A phase II multi-center trial evaluating dual targeting of the PI3K/AKT and NOS pathways for treating metaplastic breast cancer (MpBC)

摘要 化生性乳腺癌(MpBC)是一种罕见的亚型，占所有乳腺癌的1%。然而，MpBC是 这是一个重大的健康挑战，因为它表现出所有乳腺癌中最糟糕的预后，甚至比 三阴性乳腺癌(TNBC)，转移性疾病患者的生存期不超过8个月。 由于缺乏可用药靶点，转移性多发性骨髓细胞癌的主要治疗选择仍然是全身的。 化疗，尽管已知对大多数细胞毒药物具有耐药性。MpBC中一种常见的分子改变是 肌醇磷脂3-激酶和蛋白激酶B(PI3K/AKT)途径的过度激活。此外，我们 最近发表的MpBC显示了核糖体蛋白L39(RPL39)的功能获得致癌突变， 它负责治疗耐药、干细胞自我更新和肺转移。机械论 RPL39的功能是通过诱导型一氧化氮合酶(INOS)介导的一氧化氮产生来实现的。 此外，我们在一项已完成的临床试验中证明，抑制这种一氧化氮合酶(NOS)途径 使用一氧化氮合酶抑制剂N-甲基-L-精氨酸乙酸酯(L-精氨酸甲酯)可能是一种高效的治疗方法 可供TNBC患者选择。因此，我们假设一种组合靶向抑制方法 MpBC涉及的两个主要致癌途径，PI3K/AKT和NOS，将导致显著的 肿瘤消退。为了验证这一假设，这款U01应用程序汇集了休斯顿的研究团队 卫理公会癌症中心(HMCC)、德克萨斯大学MD安德森癌症中心和国家 癌症研究所(NCI)。具体目标1试图定义使用alpelisib和AKT双重抑制PI3K/AKT 应用L-NMMA联合NaB-紫杉醇抑制一氧化氮合酶可提高客观缓解率和生存率 在转移性MpBC患者中。在具体目标2中，使用试验中收集的血液和核心活检组织，我们将 确定治疗反应的机制以确定靶向PI3K/AKT和NOS的疗效 途径抑制法。此外，肿瘤细胞、髓系细胞、淋巴样细胞之间的细胞-细胞相互作用 肿瘤微环境中的细胞和基质细胞及其在支持肿瘤干细胞中的作用 将对治疗期间的种群和耐药细胞发展进行评估。不同细胞的影响 肿瘤生态系统中肿瘤干细胞维持和调节过程中的定位模式， 以及耐药性的发展，将在单细胞水平上使用空间分析 转录学、免疫荧光、细胞飞行时间成像系统和多模式数据分析模型。这 因此，研究提出了针对这两个关键问题的组合靶向方法的机械性研究 MpBC中的通路，开发独特的串扰模型，并识别抗性和细胞-细胞的生物标志物 使用来自MpBC患者的标本进行相互作用。

ABSTRACT Metaplastic breast cancer (MpBC) is a rare subset accounting for <1% of all breast cancers. However, MpBC is a significant health challenge as it exhibits the most dismal prognosis of all breast cancers, even worse than triple-negative breast cancer (TNBC), with a survival rate of 8 months or less in patients with metastatic disease. Due to a lack of druggable targets, the main therapeutic option for metastatic MpBC remains systemic chemotherapy, despite known resistance to most cytotoxic drugs. One common molecular alteration in MpBC is hyperactivation of the phosphoinositide 3-kinase and protein kinase B (PI3K/AKT) pathway. Additionally, we recently published that MpBC displays a gain-of-function oncogenic mutation in ribosomal protein L39 (RPL39), which is responsible for treatment resistance, stem cell self-renewal, and lung metastasis. The mechanistic function of RPL39 is mediated through inducible nitric oxide synthase (iNOS)-mediated nitric oxide production. In addition, we demonstrated in a completed clinical trial that inhibiting this nitric oxide synthase (NOS) pathway using pan-NOS inhibitor NG-methyl-L-arginine acetate (L-NMMA) may represent a highly effective therapeutic option for TNBC patients. Therefore, we hypothesize that a combinatorial targeted approach of inhibiting the two major oncogenic pathways implicated in MpBC, PI3K/AKT and NOS, would lead to significant tumor regression. To test this hypothesis, this U01 application brings together research teams from Houston Methodist Cancer Center (HMCC), The University of Texas MD Anderson Cancer Center, and the National Cancer Institute (NCI). Specific Aim 1 seeks to define whether dual inhibition of PI3K/AKT using alpelisib and NOS inhibition using L-NMMA combined with nab-paclitaxel will increase the objective response rate and survival in metastatic MpBC patients. In Specific Aim 2, using blood and core biopsy tissues collected in the trial, we will identify mechanisms of response to therapy to determine the efficacy of the targeted PI3K/AKT and NOS pathway inhibitory approach. Furthermore, the cell-cell interactions among tumor cells, myeloid cells, lymphoid cells, and stromal cells within the tumor microenvironment and their role in supporting cancer stem cell populations and drug-resistant cell development during treatment will be evaluated. The impact of distinct cellular localization patterns within the tumor ecosystem on the process of cancer stem cell maintenance and modulation, as well as the development of drug resistance, will be analyzed at the single-cell level using spatial transcriptomics, immunofluorescence, CyTOF imaging systems, and a multi-modal data analysis model. This study thus proposes a mechanistic investigation of a combinatorial targeted approach against the two key pathways in MpBC, develops unique crosstalk models, and identifies biomarkers of resistance and cell–cell interactions using specimens derived from MpBC patients.