Glucocorticoid receptor-PPARα axis in fetal mouse liver prepares neonates for milk lipid catabolism.

In mammals, hepatic lipid catabolism is essential for the newborns to efficiently use milk fat as an energy source. However, it is unclear how this critical trait is acquired and regulated. We demonstrate that under the control of PPARα, the genes required for lipid catabolism are transcribed before birth so that the neonatal liver has a prompt capacity to extract energy from milk upon suckling. The mechanism involves a fetal glucocorticoid receptor (GR)-PPARα axis in which GR directly regulates the transcriptional activation of PPARα by binding to its promoter. Certain PPARα target genes such as Fgf21 remain repressed in the fetal liver and become PPARα responsive after birth following an epigenetic switch triggered by β-hydroxybutyrate-mediated inhibition of HDAC3. This study identifies an endocrine developmental axis in which fetal GR primes the activity of PPARα in anticipation of the sudden shifts in postnatal nutrient source and metabolic demands

934-28 Sensitivity and Specificity of Angiographic Markers for Thrombus: A Prospective Comparison with Angioscopy

The limitations of angiography for the detection of intracoronary thrombus are well recognized. Between November 1991 and July 1994, we performed 402 angioscopy procedures in 225 vessels in 202 patients, with the Image-Cath (Baxter).We performed a prospective study in 190 of these patients, who had an interpretable angioscopy performed just before PTCA to determine the sensitivity and specificity of predetermined angiographic criteria that are considered to be indicative of the presence of intracoronary thrombus. Angiographically verified thrombus was used as the gold standard for comparison. Lesions were classified on angiography (2 orthogonal views) by independent observers. The presence of an intraluminal filling defect, of overhanging edges, of haziness, or of ulceration were noted. The characteristic ulceration was not mutually exclusive of the other 3 characteristics.Of 15 filling defects on angiography 14 (93%) had thrombus on angiography; in the 23 lesions with overhanging edges 19 (83%) had thrombus on angioscopy; in the 27 ulcerated lesions 21 (78%) had angioscopic thrombus; in the 6 lesions that were hazy on angiography 5 had angioscopic thrombus.AngioscopyThrombus+Thrombus-AngiographyThrombus+4512Thrombus-4093In our model, using 5 prespecified angiographic characteristics, angiography had high specificity (89%) but relatively low sensitivity (53%) for the detection of thrombus compared to angioscopy

An early immunoreactive folding intermediate of the tryptophan synthase β2 subunit is a ‘molten globule’

The refolding kinetics of the tryptophan synthase β2 subunit have been investigated by circular dichroism (CD) and binding of a fluorescent hydrophobic probe (ANS), using the stopped-flow technique. The kinetics of regain of the native far UV CD signal show that, upon refolding of urea denatured β2, more than half of the protein secondary structure is formed within the dead time of the CD stopped-flow apparatus (0.013 s). On the other hand, upon refolding of guanidine unfolded β2 the fluorescence of ANS passes through a maximum after about 1 s and then ‘slowly’ decreases. These results show the accumulation, in the 1–10 s time range, of an early transient folding intermediate which has a pronounced secondary structure and a high affinity for ANS. In this time range, the near UV CD remains very low. This transient intermediate thus appears to have all the characteristics of the ‘molten globule’ state [(1987) FEBS Lett. 224, 9-13]. Moreover, by comparing the intrinsic time of the disappearance of this transient intermediate (t 35 s) with the time of formation of the previously characterized [(1988) Biochemistry 27, 7633-7640] early imuno-reactive intermediate recognized by a monoclonal antibody (t 12 s), it is shown that this native-like epitope forms within the ‘molten globule’, before the tight packing of the protein side chains

TGFβ signaling regulates Epithelial-mesenchymal plasticity in ovarian cancer ascites-derived spheroids

