Involvement of cyclin-dependent kinase inhibitor p27Kip1 in growth inhibition of endometrium in the secretory phase and of hyperplastic endometrium treated with progesterone.
A cyclin-dependent kinase (cdk) inhibitor, p27Kip1 (p27), binds to the cyclin E-cdk2 complex and functions as a suppressor of cell cycle promotion. Here, the involvement of p27 in the growth of normal human endometrium was immunohistochemically studied, and the findings were compared with those of Ki-67, cyclin E and cdk2. In addition, to elucidate the effect of progesterone on the expression of p27, tissues from patients with endometrial hyperplasia were examined before and after the administration of medroxyprogesterone acetate (MPA) for the treatment of this disease. In the glandular cells of the normal endometrium, p27 was negligible during the proliferative phase, whereas it was markedly increased in the secretory phase. The staining pattern of Ki-67 was the reverse. Cyclin E/cdk2-positive cells were observed throughout the menstrual cycle. In the secretory phase, the cyclin E/cdk2-positive cells were also positive for p27, suggesting an interaction between these molecules. Stromal cells, especially in the basalis, showed a consistent expression of p27 throughout the menstrual cycle. The expression of p27 in hyperplastic epithelia before the MPA treatment was negligible, whereas it was greatly increased after the treatment. The Ki-67 positivity decreased after the treatment. These findings suggest that p27 is involved in the progesterone-induced growth suppression of normal and hyperplastic endometria.
Shiozawa
T
T
Department of Obstetrics and Gynecology, Shinshu University School of Medicine, Asahi, Matsumoto, Japan.
Nikaido
T
T
Nakayama
K
K
Lu
X
X
Fujii
S
S
D000328:Adult; D018797:Cell Cycle Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D004717:Endometrium / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D005260:Female; D006131:Growth Inhibitors / Q000378:metabolism; D006801:Humans; D006965:Hyperplasia; D007150:Immunohistochemistry; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology*; D008597:Menstrual Cycle / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008875:Middle Aged; D017154:Stromal Cells / Q000378:metabolism; D025521:Tumor Suppressor Proteins
D018797:Cell Cycle Proteins; D006131:Growth Inhibitors; D008869:Microtubule-Associated Proteins; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D017258:Medroxyprogesterone Acetate; D018844:Cyclin-Dependent Kinases