Zhao Zijun, Zhang HaiYan, Zeng Qingyv, Wang Peiru, Zhang Guolong, Ji Jie, Li Meng, Shen ShuZhan, Wang Xiuli
Institute of Photomedicine, Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, China.
Institute of Photomedicine, Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, China.
Photodiagnosis Photodyn Ther. 2020 Jun;30:101746. doi: 10.1016/j.pdpdt.2020.101746. Epub 2020 Apr 5.
5-aminolevulinic acid photodynamic therapy (ALA-PDT) is effective in skin tumours. Studies have demonstrated that the therapy has anti-tumour immunity in squamous cell carcinoma (SCC). Exosomes play an important role in tumour microenvironment (TME) crosstalk. Nevertheless, whether exosomes mediate the ALA-PDT anti-tumour effect is unclear. This study aims to investigate whether exosomes secreted from ALA-PDT-treated squamous carcinoma cells (SCCs) demonstrate an anti-tumour effect by inducing dendritic cell (DCs) maturation.
In this study, we used electron microscopy, nanoparticle tracking analysis and western blotting to identify exosomes. Subsequently, BCA assay and fluorescence staining were used to evaluate the biological activity of exosomes. Exosomes derived from ALA-PDT-treated SCCs were incubated with SCCs, fibroblasts and immature DCs, separately. A CCK-8 kit was used to analyse the cytotoxicity of exosomes to SCCs. ELISA was utilised to analyse IL-6, VEGF, MMP-3, and TGF-β1 secreted from fibroblasts. FACS and ELISA were used to analysed DC phenotypic maturation (CD80, MHC-II) and IL-12 secretion.
Herein we show that exosomes secreted from SCCs after ALA-PDT cannot exert cytotoxicity towards SCCs. However, exosomes derived from ALA-PDT-treated SCCs could induce DCs maturation and IL-12 secretion. Furthermore, exosomes secreted from SCCs after ALA-PDT promote the secretion of TGF-β1 from fibroblast.
In conclusion, we found that exosomes derived from ALA-PDT-treated SCCs have the ability to stimulate DC maturation and fibroblast secretion of TGF-β1, which results in the elevation of anti-tumour immunity. These findings provide a new promising strategy of anti-tumour immune response for ALA-PDT in treating SCCs.
5-氨基酮戊酸光动力疗法（ALA-PDT）对皮肤肿瘤有效。研究表明，该疗法在鳞状细胞癌（SCC）中具有抗肿瘤免疫作用。外泌体在肿瘤微环境（TME）串扰中起重要作用。然而，外泌体是否介导ALA-PDT的抗肿瘤作用尚不清楚。本研究旨在探讨ALA-PDT处理的鳞状癌细胞（SCC）分泌的外泌体是否通过诱导树突状细胞（DCs）成熟发挥抗肿瘤作用。
在本研究中，我们使用电子显微镜、纳米颗粒跟踪分析和蛋白质印迹法鉴定外泌体。随后，采用BCA法和荧光染色评估外泌体的生物学活性。将ALA-PDT处理的SCC来源的外泌体分别与SCC、成纤维细胞和未成熟DCs孵育。使用CCK-8试剂盒分析外泌体对SCC的细胞毒性。采用ELISA法分析成纤维细胞分泌的IL-6、VEGF、MMP-3和TGF-β1。采用流式细胞术（FACS）和ELISA法分析DC表型成熟（CD80、MHC-II）和IL-12分泌。
在此我们表明，ALA-PDT后SCC分泌的外泌体对SCC无细胞毒性。然而，ALA-PDT处理的SCC来源的外泌体可诱导DCs成熟和IL-12分泌。此外，ALA-PDT后SCC分泌的外泌体促进成纤维细胞分泌TGF-β1。
总之，我们发现ALA-PDT处理的SCC来源的外泌体具有刺激DC成熟和成纤维细胞分泌TGF-β1的能力，从而导致抗肿瘤免疫力提高。这些发现为ALA-PDT治疗SCC提供了一种新的、有前景的抗肿瘤免疫反应策略。