Epithelial-mesenchymal transition (EMT) serves as a key mechanism driving tumor cell migration, invasion, and metastasis in many carcinomas. Transforming growth factor-beta (TGFβ) signaling is implicated in several steps during cancer pathogenesis and acts as a classical inducer of EMT. Since epithelial ovarian cancer (EOC) cells have the potential to switch between epithelial and mesenchymal states during metastasis, we predicted that modulation of TGFβ signaling would significantly impact EMT and the malignant potential of EOC spheroid cells. Ovarian cancer patient ascites-derived cells naturally underwent an EMT response when aggregating into spheroids, and this was reversed upon spheroid re-attachment to a substratum. CDH1/E-cadherin expression was markedly reduced in spheroids compared with adherent cells, in concert with an up-regulation of several transcriptional repressors, i.e., SNAI1/Snail, TWIST1/2, and ZEB2. Treatment of EOC spheroids with the TGFβ type I receptor inhibitor, SB-431542, potently blocked the endogenous activation of EMT in spheroids. Furthermore, treatment of spheroids with SB-431542 upon re-attachment enhanced the epithelial phenotype of dispersing cells and significantly decreased cell motility and Transwell migration. Spheroid formation was significantly compromised by exposure to SB-431542 that correlated with a reduction in cell viability particularly in combination with carboplatin treatment. Thus, our findings are the first to demonstrate that intact TGFb signaling is required to control EMT in EOC ascites-derived cell spheroids, and it promotes the malignant characteristics of these structures. As such, we show the therapeutic potential for targeted inhibition of this pathway in ovarian cancer patients with late-stage disease

PGC-1α induced browning promotes involution and inhibits lactation in mammary glands

The PPARγ coactivator 1α (PGC-1α) is a transcriptional regulator of mitochondrial biogenesis and oxidative metabolism. Recent studies have highlighted a fundamental role of PGC-1α in promoting breast cancer progression and metastasis, but the physiological role of this coactivator in the development of mammary glands is still unknown. First, we show that PGC-1α is highly expressed during puberty and involution, but nearly disappeared in pregnancy and lactation. Then, taking advantage of a newly generated transgenic mouse model with a stable and specific overexpression of PGC-1α in mammary glands, we demonstrate that the re-expression of this coactivator during the lactation stage leads to a precocious regression of the mammary glands. Thus, we propose that PGC-1α action is non-essential during pregnancy and lactation, whereas it is indispensable during involution. The rapid preadipocyte–adipocyte transition, together with an increased rate of apoptosis promotes a premature mammary glands involution that cause lactation defects and pup growth retardation. Overall, we provide new insights in the comprehension of female reproductive cycles and lactation deficiency, thus opening new roads for mothers that cannot breastfeed

760-4 Initial Multicenter Experience with Therapeutic Ultrasonic Coronary Angioplasty in Patients

Therapeutic ultrasonic (195 kHz) catheters with 1.2 or 1.7 mm ball tips for coronary angioplasty have recently been developed. During the first phase of a multi-center European trial (CRUSADE) this system was evaluated in 100 patients (86% male, mean age 57 years) with symptomatic coronary artery disease or acute myocardial infarction. Lesions were located in the LAD (n = 61), CX (n = 17), and RCA (n = 22); 62% were type B or C; 11 lesions were restenotic, 19 occlusive, 9 longer than 20 mm, 37 calcified, 18 thrombotic, and 15 collateralised.ResultsThe ultrasound catheter crossed 82/100 lesions, adjunctive balloon angioplastywas needed in 98 lesions. There was no death and myocardial infarction, or CABG in the first 24 hours. There was no perforation, but 2 acute vessel closures; intimal cleft or dissection was seen in 17 lesions of which 1 required stenting. Procedural success was obtained in 93%. At 24 hours 11/100 vessels were reoccluded. At 6 months angiographic follow-up in 51 patients restenosis (>50% stenosis) occured in 33%.ConclusionsTherapeutic ultrasound angioplasty is a feasible and safe new treatment modality. Adjunctive balloon angioplasty is regularly necessary. Preliminary experience suggests usefulness in lesions with visible thrombus, and undilatable or uncrossable lesions

Electron-electron interactions in one- and three-dimensional mesoscopic disordered rings: a perturbative approach

We have computed persistent currents in a disordered mesoscopic ring in the presence of small electron-electron interactions, treated in first order perturbation theory. We have investigated both a contact (Hubbard) and a nearest neighbour interaction in 1D and 3D. Our results show that a repulsive Hubbard interaction produces a paramagnetic contribution to the average current (whatever the dimension) and increases the value of the typical current. On the other hand, a nearest neighbour repulsive interaction results in a diamagnetic contribution in 1D and paramagnetic one in 3D, and tends to decrease the value of the typical current in any dimension. Our study is based on numerical simulations on the Anderson model and is justified analytically in the presence of very weak disorder. We have also investigated the influence of the amount of disorder and of the statistical (canonical or grand-canonical) ensemble.Comment: 7 pages in REVTEX, 4 figure

