Anticancer Effect of Fractions From Staphylococcus aureus and Bacillus atrophaeus on the Proliferation and Death of Human Breast Cancer Cell Line (MCF-7)

Abstract

Background: Nowadays, breast cancer is known to be one of the most common cancers among women. Due to the side effects of chemotherapy and the high probability of recurrences in surgery, it is essential to identify and introduce new anticancer drugs of natural origin with fewer complications. In this regard, secondary bacterial metabolites and other microbial products have been considered. In the meantime, pathogenic and environmental bacteria have been investigated. Objective: The aim of this study is to examine the effects of the interaction between cytoplasmic extract and the cell wall of Staphylococcus aureus and Bacillus atrophaeus on the proliferation rate of human breast cancer cells. Materials and Methods: In this experimental study, cytoplasmic and cell wall extracts of bacteria were prepared. Then, SDS-PAGE was used to examine their protein contents. MCF-7 cells, as human breast cancer cells, with bacterial cytoplasmic extract and bacterial cell wall, were treated at different concentrations. Mesenchymal stem cells derived from adipose tissue were treated with different concentrations of bacterial cell wall extract. The effects of cytotoxicity were assessed by MTT assay at 24 and 48-hour intervals. The results were analyzed by SPSS. Results: The results showed that bacterial cytoplasmic extract had a concentration-dependent cytotoxic effect on cancer cells, suggesting that the increase of concentration significantly (P<0.05) increased cell death. Additionally, the bacterial cell wall extract showed a proliferative effect on cell growth (P<0.05) Conclusion: The bacterial cytoplasmic extract has a lethal effect and can, therefore, be considered as an anticancer compound in the future. This feature of the bacterium is attributed to the presence of a novel bioactive compound that can be used as an adjunct to other chemotherapy compounds. The bacterial cell wall extract, on the other hand, has cell growth-promoting components and can, therefore, be adopted as a compound for the proliferation of mesenchymal stem cells or wound healing in future studies.