Co-Oncogenic Role of ECD in HER2-Driven Breast Cancer

项目摘要/摘要 乳腺癌是一种遗传性和临床异质性疾病，分子生物学研究已证实。 BC的五个主要亚型。其中一个亚型，HER2+(~20%)BC是由受体酪氨酸激酶HER2驱动的。 HER2靶向治疗显著提高了这些患者的存活率，然而，最晚期的 分期病人是无法治愈的，耐药性的获得是普遍的。最近，它被证明大约是 30%的HER2+BC患者存在PIK3CA激活突变。HER2+/PIK3CA双转基因小鼠 肿瘤对曲妥珠单抗联合治疗完全耐药，但添加PI3K抑制剂可逆转 抵抗。因此，阐明与HER2合作的其他共癌途径有助于 和/或增强HER2驱动的肿瘤发生，可能扩大设计组合治疗的潜力 针对晚期HER2驱动的BC的方法，以及预防和/或克服对现有疗法的耐药性。 这份R03提案重点展示了ECD(无蜕皮激素)在HER2+中的新的共同致癌作用 公元前。ECD蛋白和mRNA在BC中高表达，尤其是在HER2+中，与预后不良相关 标记物和更短的无病和总生存期。为了直接解决ECD在BC中的作用，我们生成了 携带乳腺上皮靶向可诱导(Tet-off)人ECD转基因(ECDTg)的小鼠。值得注意的是，85% 的ECDTg小鼠在5-6个月内出现乳腺增生，33%的小鼠在18-6个月内出现异质性肿瘤。 24个月。重要的是，其余85%的小鼠显示出肿瘤前病变。值得注意的是，ECDTg肿瘤 C-myc和β-catenin表达增加。从功能上讲，ECD水平的降低会降低血糖 摄取，暗示了ECD和新陈代谢的潜在联系。ECDTg肿瘤中HER2过表达缺失 需要将ECDTg模型与HuHER2Tg小鼠杂交，以重述ECD的共同过表达 见于HER2+BC患者。因此，在这项R03拨款申请中建议进行研究的理由非常充分。 基于这些数据，我们假设在HER2驱动的肿瘤发生中ECD的共同过度表达进一步促进了 肿瘤的发生和ECD的产生；huHER2双转基因小鼠将检验这一假设。进一步 表征ECDTg与ECD；huHER2Tg模型将有助于描述贫血症的分子机制 同时过度表达ECD和HER2的患者的结局。目标1将研究ECD在人卵巢癌中的共同致癌作用 利用小鼠乳腺靶向ECD转基因过表达HER2驱动的乳腺癌。目标2将 使用无偏见的方法(RNA-seq和代谢组学)来描述ECD-和HER2-的机制。 不列颠哥伦比亚省的依赖肿瘤发生。验证我们的假设将有助于我们理解ECD过度表达的原因 促进HER2驱动的BC，结果更糟。经过验证的ECD；huHER2Tg型号将提供无价的 了解它们共同致癌的机制基础和未来测试新疗法的工具 HER2+/ECD过表达BC并解决治疗耐药问题。我们研究的成功也可能开启 对于ECD过度表达与肿瘤进展相关的其他恶性肿瘤，有更广阔的途径。

PROJECT SUMMARY/ABSTRACT Breast cancer (BC) is a genetically and clinically heterogeneous disease and molecular profiling has identified five major subtypes of BC. One subtype, the HER2+ (~20%) BC is driven by the receptor tyrosine kinase HER2. HER2-targeted therapies have significantly improved the survival of these patients, however, most advanced stage patients are incurable, and acquisition of resistance is universal. Recently, it has been shown that about 30% of HER2+ BC patients have activating mutations in PIK3CA. HER2+/PIK3CA double-transgenic mouse tumors are completely resistant to trastuzumab combination therapy but adding a PI3K inhibitor reversed the resistance. Therefore, elucidating additional co-oncogenic pathways that collaborate with HER2 to facilitate and/or enhance HER2-driven oncogenesis, is likely to broaden the potential to design combinatorial therapeutic approaches against advanced HER2-driven BC and to forestall and/or overcome resistance to existing therapies. This R03 proposal focuses on demonstrating a novel co-oncogenic role of ECD (Ecdysoneless) in HER2+ BC. ECD protein and mRNA is overexpressed in BC, particularly in HER2+, correlating with poor prognostic markers and shorter disease-free and overall survival. To directly address the role of ECD in BC, we generated mice with a mammary epithelium-targeted inducible (Tet-off) human ECD transgene (ECDTg). Significantly, 85% of ECDTg mice exhibit mammary hyperplasia in 5-6 months, and 33% show heterogeneous tumors within 18- 24 months. Importantly, 85% of the remaining mice show pre-neoplastic lesions. Significantly, ECDTg tumors showed increased c-MYC and β-catenin expression. Functionally, decrease in ECD levels decreased glucose uptake, suggesting a potential link of ECD and metabolism. Lack of HER2 overexpression in ECDTg tumors dictates the need to cross ECDTg model with huHER2Tg mice that recapitulates the co-overexpression of ECD seen in HER2+ BC patients. Thus, the rationale for studies proposed in this R03 grant application is very strong. Based on these data, we hypothesize that ECD co-overexpression in HER2-driven oncogenesis promotes further tumorigenesis and generating ECD;huHER2 double transgenic mice will test this hypothesis. Further characterization of the ECDTg vs. ECD;huHER2Tg models will help delineate the molecular mechanism of poor outcomes in patients overexpressing both ECD and HER2. Aim 1 will examine the co-oncogenic role of ECD in HER2-driven breast cancer using mouse mammary gland-targeted ECD transgene overexpression. Aim 2 will use unbiased approaches (RNA-seq and metabolomics) to delineate the mechanism of ECD- and HER2- dependent oncogenesis in BC. Validation of our hypothesis will help us understand how ECD overexpression promotes HER2-driven BC with worse outcomes. A validated ECD;huHER2Tg model will provide an invaluable tool to understand the mechanistic basis of their co-oncogenesis and future testing of novel therapeutics against HER2+/ECD-overexpressing BC and to address therapy resistance. Success of our studies may also open broader avenues for other malignancies where ECD overexpression is associated with tumor progression.