The Age-Dependence and Cell-Specificity of Breast Cancer Driven by Mutant p53

项目总结 乳腺癌是一种与年龄相关的疾病，老年女性发病率较高，较年轻女性预后较差。 女人。大多数乳腺肿瘤是上皮性肿瘤。乳腺上皮由外基底部组成。 肌上皮层和内腔细胞层。研究已经描述了细胞角蛋白的存在 蛋白5(K5)标记的双能祖细胞同时产生基底细胞和腔细胞，以及细胞角蛋白8 (K8)标记的仅产生腔细胞的单能祖细胞。令人惊讶的是，尽管有很长的历史 乳腺癌研究，年龄如何影响乳腺癌，以及乳腺肿瘤是否以及如何起源于K5 或K8阳性(K5或K8)的祖细胞表现出内在的差异尚不清楚。回答这些问题 可能为改进诊断和个性化治疗提供新的途径，从而延长生命 病人的数量。乳腺癌中最常见的基因变化发生在肿瘤抑制基因P53中， 精氨酸248是最大的突变热点。新发表的p53wm-R245W小鼠条件性等位基因 允许将野生型p53转化为p53R245W(对应于人类p53精氨酸到色氨酸突变 密码子248)对Cre重组酶的反应，是研究年龄依赖性的一个潜在的有价值的工具 以及突变型P53驱动的乳腺癌的细胞特异性。作为未来机械学和治疗学的前奏 研究表明，这个试点项目将利用p53wm-R245W等位基因来建立乳腺癌模型，并比较小鼠 乳腺肿瘤起源于不同的年龄或来自不同的细胞来源，假设表现为 在组织学、分子或基因组水平上的差异。这一假设将在三个具体目标上得到检验。 第一个目的是比较p53R245W突变驱动的乳腺癌起源于年轻和老年小鼠。 表达Cre的腺病毒(Ad-Cre)将被注射到2个月或10个月龄的乳管中 雌性p53wm-R245W/只小鼠。肿瘤发病率、潜伏期和生长率、动物存活、转移和 将比较注射Ad-Cre的小鼠肿瘤的组织学和分子亚型的光谱 在各自的年龄。第二个目标是比较p53R245W驱动的乳腺肿瘤起源于 K5或K8祖细胞。P53wm-R245W/雌性小鼠将接受乳腺导管内注射 腺病毒AdK5-Cre或AdK8-Cre分别表达由K5或K8启动子引导的Cre。相同 目标1中描述的参数将在接受AdK5-Cre或AdK8-Cre的小鼠之间进行比较。这个 最后，在基因组水平上研究乳腺肿瘤的年龄依赖性和细胞特异性。 将对AIMS 1和AIMS 2产生的肿瘤进行全外显子组测序。 研究人员将比较2个月大和10个月大的小鼠乳腺肿瘤的变化， 以及起源于K5或K8祖细胞的肿瘤之间的相互作用。WES数据也将进行比较 人类乳腺癌的测序数据。

PROJECT SUMMARY Breast cancer is an age-related disease, with higher incidence in elder women and worse prognosis in younger women. Most breast tumors are of epithelial origin. The mammary epithelium consists of an outer basal myoepithelial layer of cells and an inner luminal cell layer. Studies have described the existence of cytokeratin protein 5 (K5) marked bipotent progenitors giving rise to both basal and luminal cells, and cytokeratin protein 8 (K8) marked unipotent progenitors that produce luminal cells only. Surprisingly, despite the long history of breast cancer research, how age impacts breast cancer, and whether and how breast tumors initiated from K5 or K8 positive (K5+ or K8+) progenitors exhibit intrinsic differences remain unclear. Answering these questions may provide new avenues for improved diagnostics and personalized therapeutics that could prolong the lives of patients. The most frequent genetic alterations in breast cancer occur in the tumor suppressor p53, with arginine 248 being the top mutational hotspot. The newly published conditional p53wm-R245W mouse allele, which allows conversion of wild type p53 to p53R245W (corresponding to human p53 arginine to tryptophan mutation at codon 248) in response to Cre recombinase, is a potentially valuable tool for studying the age-dependence and cell-specificity of breast cancer driven by mutant p53. As a prelude for future mechanistic and therapeutic studies, this pilot project will utilize the p53wm-R245W allele to model breast cancer and compare mouse mammary tumors initiated at different ages or from different cellular origins, which are hypothesized to exhibit differences at the histological, molecular or genomic levels. This hypothesis will be tested in three specific aims. The first aim is to compare p53R245W mutant driven mammary tumors initiated in young and old mice. Adenoviruses expressing Cre (Ad-Cre), will be injected into the mammary ducts of 2 months- or 10 months old female p53wm-R245W/+ mice. Tumor incidence, latency and growth rate, animal survival, metastasis, and the spectra of histological and molecular subtypes of tumors will be compared between mice injected with Ad-Cre at the respective ages. The second aim is to compare p53R245W driven mammary tumors initiated from either K5+ or K8+ progenitor cells. p53wm-R245W/+ female mice will receive mammary intraductal injection of adenoviruses AdK5-Cre or AdK8-Cre that express Cre led by the K5 or K8 promoter, respectively. The same parameters as described in Aim 1 will be compared between the mice receiving AdK5-Cre or AdK8-Cre. The last aim is to investigate the age-dependence and cell-specificity of mammary tumors at the genomic level. Whole-exome sequencing (WES) will be performed on tumors produced in Aims 1 and 2. Genes with recurrent alterations will be compared between mammary tumors initiated from the 2 months- and 10 months old mice, as well as between tumors initiated from the K5+ or K8+ progenitor cells. The WES data will also be compared to the human breast cancer sequencing data.