Gregory E. Rice

Nuclear Factor Kappa B Regulation of Proinflammatory Cytokines in Human Gestational Tissues In Vitro

Abstract Proinflammatory cytokines are implicated in the initiation and progression of human labor and delivery, particularly in relation to infection-induced preterm labor. In nongestational tissues, the nuclear factor kappa B (NF-κB) transcription pathway is a key regulator of proinflammatory cytokine release. In these tissues, sulfasalazine (SASP), through its ability to inhibit NF-κB activation, inhibits release of interleukin (IL)-2, IL-12, and tumor necrosis factor (TNF)-α. Therefore, the aim of this study was to investigate whether or not NF-κB activation regulates the formation of proinflammatory cytokines in human gestational tissues. Human placenta, amnion, and choriodecidua (n = 9 separate placentas) were incubated with 10 μg/ml of lipopolysaccharide (LPS) in the absence (control) or presence of SASP (0.1, 1, 5, or 10 mM). After 6 h of incubation, the tissues were collected, and NF-κB DNA binding activity in nuclear extracts was assessed by electromobility shift binding assay. The incubation medium was collected and the release of IL-6, IL-8, and TNF-α was quantified by ELISA. Treatment of placenta, amnion, and choriodecidua with SASP at concentrations 5 mM or greater significantly inhibited the release of IL-6, IL-8, and TNF-α, and NF-κB activation (ANOVA, P < 0.05). The data presented in this study demonstrate that the NF-κB transcription pathway is a key regulator of LPS-stimulated IL-6, IL-8, and TNF-α release from human gestational tissues. The control of NF-κB activation may therefore provide an alternative therapeutic strategy for reducing the release of proinflammatory mediators in infection associated preterm labor.

Effects of dietary phytoestrogens in postmenopausal women

The aim of this study was to test the hypothesis that increased dietary intake of phytoestrogens reduces the health impact of the menopause. To test this hypothesis, a double-blind, randomized, entry-exit, cross-over study was conducted to assess the effects of three dietary manipulations--soy and linseed diets (high in phytoestrogens) and a wheat diet (low in phytoestrogens). Postmenopausal women were recruited and randomly assigned to one of the three dietary regimens. Urinary phytoestrogen concentrations, hot flush rate, vaginal smears, bone mineral density and bone mineral content were assessed for two 12-week periods. Comparative analysis showed no significant differences, but, when analyzed separately, groups consuming high phytoestrogen diets had between 10 and 30 times higher urinary excretion of phytoestrogens compared to those consuming the low phytoestrogen diet (p < 0.01). Study participants consuming soy, linseed and wheat diets had a 22% (not significant, n.s.), 41% (p < 0.009) and 51% (p < 0.001) reduction in hot flush rate; a 103% (p < 0.04), 5.5% (n.s.) and 11% (n.s.) increase in vaginal cytology maturation index; and a 5.2% (p < 0.04), 5.2% (n.s.) and 3.8% (n.s.) increase in bone mineral content, respectively. No changes were detected in bone mineral density. The differential effects of high phytoestrogen dietary manipulations on outcomes may represent tissue-specific responses to isoflavones and lignans contained in soy and linseed, respectively. Whilst health outcome measures were not significantly different between groups, the data obtained from separate analysis suggest that phytoestrogens in soy and linseed may be of use in ameliorating some of the symptoms of menopause. Furthermore, the significant decrease in hot flush rate in the wheat group cannot be attributable to phytoestrogens measured in this study. Due to subject variability, larger studies are still needed to evaluate population benefit.

Multicellular spheroids in ovarian cancer metastases: Biology and pathology.

