Abstract
Background: Triple-negative breast cancer (TNBC) is the most intractable subgroup of breast neoplasms due to its aggressive nature. In recent years, immune checkpoint inhibitors (ICIs) have exhibited potential efficacy in TNBC treatment. However, only a limited fraction of patients benefit from ICI therapy, primarily because of the suppressive tumor immune microenvironment (TIME). Trametes robiniophila Murr (Huaier) is a traditional Chinese medicine (TCM) with potential immunoregulatory functions. However, the underlying mechanism remains unclear.
Purpose: The present study aimed to investigate the therapeutic role of Huaier in the TIME of TNBC patients.
Methods: Single-cell RNA sequencing (scRNA-seq) was used to systematically analyze the influence of Huaier on the TNBC microenvironment for the first time. The mechanisms of the Huaier-induced suppression of cancer-associated fibroblasts (CAFs) were assessed via real-time quantitative polymerase chain reaction (qRT‒PCR) and western blotting. A tumor-bearing mouse model was established to verify the effects of the oral administration of Huaier on immune infiltration.
Results: Unsupervised clustering of the transcriptional profiles suggested an increase in the number of apoptotic cancer cells in the Huaier group. Treatment with Huaier induced immunological alterations from a "cold" to a "hot" state, which was accompanied by phenotypic changes in CAFs. Mechanistic analysis revealed that Huaier considerably attenuated the formation of myofibroblastic CAFs (myoCAFs) by impairing transforming growth factor-beta (TGF-β)/SMAD signaling. In mouse xenograft models, Huaier dramatically modulated CAF differentiation, thus synergizing with the programmed cell death 1 (PD1) blockade to impede tumor progression.
Conclusions: Our findings demonstrate that Huaier regulates cancer immunity in TNBC by suppressing the transition of CAFs to myoCAFs and emphasize the crucial role of Huaier as an effective adjuvant agent in immunotherapy.
摘要
背景：三阴性乳腺癌（TNBC）因其侵袭性而成为乳腺肿瘤中最棘手的亚组。近年来，免疫检查点抑制剂（ICIs）在 TNBC 治疗中显示出了潜在的疗效。然而，只有有限的一部分患者能从ICI治疗中获益，这主要是由于肿瘤免疫微环境（TIME）的抑制作用。槐尔是一种传统中药，具有潜在的免疫调节功能。然而，其潜在机制仍不清楚。
目的：本研究旨在探讨怀儿在TNBC患者TIME中的治疗作用。
方法：利用单细胞RNA测序（scRNA-seq）首次系统分析了槐尔对TNBC 微环境的影响。通过实时定量聚合酶链式反应（qRT-PCR）和免疫印迹法评估了怀儿抑制癌相关成纤维细胞（CAFs）的机制。建立了肿瘤小鼠模型，以验证口服槐尔对免疫浸润的影响。
结果：转录特征的无监督聚类表明，槐尔组凋亡癌细胞的数量有所增加。槐尔治疗诱导免疫学改变，从“冷”状态转变为“热”状态，并伴随着CAFs的表型变化。机理分析表明，槐尔通过影响转化生长因子-β（TGF-β）/SMAD信号传导，大大减少了肌成纤维细胞CAFs（肌CAFs）的形成。在小鼠异种移植模型中，槐尔能显著调节CAF的分化，从而与细胞程序性死亡1（PD1）阻断协同作用，阻碍肿瘤进展。
结论：我们的研究结果表明，Huaier通过抑制CAFs向myoCAFs的转化来调节TNBC的癌症免疫，并强调了Huaier作为一种有效的辅助药物在免疫治疗中的关键作用。
