmark behaviors through the activation of oncogenic signaling pathways. Based on our preliminary data we hypothesize that senescent fibroblasts in older people and the accompanying specific Senescence Associated Secretory Phenotype (SASP) secreted proteins promote the tumorigenesis of colon epithelial cells that have acquired age-related oncogenic mutations, which we have defined as cancer-initiating cells. To provide direct functional evidence to test this hypothesis, we propose the following Specific Aims: AIM 1A. To determine whether senescent fibroblasts can promote the survival and/or transformation of colon cancer initiating cells in ex vivo and in vivo organoid model systems. AIM 1B. To determine the necessary and sufficient role of specific cancer-associated SASP factors produced by the senescent fibroblasts in cancer formation. AIM 2. To determine whether a senescent tissue microenvironment is necessary for the survival and clonal expansion of mutant APC and mutant KRAS cancer-initiating cells using a well characterized CRC mouse model, the inducible Villin-Cre;Apcflx/flx; KrasLSL-G12D (AK) mice, with two approaches: AIM 2A: a pharmacological approach using the senomorphic drug rapamycin and the senolytic drug treatment DNQ (dasatinib and quercetin) AIM 2B: a genetic approach using the p16-3MR transgenic model, which allows the inducible ablation of senescent cells.

项目总结/摘要 高龄是癌症最重要的风险因素。虽然有很多 似乎与年龄有关的机制介导了老年人癌症风险的增加， 大多数这些机制缺乏功能证据。该提案将重点关注 老年微环境的作用，特别是衰老，在促进形成 结直肠癌（CRC），这是一种常见的年龄相关的癌症在美国。 大多数CRCs是通过突变和表观遗传的连续积累而产生的， 结肠上皮干细胞中癌基因和肿瘤抑制基因的改变。然而，在这方面， 我们小组和其他人已经发现了具有致癌DNA改变的细胞（例如致癌KRAS 和TP 53）在组织学正常的结肠粘膜的人，这表明， 单独的改变不足以驱动完整的CRC形成过程。 我们的研究小组最近表明，衰老的正常结肠组织微环境可以 促进离体结肠上皮细胞的肿瘤行为。我们发现衰老的增加 成纤维细胞在老年人和CRC高危人群的结肠。我们发现某些 由衰老成纤维细胞产生的衰老相关分泌表型（SASP）因子 可以通过致癌信号通路的激活诱导癌症标志行为。 根据我们的初步数据，我们假设老年人和老年人的衰老成纤维细胞， 伴随特定衰老相关分泌表型（SASP）分泌蛋白 促进结肠上皮细胞的肿瘤发生， 突变，我们将其定义为癌症起始细胞。提供直接的功能性证据 为了验证这一假设，我们提出了以下具体目标： AIM 1A.为了确定衰老的成纤维细胞是否可以促进存活和/或 在离体和体内类器官模型系统中转化结肠癌起始细胞。 AIM 1B.确定特定癌症相关SASP的必要和充分作用 在癌症形成中由衰老的成纤维细胞产生的因子。 AIM 2.为了确定衰老的组织微环境是否是生存所必需的， 和突变型APC和突变型KRAS癌症起始细胞的克隆扩增 表征的CRC小鼠模型，诱导型Villin-Cre;Apcflx/flx; KrasLSL-G12 D（AK）小鼠，具有两个 方法：AIM 2A：使用senomorphic药物雷帕霉素和 衰老清除药物治疗DNQ（达沙替尼和槲皮素）AIM 2B：一种使用 p16- 3 MR转基因模型，允许衰老细胞的诱导性消融。