Epithelial ovarian cancer (EOC) has a relatively high mortality rate ( approximately 55%). One of the presiding causes is that the current chemotherapeutic regimes are unable to achieve sustained remission, despite frequently producing a positive response at first treatment. One of the reasons that EOC is difficult to treat is that the mechanism of dissemination is unusual. EOC dissemination characteristically involves local invasion of pelvic and abdominal organs. Unlike many epithelial cancers, initial dissemination rarely requires the vasculature, although the vasculature is often implicated in the advanced stages of disease. Recently, it has become apparent that aggregates of malignant cells (spheroids) contained within malignant ascites represent a significant impediment to efficacious treatment of late stage EOC. In vivo, spheroids are present in the malignant ascites of EOC patients, while in vitro cultured spheroids are capable of tumorgenesis in vivo and display a reduced response to chemotherapeutic drugs when compared to monolayers. A major problem associated with the current generation of chemotherapy agents is that they do not address the anchorage- and vascular-independent growth conditions associated with a 3-dimensional structure that has formed and/or grown in suspension. Thus, spheroid formation may represent a key component of platinum/taxane-sensitive recurrence. If this is correct, a better understanding of spheroid biology may contribute to the identification of new treatment opportunities for the sustained treatment of metastatic EOC. This review article outlines the key biological features of spheroids, specifically discussing their role in EOC dissemination and chemo-response as well as providing insights into spheroid functionality.

Neutrophil gelatinase‐associated lipocalin (NGAL) an early‐screening biomarker for ovarian cancer: NGAL is associated with epidermal growth factor‐induced epithelio‐mesenchymal transition

The expression of neutrophil gelatinase‐associated lipocalin (NGAL) has been shown to be upregulated in ovarian cancer cells. In this study, we report that the expression of immunoreactive NGAL (irNGAL) in ovarian tumors changes with disease grade and that this change is reflected in the concentration of NGAL in peripheral blood. A total of 59 ovarian tissues including normal, benign, borderline malignant and grades 1, 2 and 3 malignant were analyzed using immunohistochemistry. irNGAL was not present in normal ovaries and the NGAL expression was weak to moderate in benign tissues. Both borderline and grade 1 tumors displayed the highest amount of NGAL expression with moderate to strong staining, whereas in grade 2 and 3 tumors, the extent of staining was significantly less (p < 0.01) and staining intensity was weak to moderate. Staining in all cases was confined to the epithelium. NGAL expression was analyzed by ELISA in 62 serum specimens from normal and different grades of cancer patients. Compared to control samples, the NGAL concentration was 2 and 2.6‐fold higher in the serum of patients with benign tumors and cancer patients with grade 1 tumors (p < 0.05) and that result was consistent with the expression of NGAL performed by Western blot. NGAL expression was evaluated by Western blot in an immortalized normal ovarian cell line (IOSE29) as well as ovarian cancer cell lines. Moderate to strong expression of NGAL was observed in epithelial ovarian cancer cell lines SKOV3 and OVCA433 while no expression of NGAL was evident in normal IOSE29 and mesenchyme‐like OVHS1, PEO.36 and HEY cell lines. NGAL expression was downregulated in ovarian cancer cell lines undergoing epithelio‐mesenchymal transition (EMT) induced by epidermal growth factor (EGF). Downregulation of NGAL expression correlated with the upregulation of vimentin expression, enhanced cell dispersion and downregulation of E‐cadherin expression, some of the hallmarks of EMT. EGF‐induced EMT phenotypes were inhibited in the presence of AG1478, an inhibitor of EGF receptor tyrosine kinase activity. These data indicate that NGAL may be a good marker to monitor changes of benign to premalignant and malignant ovarian tumors and that the molecule may be involved in the progression of epithelial ovarian malignancies.

Exosomal signaling during hypoxia mediates microvascular endothelial cell migration and vasculogenesis.

