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，因为它显示出所有乳腺癌中最令人沮丧的预后，甚至比 三阴性乳腺癌（TNBC），在具有转移性疾病的患者中具有8个月或更短的存活率。 由于缺乏药物靶点，转移性MpBC的主要治疗选择仍然是全身性的 化疗，尽管已知对大多数细胞毒性药物的耐药性。MpBC中一种常见的分子改变是 磷酸肌醇3-激酶和蛋白激酶B（PI 3 K/AKT）途径的过度活化。另外我们 最近发表了MpBC在核糖体蛋白L39（RPL 39）中显示功能获得性致癌突变， 其负责治疗抗性、干细胞自我更新和肺转移。机械论 RPL 39的功能通过诱导型一氧化氮合酶（iNOS）介导的一氧化氮产生来介导。 此外，我们在一项完整的临床试验中证明，抑制这种一氧化氮合酶（NOS）通路， 使用泛NOS抑制剂NG-甲基-L-精氨酸乙酸酯（L-NMMA）可能代表一种高效的治疗方法， TNBC患者的选择。因此，我们假设一种联合靶向抑制方法， MpBC中涉及的两个主要致癌途径，PI 3 K/AKT和NOS，将导致显著的 肿瘤消退为了验证这一假设，U 01应用程序汇集了来自休斯顿的研究团队 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中心 癌症研究所（NCI）。具体目标1试图定义使用alpelisib和alpelisib的PI 3 K/AKT的双重抑制是否 使用L-NMMA联合nab-紫杉醇抑制NOS将增加客观缓解率和生存率 在转移性MpBC患者中。在特定目标2中，使用试验中收集的血液和核心活检组织，我们将 确定对治疗的反应机制，以确定靶向PI 3 K/AKT和NOS的疗效 通路抑制法此外，肿瘤细胞、髓系细胞、淋巴样细胞和淋巴样细胞之间的细胞-细胞相互作用也是研究的热点。 肿瘤微环境中的基质细胞及其在支持癌症干细胞中的作用 将评价治疗期间的细胞群和耐药细胞发展。不同细胞的影响 肿瘤生态系统内肿瘤干细胞维持和调节过程的定位模式， 以及耐药性的发展，将在单细胞水平上进行分析， 转录组学、免疫荧光、CyTOF成像系统和多模态数据分析模型。这 因此，一项研究提出了一种针对两个关键的组合靶向方法的机制调查， MpBC中的信号通路，开发独特的串扰模型，并确定耐药性和细胞间干扰的生物标志物。 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.