PMCA2 regulates mammary gland involution and breast cancer

PMCA2 调节乳腺退化和乳腺癌

• 批准号: 10267724
• 负责人: John J Wysolmerski
• 金额: $ 54.47万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-10 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10267724
• 关键词: 3-Dimensional; Alveolar; Apical; Applications Grants; Biochemical; Biogenesis; Breast Cancer Cell; Breast Epithelial Cells; Ca(2+)-Transporting ATPase; Calcineurin; Calcium; Cell Death; Cell Polarity; Cell Survival; Cell membrane; Cells; Complex; Couples; Data; Databases; Development; Drug Targeting; ERBB2 gene; Grant; Heat-Shock Proteins 90; Human; Human Milk; In Vitro; Knockout Mice; Knowledge; Lactation; Lesion; Lysosomes; Malignant - descriptor; Mammary gland; Mediating; Membrane; Milk; Mouse Mammary Tumor Virus; Multiprotein Complexes; Mus; Noninfiltrating Intraductal Carcinoma; PMCA1 protein; Phosphorylation; Regulation; Resistance; STAT3 gene; Scaffolding Protein; Signal Transduction; Testing; Therapeutic; Trastuzumab; Up-Regulation; Weaning; apical membrane; basolateral membrane; cancer cell; experimental study; ezrin; in vivo; in vivo calcium imaging; insight; knock-down; malignant breast neoplasm; mammary; mortality; novel; overexpression; refractory cancer; response; scaffold; tumor

PMCA2 is a calcium pump expressed in the apical membrane of mammary epithelial cells (MECs) during lactation. It is responsible for transporting 60-70% of milk calcium. After weaning, milk stasis rapidly decreases PMCA2 expression, causing a sustained increase in intracellular calcium. Preliminary data suggest that this rise in intracellular calcium may serve as the biochemical signal that couples milk stasis to activation of lysosome biogenesis, STAT3 phosphorylation and lysosome-dependent cell death (LDCD). In the last cycle of this grant, we documented that PMCA2 is also re-expressed in breast cancers and correlates with ErbB2/HER2 levels and increased mortality. We have now defined interactions between PMCA2, NHERF1, Ezrin, HSP90 and ErbB2 that are required for membrane retention of ErbB2 and its downstream biochemical signaling. Inhibition of PMCA2 increases intracellular calcium and causes a PKCa-dependent disassembly of this multiprotein complex as well as the ubiquitinylation, internalization and degradation of ErbB2. In normal MECs, NHERF1, ezrin and PMCA2 interact within the apical plasma membrane while ErbB2 interacts with a different scaffolding protein called Erbin, at the basolateral membrane. Preliminary data show that, in DCIS lesions and in invasive breast cancer cells, PMCA2, Ezrin and NHERF1 intermix with Erbin and ErbB2 throughout the plasma membrane and that this complex is greatly upregulated in trastuzumab-resistant breast cancer cells. The premise/hypothesis of this grant application is three-fold: 1) that milk stasis rapidly decreases PMCA2 expression causing sustained increases in intracellular calcium, which, in turn, trigger LDCD; 2) that loss of cell polarity enables novel interactions between the apical, PMCA2-NHERF1-Ezrin complex and the basolateral, Erbin-ErbB2 complex that accelerate ErbB2-mediated transformation; and 3) that upregulation of interactions between PMCA2 and ErbB2 contribute to the development of trastuzumab resistance. We propose 3 specific aims. Aim 1 will examine the mechanisms whereby increased intracellular calcium concentrations activate lysosome biogenesis, STAT3 and LDCD. Aim 2 will test whether alterations in PMCA2 localization accelerate malignant transformation by ErbB2/HER2. Aim 3 will test whether further upregulation of interactions between PMCA2, NHERF1, Ezrin, Erbin, HSP90 and ErbB2 contributes to trastuzumab resistance. These experiments will provide important new knowledge of the mechanisms by which milk stasis triggers involution. They will contribute important insight into the early steps of transformation of MECs by ErbB2. They will validate novel cancer cell-specific drug targets for ErbB2/HER2-positive tumors and will test the potential therapeutic value of disrupting these interactions in trastuzumab-resistant cancers.

PMCA2是在乳腺上皮细胞（MEC）的顶膜中表达的钙泵 哺乳。它负责运输60-70％的牛奶钙。断奶后，牛奶滞医生迅速减少 PMCA2表达，导致细胞内钙的持续增加。初步数据表明这一点 细胞内钙的升高可能是生化信号 溶酶体生物发生，STAT3磷酸化和溶酶体依赖性细胞死亡（LDCD）。在最后一个周期 这笔赠款，我们记录了PMCA2在乳腺癌中也重新表达了 ERBB2/HER2水平和死亡率增加。现在，我们已经定义了PMCA2，NHERF1之间的相互作用 Ezrin，HSP90和ERBB2是保留ERBB2及其下游生化所必需的 信号。 PMCA2的抑制会增加细胞内钙，并导致PKCA依赖性拆卸 这种多蛋白质复合物以及ERBB2的泛素化，内在化和降解。正常 MEC，NHERF1，Ezrin和PMCA2在顶端质膜内相互作用，而ERBB2与A相互作用 基底外侧膜上称为Erbin的不同脚手架蛋白。初步数据显示，在DCIS中 病变和侵入性乳腺癌细胞中，PMCA2，Ezrin和Nherf1与Erbin和Erbb2的互化 在整个质膜中 癌细胞。该赠款申请的前提/假设是三个方面：1）牛奶停滞迅速减少 PMCA2表达导致细胞内钙的持续增加，这反过来触发了LDCD； 2）那 细胞极性的丧失使顶端，PMCA2-NHERF1-欧兹林复合蛋白与 加速ERBB2介导的转化的基底外侧，Erbin-Erbb2复合物； 3）上调 PMCA2和ERBB2之间的相互作用有助于曲妥珠单抗抗性的发展。我们 提出3个具体目标。 AIM 1将检查增加细胞内钙的机制 浓度激活溶酶体生物发生，STAT3和LDCD。 AIM 2将测试PMCA2中的更改 ERBB2/HER2的本地化加速了恶性转化。 AIM 3将测试是否进一步上调 PMCA2，NHERF1，Ezrin，Erbin，HSP90和ERBB2之间的相互作用有助于曲妥珠单抗 反抗。这些实验将为牛奶停滞的机制提供重要的新知识 触发器的互动。他们将为MEC转型的早期步骤提供重要的见解 ERBB2。他们将验证ERBB2/HER2阳性肿瘤的新型癌细胞特异性药物靶标，并将测试 破坏曲妥珠单抗癌症中这些相互作用的潜在治疗价值。