Vasculogenesis and angiogenesis are critical processes in fetal circulation and placental vasculature development. Placental mesenchymal stem cells (pMSC) are known to release paracrine factors (some of which are contained within exosomes) that promote angiogenesis and cell migration. The aims of this study were: to determine the effects of oxygen tension on the release of exosomes from pMSC; and to establish the effects of pMSC-derived exosomes on the migration and angiogenic tube formation of placental microvascular endothelial cells (hPMEC). pMSC were isolated from placental villi (8–12 weeks of gestation, n = 6) and cultured under an atmosphere of 1%, 3% or 8% O2. Cell-conditioned media were collected and exosomes (exo-pMSC) isolated by differential and buoyant density centrifugation. The dose effect (5–20 µg exosomal protein/ml) of pMSC-derived exosomes on hPMEC migration and tube formation were established using a real-time, live-cell imaging system (Incucyte™). The exosome pellet was resuspended in PBS and protein content was established by mass spectrometry (MS). Protein function and canonical pathways were identified using the PANTHER program and Ingenuity Pathway Analysis, respectively. Exo-pMSC were identified, by electron microscopy, as spherical vesicles, with a typical cup-shape and diameters around of 100 nm and positive for exosome markers: CD63, CD9 and CD81. Under hypoxic conditions (1% and 3% O2) exo-pMSC released increased by 3.3 and 6.7 folds, respectively, when compared to the controls (8% O2; p<0.01). Exo-pMSC increased hPMEC migration by 1.6 fold compared to the control (p<0.05) and increased hPMEC tube formation by 7.2 fold (p<0.05). MS analysis identified 390 different proteins involved in cytoskeleton organization, development, immunomodulatory, and cell-to-cell communication. The data obtained support the hypothesis that pMSC-derived exosomes may contribute to placental vascular adaptation to low oxygen tension under both physiological and pathological conditions.

Altered Placental Oxidative Stress Status in Gestational Diabetes Mellitus

Oxidative stress has been clearly linked to type 2 diabetes mellitus, however, limited data are available on the involvement of oxidative stress in gestational diabetes mellitus (GDM), a disease of similar pathophysiology. The aim of this study was to investigate the status of placental oxidative stress in healthy pregnant women and women with GDM. The hypothesis to be tested was that tissue markers of oxidative stress are significantly increased in GDM compared to normal placental tissues. Markers of oxidative stress measured were the release of 8-isoprostane (8-epi-prostaglandin F(2alpha)) from human term placental explants (n=11), the activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase (n=10), and protein carbonyl content (n=12). Placental release of 8-isoprostane was 2-fold greater from women with GDM (P<0.001) compared to healthy pregnant women. Superoxide dismutase activity and protein carbonyl content were elevated in placentae obtained from women with GDM (P<0.04 and P<0.004 respectively), whilst there was no significant difference in the activity of glutathione peroxidase. These data demonstrate the presence of oxidative stress in the placenta from women with GDM, in addition to the induction of a key antioxidant, collectively indicating a state of existing oxidative stress in this condition.

Proteomic-based identification of haptoglobin-1 precursor as a novel circulating biomarker of ovarian cancer

Screening for specific biomarkers of early-stage detection of ovarian cancer is a major health priority due to the asymptomatic nature and poor survival characteristic of the disease. We utilised two-dimensional gel electrophoresis (2DE) to identify differentially expressed proteins in the serum of ovarian cancer patients that may be useful as biomarkers of this disease. In this study, 38 ovarian cancer patients at different pathological grades (grade 1 (n=6), grade 2 (n=8) and grade 3 (n=24)) were compared to a control group of eight healthy women. Serum samples were treated with a mixture of Affigel-Blue and protein A (5 : 1) for 1 h to remove high abundance protein (e.g. immunoglobulin and albumin) and were displayed using 11 cm, pH 4–7 isoelectric focusing strips for the first dimension and 10% acrylamide gel electrophoresis for the second dimension. Protein spots were visualised by SYPRO-Ruby staining, imaged by FX-imager and compared and analysed by PDQuest software. A total of 24 serum proteins were differentially expressed in grade 1 (P<0.05), 31 in grade 2 (P<0.05) and 25 in grade 3 (P<0.05) ovarian cancer patients. Six of the protein spots that were significantly upregulated in all groups of ovarian cancer patients were identified by nano-electrospray quadrupole quadrupole time-of-flight mass spectrometry (n-ESIQ(q)TOFMS) and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOFMS) as isoforms of haptoglobin-1 precursor (HAP1), a liver glycoprotein present in human serum. Further identification of the spots at different pathological grades was confirmed by Western blotting using monoclonal antibody against a haptoglobin epitope contained within HAP1. Immunohistochemical localisation of HAP1-like activity was present in malignant ovarian epithelium and stroma but strong immunostaining was present in blood vessels, areas with myxomatous stroma and vascular spaces. No tissue localisation of HAP1-like immunoreactivity was observed in normal ovarian surface epithelium. These data highlight the need to assess circulating concentration of HAP1 in the serum of ovarian cancer patients and evaluate its potential as a biomarker in the early diagnosis of ovarian cancer.

