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C Le Page

Publications and source records attributed to C Le Page.

At least 19 recordsLinked to original sources
PubMed2006

Expression and localisation of Akt-1, Akt-2 and Akt-3 correlate with clinical outcome of prostate cancer patients.

We investigated the correlation between the expression and localisation of Akt-1, Akt-2, Akt-3, phospho-Akt proteins and the clinicopathological parameters in 63 prostate cancer specimens. More than 60% of cancerous tissues overexpressed Akt-1, Akt-2 or Akt-3. Cytoplasmic Akt-1 expression was correlated with a higher risk of postoperative prostate-specific antigen (PSA) recurrence and shorter PSA recurrence interval. Cytoplasmic Akt-2 did not show any significant correlation with clinicopathological parameters predicting outcomes. Cytoplasmic Akt-3 was associated with hormone-refractory disease progression and extracapsular invasion. Nuclear Akt-1 and Akt-2 expression were correlated with favourable outcome parameters such as absence of lymph node and perineural invasion. Kaplan-Meier analysis and Cox regression model also showed that Akt-1 and Akt-2, but not Akt-3 or phospho-Akt was associated with a significantly higher risk of PSA recurrence. In contrast, nuclear Akt-1 was significantly associated with a lower risk of PSA recurrence. Multivariate analysis revealed that clinical stage, Gleason score and the combined cytoplasmic nuclear Akt-1 marker in cancerous tissues were significant independent prognostic factors of PSA recurrence. This is the first report demonstrating in patients with prostate cancer and the particular role of Akt-1 isoform expression as a prognostic marker depending of its localisation.

Aged↗
PubMed2006

Gene expression profiling of primary cultures of ovarian epithelial cells identifies novel molecular classifiers of ovarian cancer.

In order to elucidate the biological variance between normal ovarian surface epithelial (NOSE) and epithelial ovarian cancer (EOC) cells, and to build a molecular classifier to discover new markers distinguishing these cells, we analysed gene expression patterns of 65 primary cultures of these tissues by oligonucleotide microarray. Unsupervised clustering highlights three subgroups of tumours: low malignant potential tumours, invasive solid tumours and tumour cells derived from ascites. We selected 18 genes with expression profiles that enable the distinction of NOSE from these three groups of EOC with 92% accuracy. Validation using an independent published data set derived from tissues or primary cultures confirmed a high accuracy (87-96%). The distinctive expression pattern of a subset of genes was validated by quantitative reverse transcription-PCR. An ovarian-specific tissue array representing tissues from NOSE and EOC samples of various subtypes and grades was used to further assess the protein expression patterns of two differentially expressed genes (Msln and BMP-2) by immunohistochemistry. This study highlights the relevance of using primary cultures of epithelial ovarian cells as a model system for gene profiling studies and demonstrates that the statistical analysis of gene expression profiling is a useful approach for selecting novel molecular tumour markers.

Biomarkers, Tumor↗
PubMed2001

Coronary and aortic vasoreactivity protection with endothelin receptor antagonist, bosentan, after ischemia and hypoxia in aged rats.

This study investigated the effects of bosentan, a dual endothelin ET(A) and ET(B) receptor antagonist, during hypoxia-reoxygenation of senescent aorta and during ischemia-reperfusion of senescent heart. Isolated aortic rings and isolated hearts from adult and senescent rats were submitted, respectively, to hypoxia/reoxygenation (20/30 min) and to low-flow ischemia/reperfusion (45/30 min), without or with bosentan (10(-5) M). In the aorta, bosentan treatment prevented the impairment of relaxation in response to acetylcholine after hypoxia-reoxygenation at both ages. In the heart, coronary flow recovery during reperfusion, which is lower in senescents than in adults (48% vs. 76% of baseline value, respectively; P<0.05) was fully prevented by bosentan. Prevention of endothelial dysfunction during reoxygenation of hypoxic aorta and of coronary vasoconstriction during reperfusion of ischemic heart with a dual endothelin ET(A) and ET(B) receptor antagonist suggests a role of endothelin in the vulnerability of aorta to hypoxia-reoxygenation, and of coronary arteries to ischemia-reperfusion, especially during aging.

Acetylcholine↗
PubMed2001

Disruption of NF-kappa B signaling and chemokine gene activation by retroviral mediated expression of IKK gamma/NEMO mutants.

