{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T13:23:21Z","timestamp":1791033801030,"version":"4.1.0"},"reference-count":46,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2025,7,2]],"date-time":"2025-07-02T00:00:00Z","timestamp":1751414400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Mackay Memorial Hospital","award":["MMH-E-114-11"],"award-info":[{"award-number":["MMH-E-114-11"]}]},{"name":"Mackay Memorial Hospital","award":["MMH-E-113-11"],"award-info":[{"award-number":["MMH-E-113-11"]}]},{"name":"Mackay Memorial Hospital","award":["MMH-E-112-11"],"award-info":[{"award-number":["MMH-E-112-11"]}]},{"name":"Mackay Memorial Hospital","award":["NSTC 112-2314-B-195-020-MY3"],"award-info":[{"award-number":["NSTC 112-2314-B-195-020-MY3"]}]},{"DOI":"10.13039\/501100004663","name":"National Science and Technology Council","doi-asserted-by":"publisher","award":["MMH-E-114-11"],"award-info":[{"award-number":["MMH-E-114-11"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004663","name":"National Science and Technology Council","doi-asserted-by":"publisher","award":["MMH-E-113-11"],"award-info":[{"award-number":["MMH-E-113-11"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004663","name":"National Science and Technology Council","doi-asserted-by":"publisher","award":["MMH-E-112-11"],"award-info":[{"award-number":["MMH-E-112-11"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004663","name":"National Science and Technology Council","doi-asserted-by":"publisher","award":["NSTC 112-2314-B-195-020-MY3"],"award-info":[{"award-number":["NSTC 112-2314-B-195-020-MY3"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cells"],"abstract":"<jats:p>Immunotherapy targeting the immune functions of the tumor microenvironment (TME) is beneficial for colorectal cancer; however, the response rate is poor. Ciprofloxacin is a fluoroquinolone-class antibiotic that is used to treat bacterial infections. The purpose of this study is to assess the mechanism of ciprofloxacin that enhances anti-PD1 in colorectal cancer. We found that ciprofloxacin induced cytosolic DNA, including single-stranded and double-stranded DNA, formation in mouse CT26 colorectal adenocarcinoma cells. Molecules in DNA-sensing signaling such as cGAS, STING, and IFN\u03b2 mRNA and protein expression were elicited after ciprofloxacin treatment in CT26 cells. STING siRNA abrogated the cGAS-STING pathway activation by ciprofloxacin. In vivo, ciprofloxacin exhibited a synergistic effect with anti-PD1 to suppress tumor growth in a CT26 syngeneic animal model without biological toxicity. The examination of TME revealed that ciprofloxacin, alone and in combination therapy, induced M1 and red pulp macrophage production in the spleen. In tumors, M1 and M2 macrophage levels were increased by ciprofloxacin, and CD8+ T cell granzyme B expression was increased after combination therapy. STING showed the highest expression in tumor specimens after combination treatment. Ciprofloxacin may enhance the anti-PD1 efficacy and modulate the TME through the cGAS-STING pathway.<\/jats:p>","DOI":"10.3390\/cells14131010","type":"journal-article","created":{"date-parts":[[2025,7,2]],"date-time":"2025-07-02T06:10:26Z","timestamp":1751436626000},"page":"1010","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Ciprofloxacin Exerts Anti-Tumor Effects In Vivo Through cGAS-STING Activation and Modulates Tumor Microenvironment"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0606-5927","authenticated-orcid":false,"given":"Jian-Syun","family":"Chen","sequence":"first","affiliation":[{"name":"Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan"},{"name":"Division of Colon and Rectal Surgery, Department of Surgery, MacKay Memorial Hospital, Taipei 104217, Taiwan"},{"name":"Department of Medicine, MacKay Medical College, New Taipei City 252005, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chih-Wen","family":"Chi","sequence":"additional","affiliation":[{"name":"Department of Medical Research, MacKay Memorial Hospital, New Taipei City 251020, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cheng-Ta","family":"Lai","sequence":"additional","affiliation":[{"name":"Division of Colon and Rectal Surgery, Department of Surgery, MacKay Memorial Hospital, Taipei 104217, Taiwan"},{"name":"Department of Medicine, MacKay Medical College, New Taipei City 252005, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shu-Hua","family":"Wu","sequence":"additional","affiliation":[{"name":"Department of Medical Research, MacKay Memorial Hospital, New Taipei City 251020, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hui-Ru","family":"Shieh","sequence":"additional","affiliation":[{"name":"Department of Medical Research, MacKay