Estrogen is implicated as playing an important role in aging and tumorigenesis of estrogen responsive tissues; however the mechanisms underlying the mitogenic actions of estrogen are not fully understood. Here we report that estrogen deficiency in mice caused by targeted disruption of the aromatase gene results in a significant inhibition of telomerase maintenance of telomeres in mouse ovaries in a tissue-specific manner. The inhibition entails a significant shortening of telomeres and compromised proliferation in the follicular granulosa cell compartment of ovary. Gene expression analysis showed decreased levels of proto-oncogene c-Myc and the telomerase catalytic subunit, telomerase reverse transcriptase (TERT), in response to estrogen deficiency. Estrogen replacement therapy led to increases in TERT gene expression, telomerase activity, telomere length and ovarian tissue growth, thereby reinstating ovary development to normal in four weeks. Our data demonstrate for the first time that telomere maintenance is the primary mechanism mediating the mitogenic effect of estrogen on ovarian granulosa cell proliferation by upregulating the genes of c-Myc and TERT in vivo. Estrogen deficiency or over-activity may cause ovarian tissue aging or tumorigenesis, respectively, through estrogen regulation of telomere remodeling.

Preeclampsia (PE) is a pregnancy-specific disorder characterized by hypertension and proteinuria after 20 wk gestation. Abnormal extravillous trophoblast (EVT) invasion and remodeling of uterine spiral arterioles is thought to contribute to PE development. Interleukin-11 (IL11) impedes human EVT invasion in vitro and is elevated in PE decidua in women. We demonstrate that IL11 administered to mice causes development of PE features. Immunohistochemistry shows IL11 compromises trophoblast invasion, spiral artery remodeling, and placentation, leading to increased systolic blood pressure (SBP), proteinuria, and intrauterine growth restriction, although nonpregnant mice were unaffected. Real-time PCR array analysis identified pregnancy-associated plasma protein A2 (PAPPA2), associated with PE in women, as an IL11 regulated target. IL11 increased PAPPA2 serum and placental tissue levels in mice. In vitro, IL11 compromised primary human EVT invasion, whereas siRNA knockdown of PAPPA2 alleviated the effect. Genes regulating uterine natural killer (uNK) recruitment and differentiation were down-regulated and uNK cells were reduced after IL11 treatment in mice. IL11 withdrawal in mice at onset of PE features reduced SBP and proteinuria to control levels and alleviated placental labyrinth defects. In women, placental IL11 immunostaining levels increased in PE pregnancies and in serum collected from women before development of early-onset PE, shown by ELISA. These results indicate that elevated IL11 levels result in physiological changes at the maternal-fetal interface, contribute to abnormal placentation, and lead to the development of PE. Targeting placental IL11 may provide a new treatment option for PE.placenta | trophoblast | cytokines | pregnancy P reeclampsia (PE) is a pregnancy-induced disorder characterized by hypertension and proteinuria, unique to humans, affecting ∼8% of pregnancies (1). The etiology is poorly understood (2); nevertheless, there is substantial evidence showing abnormal placentation is the key underlying cause. During pregnancy, highly invasive extravillous trophoblasts (EVT) acquire vascular-like properties to remodel uterine spiral arterioles. This creates low-resistance, large-diameter vessels that promote uteroplacental blood supply to sustain fetal growth (3, 4). It is widely accepted that inadequate trophoblast invasion and impaired uterine spiral artery remodeling is an initiating factor in the development of PE (5). This is thought to impair uteroplacental arterial flow and lead to placental oxidative stress (6). PE is associated with increased placental secretion of proinflammatory cytokines (7) and angiogenic regulators (8), thought to contribute to widespread maternal endothelial dysfunction. The clinical symptoms of PE are hypertension, proteinuria, and peripheral and/or cerebral edema. Symptoms can differentially manifest during the second (early-onset, EO), or third (late-onset, LO) trimester (9). In addition to the maternal symptoms, PE is also frequently associated with prematurit...

Endometrial cancer contributes to significant morbidity and mortality in women with advanced stage or recurrent disease. IL11 is a cytokine that regulates cell cycle, invasion, and migration, all hallmarks of cancer. IL11 is elevated in endometrial tumors and uterine lavage fluid in women with endometrial cancer, and alters endometrial epithelial cancer cell adhesion and migration in vitro, but its role in endometrial tumorigenesis in vivo is unknown. We injected mice subcutaneously with human-derived Ishikawa or HEC1A endometrial epithelial cancer cells (ectopic), or HEC1A cells into the uterus (orthotopic) to develop endometrial cancer mouse models. Administration of anti-human IL11 receptor (R) a blocking antibody dramatically reduced HEC1A-derived tumor growth in both models and reduced peritoneal metastatic lesion spread in the orthotopic model, compared with IgG. Anti-human IL11Ra retained a well-differentiated, endometrial epithelial phenotype in the HEC1A ectopic mice, suggesting it prevented epithelial-to-mesenchymal transition. Blockade of mouse IL11Ra with anti-mouse IL11Ra antibody did not alter tumor growth, suggesting that cancer epithelial cell IL11 signaling is required for tumor progression. In vitro, anti-human IL11Ra antibody significantly reduced Ishikawa and HEC1A cell proliferation and invasion and promoted apoptosis. Anti-human, but not anti-mouse, IL11Ra antibody reduced STAT3, but not ERK, activation in HEC1A cells in vitro and in endometrial tumors in xenograft mice. We demonstrated that targeted blockade of endometrial cancer epithelial cell IL11 signaling reduced primary tumor growth and impaired metastasis in ectopic and orthotopic endometrial cancer models in vivo. Our data suggest that therapeutically targeting IL11Ra could inhibit endometrial cancer growth and dissemination. Mol Cancer Ther; 15(4); 720-30. Ó2016 AACR.