Phosphorylation of I kappa Bs--the cytoplasmic inhibitors of the NF-kappa B transcription factors--is the key event which triggers activation of the NF-kappa B cascade. Signal-mediated phosphorylation of I kappa B alpha is mediated by a multiprotein complex, the I kappa B kinase (IKK) complex, which is composed of at least three identified subunits. Two of these polypeptides, IKK alpha and IKK beta, also known as IKK1 and IKK2, are the catalytic subunits of the kinase complex and phosphorylate I kappa B alpha and I kappa B beta. The third component, NEMO/IKK gamma, does not exhibit kinase activity, but rather constitutes a regulatory subunit. In the present study, C-terminal truncated forms of IKK gamma--Delta C-IKK gamma 306 and Delta C-IKK gamma 261--were stably expressed in the myeloid cell line U937 by retroviral-mediated gene transfer. Overexpression of Delta C-IKK gamma resulted in a reduction in IKK kinase activity in vitro, a subsequent decrease in NF-kappa B DNA binding activity, and inhibition of chemokine gene induction in response to TNFalpha stimulation or paramyxovirus infection. This study demonstrates the efficacy of Delta C-IKK gamma as a repressor of IKK signaling and NF-kappa B activation and suggests a potential gene therapy approach to limit chronic inflammation due to chemokine hyperactivation.

Blotting, Western↗
PubMed2000

Interferon activation and innate immunity.

The interferons are a family of cytokine mediators critically involved in alerting the cellular immune system to viral infection of host cells. Interferons not only exhibit important antiviral effects but also exert a key influence on the quality of the cellular immune responses and amplify antigen presentation to specific T cells. Type I interferon (IFN-alpha and IFN-beta) is secreted by virus-infected cells while type II, immune or gamma interferon (IFN-gamma) is mainly secreted by T cells, natural killer (NK) cells and macrophages. Interferons interact with specific cellular receptors, which promote production of second messengers ultimately leading to expression of antiviral and immune modulatory genes. The IFN genes themselves are regulated by transcriptional and posttranscriptional mechanisms including modulation by a family of interferon regulatory factors (IRFs) synthesised by host cells. IFNs activate macrophages, induce B cells to switch immunoglobulin type, alter T helper response, inhibit cell growth, promote apoptosis and induce an antiviral state in uninfected cells. The therapeutic potential of the IFNs is currently the focus of intense attention in a number of virus-associated diseases, tumours and autoimmune disorders.

2',5'-Oligoadenylate Synthetase↗
PubMed1999

Benznidazole, a drug employed in the treatment of Chagas' disease, down-regulates the synthesis of nitrite and cytokines by murine stimulated macrophages.

Benznidazole (BZL) is a nitroheterocyclic drug employed in the chemotherapy of Chagas' disease, a protozoan disease caused by Trypanosoma cruzi. Because this parasite mostly replicates in macrophages, we investigated whether BZL was likely to modify the synthesis of macrophage mediators such as nitrite, tumour necrosis factor-alpha (TNF-alpha), IL-1beta, IL-6 and IL-10. Control and stimulated murine macrophages (lipopolysaccharide (LPS) and/or interferon-gamma (IFN-gamma)) were treated with BZL and measurements were carried out in culture supernatants collected 24 h later. Synthesis of nitrite, IL-6 and IL-10 was maximal upon combined stimulation with LPS + IFN-gamma, whereas lower amounts of the three mediators were detected when both stimuli were given alone. BZL treatment significantly reduced nitrite, IL-6 and IL-10 production, to undetectable levels in some cases, particularly IL-6 and IL-10. LPS was the most potent stimulus of IL-1beta and TNF-alpha production, followed by LPS + IFN-gamma and IFN-gamma in decreasing order. BZL partly inhibited TNF-alpha synthesis, but this effect was smaller than that observed for nitrite, IL-6 and IL-10. LPS-induced production of IL-1beta was also affected by BZL. Semiquantification of gene expression for inducible nitric oxide synthase (iNOS) showed that BZL completely inhibited iNOS gene induction by IFN-gamma, and resulted in respective inhibitions of 30% and 50% with LPS- and LPS + IFN-gamma-stimulated cells. BZL was not cytotoxic on macrophage cultures, as shown by the lactate dehydrogenase activity. Besides its trypanocidal activity, BZL may also alter the balance between pro- and anti-inflammatory mediators with important consequences for the course of T. cruzi infection.

