Estrogen promotes the brain metastatic colonization of triple negative breast cancer cells via an astrocyte-mediated paracrine mechanism.

Brain metastases (BM) are a devastating consequence of breast cancer. BM occur more frequently in patients with estrogen receptor-negative (ER-) breast cancer subtypes; HER2 overexpressing (HER2+) tumors and triple-negative (TN) (ER-, progesterone receptor-negative (PR-) and normal HER2) tumors. Young age is an independent risk factor for the development of BM, thus we speculated that higher circulating estrogens in young, pre-menopausal women could exert paracrine effects through the highly estrogen-responsive brain microenvironment. Using a TN experimental metastases model, we demonstrate that ovariectomy decreased the frequency of magnetic resonance imaging-detectable lesions by 56% as compared with estrogen supplementation, and that the combination of ovariectomy and letrozole further reduced the frequency of large lesions to 14.4% of the estrogen control. Human BM expressed 4.2-48.4% ER+ stromal area, particularly ER+ astrocytes. In vitro, E2-treated astrocytes increased proliferation, migration and invasion of 231BR-EGFP cells in an ER-dependent manner. E2 upregulated epidermal growth factor receptor (EGFR) ligands Egf, Ereg and Tgfa mRNA and protein levels in astrocytes, and activated EGFR in brain metastatic cells. Co-culture of 231BR-EGFP cells with E2-treated astrocytes led to the upregulation of the metastatic mediator S100 Calcium-binding protein A4 (S100A4) (1.78-fold, P<0.05). Exogenous EGF increased S100A4 mRNA levels in 231BR-EGFP cells (1.40±0.02-fold, P<0.01 compared with vehicle control) and an EGFR/HER2 inhibitor blocked this effect, suggesting that S100A4 is a downstream effector of EGFR activation. Short hairpin RNA-mediated S100A4 silencing in 231BR-EGFP cells decreased their migration and invasion in response to E2-CM, abolished their increased proliferation in co-cultures with E2-treated astrocytes and decreased brain metastatic colonization. Thus, S100A4 is one effector of the paracrine action of E2 in brain metastatic cells. These studies provide a novel mechanism by which estrogens, acting through ER+ astrocytes in the brain microenvironment, can promote BM of TN breast cancers, and suggests existing endocrine agents may provide some clinical benefit towards reducing and managing BM.

Mammary epithelial cell phagocytosis downstream of TGF-ß3 is characterized by adherens junction reorganization.

After weaning, during mammary gland involution, milk-producing mammary epithelial cells undergo apoptosis. Effective clearance of these dying cells is essential, as persistent apoptotic cells have a negative impact on gland homeostasis, future lactation and cancer susceptibility. In mice, apoptotic cells are cleared by the neighboring epithelium, yet little is known about how mammary epithelial cells become phagocytic or whether this function is conserved between species. Here we use a rat model of weaning-induced involution and involuting breast tissue from women, to demonstrate apoptotic cells within luminal epithelial cells and epithelial expression of the scavenger mannose receptor, suggesting conservation of phagocytosis by epithelial cells. In the rat, epithelial transforming growth factor-ß (TGF-ß) signaling is increased during involution, a pathway known to promote phagocytic capability. To test whether TGF-ß enhances the phagocytic ability of mammary epithelial cells, non-transformed murine mammary epithelial EpH4 cells were cultured to achieve tight junction impermeability, such as occurs during lactation. TGF-ß3 treatment promoted loss of tight junction impermeability, reorganization and cleavage of the adherens junction protein E-cadherin (E-cad), and phagocytosis. Phagocytosis correlated with junction disruption, suggesting junction reorganization is necessary for phagocytosis by epithelial cells. Supporting this hypothesis, epithelial cell E-cad reorganization and cleavage were observed in rat and human involuting mammary glands. Further, in the rat, E-cad cleavage correlated with increased γ-secretase activity and ß-catenin nuclear localization. In vitro, pharmacologic inhibitors of γ-secretase or ß-catenin reduced the effect of TGF-ß3 on phagocytosis to near baseline levels. However, ß-catenin signaling through LiCl treatment did not enhance phagocytic capacity, suggesting a model in which both reorganization of cell junctions and ß-catenin signaling contribute to phagocytosis downstream of TGF-ß3. Our data provide insight into how mammary epithelial cells contribute to apoptotic cell clearance, and in light of the negative consequences of impaired apoptotic cell clearance during involution, may shed light on involution-associated breast pathologies.

Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurements.

