Nisin ZP modulates calcium homeostasis to induce apoptosis and attenuate cell proliferation in MG-63 osteosarcoma cells

Osteosarcoma (OS) is the most common primary malignant bone tumour, characterised by aggressive growth and a high risk of metastasis, particularly in children, adolescents, and the elderly. Despite advances in surgery, chemotherapy, and radiotherapy, treatment outcomes remain unsatisfactory due to therapy-associated toxicity, chemoresistance, and poor long-term survival. These limitations highlight the need for novel therapeutic strategies with greater selectivity and reduced adverse effects. Nisin, a bacterially derived antimicrobial peptide widely used as a food preservative, has recently been investigated for its anticancer properties, with no data on OS. This study evaluated the effects of nisin ZP (NZP) on MG-63 OS cells in vitro, comparing them to 0.46 µg/ml doxorubicin (DOX), the NZP–DOX combination, and NZP with bepridil (BEP), a calcium channel blocker. A comprehensive set of assays was employed, including an MTS cell viability assay, Annexin V/Dead Cell assay via flow cytometry, morphological examination, intracellular calcium concentration measurement, analysis of apoptotic gene and protein expression, and cell cycle assessment. The impact of NZP on normal osteoblasts (hFOB1.19) was also determined to evaluate selectivity.