Nanoparticle delivered miR-489 rejuvenates anthracycline-based chemotherapy

摘要 三阴性乳腺癌（TNBC）占乳腺癌的15%至20%，是最常见的乳腺癌。 与其他亚型相比，侵袭性亚型的中位总生存期显著较短。 TNBC没有靶向治疗，只有10%的TNBC患者对免疫治疗有反应。 因此，大多数TNBC患者仍主要依赖常规化疗，其中多柔比星 (Dox)作为一种常用的。使用Dox等化疗药物的两个关键问题是 严重的毒性和耐药性。广泛的研究揭示了许多改变的信号通路 导致对多柔比星耐药性的发展。然而，要确定代理人是一项艰巨的任务 可以同时针对不同的耐药途径。最近，合成的miRNA模拟物 或抑制剂已成为有吸引力的工具，以对抗癌症作为一种新型疗法或打破药物 因为一个microRNA可以靶向多个信号通路中的多个基因。我们最近 公开的数据显示，miR-489在大多数乳腺癌尤其是TNBC中丢失。损失 miR-489赋予对化疗如阿霉素（Dox）的抗性和miR-489的恢复 在体外和体内逆转Dox抗性。进一步的机制研究表明，miR489 可抑制Dox诱导的细胞保护性自噬，增加Dox在细胞核中的定位， Dox诱导的ATP释放。重要的是，我们开发了一种纳米颗粒系统， miR489用于乳腺肿瘤。基于这些发现，我们建议纳米颗粒递送miR-489 可以同时调节细胞增殖、凋亡、上皮细胞增殖、细胞凋亡和细胞凋亡等多种途径。 间充质转化（EMT），自噬和ER应激，以增强Dox诱导的细胞死亡和抗 癌症免疫力，因此延迟或逆转Dox抗性。提出了三个具体目标。 SA 1.为了配制肿瘤靶向miR-489纳米颗粒并表征递送效率， 体外和体内毒性。SA 2.为了测试miR-489是否与Dox协同诱导细胞凋亡， 使用细胞系和患者来源的异种移植（PDX）小鼠模型， SA 3.为了研究miR-489是否增强使用人源化miR-489的PDX的Dox治疗的功效， 小鼠模型。总的来说，这项研究的目的是开发miR-489作为一种新的治疗剂，以逆转 Dox耐药性，从而增强基于Dox的化疗的疗效。

Abstract Triple-negative breast cancer (TNBC) comprises 15 to 20% of breast cancers and is the most aggressive subtype with a significantly shorter median overall survival compared to other subtypes. There are no targeted therapies for TNBC and only 10% of TNBC patients respond to immune therapy. Thus, most of patients with TNBC still mainly depend on conventional chemotherapies, with doxorubicin (Dox) as a commonly used one. The two crucial concerns with use of chemotherapies such as Dox are severe toxicity and drug resistance. Extensive studies have unveiled many altered signaling pathways that contribute to the development of Dox resistance. However, it is a daunting task to identify agents that can target the diverse drug-resistant pathways simultaneously. Recently, synthetic miRNA mimics or inhibitors have become attractive tools to battle cancer as a new type of therapies or to break drug resistance because one microRNA can target multiple genes in multiple signaling pathways. Our recent published data showed that miR-489 is lost in a majority of breast cancers especially TNBC. Loss of miR-489 confers resistance to chemotherapies such as doxorubicin (Dox) and restoration of miR-489 reverses Dox resistance both in vitro and in vivo. Further mechanistic studies revealed that miR489 can inhibit Dox-induced cytoprotective autophagy, increase Dox localization in nucleus and potentiate Dox-induced ATP release. Importantly, we developed a nanoparticle system to specifically deliver miR489 to breast tumors. Based on these findings, we propose that nanoparticle delivered miR-489 can simultaneously modulate multiple pathways involved in cell proliferation, apoptosis, epithelial- mesenchymal transition (EMT), autophagy and ER stress to enhance Dox-induced cell death and anti- cancer immunity and therefore delay or reverse Dox resistance. Three specific aims are proposed. SA1. To formulate tumor-targeting miR-489 nanoparticles and characterize the delivery efficiency and toxicity both in vitro and in vivo. SA2. To test whether miR-489 synergizes with Dox to induce cell death and reverses Dox-resistance using cell line and patient-derived xenograft (PDX) mouse models. SA3. To investigate whether miR-489 enhances the efficacy of Dox treatment of PDX using humanized mouse models. Overall, this study aims to develop miR-489 as a novel therapeutic agent to reverse Dox resistance and thus enhance the efficacy of Dox-based chemotherapy.