Animals↗
PubMed1998

Inhibitors of ADP-ribosylation impair inducible nitric oxide synthase gene transcription through inhibition of NF kappa B activation.

In murine macrophages, inducible NO synthase II (iNOS or NOS-II) is induced at the transcriptional level by IFN-gamma, alone or synergistically with LPS. We investigated the possible role of reactions of ADP-ribosylation in triggering the signaling pathways involved in NOS-II gene expression. Stimulation with IFN-gamma and/or LPS of RAW 264.7 macrophages, transiently transfected with the NOS-II promoter, was inhibited by ADP-ribosylation inhibitors, indicating that they interfered with the signal(s) responsible for NOS-II gene transcription. We therefore explored the effect of these inhibitors on the activity of IRF-1 and NF kappa B transcription factors known to be involved in NOS-II induction by IFN-gamma and LPS. No effect was observed on IRF-1 activation. However, NF kappa B binding to its target sequence diminished and transfection experiments with an NF kappa B-driven reporter plasmid demonstrating that ADP-ribosylation inhibitors suppressed NF kappa B-dependent promoter activity. These results provide evidence that a step involving ADP-ribosylation is required to activate NF kappa B-mediated gene transcription.

Animals↗
PubMed1997

Effects of inhibitors of ADP-ribosylation on macrophage activation.

Nitric oxide (NO) is a potent mediator involved in many biological functions including macrophage cytotoxicity and non-specific immunity against parasites, bacteria and viruses. Murine macrophages possess the capacity to express the inducible NO synthase (iNOS) which is not constitutively expressed but induced at the transcriptional level by interferon gamma (IFN-gamma) alone or synergistically with LPS. We have investigated the possible role of ADP-ribosylation reactions in the signaling pathway involved in NO synthase induction, since ADP-ribosylation has been reported to be involved in the expression of certain IFN-gamma and LPS-inducible genes. We found that inhibitors of ADP-ribosylation inhibited nitrite synthesis in RAW 264.7 macrophages after stimulation by IFN-gamma and LPS. These ADP-ribosylation inhibitors acted by preventing NO synthase mRNA induction, without inhibiting NO synthase enzyme activity. IRF-1, a transcription factor induced and activated by IFN-gamma was recently shown to be involved in iNOS induction. We showed that inhibitors of ADP-ribosylation had no effect on IFN-gamma-mediated mRNA induction of IRF-1 nor on its activation and binding to its target sequence in the iNOS gene. In addition, the inhibitors failed to impair the IFN-gamma-mediated antiviral activity against VSV virus. Since induction by IFN-gamma of IRF-1 and induction of the antiviral state proceed through the JAK/STAT signalling pathway, our results imply that ADP-ribosylation reactions are not involved in triggering this pathway. Although the precise mechanism requires further investigation, our results indicate that ADP-ribosylation is a crucial step restricted to the signalling pathway which leads to iNOS mRNA induction, as well as TNF and MHC class II induction during macrophage activation.

Adenosine Diphosphate Ribose↗
PubMed1997

Effect of increased physical activity on growth and differentiation of regenerating rat soleus muscle.

Our purpose was to determine the effect of physical exercise on growth and differentiation during regeneration of a slow-twitch muscle. Degeneration/regeneration of the left soleus muscles of Wistar female rats was induced by injection of a snake venom. Muscular differentiation was studied by monitoring the sequential expression of the various myosin heavy chain isoforms (MHCs). Rats were assigned to one of two groups: cage sedentary (n = 14) or exercised (n = 16). The exercise programme began 1-day post-injection and the rats ran 1 h/day on a motorized treadmill. Then, 9 and 25 days after venom treatment, the soleus MHC phenotype as determined by immunohistology, electrophoresis and immunoblotting, was studied. At 25 days the expression of MHCs by regenerating soleus was not changed by the increased level of physical activity (P > 0.05). Exercised and sedentary regenerating muscles contained similar numbers of type-I fibres (100% of total fibres), levels of MHC-1 (85.4 and 89.5% of total MHCs), MHC-2a and M/HC-2x/d and their fibres expressed MHC-1 (100% of total fibres) and MHC-2 (45-50%) in the same way. Moreover, the masses of regenerating and nonregenerating soleus were significantly increased by physical exercise (P < 0.02). At 9 days no effect of muscular exercise was found. In conclusion, endurance exercise did not alter differentiation of regenerating soleus. Moreover regenerating soleus can respond to increased physical activity by enhancing its mass in the same way as mature muscle.

