Nuclear hormone receptor corepressor promotes esophageal cancer cell invasion by transcriptional repression of interferon-γ-inducible protein 10 in a casein kinase 2-dependent manner.

Aberrant expression of casein kinase 2 (CK2) is associated with tumor progression; however, the molecular mechanism by which CK2 modulates tumorigenesis is incompletely understood. In this paper, we show that CK2α phosphorylates the C-terminal domain of the nuclear receptor corepressor (NCoR) at Ser-2436 to stabilize the NCoR against the ubiquitin-dependent proteasomal degradation pathway. Importantly, NCoR promoted the invasion of esophageal cancer cells in a CK2-dependent manner. By using cyclic DNA microarray analysis, we identified CXCL10/IP-10 as a novel CK2α-NCoR cascade-regulated gene. The depletion of both NCoR and HDAC3 commonly derepressed IP-10 transcription, demonstrating the functional engagement of the NCoR-HDAC3 axis in IP-10 transcriptional repression. Furthermore, chromatin immunoprecipitation assays showed that c-Jun recruits NCoR-HDAC3 corepressor complexes to the (AP1 site of IP-10, leading to histone hypoacetylation and IP-10 down-regulation. Collectively these data suggest that the CK2α-NCoR cascade selectively represses the transcription of IP-10 and promotes oncogenic signaling in human esophageal cancer cells.ope

Mitochondrial tumor suppressor 1 is a target of AT-rich interactive domain 1A and progesterone receptor in the murine uterus

Objective: Progesterone receptor (PGR) and AT-rich interactive domain 1A (ARID1A) have important roles in the establishment and maintenance of pregnancy in the uterus. In present studies, we examined the expression of mitochondrial tumor suppressor 1 (MTUS1) in the murine uterus during early pregnancy as well as in response to ovarian steroid hormone treatment. METHODS: We performed quantitative reverse transcription polymerase chain reaction and immunohistochemistry analysis to investigate the regulation of MTUS1 by ARID1A and determined expression patterns of MTUS1 in the uterus during early pregnancy. RESULTS: The expression of MTUS1 was detected on day 0.5 of gestation (GD 0.5) and then gradually increased until GD 3.5 in the luminal and glandular epithelium. However, the expression of MTUS1 was significantly reduced in the uterine epithelial cells of Pgrcre/+Arid1af/f and Pgr knockout (PRKO) mice at GD 3.5. Furthermore, MTUS1 expression was remarkably induced after P4 treatment in the luminal and glandular epithelium of the wild-type mice. However, the induction of MTUS1 expression was not detected in uteri of Pgrcre/+Arid1af/f or PRKO mice treated with P4. CONCLUSION: These results suggest that MTUS1 is a novel target gene by ARID1A and PGR in the uterine epithelial cells.ope

KRAS Activation and over-expression of SIRT1/BCL6 Contributes to the Pathogenesis of Endometriosis and Progesterone Resistance

Endometriosis is an inflammatory condition that is associated with progesterone resistance and cell proliferation, resulting in pain, infertility and pregnancy loss. We previously demonstrated phosphorylation of STAT3 in eutopic endometrium of infertile women with this disorder leading to over-expression of the oncogene BCL6 and stabilization of hypoxia-induced factor 1 alpha (HIF-1α). Here we report coordinated activation of KRAS and over-expression of Sirtuin 1 (SIRT1), a histone deacetylase and gene silencer, in the eutopic endometrium from women with endometriosis throughout the menstrual cycle. The mice with conditional activation of KRAS in the PGR positive cells reveal an increase of SIRT1 expression in the endometrium compared to control mice. The expression of progesterone receptor target genes including the Indian Hedgehog pathway genes are significantly down-regulated in the mutant mice. SIRT1 co-localizes with BCL6 in the nuclei of affected individuals and both proteins bind to and suppress the promoter of GLI1, a critical mediator of progesterone action in the Indian Hedgehog pathway, by ChIP analysis. In eutopic endometrium, GLI1 expression is reduced in women with endometriosis. Together, these data suggest that KRAS, SIRT1 and BCL6 are coordinately over-expressed in eutopic endometrium of women with endometriosis and likely participate in the pathogenesis of endometriosis.ope

MIG-6 suppresses endometrial epithelial cell proliferation by inhibiting phospho-AKT

BACKGROUND: Aberrant hyperactivation of epithelial proliferation, AKT signaling, and association with unopposed estrogen (E2) exposure is the most common endometrial cancer dysfunction. In the normal uterus, progesterone (P4) inhibits proliferation by coordinating stromal-epithelial cross-talk, which we previously showed is mediated by the function of Mitogen-inducible gene 6 (Mig-6). Despite their attractive characteristics, non-surgical conservative therapies based on progesterone alone have not been universally successful. One barrier to this success has been the lack of understanding of the P4 effect on endometrial cells. METHOD: To further understand the role of Mig-6 and P4 in controlling uterine proliferation, we developed a Sprr2f-cre driven mouse model where Mig-6 is specifically ablated only in the epithelial cells of the uterus (Sprr2f cre+ Mig-6 f/f ). We examined P4 effect and regulation of AKT signaling in the endometrium of mutant mice. RESULTS: Sprr2f cre+ Mig-6 f/f mice developed endometrial hyperplasia. P4 treatment abated the development of endometrial hyperplasia and restored morphological and histological characteristics of the uterus. P4 treatment reduced cell proliferation which was accompanied by decreased AKT signaling and the restoration of stromal PGR and ESR1 expression. Furthermore, our in vitro studies revealed an inhibitory effect of MIG-6 on AKT phosphorylation as well as MIG-6 and AKT protein interactions. CONCLUSIONS: These data suggest that endometrial epithelial cell proliferation is regulated by P4 mediated Mig-6 inhibition of AKT phosphorylation, uncovering new mechanisms of P4 action. This information may help guide more effective non-surgical interventions in the future.ope

