Cytotoxic effects of tamoxifen in breast cancer cells

Abstract

This article is licensed under a Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, sharing, adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Abstract Aim: To investigate the cytotoxic effects of tamoxifen on the breast cancer cell line (MCF7). Methods: The cytotoxic effects of tamoxifen on MCF7 cells were investigated using caspase-9 activity and high content screening assays. Apoptosis mechanisms following tamoxifen treatment were also investigated. Results: The most significant cytotoxic effect of tamoxifen in MCF7 cells was a half-maximal inhibitory concentration (IC 50) of 4.506 µg/mL. A significant increase in caspase-9 activity was also observed when MCF7 cells were treated with tamoxifen (5 µg/mL). Furthermore, increased cell membrane permeability, cytochrome c level, and nuclear intensity were observed with tamoxifen (100 µg/mL) compared with doxorubicin (20 µg/mL) treatment. However, a noticeable decrease in cell viability and mitochondrial membrane permeability was observed with tamoxifen (100 µg/mL) treatment compared with doxorubicin (20 µg/mL) as a positive control. Conclusion: Tamoxifen showed in vitro cytotoxic effects in MCF7 cells as demonstrated by high-content screening and caspase-9 activity assays. Tamoxifen inhibits estrogen mechanisms, although toxic effect was observed.