PURPOSE Immunotherapy has recently been shown to improve outcomes for advanced PD-L1-positive triple-negative breast cancer (TNBC) in the Impassion130 trial, leading to FDA approval of the first immune checkpoint inhibitor in combination with taxane chemotherapy. To further develop predictive biomarkers and improve therapeutic efficacy of the combination, interrogation of the tumor immune microenvironment before therapy as well as during each component of treatment is crucial. Here we use single-cell RNA sequencing (scRNA-seq) on tumor biopsies to assess immune cell changes from two patients with advanced TNBC treated in a prospective trial at predefined serial time points, before treatment, on taxane chemotherapy and on chemo-immunotherapy. METHODS Both patients (one responder and one progressor) received the trial therapy, in cycle 1 nab-paclitaxel given as single agent, in cycle 2 nab-paclitaxel in combination with pembrolizumab. Tumor core biopsies were obtained at baseline, 3 weeks (after cycle 1, chemotherapy alone) and 6 weeks (after cycle 2, chemo-immunotherapy). Single-cell RNA sequencing (scRNA-seq) of both cancer cells and infiltrating immune cells isolated were performed from fresh tumor core biopsy specimens by 10 × chromium sequencing. RESULTS ScRNA-seq analysis showed significant baseline heterogeneity of tumor-infiltrating immune cell populations between the two patients as well as modulation of the tumor microenvironment by chemotherapy and immunotherapy. In the responding patient there was a population of PD-1high-expressing T cells which significantly decreased after nab-paclitaxel plus pembrolizumab treatment as well as a presence of tissue-resident memory T cells (TRM). In contrast, tumors from the patient with rapid disease progression showed a prevalent and persistent myeloid compartment. CONCLUSIONS Our study provides a deep cellular analysis of on-treatment changes during chemo-immunotherapy for advanced TNBC, demonstrating not only feasibility of single-cell analyses on serial tumor biopsies but also the heterogeneity of TNBC and differences in on-treatment changes in responder versus progressor.

中文翻译：

---

Nab-紫杉醇和派姆单抗治疗期间转移性 TNBC 的连续单细胞分析。

最近，Impassion130 试验显示，免疫疗法可以改善晚期 PD-L1 阳性三阴性乳腺癌 (TNBC) 的预后，这导致 FDA 批准了首个免疫检查点抑制剂与紫杉烷化疗相结合。为了进一步开发预测性生物标志物并提高组合的治疗效果，在治疗前以及治疗的每个组成部分期间对肿瘤免疫微环境的询问至关重要。在这里，我们对肿瘤活检使用单细胞 RNA 测序 (scRNA-seq) 来评估两名晚期 TNBC 患者的免疫细胞变化，这些患者在一项前瞻性试验中在预定的系列时间点、治疗前、紫杉烷化疗和化学免疫治疗中接受治疗。方法 两名患者（一名缓解者和一名进展者）接受了试验治疗，在第 1 周期中白蛋白结合型紫杉醇作为单药给药，在第 2 周期中白蛋白结合型紫杉醇与派姆单抗联合用药。在基线、3周（第1周期后，单独化疗）和6周（第2周期后，化疗免疫治疗）获得肿瘤核心活检。通过 10 × 铬测序对新鲜肿瘤核心活检标本中分离的癌细胞和浸润免疫细胞进行单细胞 RNA 测序 (scRNA-seq)。结果 ScRNA-seq 分析显示两名患者之间肿瘤浸润免疫细胞群的基线存在显着异质性，以及化疗和免疫疗法对肿瘤微环境的调节。在有反应的患者中，PD-1 高表达 T 细胞群在白蛋白结合型紫杉醇加派姆单抗治疗后显着减少，并且存在组织驻留记忆 T 细胞 (TRM)。相比之下，来自疾病快速进展的患者的肿瘤显示出普遍且持久的骨髓区室。结论 我们的研究对晚期 TNBC 化疗免疫治疗过程中的治疗变化进行了深入的细胞分析，不仅证明了对连续肿瘤活检进行单细胞分析的可行性，而且还证明了 TNBC 的异质性以及应答者与治疗者之间治疗变化的差异。进步者。