Several papers report that the colon is one of the tissues regulated by estrogen receptor (ER)β. To better understand the physiological role of ERβ in colonic tissue, we have compared morphology, proliferation, and differentiation of colonic epithelium in ERβ −/− mice and WT littermates. BrdUrd labeling revealed that the number of proliferating cells was higher in ERβ −/− mice and that the migration of labeled cells toward the luminal surface was faster in ERβ −/− mice than in WT littermates. Additionally, in the absence of ERβ, there was a decrease in apoptosis, which was measured by immunohistochemical staining of cleaved caspase-3. The state of differentiation of the colonic epithelial cells was studied by using epithelial markers. In ERβ −/− mice, there was a significant decrease in the expression of the differentiation marker cytokeratin (CK)20 and in the cellular adhesion molecules α-catenin (an adherens junction protein) and plectin (a hemidesmosomal protein). These changes were also evident by electron microscopy as abnormalities in tight junctions and in the number and shape of desmosomes in ERβ −/− mice. These findings suggest a role for ERβ in the organization and architectural maintenance of the colon. Furthermore, our results indicate that the rapidly proliferating cells of the colonic epithelium in ERβ −/− mice are lost by increased shedding and not by increased apoptosis. In this way, hyperproliferative cells that lack ERβ do not form hyperplastic lesions and do not accumulate in the superficial epithelium.

BackgroundResveratrol is a natural polyphenolic compound known for its beneficial effects on energy homeostasis, and it also has multiple properties, including anti-oxidant, anti-inflammatory, and anti-tumor activities. Recently, silent information regulator genes (Sirtuins) have been identified as targets of resveratrol. Sirtuin 1 (SIRT1), originally found as an NAD+-dependent histone deacetylase, is a principal modulator of pathways downstream of calorie restriction, and the activation of SIRT1 ameliorates glucose homeostasis and insulin sensitivity. To date, the presence and physiological role of SIRT1 in the ovary are not known. Here we found that SIRT1 was localized in granulosa cells of the human ovary.MethodsThe physiological roles of resveratrol and SIRT1 in the ovary were analyzed. Immunohistochemistry was performed to localize the SIRT1 expression. SIRT1 protein expression of cultured cells and luteinized human granulosa cells was investigated by Western blot. Rat granulosa cells were obtained from diethylstilbestrol treated rats. The cells were treated with increasing doses of resveratrol, and subsequently harvested to determine mRNA levels and protein levels. Cell viability was tested by MTS assay. Cellular apoptosis was analyzed by caspase 3/7 activity test and Hoechst 33342 staining.ResultsSIRT1 protein was expressed in the human ovarian tissues and human luteinized granulosa cells. We demonstrated that resveratrol exhibited a potent concentration-dependent inhibition of rat granulosa cells viability. However, resveratrol-induced inhibition of rat granulosa cells viability is independent of apoptosis signal. Resveratrol increased mRNA levels of SIRT1, LH receptor, StAR, and P450 aromatase, while mRNA levels of FSH receptor remained unchanged. Western blot analysis was consistent with the results of quantitative real-time RT-PCR assay. In addition, progesterone secretion was induced by the treatment of resveratrol.ConclusionsThese results suggest a novel mechanism that resveratrol could enhance progesterone secretion and expression of luteinization-related genes in the ovary, and thus provide important implications to understand the mechanism of luteal phase deficiency.

BACKGROUND: The phosphatidylinositol 3 0 -kinase (PI3K) -AKT pathway is activated in many human cancers and plays a key role in cell proliferation and survival. A mutation (E17K) in the pleckstrin homology domain of the AKT1 results in constitutive AKT1 activation by means of localisation to the plasma membrane. The AKT1 (E17K) mutation has been reported in some tumour types (breast, colorectal, ovarian and lung cancers), and it is of interest which tumour types other than those possess the E17K mutation. METHODS: We analysed the presence of the AKT1 (E17K) mutation in 89 endometrial cancer tissue specimens and in 12 endometrial cancer cell lines by PCR and direct sequencing. RESULTS: We detected two AKT1 (E17K) mutations in the tissue samples (2 out of 89) and no mutations in the cell lines. These two AKT1 mutant tumours do not possess any mutations in PIK3CA, PTEN and K-Ras. INTERPRETATION: Our results and earlier reports suggest that AKT1 mutations might be mutually exclusive with other PI3K -AKTactivating alterations, although PIK3CA mutations frequently coexist with other alterations (such as HER2, K-Ras and PTEN) in several types of tumours.

