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Background Alteration of signalling pathways regulating cell cycle progression is a common feature of cancer cells. Several drugs targeting distinct phases of the cell cycle have been developed but the inability of many of them to discriminate between normal and cancer cells has strongly limited their clinical potential because of their reduced efficacy at the concentrations used to limit adverse side effects. Mechanisms of resistance have also been described, further affecting their efficacy. Identification of novel targets that can potentiate the effect of these drugs or overcome drug resistance can provide a useful strategy to exploit the anti-cancer properties of these agents to their fullest. Methods The class II PI3K isoform PI3K-C2β was downregulated in prostate cancer PC3 cells and cervical cancer HeLa cells using selective siRNAs and the effect on cell growth was determined in the absence or presence of the microtubule-stabilizing agent/anti-cancer drug docetaxel. Mitosis progression was monitored by time-lapse microscopy. Clonogenic assays were performed to determine the ability of PC3 and HeLa cells to form colonies upon PI3K-C2β downregulation in the absence or presence of docetaxel. Cell multi-nucleation was assessed by immunofluorescence. Tumour growth in vivo was assessed using a xenograft model of PC3 cells upon PI3K-C2β downregulation and in combination with docetaxel. Results Downregulation of PI3K-C2β delays mitosis progression in PC3 and HeLa cells, resulting in reduced ability to form colonies in clonogenic assays in vitro. Compared to control cells, PC3 cells lacking PI3K-C2β form smaller and more compact colonies in vitro and they form tumours more slowly in vivo in the first weeks after cells implant. Stable and transient PI3K-C2β downregulation potentiates the effect of low concentrations of docetaxel on cancer cell growth. Combination of PI3K-C2β downregulation and docetaxel almost completely prevents colonies formation in clonogenic assays in vitro and strongly inhibits tumour growth in vivo. Conclusions These data reveal a novel role for the class II PI3K PI3K-C2β during mitosis progression. Furthermore, data indicate that blockade of PI3K-C2β might represent a novel strategy to potentiate the effect of docetaxel on cancer cell growth.

Additional file 7: Figure S6. Low concentrations of docetaxel reduce cell numbers and induce multi-nucleation in PC3 cells. (a) PC3 cells were treated with the indicated concentrations of docetaxel for 72 h before cell counting. Control cells were treated with vehicle (DMSO) alone. Data are expressed as percentage of cells treated with DMSO and are means ± s.e.m. of n = 3–11 independent experiments performed in duplicate. **p

Phosphoinositide 3-kinases (PI3Ks) regulate several cellular functions such as proliferation, growth, survival and migration. The eight PI3K isoforms are grouped into three classes and the three enzymes belonging to the class II subfamily (PI3K-C2α, β and γ) are the least investigated amongst all PI3Ks. Interest on these isoforms has been recently fuelled by the identification of specific physiological roles for class II PI3Ks and by accumulating evidence indicating their involvement in human diseases. While it is now established that these isoforms can regulate distinct cellular functions compared to other PI3Ks, there is still a limited understanding of the signalling pathways that can be specifically regulated by class II PI3Ks. Here we show that PI3K-C2β regulates mitogen-activated protein kinase kinase (MEK1/2) and extracellular signal-regulated kinase (ERK1/2) activation in prostate cancer (PCa) cells. We further demonstrate that MEK/ERK and PI3K-C2β are required for PCa cell invasion but not proliferation. In addition we show that PI3K-C2β but not MEK/ERK regulates PCa cell migration as well as expression of the transcription factor Slug. These data identify novel signalling pathways specifically regulated by PI3K-C2β and they further identify this enzyme as a key regulator of PCa cell migration and invasion.

Genetic variants in the FTO (fat mass- and obesity-associated) gene have the highest association of all obesity-associated genes. Its placental expression was shown to relate to birth weight, suggesting that it may participate in the control of fetal weight gain. To gain more insight into the implication of FTO in fetal growth, we measured its placental expression in samples including extremes of abnormal fetal growth, such as after intrauterine growth restriction (IUGR) or macrosomia in both rats and humans. In rats, fetal growth was modulated by maternal nutritional modifications. In humans, placental villi were collected from pathological pregnancies (i.e. with IUGR or fetal macrosomia). Placental FTO mRNA expression was reduced by IUGR but was not significantly affected by macrosomia in either rats or humans. Our data suggest that placental FTO may participate in interactions between the in utero environment and the control of fetal growth under IUGR conditions by modulating epigenetic processes.

