Selective apoptosis induction by antimicrobial peptide TP4 in MCF-7 breast cancer cells

Antimicrobial peptides (AMPs), including Tilapia piscidin 4 (TP4), have emerged as a promising therapeutic approach for treating different types of cancers. These peptides specifically target tumor cells while minimizing harm to normal tissues. This study aims to investigate the cytotoxic effects of TP4 and elucidate its molecular mechanisms of apoptosis in MCF-7 human breast cancer cell line. MCF-7 and MCF-10 cell viability was assessed after treating the cells with various concentrations of TP4 for 24 h using the MTT assay. The MCF-7 cells were allocated into three groups including control cells (Cnt), cells treated with 0.5 IC₅₀, and 0.25 IC₅₀ of TP4. The results demonstrated the inhibitory effect of TP4 on MCF-7 cell proliferation after 24 h (IC₅₀ = 50.11 µg/mL), while no cytotoxicity was observed in normal breast cells (MCF-10) at this concentration. The selectivity index (SI) value exceeded 2, indicating TP4's high specificity for cancer cells. Treatment with 25% and 50% IC₅₀TP4 induced apoptosis, DNA fragmentation, and mitochondrial membrane potential changes (JC-1 staining) in MCF-7 cells. This induction was accompanied by increased expression of apoptotic genes (Bax, caspase3, and p53), decreased expression of the anti-apoptotic gene Bcl2, elevated levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) content, and reduced activity of the superoxide dismutase (SOD) and catalase (CAT) enzymes when compared to the control group (P < 0.05). Based on the data, we can infer that TP4 induces apoptosis in breast cancer cells via a ROS-dependent pathway.