Testosterone dependent androgen receptor stabilization and activation of cell proliferation in primary human myometrial microvascular endothelial cells
W. Dietrich, A. Gaba, Z. Zhegu, C. Bieglmayer, M. Mairhofer, M. Mikula, W. Tschugguel, I. Yotova - Testosterone dependent androgen receptor stabilization and activation of cell proliferation in primary human myometrial microvascular endothelial cells - FERTILITY AND STERILITY, Vol. 95, No. 11, 2011, pp. 1247-1258
OBJECTIVE: To clarify, whether uterine endothelial proliferation could be
regulated via an autocrine estrogen producing mechanism or direct actions of
DESIGN: In vitro study.
SETTING: Tertiary care facility.
PATIENT(S): Human myometrial tissue obtained from 40 women undergoing
hysterectomy without further intrauterine pathology.
INTERVENTION(S): Cell culture, proliferation assay and CYP19 activity assay on
human myometrial endothelial cells treated with testosterone, estradiol,
letrozole, flutamide, PD98059, MG-132 alone or in combination.
MAIN OUTCOME MEASURE(S): We analyzed whether aromatase is expressed in human
myometrial microvascular endothelial cells (HMMECs) and whether it affects
proliferation and converts androgens to estrogens. In addition, we aimed to
define whether or not T could have a direct capability to affect HMMEC
RESULT(S): Using quantitative real-time PCR and Western analysis, primary passage
four HMMECs were shown to express low levels of aromatase mRNA and protein,
respectively. However, HMMECs were unable to convert radioactively labeled
3∗H-1β-androstenedione to estrogen. Pharmacologic doses of T (10(-6) and 10(-4)
M) increased HMMEC proliferation, assessed through a bromodeoxyuridine ELISA.
This effect of T on proliferation could not be blocked after pretreatment of
cells with the aromatase inhibitor letrozole. In addition, HMMECs were found to
express androgen receptors (ARs), and the AR antagonist flutamide abolished
T-dependent proliferation. T was shown to increase AR protein levels, which was
due to T-dependent receptor stabilization and not activation of gene
CONCLUSION(S): We conclude that myometrial endothelial proliferation is not
regulated through myometrial endothelial estrogen production. However,
pharmacologic doses of T increase myometrial endothelial proliferation through a
receptor-dependent and -stabilizing mechanism.