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Background Receptive endometrium is a restraining factor in the establishment of pregnancy in several estrogendependent gynecological disorders including uterine leiomyomas. Recently, data are beginning to accrue suggesting negative impact of non-cavity distorting intramural fibroids on molecular mediators of endometrial receptivity. The potential importance of the mammalian target of rapamycin (mTOR) signaling pathway has been suggested during embryo implantation. However, its exact role in fibroid-associated endometrium during the window of implantation is poorly defined. The objective of the study was to examine the expression and cellular distribution of key components of the mTOR signaling pathway during window of implantation in infertile women with non-cavity distorting intramural uterine leiomyomas (n = 24) as compared to fertile controls (n = 17). Relative gene expression analysis of mTOR, TSC1, and TSC2 was performed by real-time PCR. Immunohistochemistry was used to evaluate the expression of mTOR, phospho-mTOR (Serine 2448), TSC1, TSC2, phospho-TSC2 (Threonine 1462), and phospho-S6 ribosomal protein (Serines 235 and 236) and Ki67. Results In comparison to fertile controls, statistically significant upregulation of mTOR (8.97-fold; p < 0.001) and downregulation of TSC2 mRNA (-6.01-fold; p < 0.01) levels and cell-specific upregulation of proteins phospho-mTOR, phospho-TSC2, and phospho-S6 and downregulation of TSC1 and TSC2 were observed in infertile women. The ratio of p-mTOR/mTOR and p-TSC2/TSC2 was significantly higher in infertile women. Pearson's correlation analysis revealed significant negative correlation between p-mTOR and TSC2 and positive correlation between p-mTOR and p-S6 in the infertile group. Increased Ki67 labelling index was observed in the glandular epithelium (GE) and stroma of endometrium from infertile women as compared to controls. Conclusions Loss of TSC2 function and enhanced expression of activated mTOR and its downstream targets, observed in the infertile group, indicate heightened mTOR signaling which might contribute to impaired endometrial receptivity. Increased number of Ki67-positive nuclei suggests that enhanced mTOR signaling may help drive dysregulated proliferation of midsecretory endometrium leading to compromised fertility in women with non-cavity distorting intramural uterine leiomyomas. The present findings provide avenues for future investigation of mTOR pathway as a nonsurgical alternative for treatment of infertility in these patients. [ABSTRACT FROM AUTHOR]

The objective of the study was to examine the expression and cellular distribution of key signaling components of the phosphatidylinositol-3-kinase (PI3K)/Phosphatase and Tensin Homolog Deleted on Chromosome Ten (PTEN)/Protein Kinase B (PKB/Akt) pathway during the window of implantation in infertile women with noncavity-distorting intramural uterine fibroids (n = 21) as compared to fertile controls (n = 15). Relative gene expression analysis of PIK3CA, PTEN, Akt1, and Akt2 genes in midluteal endometrial biopsies was performed by real-time polymerase chain reaction. Immunohistochemistry was used to evaluate the expression of PIK3CA, PTEN, phospho-PTEN, Akt1, Akt2, phospho-Akt1 (serine 473), phospho-Akt1 (threonine 308), and Ki67 proteins. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling assay was performed for apoptosis detection. In comparison to fertile controls, significant upregulation of Akt1 messenger RNA levels (2.16-fold; P < .05); cell-specific upregulation of the proteins phospho-PTEN (P < .05), Akt1 (P < .05), Akt2 (P < .05), and p-Akt (S473; P < .001); and downregulation of PTEN (P < .01) were observed in endometrium of infertile women with intramural fibroids. The ratio of p-PTEN/PTEN and p-Akt1 (S473)/Akt1 was also significantly higher in infertile women. Increased Ki67 labeling index in the glandular epithelium and significantly lower apoptotic index in glandular epithelium and stroma were seen in infertile women during the window of implantation. Aberrant Akt activation and the associated imbalance in endometrial proliferation and apoptosis observed in infertile women with intramural fibroids during the midsecretory phase might contribute to impaired endometrial receptivity leading to infertility in these patients. [ABSTRACT FROM AUTHOR]