Feedbacks between land carbon pools and climate provide one of the largest sources of uncertainty in our predictions of global climate. Estimates of the sensitivity of the terrestrial carbon budget to climate anomalies in the tropics and the identification of the mechanisms responsible for feedback effects remain uncertain. The Amazon basin stores a vast amount of carbon, and has experienced increasingly higher temperatures and more frequent floods and droughts over the past two decades. Here we report seasonal and annual carbon balances across the Amazon basin, based on carbon dioxide and carbon monoxide measurements for the anomalously dry and wet years 2010 and 2011, respectively. We find that the Amazon basin lost 0.48 ± 0.18 petagrams of carbon per year (Pg C yr(-1)) during the dry year but was carbon neutral (0.06 ± 0.1 Pg C yr(-1)) during the wet year. Taking into account carbon losses from fire by using carbon monoxide measurements, we derived the basin net biome exchange (that is, the carbon flux between the non-burned forest and the atmosphere) revealing that during the dry year, vegetation was carbon neutral. During the wet year, vegetation was a net carbon sink of 0.25 ± 0.14 Pg C yr(-1), which is roughly consistent with the mean long-term intact-forest biomass sink of 0.39 ± 0.10 Pg C yr(-1) previously estimated from forest censuses. Observations from Amazonian forest plots suggest the suppression of photosynthesis during drought as the primary cause for the 2010 sink neutralization. Overall, our results suggest that moisture has an important role in determining the Amazonian carbon balance. If the recent trend of increasing precipitation extremes persists, the Amazon may become an increasing carbon source as a result of both emissions from fires and the suppression of net biome exchange by drought.

Perfil de natimortalidade de acordo com ordem de nascimento, peso e sexo de leitões / Stillbirth pattern according to birth order, birth weight, and gender of piglets

Foram acompanhados 575 partos para avaliar a influência da ordem de nascimento, do sexo e do peso dos leitões na ocorrência de natimortos. Dos 7061 leitões, 90,2 por cento, 6,0 por cento e 3,8 por cento nasceram vivos, natimortos ou mumificados, respectivamente. O percentual de partos com natimortos foi 44,5 por cento. Partos com dois ou mais natimortos foram responsáveis por 63,1 por cento das perdas por natimortalidade, embora tenham sido responsáveis por 17,2 por cento das leitegadas. O percentual de natimortos aumentou com a ordem de nascimento; a maior taxa de natimortos, 21,7 por cento, ocorreu a partir da 14ª ordem. A taxa de natimortalidade foi de 3,6 por cento e 10,1 por cento nos leitões de primeira a nona e de 10ª a 13ª ordem, respectivamente. Em leitões com até 500g a taxa de natimortos foi de 52,1 por cento, mais alta que a de leitões mais pesados. Em leitões com 501 a 1200g foi de 10,1 por cento, maior que entre os com mais de 1200g (4,0 por cento). Não houve efeito de sexo dos leitões na ocorrência de natimortos, que foi de 6,2 por cento e 5,8 por cento para machos e fêmeas, respectivamente. A natimortalidade é maior entre os leitões com baixo peso ou com ordem de nascimento elevada.

To examine the influence of birth order, gender, and birth weight of piglets on stillbirth, records of 575 farrowings were analyzed. Out of 7,061 piglets, 90.2 percent, 6.0 percent, and 3.8 percent were born alive, stillborns and mummified, respectively. The percentage of farrowings with stillborns was 44.5 percent. Farrowings with two or more stillborns accounted for 63.1 percent of losses, although they produced 17.2 percent of the litters. Stillbirth rate increased with the increase of the birth order. Piglets born from the 14th order onward had the highest stillbirth rate (21.7 percent). Piglets born from the 1st to the 9th and from the 10th to the 13th order had stillbirth rates of 3.6 percent and 10.1 percent, respectively. For piglets weighting up to 500g, the stillbirth rate was 52.1 percent, which was higher than that recorded for heavier piglets. Piglets weighting from 501 to 1,200g had a stillbirth rate of 10.1 percent, which was higher than that observed for piglets weighing more than 1,200g (4.0 percent). There was no effect of gender of piglets on stillbirth occurrence, which reachead 6.2 percent and 5.8 percent for males and females, respectively. The stillbirth occurrence was higher for low weight piglets or higher birth order.

Clinicopathologic characterization of squamous-cell carcinoma arising from pilonidal disease in association with condylomata acuminatum in HIV-infected patients: report of two cases.

Pilonidal disease is a common acquired condition believed to arise from penetration of short hairs into the subcutaneous tissue that induces a cyst or sinus formation. Malignant degeneration is rare and is typically seen only after decades of antecedent disease presence. Condylomata acuminatum in association with pilonidal disease have been described in two prior case reports, however, the coexistence of condyloma with pilonidal disease complicated by malignant degeneration has not been previously reported. Condylomata have known potential for malignant degeneration and are correlated with human papilloma virus infection, with certain serotypes of higher oncogenic potential. Coinfection with human immunodeficiency virus and human papilloma virus is associated with higher rates of anal neoplasia. We report two cases of human immunodeficiency virus-infected patients with the constellation of pilonidal disease, condylomata acuminatum, and subsequent malignant degeneration into squamous-cell carcinoma. In contrast to other case reports in the literature, these two patients had considerably shorter antecedent periods of pilonidal disease before malignant degeneration was detected. Both cases also had intractable courses. We conclude that the existence of condylomata acuminatum and pilonidal disease in an immunocompromised patient may represent a more ominous condition than solitary pilonidal disease. Therefore, careful inspection of the pilonidal area in human immunodeficiency virus-infected patients presenting with condylomata is important and earlier intervention should be considered. Moreover, further evaluation of the prevalence of squamous-cell carcinoma arising from pilonidal disease complicated by condylomata, particularly in the immunosuppressed, is warranted.