Abstract
Osteosarcoma is one of the most malignant bone tumors of childhood and adolescence. Interestingly, the presence of estrogen receptors α and β has been reported in human bone cells, including osteosarcoma. Thus, inhibitors of estrogens such as fulvestrant, are considered candidates for novel endocrine therapy in treatment of osteosarcoma. Another anticancer agent that seems to be very effective in treatment of osteosarcoma is a derivative of 17β-estradiol, 2-methoxyestradiol. The aim of this study was to determine the anticancer activities of pure anti-estrogen, fulvestrant and combined treatment of fulvestrant and 2-methoxyestradiol towards highly metastatic osteosarcoma 143B cells. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay was used in order to determine the antiproliferative potential of the compounds, and western blotting for estrogen receptors α and β. Flow cytometry was used in order to determine induction of cell death, cell-cycle arrest, mitochondrial depolarization, and DNA damage. Herein, we showed that fulvestrant has anticancer activity only at high concentrations. We were able to find and expression of estrogen receptor β, while we did not detect estrogen receptor α in osteosarcoma 143B cells. Moreover, fulvestrant down-regulated the expression of estrogen receptor β, and this effect was reversed by 2-methoxyestradiol. Thus, the obtained data suggest that 2-methoxyestradiol may exert part of its anticancer activity through modulation of expression of estrogen receptor β.
Footnotes
Funding
The studies concerning anticancer activity of 2-methoxyestradiol and article publication were by funded grant no. 2012/07/B/NZ1/00010 from National Science Center resources.
The studies concerning anticancer activity of fulvestrant were funded by MN grant no. 01-0175-08/259 from Medical University of Gdansk and Ministry of Science and Higher Education.
GraphPad Prism 6 for statistical analysis, LAS 500 (GE Healthcare) for Western blot analysis were purchased thanks to grant no. 2012/07/B/NZ1/00010 from National Science Center resources.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of this article.
Conflicts of Interest
The Authors declare no conflict of interest.
- Received February 23, 2016.
- Revision received April 5, 2016.
- Accepted April 6, 2016.
- Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved