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PURPOSE Progesterone resistance is thought to be a major factor that contributes to progression of endometriosis. However, it is not clear what causes progesterone resistance in endometriosis. This study aimed to assess whether cytokines or peritoneal fluid can affect progesterone receptor (PR) expression in endometrial cells and to verify whether PR expression is reduced in endometriosis. MATERIALS AND METHODS The PR-B/A ratio was measured via real-time polymerase chain reaction after in vitro culture, in which endometrial cells were treated with either tumor necrosis factor-alpha (TNF-α), interleukin-1 beta, or peritoneal fluid obtained from women with advanced-stage endometriosis. Immunohistochemistry was performed to compare PR-B expression between eutopic and ectopic endometrial tissues from women with and without advanced-stage endometriosis. RESULTS The PR-B/A ratio was significantly decreased by treatment with either TNF-α (p=0.011) or peritoneal fluid from women with advanced-stage endometriosis (p=0.027). Immunoreactivity of PR-B expression was significantly lower during the secretory phase than during the proliferative phase in endometrial tissues from control subjects (p

Although phthalates were shown to have several negative effects on reproductive function in animals, its role in the pathogenesis of endometriosis remains to be elucidated.We aimed to investigate the in vitro and in vivo effects of di-(2-ethylhexyl)-phthalate (DEHP) and to compare the urinary levels of several phthalate metabolites between women with and without endometriosis.For experimental studies, we used endometrial cell culture and nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mouse models. We also performed a prospective case-control study for human sample analyses.The study was conducted at an academic center.The activities of matrix metalloproteinase (MMP)-2 and 9, cellular invasiveness, phosphorylation of extracellular signal-regulated kinase (Erk), and expression of p21-activated kinase 4 were analyzed in endometrial cells treated with DEHP. The implant size was compared between NOD/SCID mice fed with and without DEHP. Urinary concentrations of several phthalate metabolites were compared between women with and without endometriosis.In vitro treatment of endometrial cells with DEHP led to significant increases of MMP-2 and 9 activities, cellular invasiveness, Erk phosphorylation, and p21-activated kinase 4 expression. The size of the endometrial implant was significantly larger in the NOD/SCID mice fed with DEHP compared with those fed with vehicle. The urinary concentration of mono (2-ethyl-5-hydroxyhexyl) phthalate, mono (2-ethyl-5-oxohexyl) phthalate, and mono (2-ethyl-5-carboxyphentyl) phthalate were significantly higher in women with endometriosis compared with controls.These findings strongly suggest that exposure to phthalate may lead to establishment of endometriosis by enhancing invasive and proliferative activities of endometrial cells.

Objective To investigate the expression of p21-activated kinase 4 (Pak4) in both adenomyotic foci and the eutopic endometrium of women with adenomyosis, and whether the activities of matrix metalloproteinases (MMPs)-2 and -9 are regulated by Pak4 in endometrial cells. Design Experimental study using human samples and cell lines. Setting University hospital. Patient(s) Thirty-nine patients with histologic evidence of adenomyosis, and 34 patients with carcinoma in situ of the uterine cervix without adenomyosis or endometriosis. Intervention(s) Immunohistochemistry, zymography after transfection with Pak4 small interfering RNA (siRNA), and western blot analyses after nuclear factor kappa-B (NF-кB) inhibitor treatment. Main Outcome Measure(s) The Pak4 immunoreactivity of women with vs. without adenomyosis was compared semiquantitatively. The activities of MMP-2 and -9 were analyzed in eutopic endometrial stromal cells and Ishikawa cells after transfection with Pak4 siRNA. The Pak4 expression was evaluated in endometrial cells after treatment with NF-кB inhibitor. Result(s) Pak4 immunoreactivity was increased in adenomyotic foci and in the eutopic endometrium of women with adenomyosis. Transfection of endometrial cells with Pak4 siRNA led to significant decreases of MMP-2 and -9 activities. In vitro treatment of endometrial cells with tumor necrosis factor-alpha caused a significant increase of NF-кB activation and Pak4 expression, which was obviously decreased by the NF-кB inhibitor pyrrolidinedithiocarbamate. Conclusion(s) Our results suggest that Pak4 is regulated by NF-кB and that increased Pak4 expression can lead to development of adenomyosis by enhancing the invasiveness of endometrial cells through regulation of MMP-2 and -9 activities.

Problem We evaluated whether the expression of NF-кB p65 subunit is increased in the eutopic endometrium and/or in the ovarian endometrioma of women with advanced stage endometriosis, and ascertained in vitro effects of proinflammatory cytokines on the expression and DNA binding of NF-кB p65 subunit in endometrial cells. Method of Study Immunohistochemistry was performed to compare the nuclear NF-кB p65 subunit immunoreactivity between women with and without advanced stage endometriosis. The nuclear NF-кB p65 subunit expression and DNA binding were also analyzed in endometrial cells treated with tumor necrosis factor-alpha (TNF-α) or interleukin-1beta (IL-1β) utilizing Western blot analysis, enzyme-linked immunosorbent assay, and electrophoretic mobility shift assay. Results The immunoreactivity of the nuclear NF-кB p65 subunit was significantly increased in the eutopic endometrium as well as in the ovarian endometrioma of women with endometriosis compared with the controls. In vitro treatment of endometrial cells with TNF-α and IL-1β led to a significant increase in nuclear NF-кB p65 subunit expression and DNA binding. Conclusions The nuclear expression of NF-κB p65 is increased in the eutopic endometrium and ovarian endometrioma of women with advanced stage endometriosis, which strongly suggests that NF-кB signaling plays a crucial role in the pathogenesis and/or pathophysiology of endometriosis.

Endometriosis is a common gynecological condition characterized by enhanced proliferation, adhesiveness, invasiveness, and survival of endometrial cells after retrograde menstruation. Originally identified as a cytoskeletal regulatory kinase, p21-activated kinase 4 (Pak4) regulates diverse cellular activities that might be altered in the establishment and progression of endometriosis.The aim was to evaluate the effects of sex steroids and proinflammatory cytokines on the Pak4 expression in endometrial cells along with the functional change caused by inhibition of Pak4 expression as well as to see whether the Pak4 expression is altered in endometriosis.Pak4 expression was analyzed using immunohistochemistry and Western blot analysis. Viability and invasiveness were assayed after transfection of endometrial cells with Pak4 small interfering RNA.The Pak4 expression was significantly decreased in the stromal cells during the secretory phase as well as by in vitro treatment with progesterone. The immunoreactivity of Pak4 was significantly increased in the eutopic endometrium as well as in the ovarian endometriotic cyst of women with endometriosis compared with the control subjects. TNF-α induced a significant increase in the Pak4 expression in endometrial cells in vitro, whereas IL-1β had no effects. Transfection of endometrial cells with Pak4 small interfering RNA led to a significant decrease in viability and invasiveness in endometrial cells.These findings suggest that Pak4 is regulated by progesterone and TNF-α in endometrial cells and that the increased expression of Pak4 might lead to the establishment and progression of endometriosis by enhanced cellular viability and invasiveness in endometrial cells.

We evaluated whether the proinflammatory cytokines can regulate p21-activated kinase (Pak1) expression in endometrial cells as well as whether its expression is increased in endometriotic cysts. We found that interleukin-1β up-regulates Pak1 expression in endometrial stromal cells (ESC) and that the immunoreactivity of Pak1 is increased in the endometriotic cysts.