MIG-6 negatively regulates STAT3 phosphorylation in uterine epithelial cells

Endometrial cancer is the most common malignancy of the female genital tract. Progesterone (P4) has been used for several decades in endometrial cancer treatment, especially in women who wish to retain fertility. However, it is unpredictable which patients will respond to P4 treatment and which may have a P4-resistant cancer. Therefore, identifying the mechanism of P4 resistance is essential to improve the therapies for endometrial cancer. Mitogen-inducible gene 6 (Mig-6) is a critical mediator of progesterone receptor (PGR) action in the uterus. In order to study the function of Mig-6 in P4 resistance, we generated a mouse model in which we specifically ablated Mig-6 in uterine epithelial cells using Sprr2f-cre mice (Sprr2fcre+Mig-6f/f). Female mutant mice develop endometrial hyperplasia due to aberrant phosphorylation of signal transducers and activators of transcription 3 (STAT3) and proliferation of the endometrial epithelial cells. The results from our immunoprecipitation and cell culture experiments showed that MIG-6 inhibited phosphorylation of STAT3 via protein interactions. Our previous study showed P4 resistance in mice with Mig-6 ablation in Pgr-positive cells (Pgrcre/+Mig-6f/f). However, Sprr2fcre+Mig-6f/f mice were P4-responsive. P4 treatment significantly decreased STAT3 phosphorylation and epithelial proliferation in the uterus of mutant mice. We showed that Mig-6 has an important function of tumor suppressor via inhibition of STAT3 phosphorylation in uterine epithelial cells, and the antitumor effects of P4 are mediated by the endometrial stroma. These data help to develop a new signaling pathway in the regulation of steroid hormones in the uterus, and to overcome P4 resistance in human reproductive diseases, such as endometrial cancer.ope

Pik3ca is required for mouse uterine gland development and pregnancy

The PI3K/AKT signaling pathway plays a critical role in the maintenance of equilibrium between cell survival and apoptosis. The Pik3ca gene is mutated in a range of human cancers. It has been found to be oncogenic, and mutations lead to constitutive activation of the PI3K/AKT pathway. The expression patterns of PIK3CA proteins in the uterus of mice during early pregnancy indicate that it may play a role in the regulation of glandular epithelial cells, which is required to support uterine receptivity. To further investigate the role of Pik3ca in uterine function, Pik3ca was conditionally ablated only in the PGR-positive cells (Pgrcre/+Pik3caf/f; Pik3cad/d). A defect of uterine gland development and decidualization led to subfertility observed in Pik3cad/d mice. Pik3cad/d mice showed significantly decreased uterine weight compared to Pik3caf/f mice. Interestingly, a significant decrease of gland numbers were detected in Pik3cad/d mice compared to control mice. In addition, we found a decrease of Foxa2 expression, which is a known uterine gland marker in Pik3cad/d mice. Furthermore, the excessive proliferation of endometrial epithelial cells was observed in Pik3cad/d mice. Our studies suggest that Pik3ca has a critical role in uterine gland development and female fertility.ope

β-catenin activates TGF-β-induced epithelial-mesenchymal transition in adenomyosis

Adenomyosis is defined as the presence of ectopic nests of endometrial glands and stroma within the myometrium. Adenomyosis is a common cause of dysmenorrhea, menorrhagia, and chronic pelvic pain but is often underdiagnosed. Despite its prevalence and severity of symptoms, its pathogenesis and etiology are poorly understood. Our previous study showed that aberrant activation of beta-catenin results in adenomyosis through epithelial-mesenchymal transition. Using transcriptomic and ChIP-seq analysis, we identified activation of TGF-beta signaling in the uteri of mutant mice that expressed dominant stabilized beta-catenin in the uterus. There was a strong positive correlation between beta-catenin and TGF-beta 2 proteins in women with adenomyosis. Furthermore, treatment with pirfenidone, a TGF-beta inhibitor, increased E-cadherin expression and reduced cell invasiveness in Ishikawa cells with nuclear beta-catenin. Our results suggest that beta-catenin activates TGF-beta-induced epithelial-mesenchymal transition in adenomyosis. This finding describes the molecular pathogenesis of adenomyosis and the use of TGF-beta as a potential therapeutic target for adenomyosis. Uterine disease: Regulatory pathways identified A regulatory link between two proteins involved in the progression of a debilitating uterine condition highlights a potential therapeutic target. Adenomyosis involves the invasion of cells from the inner lining of the uterus (the endometrium) into the uterine muscle wall (the myometrium), resulting in heavy, prolonged periods and chronic pain. The aberrent activation of a protein called beta-catenin triggers adenomyosis, but the precise mechanisms are unclear. A team led by Jung-Ho Shin at the Korea University Medical Center, Seoul, South Korea, and Jae-Wook Jeong, Michigan State University, Grand Rapids, USA, used sequencing techniques in mice and human tissue samples to identify the pathways governed by beta-catenin in adenomyosis. They found that theTgf-beta 2gene is directly regulated by beta-catenin in the uterus. TGF-beta 2 levels were elevated in human adenomyosis lesions, suggesting the protein could be a therapeutic target.ope

