In Vitro Cytotoxic Activity of a Lactococcus lactis Antimicrobial Peptide Against Breast Cancer Cells

Background: Nisin, an effective natural food preservative, is an antimicrobial peptide produced by Lactococcus lactis. Although it has been mainly studied and developed as a potential alternative for antibiotics, other pharmacological effects of the nisin including cytotoxic and anti-tumor activity have been attracted many attentions.Objectives: Here, we aimed to evaluate in vitro cytotoxic activity of the nisin against breast cancer cells.Materials and Methods: The effect of temperature, pH, and chemical composition of the medium on the yield of nisin production was evaluated. As well, the anti-proliferative effect of nisin against a breast cancer cell line (i. e., MCF-7) and a non-cancerous cell line (i.e, HUVEC) was determined using MTT assay. Furthermore, the potential of the synergistic effect of the nisin on the doxorubicin cytotoxicity was evaluated.Results: The optimum culture condition for the nisin production by L. lactis was found to be MRS medium (pH 6.3) supplemented with the tryptone and incubation at 30 °C. MTT assay results indicate that nisin exhibits a high and selective cytotoxicity against MCF-7 cell line with IC50 value of 5 μM. Furthermore, a combination of nisin and doxorubicin at sub-inhibitory concentrations were more cytotoxic compared to either of drugs alone.Conclusion: It could be suggested that nisin, either alone or in combination with other chemotherapeutic agents, could be a potential therapeutic for the breast cancer cells.