BACKGROUND: DBC1/KIAA1967 (deleted in breast cancer 1) is a putative tumour-suppressor gene cloned from a heterozygously deleted region in breast cancer specimens. Caspase-dependent processing of DBC1 promotes apoptosis, and depletion of endogenous DBC1 negatively regulates p53-dependent apoptosis through its specific inhibition of SIRT1. Hereditary breast and ovarian cancer susceptibility gene product BRCA1, by binding to the promoter region of SIRT1, is a positive regulator of SIRT1 expression. METHODS: A physical interaction between DBC1 and BRCA1 was investigated both in vivo and in vitro. To determine the pathophysiological significance of DBC1, its role as a transcriptional factor was studied. RESULTS: We found a physical interaction between the amino terminus of DBC1 and the carboxyl terminus of BRCA1, also known as the BRCT domain. Endogenous DBC1 and BRCA1 form a complex in the nucleus of intact cells, which is exported to the cytoplasm during ultraviolet-induced apoptosis. We also showed that the expression of DBC1 represses the transcriptional activation function of BRCT by a transient expression assay. The expression of DBC1 also inhibits the transactivation of the SIRT1 promoter mediated by full-length BRCA1. CONCLUSION: These results revealed that DBC1 may modulate the cellular functions of BRCA1 and have important implications in the understanding of carcinogenesis in breast tissue.

In this study, we compared the uterine tissue of estrogen receptor (ER)␤ ؊/؊ mice and their WT littermates for differences in morphology, proliferation [the percentage of labeled cells 2 h after BrdUrd injection and EGF receptor (EGFR) expression], and differentiation (expression of progesterone receptor, E-cadherin, and cytokeratins). In ovariectomized mice, progesterone receptor expression in the uterine epithelium was similar in WT and ER␤ ؊/؊ mice, but E-cadherin and cytokeratin 18 expression was lower in ER␤ ؊/؊ mice. The percentage of cells in S phase was 1.5% in WT mice and 8% in ER␤ ؊/؊ mice. Sixteen hours after injection of 17␤-estradiol (E2), the number of BrdUrd-labeled cells increased 20-fold in WT mice and 80-fold in ER␤ ؊/؊ mice. Although ER␣ was abundant in intact mice, after ovariectomy, ER␣ could not be detected in the luminal epithelium of either WT or ER␤ ؊/؊ mice. In both untreated and E2-treated mice, ER␣ and ER␤ were colocalized in the nuclei of many stromal and glandular epithelial cells. However, upon E2 ؉ progesterone treatment, ER␣ and ER␤ were not coexpressed in any cells. In WT mice, EGFR was located on the membranes and in the cytoplasm of luminal epithelium, but not in the stroma. In ER␤ ؊/؊ mice, there was a marked expression of EGFR in the nuclei of epithelial and stromal cells. Upon E2 treatment, EGFR on cell membranes was down-regulated in WT but not in ER␤ ؊/؊ mice. These findings reveal an important role for ER␤ in response to E2 and in the organization, growth, and differentiation of the uterine epithelium.differentiation ͉ proliferation ͉ uterus P roliferation of epithelial cells (1, 2), uterine hyperemia, fluid uptake (termed water imbibition), recruitment of inflammatory leukocytes from the bloodstream into the stromal compartment (3, 4), and the induction of the progesterone receptor (PR) are caused by 17␤-estradiol (E 2 ). Progesterone (P 4 ) inhibits estrogen-induced cell proliferation of the luminal and glandular epithelial compartment (5) and stimulates epithelial differentiation in preparation for embryo implantation. Physiologically and pharmacologically, P 4 is important for prevention of endometrial hyperplasia (6). After the cessation of ovarian function, estrogen replacement is needed for preservation of the skeletal, cardiovascular, and central nervous systems. To oppose the proliferative effects of estrogen on the uterus and reduce the risk of endometrial cancer, progesterone is used together with estrogen in hormone replacement therapy after menopause (7,8).Most of the known actions of estrogen are mediated by the estrogen receptors (ERs) ER␣ and ER␤, both of which bind E 2 and modulate transcription of E 2 -responsive genes (9). A single injection of E 2 results in a synchronized wave of cell proliferation, with DNA synthesis in epithelial cells beginning 6-9 h after E 2 injection and peaking at 12-15 h. DNA synthesis is followed by a wave of cell division (1, 2, 10). P 4 elicits its function through binding to the PR.During the secretory phase of the estrus...