Cytotoxic and apoptosis-inducing properties of Staphylococcus aureus cytoplasmic extract on lung cancer cells: Insights from MTT assay and bax/bcl-2 gene expression analysis

Abstract

Background

Lung cancer ranks as the second most prevalent cancer in both men and women and stands as one of the most prevalent and lethal malignancies globally. In recent decades, the therapeutic potential of bacteria has gained recognition in pharmaceutical and therapeutic research. While bacteria have historically been associated with cancer causation, recent studies have unveiled their potential as efficacious agents for targeted cancer therapy. However, limited data exist on the characterization and impact of Staphylococcus aureus (S. aureus) extract on lung cancer cell lines. Consequently, this study aims to investigate the effect of S. aureus extract on inducing apoptosis in A549, a lung cancer cell line, and MRC-5, a lung normal cell line, by evaluating the expression levels of the bax and bcl-2 genes.

Methods

Initially, cytoplasmic extract of S. aureus was prepared using the sonication technique. The protein concentration was determined via the Bradford assay, and the presence of proteins was confirmed using SDS-PAGE. A549, representing a lung cancer cell line, and MRC-5, representing a lung normal cell line, were exposed to varying concentrations of bacterial extract, and cell viability was assessed using the MTT assay. Subsequently, the expression levels of the bax and bcl-2 genes were quantified utilizing the Real-Time PCR method.

Results

Cytoplasmic extract derived from S. aureus demonstrated the ability to modulate the expression levels of apoptotic genes. Relative to the control group, the bax gene exhibited a fivefold overexpression, while the expression of the bcl-2 gene decreased by more than half compared to the control. Furthermore, the results of the MTT assay indicated that the bacterial cytoplasmic extract exhibited concentration-dependent cytotoxicity on cancer cells, highlighting a significant increase in cell death with escalating concentrations.

Conclusions

This research highlights the potential of S. aureus extract for targeted lung cancer therapy by promoting cancer cell apoptosis while sparing normal cells. These findings open up exciting possibilities for innovative cancer treatments and improved patient outcomes, emphasizing the promise of S. aureus extract in the fight against lung cancer.