Several studies indicate that maternal undernutrition sensitizes the offspring to the development of metabolic disorders, such as obesity. Using a model of perinatal maternal 50% food-restricted diet (FR50), we recently reported that rat neonates from undernourished mothers exhibit decreased leptin plasma levels associated with alterations of hypothalamic proopiomelanocortin system. The present study aimed at examining the consequences of FR50 on the brain-adipose axis in male rat neonates. Using quantitative RT-PCR array containing 84 obesity-related genes, we demonstrated that most of the genes involved in energy metabolism regulation are expressed in rat gonadal white adipose tissue (WAT) and are sensitive to maternal perinatal undernutrition (MPU). In contrast, hypothalamic gene expression was not substantially affected by MPU. Gene expression of uncoupling protein 1 (UCP1), a marker of brown adipocytes, showed an almost 400-fold stimulation in postnatal day 21 (PND21) FR50 animals, suggesting that their gonadal WAT possesses a brown-like phenotype. This was confirmed by histological and immunoshistochemical procedures, which demonstrated that PND21 FR50 gonadal adipocytes are multilocular, resembling those present in interscapular brown adipose tissue, and exhibit an overexpression of UCP1 and neuropeptide Y (NPY) at the protein level. Control animals contained almost exclusively “classical” unilocular white adipocytes that did not show high UCP1 and NPY labeling. After weaning, FR50 animals exhibited a transient hyperphagia that was associated with the disappearance of brown-like fat pads in PND30 WAT. Our results demonstrate that MPU delays the maturation of gonadal WAT during critical developmental time windows, suggesting that it could have long-term consequences on body weight regulation in the offspring.

Mild gestational hyperglycemia is often associated with fetal overgrowth that can predispose the offspring to metabolic diseases later in life. We hypothesized that unfavorable intrauterine environment may compromise the development of placenta and contribute to fetal overgrowth. Therefore, we developed a rat model and investigated the effects of maternal dysglycemia on fetal growth and placental gene expression. Female rats were treated with single injection of nicotinamide plus streptozotocin (N-STZ) 1-week before mating and were studied at gestational day 21. N-STZ pregnant females displayed impaired glucose tolerance that is associated with a lower insulin secretion. Moderate hyperglycemia induced fetal overgrowth in 40% of newborns, from pregnancies with 10 to 14 pups. The incidence of macrosomia was less than 5% in the N-STZ pregnancies when the litter size exceeds 15 newborns. We found that placental mass and the labyrinthine layer were increased in macrosomic placentas. The expression of genes involved in placental development and nutrient transfer was down regulated in the N-STZ placentas of macrosomic and normosomic pups from pregnancies with 10 to 14 ones. However, we observed that lipoprotein lipase 1 (LPL1) gene expression was significantly increased in the N-STZ placentas of macrosomic pups. In pregnancies with 15 pups or more, the expression of IGFs and glucose transporter genes was also modulated in the control placentas with no additional effect in the N-STZ ones. These data suggest that placental gene expression is modulated by gestational conditions that might disrupt the fetal growth. We described here a new model of maternal glucose intolerance that results in fetal overgrowth. We proposed that over-expression of LPL1 in the placenta may contribute to the increased fetal growth in the N-STZ pregnancies. N-STZ model offers the opportunity to determinate whether these neonatal outcomes may contribute to developmental programming of metabolic diseases in adulthood.

Introduction Le DG est associe a des anomalies de croissance qui sont soit une macrosomie soit un retard de croissance intra uterin (RCIU) en cas d'anomalies vasculaires. Ces anomalies de croissance dependent du metabolisme maternel et placentaire. Objectifs Nous avons caracterise les phenotypes maternels et fœtaux dans differents modeles de DG et determine les facteurs impliques dans la croissance foeto-placentaire. Materiels et methodes 4 groupes de rates Wistar diabetiques a J7 de gestation comparativement a un groupe temoin T (n=14) : D (nicotinamide (NCT) 230mg/kg, streptozotocine (STZ) 65mg/kg) n=9 ; D50 (NCT O115mg/kg, STZ 65mg/kg) n=10 ; D30 (NCT 75mg/kg, STZ 65mg/kg) n=16 ; DS (STZ a 40mg/kg) n=6. Nous avons evalue les phenotypes des meres, glycemie, insulinemie en base et apres OGTT. Chez le raton, nous avons determine les poids de naissance et placentaire ainsi que la glycemie et l'insulinemie. Les genes placentaires influant la croissance etaient etudies par RT PCR. Resultats La glycoregulation maternelle est d'autant plus alteree que la dose de NCT est faible. Nous n'avons que des RCIU, dependant de la severite de l'hyperglycemie maternelle et independamment de l'insulinemie fœtale. Le poids placentaire des ratons les plus petits (DS) n'est pas different de celui des temoins. Les ratons D30 presentent en revanche des placentas plus gros (p Conclusion Nos resultats sont en faveur d'une heterogeneite des phenotypes. Les RCIU semblent etre lies a des troubles nutritionnels et d'oxygenation fœtale. Les variations de VEGF et PLGF pourraient temoigner d'une hyperoxie placentaire.