This study was designed to examine the expression and cellular distribution of homeobox (HOX) genes (HOXA10 and HOXA11) and cell adhesion molecules (E-cadherin, N-cadherin, and β-catenin) during the window of implantation in infertile women with noncavity-distorting intramural (IM) fibroids (n = 18) and in fertile controls (n = 12). Quantitative real-time polymerase chain reaction and immunohistochemistry were used to evaluate the messenger RNA (mRNA) levels and protein expression, respectively. When compared to fertile controls, reduced HOXA10 and HOXA11 transcript and protein levels were observed in infertile women. However, changes only in the expression of HOXA10 mRNA (−1.72-fold; P = .03) and stromal protein (P = .001) were statistically significant. Significantly lower E-cadherin mRNA (−10.97-fold; P = .02) and protein levels were seen in infertile patients. E-cadherin immunostaining was significantly reduced both in the luminal (P = .048) and in the glandular (P = .014) epithelium of endometrium from infertile patients when compared to controls. No significant change was observed either in the mRNA levels or in the immunoexpression of N-cadherin and β-catenin. However, a trend toward lower N-cadherin expression in the luminal epithelium (P = .054) and decreased β-catenin expression in the glandular epithelium (P = .070) was observed in infertile patients. The present findings suggest that altered endometrial HOXA10 and E-cadherin mRNA and protein expression observed in infertile women with IM fibroids during the mid-secretory phase might impair endometrial receptivity leading to infertility in these patients. [ABSTRACT FROM AUTHOR]

Background & objectives: Despite their high occurrence and associated significant level of morbidity manifesting as spectrum of clinical symptoms, the pathogenesis of uterine leiomyomas (ULs) remains unclear. We investigated expression profile of tumour suppressor genes PTEN (phosphatase and tensin homolog deleted on chromosome ten) and LKB1 (liver kinase B1), and key signaling components of P13K (phosphatidylinositol 3-kinase)/Akt (protein kinase B)/mTOR (mammalian target of rapamycin) pathway in leiomyomas and adjacent normal myometrium in women of reproductive age, to explore the possibility of targeting this pathway for future therapeutic implications. Methods: Real time PCR (qPCR) was used to quantify relative gene expression levels of PTEN, Akt1, Akt2, mTOR, LKB1 and VEGFA (vascular endothelial growth factor A) in leiomyoma as compared to adjacent normal myometrium. Immunohistochemistry was subsequently performed to analyze expression of PTEN, phospho-Akt, phospho-mTOR, phospho-S6, LKB1 and VEGFA in leiomyoma and adjacent normal myometrium. Results: Significant upregulation of PTEN (2.52 fold; P=0.03) and LKB1 (3.93 fold; P=0.01), and downregulation of VEGFA (2.95 fold; P=0.01) genes were observed in leiomyoma as compared to normal myometrium. Transcript levels of Akt1, Akt2 and mTOR did not vary significantly between leiomyoma and myometrium. An increased immunoexpression of PTEN (P=0.015) and LKB1 (P<0.001) and decreased expression of VEGFA (P=0.01) was observed in leiomyoma as compared to myometrium. Immunostaining for activated (phosphorylated) Akt, mTOR and S6 was absent or low in majority of leiomyoma and myometrium. Interpretation & conclusions: Upregulation of PTEN and LKB1 in concert with negative or low levels of activated Akt, mTOR and S6 indicates that PI3K/Akt/mTOR pathway may not play a significant role in pathogenesis of leiomyoma [ABSTRACT FROM AUTHOR]

Impaired endometrial receptivity is an important contributing factor to implantation failure. Uterine leiomyomas are widely prevalent steroid hormone–dependent benign tumors that act as a restraint to conception and successful outcome of pregnancies. Reports are available, which suggest that leiomyomas have negative influence on endometrial receptivity to blastocyst implantation. The aim of the present review is to provide a comprehensive picture of the current knowledge of the effect of uterine leiomyomas on the architectural, cellular, and molecular determinants of endometrial receptivity. Understanding the potential role of these factors will provide insight into the underlying mechanisms of leiomyoma-associated infertility and provide new areas for basic and translational research. [ABSTRACT FROM AUTHOR]