CDK4 Phosphorylates AMPKα2 to Inhibit Its Activity and Repress Fatty Acid Oxidation

The roles of CDK4 in the cell cycle have been extensively studied, but less is known about the mechanisms underlying the metabolic regulation by CDK4. Here, we report that CDK4 promotes anaerobic glycolysis and represses fatty acid oxidation in mouse embryonic fibroblasts (MEFs) by targeting the AMP-activated protein kinase (AMPK). We also show that fatty acid oxidation (FAO) is specifically induced by AMPK complexes containing the α2 subunit. Moreover, we report that CDK4 represses FAO through direct phosphorylation and inhibition of AMPKα2. The expression of non-phosphorylatable AMPKα2 mutants, or the use of a CDK4 inhibitor, increased FAO rates in MEFs and myotubes. In addition, Cdk4(-/-) mice have increased oxidative metabolism and exercise capacity. Inhibition of CDK4 mimicked these alterations in normal mice, but not when skeletal muscle was AMPK deficient. This novel mechanism explains how CDK4 promotes anabolism by blocking catabolic processes (FAO) that are activated by AMPK

The regulation of RhoA at focal adhesions by StarD13 is important for astrocytoma cell motility

Malignant astrocytomas are highly invasive into adjacent and distant regions of the normal brain. Rho GTPases are small monomeric G proteins that play important roles in cytoskeleton rearrangement, cell motility, and tumor invasion. In the present study, we show that the knock down of StarD13, a GTPase activating protein (GAP) for RhoA and Cdc42, inhibits astrocytoma cell migration through modulating focal adhesion dynamics and cell adhesion. This effect is mediated by the resulting constitutive activation of RhoA and the subsequent indirect inhibition of Rac. Using Total Internal Reflection Fluorescence (TIRF)-based Förster Resonance Energy Transfer (FRET), we show that RhoA activity localizes with focal adhesions at the basal surface of astrocytoma cells. Moreover, the knock down of StarD13 inhibits the cycling of RhoA activation at the rear edge of cells, which makes them defective in retracting their tail. This study highlights the importance of the regulation of RhoA activity in focal adhesions of astrocytoma cells and establishes StarD13 as a GAP playing a major role in this process