Animals↗
PubMed1996

Effect of physical exercise on adoptive experimental auto-immune encephalomyelitis in rats.

The aim of the study was to determine whether different programmes of exercise influence adoptive monophasic experimental auto-immune encephalomyelitis (adoptive EAE), a paralytic disease mediated by T-cells. Adoptive EAE was induced by the transfer of activated encephalitogenic T-lymphocytes into syngeneic recipients (Lewis rats, n = 85) and its development was followed by two independent observers. The results showed that 2 days of severe exercise (250 and 300 min) performed after the adoptive transfer of EAE slightly delayed the onset of the disease (P <0.008) and the day of its maximal severity (P <0.016) without affecting the overall severity of the disease. When this programme of exercise was performed before the cell transfer, it had no effect (P > 0.05). Two more moderate exercise programmes (5 x 120 min of running at constant speed or 5 x 60 min of running at variable speed, 5 consecutive days) performed between the adoptive transfer and the onset of the disease did not modify the development of the clinical signs of adoptive EAE (P >0.05). These results showed that severe exercise slightly influenced the effector phase of monophasic EAE and confirmed that physical exercise performed before the onset of experimental auto-immune diseases did not exacerbate the clinical signs.

Animals↗
PubMed1996

Differential expression of inducible NO synthase in two murine macrophage cell lines.

Although primary macrophages and most murine macrophage cell lines such as RAW 264.7 cells respond to interferon-gamma (IFN-gamma) and/or lipopolysaccharide (LPS) by producing large amounts of nitrite, i.e. the oxidation product of nitric oxide (NO) produced by inducible NO synthase (iNOS), other cell lines like P388.D1 cells do not produce significant amounts. To gain insight into the signalling pathway that leads to the induction of iNOS activity, we compared iNOS expression in RAW 264.7 and P388.D1 cells. We showed that IFN-gamma binds to each cell line with a similar affinity. Furthermore, no differences in iNOS gene structure were detectable by Southern blot analysis. Even though no significant nitrite secretion was found in the supernatant of P388:D1 cells stimulated with IFN-gamma and/or LPS, iNOS mRNA expression was induced. In addition, IFN-gamma induced the interferon regulatory factor-1 (IRF-1) gene and activated the binding of this factor to its target sequence in the iNOS gene. This binding was recently shown to be necessary for iNOS expression. However, in P388.D1 cells, we were unable to detect the corresponding iNOS protein. These results indicate a deficiency in P388.D1 cells which appears to be restricted to the signalling pathway controlling iNOS protein synthesis. This deficiency does not affect the overall IFN-gamma biological response, but rather a convergent post-transcriptional step common to IFN-gamma and LPS.

Animals↗
PubMed1995

Anergy induction in encephalitogenic T cells by brain microvessel endothelial cells is inhibited by interleukin-1.

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the central nervous system (CNS) which can be induced, in susceptible strains like Lewis rats, by transfer of activated myelin basic protein (MBP)-specific CD4+ T lymphocytes. The role of cerebral endothelium in the onset of EAE, with regard to adhesion, activation and infiltration in the CNS of encephalitogenic T lymphocytes, is not fully understood. When pretreated by interferon-gamma, the immortalized Lewis rat brain microvessel endothelial (RBE4) cells expressed major histocompatibility complex class II molecules and stimulated MBP-specific proliferation and cytolytic activity of the syngeneic encephalitogenic T cell line, designated PAS. However, RBE4-stimulated PAS lymphocytes subsequently entered an unresponsive state, known as anergy. When inoculated in syngeneic animals, anergic PAS cells, although still cytotoxic, failed to induce EAE, and no cell infiltration was detectable within CNS. The addition of interleukin-1 beta (IL-1 beta) during MBP presentation by RBE4 cells prevented T cell anergy induction, and maintained T cell encephalitogenicity, although PAS cells stimulated in these conditions caused delayed and attenuated clinical signs of EAE, with only discrete inflammatory lesions in the CNS, compared with EAE induced by PAS cells fully activated by thymic cells. Altogether, our results indicate that MBP presentation by brain microvessel endothelial cells to encephalitogenic T cells induces T cell anergy and loss of pathogenicity. In addition, IL-1 beta co-stimulation of T cells prevents anergy induction in vitro and at least partially maintains encephalitogenicity in vivo.

