Clinical and Experimental Obstetrics & Gynecology (CEOG) is published by IMR Press from Volume 47 Issue 1 (2020). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with S.O.G.
‘Pulsed’ estradiol action can stimulate breast cancer cell proliferation
Purpose of investigation: The newly ava山ble nasal estradiol application serum concentrations measure up to I 0-fold higher compared to common hormone replacement therapy (HRT). Since this has only a short-time peak it has been suggested that breast cancer risk may be reduced、because of lower activation of the estradiol-receptor-transcription cascade. Methods: Estradiol was tested at 10-9 and 10-8 M corresponding to the serum levels achieved with nasal application. In addition also comparable exposure times were investigated: Incubation time was 10, 20, 40, 60 and 180 min every day for four days, compared with continuous non-stop incubation for four days. The well-recognized MCF-7 breast cancer cell line was used. Cell proliferation was measured by the ATP-assay. Results: Estradiol in concentrations achieved with ‘pulsed’ HT was able to elicit proliferation of MCF-7 cells already after an incubation time of ten minutes which correlates with the minimum of exposure time using nasal estradiol application. Compared to nonstop continuous estradiol added in the same high concentrations over four days no significant differences were observed. Conclusions: Short-time application of estradiol is able to stimulate breast cell proliferation to the same degree as continuously administered estradiol in high concentrations. Thus it remains questionable, if a ‘pulsed’ estradiol therapy may reduce breast cancer risk during HRT. Clinical studies are urgently needed to reveal the breast cancer risk during nasal estradiol application especially since this risk might be increased depending on the concentrations used.