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

The Rôle of Novel Kinases in Adipose Tissue Biology

Obesity, the accumulation of excess body fat, is an epidemic leading to numerous human metabolic diseases, such as type 2 diabetes (T2D). T2D is mainly characterized by hyperglycemia, accompanied by local (adipose tissue) and systemic insulin resistance. In the adipose tissue, insulin resistance involves alterations in the cross-talk of various signaling cascades, implicating numerous kinases and phosphatases. To identify molecular changes that occur during the development of insulin resistance, we have used here a new activity-based method to study the global kinase activity in human adipose tissue, the PamGene. Our study is based on the observation that some obese subjects do not develop insulin resistance. This population represents our control group, which avoids confounding results, due to obesity by itself rather than to insulin resistance. We found that a specific set of kinase activities are representative of insulin resistance in the obese population, such as PIM family, CHK2, and CDK10. In particular, we found that the Serine/Threonine kinase (STK) PIM-1, unlike the other PIM proteins, has increased activity in the visceral adipose tissue (VAT) of morbid obese diabetic (MOD) insulin resistant (IR) patients. We show that PIM-1 inhibition decreases the inflammatory capacity of bone marrow-derived macrophages in vitro, and leads to a decrease in the inflammatory profile in visceral adipose tissue (VAT), as well as to an increase in insulin sensitivity in diabetic mice.. Furthermore, we found that CHK2 has higher activity in VAT of MOD patients, and we prove that the pharmaceutical inhibition of CHK2 in diabetic mice reduces their IR phenotype. Even though CDK10 was also found to be upregulated in VAT of MOD patients, it does not show any clear cut metabolic phenotype in CDK10 ablated knock out mice. Finally, the use of this innovative technique has paved the way to finding new kinases implicated in insulin resistance of the visceral adipose tissue, and to initiating new lines of research for further validation studies. -- L'obésité, l'accumulation de l'excès de graisse corporelle, est une épidémie qui entraîne de nombreuses maladies métaboliques chez l'homme, telles que le diabète de type 2 (DT2). Le DT2 est principalement caractérisé par une hyperglycémie, accompagnée d'une résistance à l'insuline locale (tissu adipeux) et systémique. Dans le tissu adipeux, la résistance à l'insuline implique des modifications de la diaphonie de différentes cascades de signalisation, impliquant de nombreuses kinases et phosphatases. Pour identifier les changements moléculaires survenant au cours du développement de la résistance à l'insuline, nous avons utilisé ici une nouvelle méthode basée sur l'activité pour étudier l'activité de la kinase globale dans le tissu adipeux humain, le PamGene. Notre étude est basée sur l'observation que certains sujets obèses ne développent pas de résistance à l'insuline. Cette population représente notre groupe témoin, ce qui évite les résultats confondants, dus à l'obésité en soi plutôt qu'à la résistance à l'insuline. Nous avons constaté qu'un ensemble spécifique d'activités de kinases est représentatif de la résistance à l'insuline dans la population obèse, tel que la famille PIM, CHK2 et CDK10. En particulier, nous avons constaté que la protéine PIM-1 de la sérine / thréonine (STK), contrairement aux autres protéines de la protéine PIM, avait augmenté l'activité du tissu adipeux viscéral (VAT) des patients insulino- résistants (IR) morbides diabétiques obèses (MOD). Nous montrons que l'inhibition de PIM-1 diminue la capacité inflammatoire des macrophages dérivés de la moelle osseuse in vitro et conduit à une diminution du profil inflammatoire dans le tissu adipeux viscéral (TVA), ainsi qu'à une augmentation de la sensibilité à l'insuline chez la souris diabétique. De plus, nous avons constaté que la CHK2 a une activité plus élevée dans la TVA des patients MOD et nous prouvons que l’inhibition pharmaceutique de la CHK2 chez les souris diabétiques réduit leur phénotype IR. Même si CDK10 a également été retrouvée régulée à la hausse dans la TVA des patients MOD, elle ne montre aucun phénotype métabolique net chez les souris neutralisées par CDK10. Enfin, l'utilisation de cette technique innovante a ouvert la voie à la découverte de nouvelles kinases impliquées dans la résistance à l'insuline du tissu adipeux viscéral et au lancement de nouvelles lignes de recherche pour des études de validation ultérieures

Cancer: Linking Powerhouses to Suicidal Bags

Membrane-bound organelles are integrated into cellular networks and work together for a common goal: regulating cell metabolism, cell signaling pathways, cell fate, cellular maintenance, and pathogen defense. Many of these interactions are well established, but little is known about the interplay between mitochondria and lysosomes, and their deregulation in cancer. The present review focuses on the common signaling pathways of both organelles, as well as the processes in which they both physically interact, their changes under pathological conditions, and the impact on targeting those organelles for treating cancer

Daucus carota pentane/diethyl ether fraction inhibits motility and reduces invasion of cancer cells

Daucus carota (DC) is a herb used in folklore medicine in Lebanon to treat numerous diseases including cancer. Recent studies in our laboratory on DC oil and its fractions revealed potent anticancer activities in vitro and in vivo. The present study aims to investigate the effect of the most potent DC fraction, pentane/diethyl ether (50:50), on lung, skin, breast and glioblastoma cancer cell motility and invasion. Upon treatment, a pronounced decrease in cancer cell motility was observed in the 4 cell lines. The treatment also led to a decrease in cancer cell invasion and an increased cell adhesion. Additionally, the DC fraction caused a decrease in the activation of the ρ-GTPases Rac and CDC42, a finding that may partially explain the treatment-induced decrease in cell motility. The current study demonstrates a crucial effect of the DC pentane/diethyl ether fraction on cancer cell motility and metastasis, making it a potential candidate for cancer therapy specifically targeting cancer motility and metastasis.PublishedN/