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Changes in Endometrial PTEN Expression throughout the Human Menstrual Cycle1
Ist Teil von
The journal of clinical endocrinology and metabolism, 2000-06, Vol.85 (6), p.2334-2338
Ort / Verlag
Endocrine Society
Erscheinungsjahr
2000
Quelle
Oxford Journals 2020 Medicine
Beschreibungen/Notizen
Frequent mutation of the PTEN tumor suppressor gene in
endometrial adenocarcinoma has led to the prediction that its product,
a phosphatase that regulates the cell cycle, apoptosis, and possibly
cell adhesion, is functionally active within normal endometrial
tissues. We examined PTEN expression in normal human
endometrium during response to changing physiological levels of steroid
hormones. PTEN ribonucleic acid levels, assessed by
RT-PCR, increase severalfold in secretory compared to proliferative
endometrium. This suggested that progesterone, a known antineoplastic
factor for endometrial adenocarcinoma, increases PTEN
levels. Immunohistochemistry with an anti-PTEN
monoclonal antibody displayed a complex pattern of coordinate stromal
and epithelial expression. Early in the menstrual cycle under the
dominant influence of estrogens, the proliferative endometrium shows
ubiquitous cytoplasmic and nuclear PTEN expression.
After 3–4 days of progesterone exposure, glandular epithelium of early
secretory endometrium maintains cytoplasmic PTEN protein
in an apical distribution offset by expanding PTEN-free
basal secretory vacuoles. By the midsecretory phase, epithelial
PTEN is exhausted, but increases dramatically in the
cytoplasm of stromal cells undergoing decidual change. We conclude that
stromal and epithelial compartments contribute to the hormone-driven
changes in endometrial PTEN expression and infer that
abnormal hormonal conditions may, in turn, disrupt normal patterns of
PTEN expression in this tissue.