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Salinomycin efficiency assessment in non-tumor (HB4a) and tumor (MCF-7) human breast cells
Andressa Megumi Niwa1, Gláucia Fernanda Rocha D Epiro1, Lilian Areal Marques1
1Laboratório de Genética Toxicológica, Universidade Estadual de Londrina-CCB-BIO, Campus Universitário-Caixa Postal 10011, Rodovia Celso Garcia Cid (PR-445), Km 380, Londrina, Paraná, CEP 86057-970, Brazil.
Abstract:
The search for anticancer drugs has led researchers to study salinomycin, an ionophore antibiotic that selectively destroys cancer stem cells. In this study, salinomycin was assessed in two human cell lines, a breast adenocarcinoma (MCF-7) and a non-tumor breast cell line (HB4a), to verify its selective action against tumor cells. Real-time assessment of cell proliferation showed that HB4a cells are more resistant to salinomycin than MCF-7 tumor cell line, and these data were confirmed in a cytotoxicity assay. The half maximal inhibitory concentration (IC50) values show the increased sensitivity of MCF-7 cells to salinomycin. In the comet assay, only MCF-7 cells showed the induction of DNA damage. Flow cytometric analysis showed that cell death by apoptosis/necrosis was only induced in the MCF-7 cells. The increased expression of GADD45A and CDKN1A genes was observed in all cell lines. Decreased expression of CCNA2 and CCNB1 genes occurred only in tumor cells, suggesting G2/M cell cycle arrest. Consequently, cell death was activated in tumor cells through strong inhibition of the antiapoptotic genes BCL-2, BCL-XL, and BIRC5 genes in MCF-7 cells. These data demonstrate the selectivity of salinomycin in killing human mammary tumor cells. The cell death observed only in MCF-7 tumor cells was confirmed by gene expression analysis, where there was downregulation of antiapoptotic genes. These data contribute to clarifying the mechanism of action of salinomycin as a promising antitumor drug and, for the first time, we observed the higher resistance of HB4a non-tumor breast cells to salinomycin.
Insights
Salinomycin selectively kills human breast tumor cells (MCF-7) while sparing non-tumor cells (HB4a). This anticancer drug induces DNA damage and apoptosis in tumor cells, demonstrating its potential therapeutic efficacy.
Area of Science:
- Oncology
- Pharmacology
- Molecular Biology
Background:
- Salinomycin, an ionophore antibiotic, is being investigated for its potential anticancer properties.
- Previous research suggests salinomycin selectively targets cancer stem cells.
Purpose of the Study:
- To evaluate the selective action of salinomycin against human breast adenocarcinoma (MCF-7) and non-tumorigenic breast (HB4a) cell lines.
- To elucidate the molecular mechanisms underlying salinomycin's differential effects on tumor and non-tumor cells.
Main Methods:
- Cell proliferation and cytotoxicity assays were performed to determine drug sensitivity.
- Comet assay and flow cytometry were used to assess DNA damage and cell death (apoptosis/necrosis).
- Gene expression analysis (RT-qPCR) was conducted to investigate cell cycle regulation and apoptosis pathways.
Main Results:
- MCF-7 cells exhibited significantly higher sensitivity to salinomycin compared to HB4a cells (lower IC50 values).
- Salinomycin induced DNA damage, apoptosis/necrosis, and G2/M cell cycle arrest specifically in MCF-7 cells.
- Gene expression analysis revealed downregulation of antiapoptotic genes (BCL-2, BCL-XL, BIRC5) in MCF-7 cells, contributing to tumor cell death.
Conclusions:
- Salinomycin demonstrates selective cytotoxicity towards human mammary tumor cells.
- The drug's mechanism involves inducing DNA damage and apoptosis, coupled with cell cycle arrest in tumor cells.
- HB4a non-tumor breast cells exhibit higher resistance to salinomycin, supporting its potential as a targeted anticancer therapeutic.