Intact LKB1 activity is required for survival of dormant ovarian cancer spheroids

Metastatic epithelial ovarian cancer (EOC) cells can form multicellular spheroids while in suspension and disperse directly throughout the peritoneum to seed secondary lesions. There is growing evidence that EOC spheroids are key mediators of metastasis, and they use specific intracellular signalling pathways to control cancer cell growth and metabolism for increased survival. Our laboratory discovered that AKT signalling is reduced during spheroid formation leading to cellular quiescence and autophagy, and these may be defining features of tumour cell dormancy. To further define the phenotype of EOC spheroids, we have initiated studies of the Liver kinase B1 (LKB1)-5′-AMP-activated protein kinase (AMPK) pathway as a master controller of the metabolic stress response. We demonstrate that activity of AMPK and its upstream kinase LKB1 are increased in quiescent EOC spheroids as compared with proliferating adherent EOC cells. We also show elevated AMPK activity in spheroids isolated directly from patient ascites. Functional studies reveal that treatment with the AMP mimetic AICAR or allosteric AMPK activator A-769662 led to a cytostatic response in proliferative adherent ovarian cancer cells, but they fail to elicit an effect in spheroids. Targeted knockdown of STK11 by RNAi to reduce LKB1 expression led to reduced viability and increased sensitivity to carboplatin treatment in spheroids only, a phenomenon which was AMPK-independent. Thus, our results demonstrate a direct impact of altered LKB1-AMPK signalling function in EOC. In addition, this is the first evidence in cancer cells demonstrating a pro-survival function for LKB1, a kinase traditionally thought to act as a tumour suppressor

Combination of AKT inhibition with autophagy blockade effectively reduces ascites-derived ovarian cancer cell viability

Recent genomics analysis of the high-grade serous subtype of epithelial ovarian cancer (EOC) show aberrations in the phosphatidylinositol 3-kinase (PI3K)/AKT pathway that result in upregulated signaling activity. Thus, the PI3K/AKT pathway represents a potential therapeutic target for aggressive high-grade EOC. We previously demonstrated that treatment of malignant ascites-derived primary human EOC cells and ovarian cancer cell lines with the allosteric AKT inhibitor Akti-1/2 induces a dormancy-like cytostatic response but does not reduce cell viability. In this report, we show that allosteric AKT inhibition in these cells induces cytoprotective autophagy. Inhibition of autophagy using chloroquine (CQ) alone or in combination with Akti-1/2 leads to a significant decrease in viable cell number. In fact, Akti-1/2 sensitizes EOC cells to CQ-induced cell death by exhibiting markedly reduced EC50 values in combination-treated cells compared with CQ alone. In addition, we evaluated the effects of the novel specific and potent autophagy inhibitor-1 (Spautin-1) and demonstrate that Spautin-1 inhibits autophagy in a Beclin-1-independent manner in primary EOC cells and cell lines. Multicellular EOC spheroids are highly sensitive to Akti-1/2 and CQ/Spautin-1 cotreatments, but resistant to each agent alone. Indeed, combination index analysis revealed strong synergy between Akti-1/2 and Spautin-1 when both agents were used to affect cell viability; Akti-1/2 and CQ cotreatment also displayed synergy in most samples. Taken together, we propose that combination AKT inhibition and autophagy blockade would prove efficacious to reduce residual EOC cells for supplying ovarian cancer recurrence. © The Author 2014. Published by Oxford University Press. All rights reserved

Spin-stiffness and topological defects in two-dimensional frustrated spin systems

Using a {\it collective} Monte Carlo algorithm we study the low-temperature and long-distance properties of two systems of two-dimensional classical tops. Both systems have the same spin-wave dynamics (low-temperature behavior) as a large class of Heisenberg frustrated spin systems. They are constructed so that to differ only by their topological properties. The spin-stiffnesses for the two systems of tops are calculated for different temperatures and different sizes of the sample. This allows to investigate the role of topological defects in frustrated spin systems. Comparisons with Renormalization Group results based on a Non Linear Sigma model approach and with the predictions of some simple phenomenological model taking into account the topological excitations are done.Comment: RevTex, 25 pages, 14 figures, Minor changes, final version. To appear in Phys.Rev.