Memorial Hospital, New Taipei City 251020, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiin-Cherng","family":"Yen","sequence":"additional","affiliation":[{"name":"Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9794-8938","authenticated-orcid":false,"given":"Yu-Jen","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Medical Research, MacKay Memorial Hospital, New Taipei City 251020, Taiwan"},{"name":"Department of Radiation Oncology, MacKay Memorial Hospital, Taipei 104217, Taiwan"},{"name":"Department of Artificial Intelligence and Medical Application, MacKay Junior College of Medicine, Nursing and Management, Taipei 112021, Taiwan"},{"name":"Department of Medical Research, China Medical University Hospital, Taichung 404332, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"229","DOI":"10.3322\/caac.21834","article-title":"Global cancer statistics 2022: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries","volume":"74","author":"Bray","year":"2024","journal-title":"CA Cancer J. Clin."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Adebayo, A.S., Agbaje, K., Adesina, S.K., and Olajubutu, O. (2023). Colorectal Cancer: Disease Process, Current Treatment Options, and Future Perspectives. Pharmaceutics, 15.","DOI":"10.3390\/pharmaceutics15112620"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1002\/cam4.2673","article-title":"Metastatic patterns and survival outcomes in patients with stage IV colon cancer: A population-based analysis","volume":"9","author":"Wang","year":"2020","journal-title":"Cancer Med."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"4680","DOI":"10.1158\/1078-0432.CCR-21-0557","article-title":"FDA Approval Summary: Pembrolizumab for the First-line Treatment of Patients with MSI-H\/dMMR Advanced Unresectable or Metastatic Colorectal Carcinoma","volume":"27","author":"Casak","year":"2021","journal-title":"Clin. Cancer Res. Off. J. Am. Assoc. Cancer Res."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"eaat7807","DOI":"10.1126\/scitranslmed.aat7807","article-title":"The hallmarks of successful anticancer immunotherapy","volume":"10","author":"Galluzzi","year":"2018","journal-title":"Sci. Transl. Med."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1016\/j.immuni.2015.11.024","article-title":"Immunogenic Chemotherapy Sensitizes Tumors to Checkpoint Blockade Therapy","volume":"44","author":"Pfirschke","year":"2016","journal-title":"Immunity"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"374","DOI":"10.1016\/j.ccell.2023.02.016","article-title":"The evolving tumor microenvironment: From cancer initiation to metastatic outgrowth","volume":"41","author":"Joyce","year":"2023","journal-title":"Cancer Cell"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Tiwari, A., Trivedi, R., and Lin, S.Y. (2022). Tumor microenvironment: Barrier or opportunity towards effective cancer therapy. J. Biomed. Sci., 29.","DOI":"10.1186\/s12929-022-00866-3"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Lu, C., Liu, Y., Ali, N.M., Zhang, B., and Cui, X. (2022). The role of innate immune cells in the tumor microenvironment and research progress in anti-tumor therapy. Front. Immunol., 13.","DOI":"10.3389\/fimmu.2022.1039260"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"826","DOI":"10.1126\/science.1229963","article-title":"Cyclic GMP-AMP is an endogenous second messenger in innate immune signaling by cytosolic DNA","volume":"339","author":"Wu","year":"2013","journal-title":"Science"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"E4612","DOI":"10.1073\/pnas.1705499114","article-title":"cGAS is essential for cellular senescence","volume":"114","author":"Yang","year":"2017","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1038\/nature12306","article-title":"cGAS produces a 2\u2032-5\u2032-linked cyclic dinucleotide second messenger that activates STING","volume":"498","author":"Ablasser","year":"2013","journal-title":"Nature"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1094","DOI":"10.1016\/j.cell.2013.04.046","article-title":"Cyclic [G(2\u2032,5\u2032)pA(3\u2032,5\u2032)p] is the metazoan second messenger produced by DNA-activated cyclic GMP-AMP synthase","volume":"153","author":"Gao","year":"2013","journal-title":"Cell"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"786","DOI":"10.1126\/science.1232458","article-title":"Cyclic GMP-AMP synthase is a cytosolic DNA sensor that activates the type I interferon pathway","volume":"339","author":"Sun","year":"2013","journal-title":"Science"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"788","DOI":"10.1038\/nature08476","article-title":"STING regulates intracellular DNA-mediated, type I interferon-dependent innate immunity","volume":"461","author":"Ishikawa","year":"2009","journal-title":"Nature"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1186\/s13045-020-00916-z","article-title":"cGAS-STING, an important pathway in cancer immunotherapy","volume":"13","author":"Jiang","year":"2020","journal-title":"J. Hematol. Oncol."