Metronidazole affects breast cancer cell lines.

PURPOSE The aim of our study was to evaluate the impact of metronidazole (MTZ) on cytotoxicity and DNA synthesis in MCF-7 (estrogen receptor positive) and MDA-MB-231 (estrogen receptor negative) breast cancer cell lines. MATERIAL/METHODS Toxicity of MTZ was determined by MTT test. MCF-7 and MDA-MB-231 cells were incubated with metronidazole used in different concentrations for 24, 48 and 72 hours. The effect of MTZ on DNA synthesis was measured as [3H]-thymidine incorporation. RESULTS We showed that MTZ in concentration 250 μg/ml significantly increases the growth of MCF-7 cell lines after 24 hours of incubation, but it reduces cell viability in concentrations 1 and 10 μg/ml 72 hours after the drug application. Significant increase of MDA-MB-231 cell viability was obtained in MTZ concentration of 250 μg/ml after 24 and 72 hours. The increase of [3H]-thymidine incorporation in MCF-7 cell line treated with MTZ in concentration 250 μg/ml was statistically significant after 24 hours. Great suppression of cell proliferation was obtained in MDA-MB-231 breast cell line after application of the following concentrations of MTZ: 0.1 μg/ml (after 24 hours) and 0.1, 10, 50, 250 μg/ml (after 72h). CONCLUSIONS We found that metronidazole exerts different dose- and time- dependent effects on human breast cancer cell lines characterized by presence or absence of estrogen receptors. We suggest that these discrepancies may be influenced by the estrogen signaling.