Progesterone promotes mammary gland tumorigenesis through immunosuppressive effects on dendritic cells

摘要 乳腺癌是癌症相关死亡的第二大常见原因，也是最常见的癌症 许多大规模的临床试验表明，使用外源性孕激素 （合成孕酮[P4]）增加女性浸润性乳腺癌的风险。虽然已经 在文献中明确确定P4在人类乳腺癌的发展中起作用， P4促进乳腺癌发生的机制尚不清楚。最近，我们报道了 孕激素受体（PR）和免疫信号通路之间的关系。我们最近的出版物 证明P4/PR可以抑制人乳腺癌细胞中的I型干扰素信号通路。给定 根据这些发现，我们试图研究P4/PR是否驱动乳腺的免疫调节， 促进乳腺肿瘤的形成。因此，该提议的中心假设是，P4 和PR减少乳腺中DC的募集和功能，从而促进免疫抑制 以及随后的乳腺肿瘤的发展和生长。我们将通过以下方式来解决这一假设： 具体目的如下：1）明确P4处理和PR表达影响DC的机制 募集至鼠乳腺和PR+乳腺肿瘤; 2）表征 和活性状态;和3）确定从P4处理的PR+乳腺肿瘤分离的DC的活性状态。 P4介导的DC抑制对乳腺肿瘤生长的贡献。对于目标1，我们将使用单个 细胞RNA测序（scRNA-seq）以确定P4是否影响DC中涉及的细胞因子的释放 募集到乳腺肿瘤细胞。在目标2中，我们将确定P4处理如何影响活性 和肿瘤浸润DC的功能，其中标记物将通过 scRNA-seq、流式细胞术和T细胞增殖测定。Aim 3将利用转基因小鼠模型， 确定DCs的耗竭是否影响P4对乳腺肿瘤的生长促进作用。 这项工作的成功完成将为免疫耐受机制提供新的见解 促进乳腺癌的发展和生长。此外，它将提供一个基本原理， P4/PR信号传导与抗孕激素一起促进DC功能并增强免疫介导的 肿瘤细胞

ABSTRACT Breast cancer is the second most common cause of cancer-related death and most common cancer occurring in females in the U.S. Numerous large-scale clinical trials have demonstrated that use of exogenous progestins (synthetic progesterone [P4]) increases the risk of invasive breast cancer in females. Although it has been clearly established in the literature that P4 plays a role in the development of human breast cancer, the mechanism by which P4 promotes breast cancer tumorigenesis remains unknown. Recently, we reported a link between progesterone receptor (PR) and immune signaling pathways. Our recent publications have demonstrated that P4/PR can repress type I interferon signaling pathways in human breast cancer cells. Given these findings, we sought to investigate whether P4/PR drive immunomodulation in the mammary gland to promote formation of mammary gland tumors. Therefore, the central hypothesis of this proposal is that P4 and PR decrease recruitment and function of DCs in the mammary gland, which promotes immunosuppression and subsequent development and growth of mammary gland tumors. We will address this hypothesis through the following specific aims: 1) Define the mechanism by which P4 treatment and PR expression affect DC recruitment to the murine mammary gland and PR+ mammary gland tumors; 2) Characterize the maturation and activity state of DCs isolated from P4-treated PR+ mammary gland tumors; and 3) Determine the contribution of P4-mediated DC suppression to mammary gland tumor growth. For aim 1, we will utilize single cell RNA sequencing (scRNA-seq) to determine if P4 affects the release of cytokines involved in DC recruitment to mammary gland tumor cells. In aim 2, we will determine how P4 treatment affects the activity and function of tumor-infiltrating DCs using syngeneic tumor models, in which markers will be measured via scRNA-seq, flow cytometry, and T cell proliferation assays. Aim 3 will utilize transgenic mouse models to determine whether depletion of DCs impacts P4’s growth-promoting effects on mammary gland tumors. Successful completion of the proposed work will provide novel insight into immune tolerance mechanisms promoting the development and growth of breast cancers. Additionally, it will provide a rationale to target P4/PR signaling with anti-progestins to promote DC function and enhance immune-mediated elimination of tumor cells.