We found that (1) ER binding was twice and PR binding was three times as great in fibroid as in myometrium and that there was no difference in binding for either receptor between fibroids from untreated and GnRHa pretreated women, (2) ER and PR mRNA abundances were similar in fibroids and myometrium from untreated women and in fibroids from untreated and GnRHa pretreated women, and (3) ER binding and ER mRNA abundance in both groups of fibroids and myometrium were independent of each other, but there was a positive correlation between PR binding and PR mRNA abundance in untreated fibroids and myometrium but not in GnRHa pretreated tumours.
Can asoprisnil, a selective progesterone receptor modulator, provide clinically meaningful improvements in heavy menstrual bleeding (HMB) associated with uterine fibroids with an acceptable safety profile?
Corresponding to increased progesterone receptor gene expression, the proliferation-associated antigen Ki-67 was also significantly elevated in the leiomyoma tissue.
RU486 stimulated recruitment of Sp1, RNA polymerase II, PR, and the coactivators SRC-1 and SRC-2 to the distal region and basal promoter. siRNA knockdown of PR increased KLF11 expression, whereas knockdown of KLF11 increased leiomyoma cell proliferation and abolished the antiproliferative effect of RU486.
In this study, we determined the expression of progesterone receptor and compared the expression level of progesterone-regulated genes (PRGs) in human myometrial cells from normal uteri (MyoN) versus uteri with UFs (MyoF) in response to progesterone.
To evaluate progesterone receptor (PR), epithelial growth factor receptor (EGF-R), and galectin-3 expression in LMs, ALMs, STUMPs, and leiomyosarcomas and to assess their possible role in differentiating those tumors.
We propose that increased expression of progesterone receptor in leiomyoma is most likely a consequence of overexpression of functional ER that results in increased end-organ sensitivity to estradiol.
A significantly higher expression of CKS2 was found in ULMS tissues than in ULM tissues (P<0.01) and high CKS2 expression was associated with increased tumor size, low progesterone receptor expression and poor prognosis in patients with ULMS.
Analysis of cells for estrogen receptor-alpha and progesterone receptor proteins by Western blotting showed no change in expression of these proteins between the immortalized and parental leiomyoma and myometrial cells.
In contrast to the reduced transcript levels observed for the immediate early genes, the ER and PR mRNA contents of the leiomyomas and myometrium did not differ.
Our analyses identified secreted Frizzled-related protein 4 (sFRP4) as a key gene product functionally linked to PR activation whose expression was 2.6 times higher in leiomyomas than myometrium (n = 26, P < 0.01) and 2.5 times higher during the proliferative phase of the menstrual cycle (n = 26, P < 0.01).