Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 0 0 2026 05 19 1 14 Milad Karimi Molecular Biology Research Center, Biomedicine Technologies Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran Reza Falak Breast Cancer Research Center, Iran University of Medical Sciences, Tehran, Iran AND Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Mahdi Fasihi-Ramandi Molecular Biology Research Center, Biomedicine Technologies Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran Ramezan-Ali Taheri Nanobiotechnology Research Center, New Health Technologies Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran 2025 12 13 2026 02 01 Cervical cancer is the fourth most prevalent malignancy among women globally. Zinc oxide nanoparticles (ZnO-NPs) possess significant potential in cancer therapy due to their unique physicochemical properties, biocompatibility, and apoptosis-inducing abilities. While ZnO-NPs have been examined in HeLa cells and peripheral blood mononuclear cells (PBMCs) individually, their immunological and angiogenesis-related effects in immune-tumor co-culture systems was insufficiently investigated. This study assessed the apoptotic, anti-angiogenic, and cytokine-modulating effects of ZnO-NPs in a HeLa/PBMC co-culture model. HeLa cells were co-cultured with PBMCs and treated with ZnO-NPs under different groups. Cytotoxicity was evaluated using MTT assay, apoptosis was analyzed by flow cytometry, and gene expression levels were measured using real-time PCR. ZnO-NPs significantly reduced HeLa cells viability with a half maximal inhibitory concentration (IC50) of 7 µg/mL, while PBMCs showed more resistance (IC50=40 µg/mL). In the HeLa/PBMC/ZnO co-culture group, gene expression analysis in PBMCs revealed significant upregulation of IL1B, TNF, IFNG, and TGFB1 compared with the HeLa/PBMC group, while IL2 and IL4 expression levels showed no significant changes. VEGFA expression in HeLa cells was reduced in all treated groups, with the greatest decrease in the HeLa/PBMC/ZnO group. Co-culture with PBMCs and ZnO-NP treatment significantly promoted apoptosis in HeLa cells. In conclusion, ZnO-NPs induce cytotoxic and anti-angiogenic effects on HeLa cells, particularly within a PBMC co-culture setting, highlighting the contribution of immune–tumor interactions to ZnO-NP–mediated anti-cancer responses; however, more investigations at the protein and functional levels are necessary to validate these effects. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/4699 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/4699/2343