Rationnel L’environnement nutritionnel et metabolique au cours des phases precoces du developpement constitue un element cle dans le determinisme de l’obesite et du diabete et entraine des modifications epigenetiques susceptibles d’expliquer la transmission d’une generation a l’autre des pathologies metaboliques Objectif : Evaluer l’impact de la programmation nutritionnelle et d’un regime hyperlipidique sur la croissance et le metabolisme de la descendance. Materiels et methodes Des rats femelles issus de meres (F0) denutries (FR) ou de meres controles (C) nourries ad libitum sont soumises pendant 2 mois a un regime standard (S) ou un regime hyperlipidique (HF). Les femelles de la F1 sont reparties en 6 groupes experimentaux, 3 groupes C et 3 groupes FR recevant pendant la gestation un regime S (CS-S, CHF-S, FRS-S, FRHF-S) ou un regime HF (CHF-HF, FRHF-HF). Resultats Les femelles gestantes CHF-HF, FRS-S, FRHF-S et FRHF-HF presentent une intolerance partielle au glucose en l’absence d’obesite. Nous observons une macrosomie chez pres de 30 % de nouveau-nes des meres FRHF-S associee a une baisse des triglycerides plasmatiques maternels. A l’inverse, nous observons un retard de croissance intra-uterin (RCIU) chez pres de 22 % des nouveau-nes issus de meres CHF-HF et FRHF-HF en rapport avec une augmentation des NEFA plasmatiques maternels. L’analyse moleculaire des genes placentaires montre que la macrosomie est associee a une modification de l’expression des genes impliques dans le metabolisme lipidique, tandis que le RCIU implique l’expression de genes du stress oxydatif. Discussion La denutrition maternelle programme chez les femelles des anomalies de la tolerance au glucose responsables des alterations de la croissance fœtale dans la descendance. La manipulation du regime lipidique des meres conduit a des phenotypes opposes (macrosomie vs RCIU) en relation avec une expression genique placentaire differentielle. Conclusion Il reste a determiner si les nouveau-nes macrosomes et RCIU developpent a l’âge adulte des pathologies similaires.

Rationnel L'environnement diabetique in utero , est implique dans la survenue de macrosomie neonatale et predispose a la survenue a l'âge adulte de pathologies apparentees au syndrome metabolique. Afin d'identifier des parametres metaboliques maternels, placentaires et neonataux associes a la survenue de macrosomie dans un contexte de diabete, nous avons developpe un nouveau modele experimental de diabete induit par injection de Streptozotocine et de Nicotinamide. Materiels et Methodes Des rates femelles Wistar, 7 jours avant le debut de la gestation, ont recu une injection de Nicotinamide (N a 230 mg/kg) et de Streptozotocine (STZ a 65 mg/kg), definissant un groupe N-STZ (n = 22), tandis qu'un groupe controle (n = 12) recoit une injection de solvant. Resultats Au 19 e jour de gestation les femelles N-STZ presentent des anomalies des glycemies en reponse a l'OGTT (t0, 62 ± 3 mg/dl ; t15, 163 ± 7 mg/dl ; t30, 216 ± 11 mg/dl ; t60, 187 ± 20 mg/dl ; t90, 86 ± 10 mg/dl et t120, 63 ± 2 mg/ dl) ainsi qu'une diminution de l'index insulinogenique (5,50 ± 4 mU/mmol vs 47,96 ± 28 mU/mmol, p vs 152 ± 25 μU/ml, p versus une absence de macrosomie dans le groupe controle. La quantification des transcrits placentaires de genes impliques dans la croissance (IGF1 et 2, recepteurs IGF1R, IGF2R, IRS1) et le transport des nutriments tels que le glucose (GLUT1, 3 et 4), les acides amines, (SNAT 2 et 4, LAT) et les acides gras (lipoproteine lipase 1, LPL1, lipase endotheliale LIPG) montre une surexpression significative de la LPL1 et une baisse de l'IGF2, IGFR1 et IRS1 dans les placentas du groupe N-STZ. Discussion La surexpression de la LPL1 apparaitrait comme un determinant de la macrosomie. Des dosages des triglycerides et des acides gras libres plasmatiques maternels et fœtaux sont en cours afin de confirmer cette hypothese. Conclusion Nous validons ce modele experimental par l'obtention d'un diabete avec glycemie moderement elevee et stable au cours de la gestation avec pour consequence un pourcentage significatif de nouveau-nes macrosomes.