Barbosa Gabriela, De Godoy Maria Carolina Ximenes, Bighetto Caroline Cavalli, Skakum Emily Macedo, Pascoal Lívia Bitencourt, Gambero Alessandra, Reis Leonardo O
ImmunOOncology, Pontifical Catholic University of Campinas, Campinas, São Paulo, Brazil.
UroGen, National Institute of Science, Technology and Innovation in Genitourinary Cancer (INCT), Campinas, São Paulo, Brazil.
Int J Gen Med. 2025 Jun 25;18:3401-3411. doi: 10.2147/IJGM.S531858. eCollection 2025.
Programmed death-ligand 1 (PD-L1) is a key immune checkpoint molecule involved in tumor immune evasion. Its expression is highly heterogeneous across cancer types and subtypes, influencing therapeutic response. Understanding how different immunomodulatory agents influence PD-L1 expression in breast cancer cells could inform novel therapeutic strategies. This study aimed to investigate the temporal and dose-dependent effects of Bacillus Calmette-Guérin (BCG) and Toll-like receptor (TLR) agonists on PD-L1 expression in two breast cancer cell lines: MCF7 (luminal) and MDA-MB-231 (triple-negative).
MTT (thiazolyl blue tetrazolium bromide) assays were conducted to determine non-cytotoxic concentrations of the immunomodulatory agents: 25 µM IMQ (imiquimod), 10 µg PPG (peptidoglycan), 1 mg LPS (lipopolysaccharide), and two BCG doses (200 µg/mL and 800 µg/mL). Flow cytometry assessed anti-PD-L1 (CD274) antibody expression at 24- and 48 hours post-treatment.
In MCF7 cells, BCG induced a dose-dependent upregulation of PD-L1 at 24 hours, which was not sustained at 48 hours, while TLR agonists had minimal or slightly suppressive effects. In contrast, MDA-MB-231 cells exhibited a time-dependent modulation of PD-L1, with an increase at 24 hours followed by a reduction at 48 hours in response to BCG, while TLR agonists consistently decreased PD-L1 levels compared to controls.
These findings suggest distinct immunomodulatory responses between cancer subtypes, emphasizing the need for tailored approaches targeting the PD-1/PD-L1 axis. Further studies should explore the molecular mechanisms underlying these differential effects and assess the potential for combinatorial immunotherapeutic strategies in cancer.
程序性死亡配体1（PD-L1）是参与肿瘤免疫逃逸的关键免疫检查点分子。其表达在不同癌症类型和亚型中高度异质，影响治疗反应。了解不同免疫调节药物如何影响乳腺癌细胞中PD-L1的表达可为新的治疗策略提供依据。本研究旨在探讨卡介苗（BCG）和Toll样受体（TLR）激动剂对两种乳腺癌细胞系（MCF7（管腔型）和MDA-MB-231（三阴性））中PD-L1表达的时间和剂量依赖性影响。
进行MTT（噻唑蓝四氮唑溴盐）试验以确定免疫调节药物的非细胞毒性浓度：25 μM咪喹莫特（IMQ）、10 μg肽聚糖（PPG）、1 mg脂多糖（LPS）以及两种卡介苗剂量（200 μg/mL和800 μg/mL）。流式细胞术评估治疗后24小时和48小时抗PD-L1（CD274）抗体表达。
在MCF7细胞中，卡介苗在24小时诱导PD-L1剂量依赖性上调，但在48小时未持续，而TLR激动剂具有最小或轻微的抑制作用。相比之下，MDA-MB-231细胞表现出PD-L1的时间依赖性调节，卡介苗作用下24小时增加，48小时减少，而TLR激动剂与对照组相比持续降低PD-L1水平。
这些发现表明癌症亚型之间存在不同的免疫调节反应，强调针对PD-1/PD-L1轴的定制方法的必要性。进一步研究应探索这些差异效应的分子机制，并评估癌症联合免疫治疗策略的潜力。