Therapeutic effects of selective p300 histone acetyl-transferase inhibitor on liver fibrosis

Liver fibrosis is caused by chronic liver damage and results in the aberrant accumulation of extracellular matrix during disease progression. Despite the identification of the HAT enzyme p300 as a major factor for liver fibrosis, the development of therapeutic agents targeting the regulation of p300 has not been reported. We validated a novel p300 inhibitor (A6) on the improvement of liver fibrosis using two mouse models, mice on a choline-deficient high-fat diet and thioacetamide-treated mice. We demonstrated that pathological hall-marks of liver fibrosis were significantly diminished by A6 treatment through Masson's trichrome and Sirius red staining on liver tissue and found that A6 treatment reduced the expression of matricellular protein genes. We further showed that A6 treatment improved liver fibrosis by reducing the stability of p300 protein via disruption of p300 binding to AKT. Our findings suggest that targeting p300 through the specific inhibitor A6 has potential as a major therapeutic avenue for treating liver fibrosis. [BMB Reports 2023; 56(2): 114-119].ope

CK2-NCoR signaling cascade promotes prostate tumorigenesis

The aberrant expressions of casein kinase 2 (CK2) was found in prostate cancer patient and cell lines, but little is known of the detailed mechanisms implicated in prostate tumorigenesis. In this study, we report that both CK2 activity and CK2-mediated NCoR phosphorylation are significantly elevated in the androgen-independent prostate cancer cell line DU145 and PC-3 compared with RWPE1 and LNCaP cells. Increased phosphorylation inversely correlates with the mRNA level of the NCoR-regulated gene, interferon-γ-inducible protein 10 (IP-10). CK2 inhibition abrogated NCoR phosphorylation, IP-10 transcriptional repression, and the invasion activity of PC-3 cells. Inhibition of the CK2-NCoR network significantly reduced in vivo PC-3 cell tumorigenicity, likely due to transcriptional derepression of IP-10. Clinicopathological analyses revealed that increased CK2-mediated NCoR phosphorylation significantly correlates with poor survival among prostate cancer patients. These findings elucidate a CK2-modulated oncogenic cascade in prostate tumorigenesis.ope

The extracellular signal-regulated kinase mitogen-activated protein kinase/ribosomal S6 protein kinase 1 cascade phosphorylates cAMP response element-binding protein to induce MUC5B gene expression via D-prostanoid receptor signaling.

Mucus hypersecretion is a prominent feature of respiratory diseases, and MUC5B is a major airway mucin. Mucin gene expression can be affected by inflammatory mediators, including prostaglandin (PG) D(2,) an inflammatory mediator synthesized by hematopoietic PGD synthase (H-PGDS). PGD(2) binds to either D-prostanoid receptor (DP1) or chemoattractant receptor homologous molecule expressed on T-helper type 2 cells (CRTH2). We investigated the mechanisms by which PGD(2) induces MUC5B gene expression in airway epithelial cells. Western blot analysis showed that H-PGDS was highly expressed in nasal polyps. Similar results were obtained for PGD(2) expression. In addition, we could clearly detect the expressions of both H-PGDS and DP1 in nasal epithelial cells but not CRTH2. We demonstrated that PGD(2) increased MUC5B gene expression in normal human nasal epithelial cells as well as in NCI-H292 cells in vitro. S5751, a DP1 antagonist, inhibited PGD(2)-induced MUC5B expression, whereas a CRTH2 antagonist (OC0459) did not. These data suggest that PGD(2) induced MUC5B expression via DP1. Pretreatment with extracellular signal-regulated kinase (ERK) inhibitor (PD98059) blocked both PGD(2)-induced ERK mitogen-activated protein kinase (MAPK) activation and MUC5B expression. Proximity ligation assays showed direct interaction between RSK1 and cAMP response element-binding protein (CREB). Stimulation with PGD(2) caused an increase in intracellular cAMP levels, whereas intracellular Ca(2+) did not have such an effect. PGD(2)-induced MUC5B mRNA levels were regulated by CREB via direct interaction with two cAMP-response element sites (-921/-914 and -900/-893). Finally, we demonstrated that PGD(2) can induce MUC5B overproduction via ERK MAPK/RSK1/CREB signaling and that DP1 receptor may have suppressive effects in controlling MUC5B overproduction in the airway.ope