In vitro effects of 2‐methoxyestradiol on MCF‐12A and MCF‐7 cell growth, morphology and mitotic spindle formation

Abstract

The influence of 2-methoxyestradiol (2ME) was investigated on cell growth, morphology and spindle formation in a tumorigenic (MCF-7) and non-tumorigenic (MCF-12A) epithelial breast cell line. Inhibition of cell growth was more pronounced in the MCF-7 cells compared to the MCF-12A cells following 2ME treatment. Dose-dependent studies (10 -5 -10 -9 M) revealed that 10 -6 M 2ME inhibited cell growth by 44% in MCF-12A cells and by 84% in MCF-7 cells (P-value < 0.05). 2ME-treated MCF-7 cells showed abnormal metaphase cells, membrane blebbing, apoptotic cells and disrupted spindle formation. These observations were either absent, or less prominent in MCF-12A cells. 2ME had no effect on the length of the cell cycle between S-phase and the time a mitotic peak was reached in either cell line but MCF-7 cells were blocked in mitosis with no statistically significant alterations in the phosphorylation status of Cdc25C.Nevertheless, Cdc2 activity was significantly increased in MCF-7 cells compared to MCF-12A cells (P-value < 0.05). The results indicate that 2ME disrupts mitotic spindle formation and enhances Cdc2 kinase activity, leading to persistence of the spindle checkpoint and thus prolonged metaphase arrest that may result in the induction of apoptosis. The tumorigenic MCF-7 cells were especially sensitive to 2ME treatment compared to the normal MCF-12A cells.Therefore, differential mechanism(s) of growth inhibition are evident between the normal and tumorigenic cells.

Effects of Estrogen Metabolite 2-Methoxyestradiol on Tumor Suppressor Protein p53 and Proliferation of Breast Cancer Cells

“…Although the use of physiological steroid hormones in experimental studies employs steroid concentrations in the nanomolar range, the metabolite 2-ME 2 is effective in cell free systems at higher concentrations. Previous studies have shown inhibition of cellular proliferation by use of 1 -10 µM 2-ME 2 [Azab et al 2009;LaVallee et al 2002;Mueck and Seeger 2010;Pribluda et al 2000;Van Zijl et al 2008]. Thus the use of 2-ME 2 at the concentrations utilized in our studies is consistent with similar concentrations employed by other investigators in the literature.…”

Novel in silico-designed estradiol analogues are cytotoxic to a multidrug-resistant cell line at nanomolar concentrations

“…This suggests that these compounds may be able to circumvent drug resistance induced by the activity of PgP efflux pumps [22]. MCF7 and MDA-MB-231 cells were similarly sensitive to the sulphamoylated compounds indicating that these compounds act independently of the estrogen and/or progesterone receptors to induce cell death.…”

Structure Activity Analysis of 2-Methoxyestradiol Analogues Reveals Targeting of Microtubules as the Major Mechanism of Antiproliferative and Proapoptotic Activity

“…However, at therapeutic doses in vivo, the drug is likely to act by impairing microtubule dynamics (4,5). Given that rapid microtubule dynamics are essential for the correct assembly and function of the mitotic spindle, 2ME2 activates the spindle assembly checkpoint and causes metaphase arrest, and as a consequence, inhibition of cell proliferation and induction of cellular apoptosis (6,7).…”