Mutating E-cadherin in rats to model lobular breast cancer

本申请是对特别利益通知(NOSI)的回应，该通知被确认为 父母奖R01CA271498专注于研究导管乳腺癌的大鼠模型， 但它没有研究浸润性小叶性乳腺癌(ILC)，它每年在美国占高达4万例 我们。ILC主要为雌激素受体阳性(ER+)。E-钙粘附素丢失(由CDH1基因编码) 在超过95%的病例中，ILC的病原学特征在蛋白质水平上丢失了，而突变 CDH1出现在65%的病例中。CDH1的基因缺失还没有被工程改造到大鼠乳腺细胞中 正在研究ILC，但我们现在有技术能力将CDH1突变工程到大鼠乳房 腺体。我们预测CDH1的丢失将使大鼠乳腺易患ER+ILC。在这份增刊奖中， 我们将与Oester reich-Lee实验室合作，该实验室在研究ILC方面拥有广泛的专业知识，使用 人体标本、细胞培养和致癌物诱发的大鼠肿瘤的有机类物质。我们的目标是开发一种 临床相关的ER+ILC大鼠模型。两个具体目标被追求：目标1：检验躯体效应 CDH1缺失对大鼠乳腺发育和功能的影响这种体细胞的CDH1KO将被实现 使用我们最近发表的导管内注射病毒的方法在体内高效CRISPR- 基因组编辑。目的2：检测体细胞CDH1缺失与PIK3CA激活或 DMBA治疗大鼠ER阳性乳腺肿瘤的组织病理学和基因表达类似于 人类国际法委员会。我们选择了CDH1 KO和PIK3CA激活的组合，因为CDH1 KO单独是 不太可能足以致癌，因为PIK3CA是原癌基因最常见的突变 包括ILC在内的人类乳腺癌。

This application is being submitted in response to the Notice of Special Interest (NOSI) identified as NOT-CA-23-045.”The parent award R01CA271498 is focused on studying rat models of ductal breast cancer, but it does not study invasive lobular breast cancer (ILC), which accounts for up to 40,000 cases yearly in the US. ILC is predominantly estrogen receptor-positive (ER+). Loss of E-cadherin (encoded by the CDH1 gene) is the pathognomonic feature of ILC being lost at the protein level in over 95% of cases, while mutations of CDH1 occur in 65% of cases. Genetic loss of CDH1 has not been engineered into rat mammary gland cells for studying ILC, but we now have the technical capabilities to engineer CDH1 mutations into rat mammary glands. We predict that CDH1 loss will predispose rat mammary glands for ER+ ILC. In this supplement award, we will team up with the Oesterreich-Lee laboratory, which has extensive expertise in studying ILC, using human specimens, cell culture, and organoids of carcinogen-induced rat tumors. The goal is to develop a clinically relevant rat model of ER+ ILC. Two specific aims are pursued: Aim 1: Examine the effect of somatic CDH1 deletion on rat mammary gland development and function. This somatic CDH1 KO will be achieved using our recently published method using intraductal injection of virus for high efficiency in vivo CRISPR- genome editing. Aim 2: Test whether the combination of somatic CDH1 deletion and PIK3CA activation or DMBA treatment results in rat ER+ mammary tumors with a histopathology and gene expression similar to human ILC. We select the combination of CDH1 KO and PIK3CA activation because CDH1 KO alone is unlikely to sufficient to cause cancer and because PIK3CA is the protooncogene most commonly mutated in human breast cancer including ILC.