Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 20 5 2021 09 28 600 613 EN Fereshteh Taghipour Department of Immunology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran AND Molecular Medicine Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran Omolbanin Oladpour Department of Immunology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran AND Molecular Medicine Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran Mohammad Taghi Rezayati Molecular Medicine Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran Hossain Khorramdelazad Molecular Medicine Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran Maryam Nemati Department of Hematology and Laboratory Sciences, School of Para-Medicine, Kerman University of Medical Sciences, Kerman, Iran Zahra Taghipour Department of Histology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran Javad Masoumi Molecular Medicine Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran Zuhair Mohammad Hassan Department of Immunology, School of Medicine, Tarbiat Modarres University, Tehran, Iran Abdollah Jafarzadeh Molecular Medicine Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran AND Immunology of Infectious Diseases Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran AND Department of Immunology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran 2021 01 10 2021 06 13 Metformin, cimetidine, and ibuprofen separately exhibit immunomodulatory and anti-tumorigenic effects. Herein, the impacts of metformin alone and in combination with cimetidine/ibuprofen on some Th1- and regulatory T (Treg) cell-related parameters were evaluated using a breast cancer (BC) model. For establishing the BC model, four groups of Balb/c mice were challenged with the carcinoma cell line. After 11-30 days post-induction, they were treated intraperitoneally (with metformin (200 mg/kg), "metformin plus cimetidine (20 mg/kg)"; "metformin plus ibuprofen (20 mg/kg)", or with all three drugs in mentioned doses. Untreated BC and without tumor mice were enrolled as control groups. On day 31, splenic Th1 and Treg cell frequencies, serum interferon-gamma (IFN-γ), and transforming growth factor-beta (TGF-β) concentration, and intra-tumoral T-bet, TGF-β, and forkhead box protein P3 (FOXP3) expression were measured; using flow cytometry, enzyme-linked immunosorbent assay (ELISA), and real-time-PCR, respectively. Treatment of the BC mice with metformin alone and in combination with cimetidine and/or ibuprofen enhanced the frequency of Th1 cells, and IFN-γ concentration, while it resulted in a decrease in the frequency of Treg cells, serum TGF-β concentration, and the expression of FOXP3 and TGF-β compared with un-treated BC mice. FOXP3 expression in the metformin-treated group was lower in mice who received combination therapy. Survival rate and body weight were increased, while tumor size and spleen index were reduced in mice treated with metformin alone and its combination with cimetidine and/or ibuprofen. No remarkable differences were found between metformin-treated mice and those who received combination therapies regarding Th1 and Treg cell percentages, TGF-β expression, body weight, tumor size, and spleen index. The benefits of combinational therapy may be largely attributed to metformin. Immunotherapeutic potentials of metformin in cancers need further considerations. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/3091 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/3091/1741