A phenol amine molecule from Salinivenus iranica acts as the inhibitor of cancer stem cells in breast cancer cell lines

In recent years, the anticancer properties of metabolites from halophilic microorganisms have received a lot of attention. Twenty-nine halophilic bacterial strains were selected from a culture collection to test the effects of their supernatant metabolites on stem cell-like properties of six human cancer cell lines. Human fibroblasts were used as normal control. Sphere and colony formation assay were done to assess the stem cell-like properties. invasion and migration assay, and tumor development in mice model were done to assess the anti-tumorigenesis effect in vitro and in vivo. The metabolites from Salinivenus iranica demonstrated the most potent cytotoxic effect on breast cancer cell lines (IC50 = 100 µg/mL) among all strains, with no effect on normal cells. In MDA-MB-231 cells, the supernatant metabolites enhanced both early and late apoptosis (approximately 9.5% and 48.8%, respectively) and decreased the sphere and colony formation ability of breast cancer cells. Furthermore, after intratumor injection of metabolites, tumors developed in the mice models reduced dramatically, associated with increased pro-apoptotic caspase-3 expression. The purified cytotoxic molecule, a phenol amine with a molecular weight of 1961.73 Dalton (IC50 = 1 µg/mL), downregulated pluripotency gene SRY-Box Transcription Factor 2 (SOX-2) expression in breast cancer cells which is associated with resistance to conventional anticancer treatment. In conclusion, we suggested that the phenol amine molecule from Salinivenus iranica could be a potential anti-breast cancer component.