{"title":"Enhanced systemic antitumor efficacy of PD-1/PD-L1 blockade with immunological response induced by photodynamic therapy.","authors":"Takumi Sonokawa, Yukio Fujiwara, Cheng Pan, Yoshihiro Komohara, Jitsuo Usuda","doi":"10.1111/1759-7714.15325","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Photodynamic therapy (PDT) is an antitumor therapy and has traditionally been regarded as a localized therapy in itself. However, recent reports have shown that it not only exerts a direct cytotoxic effect on cancer cells but also enhances body's tumor immunity. We hypothesized that the immunological response induced by PDT could potentially enhance the efficacy of programmed death-1 (PD-1) / programmed death-ligand 1 (PD-L1) blockade.</p><p><strong>Methods: </strong>The cytotoxic effects of PDT on colon 26 cells were investigated in vitro using the WST assay. We investigated whether the antitumor effect of anti-PD-1 antibodies could be amplified by the addition of PDT. We performed combination therapy by randomly allocating tumor-bearing mice to four treatment groups: control, anti-PD-1 antibodies, PDT, and a combination of anti-PD-1 antibodies and PDT. To analyze the tumor microenvironment after treatment, the tumors were resected and pathologically evaluated.</p><p><strong>Results: </strong>The viability rate of colon 26 cells decreased proportionally with the laser dose. In vivo experiments for combined PDT and anti-PD-1 antibody treatment, combination therapy showed an enhanced antitumor effect compared with the control. Immunohistochemical findings of the tumor microenvironment 10 days after PDT indicated that the number of CD8+ cells, the area of Iba-1+ cells and the area expressing PD-L1 were significantly higher in tumors treated with combination therapy than in tumors treated with anti-PD-1 antibody alone, PDT alone, or the control.</p><p><strong>Conclusions: </strong>PDT increased immune cell infiltration into the tumor microenvironment. The immunological response induced by PDT may enhance the efficacy of PD-1/PD-L1 blockade.</p>","PeriodicalId":23338,"journal":{"name":"Thoracic Cancer","volume":null,"pages":null},"PeriodicalIF":2.3000,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11194119/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Thoracic Cancer","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1111/1759-7714.15325","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/5/13 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"ONCOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Background: Photodynamic therapy (PDT) is an antitumor therapy and has traditionally been regarded as a localized therapy in itself. However, recent reports have shown that it not only exerts a direct cytotoxic effect on cancer cells but also enhances body's tumor immunity. We hypothesized that the immunological response induced by PDT could potentially enhance the efficacy of programmed death-1 (PD-1) / programmed death-ligand 1 (PD-L1) blockade.
Methods: The cytotoxic effects of PDT on colon 26 cells were investigated in vitro using the WST assay. We investigated whether the antitumor effect of anti-PD-1 antibodies could be amplified by the addition of PDT. We performed combination therapy by randomly allocating tumor-bearing mice to four treatment groups: control, anti-PD-1 antibodies, PDT, and a combination of anti-PD-1 antibodies and PDT. To analyze the tumor microenvironment after treatment, the tumors were resected and pathologically evaluated.
Results: The viability rate of colon 26 cells decreased proportionally with the laser dose. In vivo experiments for combined PDT and anti-PD-1 antibody treatment, combination therapy showed an enhanced antitumor effect compared with the control. Immunohistochemical findings of the tumor microenvironment 10 days after PDT indicated that the number of CD8+ cells, the area of Iba-1+ cells and the area expressing PD-L1 were significantly higher in tumors treated with combination therapy than in tumors treated with anti-PD-1 antibody alone, PDT alone, or the control.
Conclusions: PDT increased immune cell infiltration into the tumor microenvironment. The immunological response induced by PDT may enhance the efficacy of PD-1/PD-L1 blockade.
期刊介绍:
Thoracic Cancer aims to facilitate international collaboration and exchange of comprehensive and cutting-edge information on basic, translational, and applied clinical research in lung cancer, esophageal cancer, mediastinal cancer, breast cancer and other thoracic malignancies. Prevention, treatment and research relevant to Asia-Pacific is a focus area, but submissions from all regions are welcomed. The editors encourage contributions relevant to prevention, general thoracic surgery, medical oncology, radiology, radiation medicine, pathology, basic cancer research, as well as epidemiological and translational studies in thoracic cancer. Thoracic Cancer is the official publication of the Chinese Society of Lung Cancer, International Chinese Society of Thoracic Surgery and is endorsed by the Korean Association for the Study of Lung Cancer and the Hong Kong Cancer Therapy Society.
The Journal publishes a range of article types including: Editorials, Invited Reviews, Mini Reviews, Original Articles, Clinical Guidelines, Technological Notes, Imaging in thoracic cancer, Meeting Reports, Case Reports, Letters to the Editor, Commentaries, and Brief Reports.