Overcoming in vivo resistance to chemotherapy in triple-negative breast cancer

摘要 三阴性乳腺癌（TNBC）是乳腺癌（BC）中最具侵袭性的亚型，没有靶向治疗。 治疗选择尚未提供，主要依赖于常规化疗。然而，TNBC患者通常 在治疗过程中产生化疗耐药性。新型“可药物化”介质的鉴定 TNBC中化疗耐药性的降低具有改善化疗耐药性TNBC的治疗的潜力。 最近的研究表明，染色体不稳定，异常NF B信号，DNA突变， 修复酶，改变药物转运蛋白的表达，更大的药物解毒和失衡， 调节细胞凋亡的基因作为TNBC的化疗耐药机制。除了这些细胞固有的 细胞外基质（ECM）作为肿瘤微环境的主要成分， 在TNBC化疗耐药性中的多方面作用。然而，ECM的研究主要是在以下背景下进行的： 而不是乳腺癌的耐药性。这项建议是基于我们最近的发现， 低氧诱导赖氨酰氧化酶（LOX：ECM重塑剂）促进对化疗剂的抗性 （蒽环类和紫杉烷类）在TNBC中通过过度激活整联蛋白信号传导而发挥作用。此外，LOX的抑制 其表达或其活性与化疗剂协同作用并克服TNBC中的治疗抗性。 此外，除了细胞外LOX（成熟形式）的已知基质重建功能外，我们 发现LOX的核定位（前蛋白LOX形式）潜在地调节转录。目标1： 阐明脂氧合酶调节整合素信号传导的机制并研究其对整合素信号传导的贡献 在体外和体内TNBC的化学抗性。目的2是进行高通量筛选（HTS）， 使用LOX活性测定的多样化化合物文库和使用药效团模型的计算机筛选 来鉴定新的LOX抑制剂。然后将使用蛋白水解靶向嵌合分子（PROTAC）方法 以产生LOX降解化合物。不同类型的LOX抑制剂作为致敏剂的潜力 将研究不同的化疗剂。目的3是测试LOX抑制剂与 在转录表征的患者来源的异种移植物（PDX）模型中， 肿瘤异质性和源自PDX的类器官。本研究的最终目标是开发一种 化学治疗剂与有效的和选择性LOX抑制剂的组合，这将为 提高TNBC患者的化疗效果和生存率。

ABSTRACT Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer (BC) with no targeted therapy options yet available and relying primarily on conventional chemotherapy. However, TNBC patients often develop chemotherapy resistance during the course of treatment. Identification of novel “druggable” mediators of chemotherapy resistance in TNBC has potential to improve the treatment of chemotherapy-resistant TNBCs. Recent studies revealed a high rate of chromosomal instability, aberrant NF B signaling, mutations in DNA repair enzymes, altered expression of drug transporter proteins, greater drug detoxification and imbalance of genes regulating apoptosis as chemotherapy resistance mechanisms in TNBC. In addition to these cell intrinsic mechanisms, the extracellular matrix (ECM) being a major component of tumor microenvironment may play a multifaceted role in chemotherapy resistance in TNBC. However, ECM has been studied mostly in the context of metastasis rather than drug resistance in breast cancer. This proposal is based on our recent findings that hypoxia-induced lysyl oxidase (LOX: an ECM re-modeler) promotes resistance to chemotherapeutic agents (anthracyclines and taxanes) in TNBC by hyperactivating integrin signaling. In addition, inhibition of LOX expression or its activity synergizes with chemotherapeutic agents and overcomes therapy resistance in TNBCs. Furthermore, in addition to the known matrix re-modeling function of LOX (mature form) outside the cell, we discovered nuclear localization of LOX (pre pro-protein LOX form) potentially regulating transcription. Aim 1 is to elucidate the mechanism of integrin signaling regulation by LOX and to investigate its contribution to chemoresistance in TNBCs both in vitro and in vivo. Aim 2 is to perform a high-throughput screen (HTS) of a diversified compound library using a LOX activity assay and an in silico screen using a pharmacophore model to identify novel inhibitors of LOX. Proteolysis targeting chimeric molecule (PROTAC) approach will then be used to generate LOX-degrading compounds. The potential of different types of LOX inhibitors as sensitizers to different chemotherapeutic agents will be investigated. Aim 3 is to test LOX inhibitors in combination with chemotherapeutic agents in transcriptionally-characterized patient derived xenograft (PDX) models representing tumor heterogeneity and organoids derived from the PDXs. The ultimate goal of this study is to develop a combination of chemotherapeutic agents with potent and selective LOX inhibitors that will pave the way towards improving the efficacy of chemotherapy and survival of TNBC patients.