{"title":"Local radiotherapy polarized tumor-associated macrophages enhance the efficacy of Claudin18.2-targeted CAR-T therapy in pancreatic cancer.","authors":"Xiaokang Zhang, Hongtai Shi, Leran Qiu, Zhunyi Gao, Jiahe Xu, Xingyu Zhou, Zeya Xia, Ganesh Radhakrishna, Jiao Xue, Songbing Qin","doi":"10.21037/jgo-2025-564","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, and a 5-year survival rate of less than 10%. Its dense, immunosuppressive tumor microenvironment (TME) limits the effectiveness of conventional therapies, including immunotherapy. Chimeric antigen receptor T-cell (CAR-T) therapy targeting the tight junction protein claudin18.2 (CLDN18.2) has shown promise in preclinical PDAC studies, but its efficacy is severely constrained by immunosuppressive components in the TME, such as tumor-associated macrophages (TAMs). In addition to directly killing tumor cells, radiotherapy (RT) can modulate the TME, promote immune cell infiltration, and potentially enhance the efficacy of CAR-T in solid tumors. This study aimed to investigate the effects of combining RT with CLDN18.2-targeted CAR-T therapy for PDAC, focusing on elucidating whether RT can overcome the major barriers to immunotherapy in PDAC by reshaping the immunosuppressive TME and enhancing CAR-T infiltration and function.</p><p><strong>Methods: </strong>Second-generation anti-CLDN18.2 CAR-Ts with high transduction efficiency were generated. <i>In vitro</i>, we assessed the cytotoxicity of CAR-Ts against PDAC cells expressing CLDN18.2 both with and without prior irradiation. <i>In vivo</i>, the combination of RT and CAR-T therapy was tested in PDAC-bearing mice, and survival and tumor growth were monitored. The immune response and TME were analyzed for CAR-T infiltration, effector function production [tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and granzyme B], and immune cell composition (Tregs, MDSCs, and M1 macrophages).</p><p><strong>Results: </strong><i>In vitro</i>, the CAR-Ts exhibited potent cytotoxicity against the CLDN18.2-positive PDAC cells, and the efficacy was enhanced in the irradiated PDAC cells compared to the non-irradiated control PDAC cells. <i>In vivo</i>, local RT combined with CAR-T therapy significantly prolonged survival and delayed tumor growth in the PDAC-bearing mice. Additionally, the combination therapy increased the CAR-T infiltration and effector functions. Local RT also reshaped the TME by increasing M1 macrophages and reducing M2 macrophages.</p><p><strong>Conclusions: </strong>Local RT significantly enhanced the anti-tumor efficacy of CLDN18.2-targeted CAR-T therapy against PDAC. <i>In vitro</i>, RT increased CAR-T cytotoxicity against CLDN18.2-positive PDAC cells. <i>In vivo</i>, combining RT with CAR-T therapy prolonged survival and delayed tumor growth in tumor-bearing mice. This synergy resulted from RT promoting CAR-T infiltration and effector function, while reshaping the tumor microenvironment (TME) by increasing pro-inflammatory M1 macrophages and reducing immunosuppressive M2 macrophages. These findings show the potential of this combination approach as a promising therapeutic strategy for improving outcomes in PDAC patients.</p>","PeriodicalId":15841,"journal":{"name":"Journal of gastrointestinal oncology","volume":"16 4","pages":"1682-1698"},"PeriodicalIF":2.0000,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12433137/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of gastrointestinal oncology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.21037/jgo-2025-564","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2025/8/27 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"GASTROENTEROLOGY & HEPATOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Background: Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, and a 5-year survival rate of less than 10%. Its dense, immunosuppressive tumor microenvironment (TME) limits the effectiveness of conventional therapies, including immunotherapy. Chimeric antigen receptor T-cell (CAR-T) therapy targeting the tight junction protein claudin18.2 (CLDN18.2) has shown promise in preclinical PDAC studies, but its efficacy is severely constrained by immunosuppressive components in the TME, such as tumor-associated macrophages (TAMs). In addition to directly killing tumor cells, radiotherapy (RT) can modulate the TME, promote immune cell infiltration, and potentially enhance the efficacy of CAR-T in solid tumors. This study aimed to investigate the effects of combining RT with CLDN18.2-targeted CAR-T therapy for PDAC, focusing on elucidating whether RT can overcome the major barriers to immunotherapy in PDAC by reshaping the immunosuppressive TME and enhancing CAR-T infiltration and function.
Methods: Second-generation anti-CLDN18.2 CAR-Ts with high transduction efficiency were generated. In vitro, we assessed the cytotoxicity of CAR-Ts against PDAC cells expressing CLDN18.2 both with and without prior irradiation. In vivo, the combination of RT and CAR-T therapy was tested in PDAC-bearing mice, and survival and tumor growth were monitored. The immune response and TME were analyzed for CAR-T infiltration, effector function production [tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and granzyme B], and immune cell composition (Tregs, MDSCs, and M1 macrophages).
Results: In vitro, the CAR-Ts exhibited potent cytotoxicity against the CLDN18.2-positive PDAC cells, and the efficacy was enhanced in the irradiated PDAC cells compared to the non-irradiated control PDAC cells. In vivo, local RT combined with CAR-T therapy significantly prolonged survival and delayed tumor growth in the PDAC-bearing mice. Additionally, the combination therapy increased the CAR-T infiltration and effector functions. Local RT also reshaped the TME by increasing M1 macrophages and reducing M2 macrophages.
Conclusions: Local RT significantly enhanced the anti-tumor efficacy of CLDN18.2-targeted CAR-T therapy against PDAC. In vitro, RT increased CAR-T cytotoxicity against CLDN18.2-positive PDAC cells. In vivo, combining RT with CAR-T therapy prolonged survival and delayed tumor growth in tumor-bearing mice. This synergy resulted from RT promoting CAR-T infiltration and effector function, while reshaping the tumor microenvironment (TME) by increasing pro-inflammatory M1 macrophages and reducing immunosuppressive M2 macrophages. These findings show the potential of this combination approach as a promising therapeutic strategy for improving outcomes in PDAC patients.
期刊介绍:
ournal of Gastrointestinal Oncology (Print ISSN 2078-6891; Online ISSN 2219-679X; J Gastrointest Oncol; JGO), the official journal of Society for Gastrointestinal Oncology (SGO), is an open-access, international peer-reviewed journal. It is published quarterly (Sep. 2010- Dec. 2013), bimonthly (Feb. 2014 -) and openly distributed worldwide.
JGO publishes manuscripts that focus on updated and practical information about diagnosis, prevention and clinical investigations of gastrointestinal cancer treatment. Specific areas of interest include, but not limited to, multimodality therapy, markers, imaging and tumor biology.