},{"key":"ref_17","unstructured":"Thai, T., Salisbury, B.H., and Zito, P.M. (2025). Ciprofloxacin. StatPearls, StatPearls Publishing."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1002\/j.1875-9114.1988.tb04058.x","article-title":"Ciprofloxacin: Chemistry, mechanism of action, resistance, antimicrobial spectrum, pharmacokinetics, clinical trials, and adverse reactions","volume":"8","author":"LeBel","year":"1988","journal-title":"Pharmacotherapy"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"4850","DOI":"10.1172\/JCI127471","article-title":"cGAS\/STING axis mediates a topoisomerase II inhibitor-induced tumor immunogenicity","volume":"129","author":"Wang","year":"2019","journal-title":"J. Clin. Investig."},{"key":"ref_20","unstructured":"National Research Council (US) Committee for the Update of the Guide for the Care and Use of Laboratory Animals (2011). Guide for the Care and Use of Laboratory Animals, National Academies Press (US). [8th ed.]."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"443","DOI":"10.1038\/sj.bjc.6600079","article-title":"Ciprofloxacin induces apoptosis and inhibits proliferation of human colorectal carcinoma cells","volume":"86","author":"Herold","year":"2002","journal-title":"Br. J. Cancer"},{"key":"ref_22","first-page":"891","article-title":"Ciprofloxacin mediated cell growth inhibition, S\/G2-M cell cycle arrest, and apoptosis in a human transitional cell carcinoma of the bladder cell line","volume":"6","author":"Aranha","year":"2000","journal-title":"Clin. Cancer Res. Off. J. Am. Assoc. Cancer Res."},{"key":"ref_23","first-page":"787","article-title":"Suppression of human prostate cancer cell growth by ciprofloxacin is associated with cell cycle arrest and apoptosis","volume":"22","author":"Aranha","year":"2003","journal-title":"Int. J. Oncol."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Kloskowski, T., Szeliski, K., Fekner, Z., Rasmus, M., D\u0105browski, P., Wolska, A., Siedlecka, N., Adamowicz, J., Drewa, T., and Pokrywczy\u0144ska, M. (2021). Ciprofloxacin and Levofloxacin as Potential Drugs in Genitourinary Cancer Treatment-The Effect of Dose-Response on 2D and 3D Cell Cultures. Int. J. Mol. Sci., 22.","DOI":"10.3390\/ijms222111970"},{"key":"ref_25","first-page":"1727","article-title":"Ciprofloxacin triggers the apoptosis of human triple-negative breast cancer MDA-MB-231 cells via the p53\/Bax\/Bcl-2 signaling pathway","volume":"52","author":"Beberok","year":"2018","journal-title":"Int. J. Oncol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"738","DOI":"10.1093\/nar\/gkn937","article-title":"The DNA cleavage reaction of topoisomerase II: Wolf in sheep\u2019s clothing","volume":"37","author":"Deweese","year":"2009","journal-title":"Nucleic Acids Res."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Hassan, H.M., Hassan, R., Elmagzoub, R.M., Al-Emam, A., Kossenas, K., Abdel-Samea, A.S., Khalifa, H.O., Akocak, S., Br\u00e4se, S., and Hashem, H. (2025). From Infection to Tumor: Exploring the Therapeutic Potential of Ciprofloxacin Derivatives as Anticancer Agents. Pharmaceuticals, 18.","DOI":"10.3390\/ph18010072"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1038\/nrc2608","article-title":"DNA topoisomerase II and its growing repertoire of biological functions","volume":"9","author":"Nitiss","year":"2009","journal-title":"Nat. Rev. Cancer"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"9625","DOI":"10.1093\/nar\/gky793","article-title":"Ciprofloxacin impairs mitochondrial DNA replication initiation through inhibition of Topoisomerase 2","volume":"46","author":"Hangas","year":"2018","journal-title":"Nucleic Acids Res."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1664","DOI":"10.1128\/AAC.50.5.1664-1671.2006","article-title":"Calcium signals are affected by ciprofloxacin as a consequence of reduction of mitochondrial DNA content in Jurkat cells","volume":"50","year":"2006","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1178","DOI":"10.1016\/S0026-895X(25)09546-X","article-title":"Delayed cytotoxicity and cleavage of mitochondrial DNA in ciprofloxacin-treated mammalian cells","volume":"50","author":"Lawrence","year":"1996","journal-title":"Mol. Pharmacol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"4049","DOI":"10.1021\/acsomega.8b03428","article-title":"Examining the Impact of Antimicrobial Fluoroquinolones on Human DNA Topoisomerase II\u03b1 and II\u03b2","volume":"4","author":"Fief","year":"2019","journal-title":"ACS Omega"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1261","DOI":"10.1016\/j.celrep.2019.09.050","article-title":"Mitochondrial Damage Causes Inflammation via cGAS-STING Signaling in Acute Kidney Injury","volume":"29","author":"Maekawa","year":"2019","journal-title":"Cell Rep."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"R1177","DOI":"10.1016\/j.cub.2017.09.015","article-title":"The Origin and Diversification of Mitochondria","volume":"27","author":"Roger","year":"2017","journal-title":"Curr. Biol. CB"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"510","DOI":"10.1038\/s12276-023-00965-7","article-title":"Molecular mechanisms of mitochondrial DNA release and activation of the cGAS-STING pathway","volume":"55","author":"Kim","year":"2023","journal-title":"Exp. Mol. Med."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Swedan, H.K., Kassab, A.E., Gedawy, E.M., and Elmeligie, S.E. (2023). Topoisomerase II inhibitors design: Early studies and new perspectives. Bioorg. Chem., 136.","DOI":"10.1016\/j.bioorg.2023.106548"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"3877","DOI":"10.1038\/s41467-023-39607-x","article-title":"Ultrasound-responsive low-dose doxorubicin liposomes trigger mitochondrial DNA release and activate cGAS-STING-mediated antitumour immunity","volume":"14","author":"Wang","year":"2023","journal-title":"Nat. Commun."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"e181804","DOI":"10.1001\/jamasurg.2018.1804","article-title":"Effect of Ciprofloxacin on Susceptibility to Aortic Dissection and Rupture in Mice","volume":"153","author":"LeMaire","year":"2018","journal-title":"JAMA Surg."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"161","DOI":"10.18773\/austprescr.2021.035","article-title":"Fluoroquinolone antibiotics and adverse events","volume":"44","author":"Baggio","year":"2021","journal-title":"Aust. Prescr."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"955","DOI":"10.1093\/jac\/24.6.955","article-title":"Oral ciprofloxacin therapy for infections in cancer patients","volume":"24","author":"Haron","year":"1989","journal-title":"J. Antimicrob. Chemother."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"337","DOI":"10.1016\/j.actbio.2022.12.004","article-title":"Idarubicin-loaded biodegradable microspheres enhance sensitivity to anti-PD1 immunotherapy in transcatheter arterial chemoembolization of hepatocellular carcinoma","volume":"157","author":"Zheng","year":"2023","journal-title":"Acta Biomater."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"606","DOI":"10.1159\/000518090","article-title":"Use of Antibiotics during Immune Checkpoint Inhibitor Treatment Is Associated with Lower Survival in Hepatocellular Carcinoma","volume":"10","author":"Cheung","year":"2021","journal-title":"Liver Cancer"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1572","DOI":"10.1093\/annonc\/mdz206","article-title":"The negative impact of antibiotics on outcomes in cancer patients treated with immunotherapy: A new independent prognostic factor?","volume":"30","author":"Elkrief","year":"2019","journal-title":"Ann. Oncol. Off. J. Eur. Soc. Med. Oncol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"445","DOI":"10.1007\/s00280-008-0892-6","article-title":"Ciprofloxacin sensitizes hormone-refractory prostate cancer cell lines to doxorubicin and docetaxel treatment on a schedule-dependent manner","volume":"64","author":"Pinto","year":"2009","journal-title":"Cancer Chemother. Pharmacol."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Gupta, P., Gao, H.L., Ashar, Y.V., Karadkhelkar, N.M., Yoganathan, S., and Chen, Z.S. (2019). Ciprofloxacin Enhances the Chemosensitivity of Cancer Cells to ABCB1 Substrates. Int. J. Mol. Sci., 20.","DOI":"10.3390\/ijms20020268"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1156","DOI":"10.1126\/science.aah5043","article-title":"Potential role of intratumor bacteria in mediating tumor resistance to the chemotherapeutic drug gemcitabine","volume":"357","author":"Geller","year":"2017","journal-title":"Science"}],"container-title":["Cells"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4409\/14\/13\/1010\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:02:56Z","timestamp":1760032976000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4409\/14\/13\/1010"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,2]]},"references-count":46,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2025,7]]}},"alternative-id":["cells14131010"],"URL":"https:\/\/doi.org\/10.3390\/cells14131010","relation":{},"ISSN":["2073-4409"],"issn-type":[{"value":"2073-4409","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,7,2]]}}}