Glucose-induced release of tumour necrosis factor- alpha from human placental and adipose tissues in gestational diabetes mellitus

Aims  The cytokine tumour necrosis factor‐alpha (TNF‐α) has been implicated in the pathogenesis of insulin resistance in Type 2 diabetes mellitus, but limited data are available in relation to gestational diabetes mellitus (GDM), a disease in which similar biochemical abnormalities exist. We investigated the effect of exogenous glucose on the release of TNF‐α from placental and adipose (omental and subcutaneous) tissue obtained from normal pregnant women, and women with GDM.

Proteomic analysis of human plasma: failure of centrifugal ultrafiltration to remove albumin and other high molecular weight proteins.

Determination of specific low abundance proteins, usually by radiolabelled or enzyme‐linked immunoassays in serum or plasma is widely used in diagnostic medicine. Substitution of these assays by a proteomic approach has been suggested, but this methodology has far from realised its potential as a diagnostic tool. The main protein fractions of plasma represent more than 80% of total protein, making the hundreds or even thousands of other proteins difficult to detect by two‐dimensional electrophoresis (2‐DE). Thus, loading sufficient sample to detect trace proteins invariably means excessive loading of albumin and other high abundance proteins. The aim of this study was to determine whether centrifugal ultrafiltration of whole plasma could be used to eliminate proteins exceeding a desired molecular weight cut‐off. Cellulose filters with a 30 kDa molecular weight cut‐off were used with whole plasma, and total protein was determined before and after ultrafiltration. Samples were processed by routine methods for 2‐DE using 18 cm, pH 3–10 isoelectric focusing strips for the first dimension and 7–15% gradient gels for the second dimension followed by silver staining. Gel analysis of the retentate fraction (30 kDa) revealed a typical 2‐DE plasma profile with most of the major landmark proteins in place and as expected, the gels lacked many of the smaller ( 30 kDa) proteins. Comparison with gels of the filtrate fraction ( 30 kDa) revealed very little difference. Not only were many of the higher molecular weight proteins still present, but some of the smaller 30 kDa landmark proteins were absent. Overall, gels of both the retentate and filtrate fractions were less informative than gels of whole plasma.

A Gestational Profile of Placental Exosomes in Maternal Plasma and Their Effects on Endothelial Cell Migration

Studies completed to date provide persuasive evidence that placental cell-derived exosomes play a significant role in intercellular communication pathways that potentially contribute to placentation and development of materno-fetal vascular circulation. The aim of this study was to establish the gestational-age release profile and bioactivity of placental cell-derived exosome in maternal plasma. Plasma samples (n = 20 per pregnant group) were obtained from non-pregnant and pregnant women in the first (FT, 6–12 weeks), second (ST, 22–24 weeks) and third (TT, 32–38 weeks) trimester. The number of exosomes and placental exosome contribution were determined by quantifying immunoreactive exosomal CD63 and placenta-specific marker (PLAP), respectively. The effect of exosomes isolated from FT, ST and TT on endothelial cell migration were established using a real-time, live-cell imaging system (Incucyte). Exosome plasma concentration was more than 50-fold greater in pregnant women than in non-pregnant women (p<0.001). During normal healthy pregnancy, the number of exosomes present in maternal plasma increased significantly with gestational age by more that two-fold (p<0.001). Exosomes isolated from FT, ST and TT increased endothelial cell migration by 1.9±0.1, 1.6±0.2 and 1.3±0.1-fold, respectively compared to the control. Pregnancy is associated with a dramatic increase in the number of exosomes present in plasma and maternal plasma exosomes are bioactive. While the role of placental cell-derived exosome in regulating maternal and/or fetal vascular responses remains to be elucidated, changes in exosome profile may be of clinical utility in the diagnosis of placental dysfunction.