PO.ET02.08 · 实验与分子治疗
仿生外泌体递送的STAT3抑制剂用于口腔鳞状细胞癌细胞的放射增敏
Biomimetic exosome-delivered STAT3 inhibitor for radiosensitization in oral squamous cell carcinoma cells
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摘要 Abstract
中文摘要
背景：信号转导及转录激活因子3（STAT3）是晚期口腔鳞状细胞癌（OSCC）对放疗产生耐受的关键驱动因素，通过上调包括PD-L1在内的免疫检查点促进免疫抑制性微环境。尽管抑制STAT3是一种有前景的放射增敏策略，但其临床应用受限于药物递送不佳。外泌体作为天然纳米载体，凭借其优异的生物相容性、低免疫原性和固有的靶向能力，提供了一种理想的解决方案。本研究旨在开发一种基于外泌体的STAT3抑制剂靶向递送系统，以提高OSCC放疗的疗效。
方法：我们通过超声处理将STAT3抑制剂（S3I-201）载入源自小鼠口腔鳞状细胞癌（MOC2）细胞的外泌体中，构建了一种仿生递送系统（Exo@S3I-201）。通过透射电子显微镜（TEM）、纳米颗粒跟踪分析（NTA）和蛋白质印迹对该系统进行表征。通过紫外光谱测定载药效率和pH依赖性释放曲线。通过荧光显微镜可视化细胞摄取和靶向。通过CCK-8实验、集落形成实验、流式细胞术、活死染色，在体外评估Exo@S3I-201对MOC2细胞的放射增敏效应。
结果：成功构建的Exo@S3I-201表现出与普通外泌体相似的尺寸、分散性和稳定性。紫外吸收证实Exo@S3I-201保留了S3I-201的特征吸收峰，表现出高载药效率，并展现出pH响应性药物释放行为，在模拟肿瘤微环境的酸性条件下（pH=5.5）释放量最大。荧光显微镜显示Exo@S3I-201被高效摄取入MOC2细胞。蛋白质印迹分析显示，与游离S3I-201相比，Exo@S3I-201联合放疗更有效地抑制STAT3磷酸化及其下游靶基因的表达。在功能上，与单独放疗或游离S3I-201相比，联合治疗显著抑制了MOC2细胞的增殖和集落形成能力，并诱导更高水平的细胞凋亡。
结论：我们的研究提出了一种基于自体外泌体的STAT3抑制剂靶向递送系统。Exo@S3I-201通过抑制STAT3通路显著增强了OSCC的放射敏感性，展示了其作为克服放射耐受的新型联合疗法的潜力。
查看英文原文 English abstract
Background: Signal transducer and activator of transcription 3 (STAT3) is a key driver of resistance to radiotherapy in advanced oral squamous cell carcinoma (OSCC), promoting an immunosuppressive microenvironment via upregulation of immune checkpoints including PD-L1. Although STAT3 inhibition represents a promising radiosensitizing strategy, its clinical application is limited by poor drug delivery. Exosomes, as natural nanocarriers, present an ideal solution with their excellent biocompatibility, low immunogenicity, and inherent targeting capabilities. This study aimed to develop an exosome-based targeted delivery system for a STAT3 inhibitor to improve the efficacy of radiotherapy in OSCC.
Methods: We constructed a biomimetic delivery system (Exo@S3I-201) by loading the STAT3 inhibitor (S3I-201) into exosomes derived from mouse oral squamous cell carcinoma (MOC2) cells via sonication. The system was characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western Blot. Drug loading efficiency and pH-dependent release profile were determined by ultraviolet spectroscopy. Cellular uptake and targeting were visualized by fluorescence microscopy. The radiosensitizing effect of Exo@S3I-201 on MOC2 cells were evaluated in vitro through CCK-8 assay, colony formation assay, flow cytometry, live-dead staining.
Results: The successfully constructed Exo@S3I-201 exhibited similar size, dispersion, and stability to plain exosomes. UV absorption confirmed that Exo@S3I-201 retained the characteristic absorption peak of S3I-201, exhibited high drug loading efficiency, and displayed pH-responsive drug release behavior, with maximal release under acidic conditions (pH=5.5) mimicking the tumor microenvironment. Fluorescence microscopy revealed efficient cellular uptake of Exo@S3I-201 into MOC2 cells. Western Blot analysis revealed that Exo@S3I-201 combined with radiotherapy more effectively suppressed STAT3 phosphorylation and expression of its downstream target genes, compared with free S3I-201. Functionally, compared to radiotherapy alone or free S3I-201, the combined treatment markedly inhibited MOC2 cell proliferation and colony-forming ability and induced higher levels of cellular apoptosis.
Conclusion: Our study presented an autologous exosome-based system for targeted STAT3 inhibitor delivery. Exo@S3I-201 significantly enhanced radiosensitivity in OSCC by inhibiting the STAT3 pathway, demonstrating its potential as a novel combination therapy to overcome radioresistance.
利益披露 Disclosure
K. Hu, None..
S. Yan, None..
X. Guo, None..
R. Xue, None..
Y. Mo, None..
H. Qiu, None..
L. Bu, None..
Q. Wu, None.