Animals↗
PubMed1994

Sex as a determining factor in the effect of exercise on in vivo autoimmune response adjuvant arthritis.

The present study was conducted to examine the effect of physical exercise on the development of adjuvant arthritis (AA), an animal model of the human rheumatoid arthritis, which is a T-cell-dependent autoimmune response. AA was inducted on day 0 in 8-wk-old Lewis rats of both sexes. Between postinjection days 1 and 12, two groups of rats (male and female) were trained on a treadmill every day (45-120 min/day and 15-30 m/min) before the onset of arthritic disease. Trained female (n = 27) and male (n = 22) rats and control female (n = 29) and male (n = 17) rats were observed every 2 days for the following clinical signs of AA: number of arthritic joints (swelling and redness), paw thickness, and weight gain during the disease. The results show that the incidence of arthritis (% of arthritic rats) was significantly higher in trained female rats (74%; P < 0.03) and significantly lower in trained male rats (27%; P < 0.05) compared with control rats of both sexes (female, 45%; male, 59%). There was no difference in the severity and development of the disease between trained rats and control rats of both sexes (P > 0.05). The present study indicates that the effect of exercise on the incidence of AA, an in vivo autoimmune response, depends on the sex of the animal.

Animals↗
PubMed1994

Effect of muscular exercise on chronic relapsing experimental autoimmune encephalomyelitis.

We examined whether physical exercise affected the development of an autoimmune response, experimental autoimmune encephalomyelitis (EAE), which is a demyelinating disease leading to paralysis. EAE was inducted on day 0, in rats of both sexes, by injecting them with spinal cord tissue in adjuvant. From days 1 to 10 after injection, exercised rats (n = 55) ran on a treadmill (60-120 min/day) before the onset of the paralytic disease. Clinical signs of the disease (ataxia, paralysis, and body mass loss) were examined in exercised and control rats (n = 54). Three types of EAE were induced: monophasic, acute, and chronic relapsing (CR)-EAE (3 bouts of disease, CR-EAE 1, 2, and 3, separated by remissions). Exercise significantly delayed the onset of CR-EAE 1 (P = 0.001) and the 1st day of maximum severity of CR-EAE 1 (P = 0.001) and CR-EAE 2 (P = 0.002). Moreover, the duration of CR-EAE 1 was significantly decreased in exercised rats compared with control rats (P = 0.004). The peak severity of the different types of EAE was not modified by exercise. The present study indicates that endurance exercise during the phase of induction of EAE diminished lightly only one type of EAE (CR-EAE) and therefore did not exacerbate the autoimmune disease.

Animals↗
PubMed1993

Effect of physical exhaustion and glucocorticoids (dexamethasone) on T-cells of trained rats.

Following a previous observation that moderate physical training (running) of rats did not impair T-cells, in this study moderately trained Wistar rats were run to exhaustion on 2 consecutive days: in one case (T-dex) this was preceded by an intraperitoneal injection of 0.5 mg.kg-1 of dexamethasone (dex) and in the other case there was no prior injection (T). Similarly one group of sedentary control rats, was injected with dex (C-dex) and the other group was not (C). Rats were killed 24 h after the last treatment (dex, exercise). Compared with the C rats, the T rats exhibited a decreased number of thymocytes (75%), in particular CD4+CD8+ thymocytes and splenocytes (55%), notably CD4+CD8- splenocytes (P < 0.01). Also noted in the T rats was a lower (45%) in vitro (+mitogen) percentage of IL2r+CD4- splenocytes (expressing the IL2 receptor), and reduced (40%, P < 0.01) or unchanged in vitro production of T-cell growth factor (TCGF) by splenocytes or blood mononucleated cells (BMC), respectively. The dex decreased the number of thymocytes and splenocytes in the same way in T-dex rats (compared to T rats) and in C-dex rats (compared to C rats, P < 0.01). In T-dex rats compared with C-dex rats, on the other hand, dex had little effect on in vitro TCGF production by BMC, and no effect on other in vitro parameters. These results would indicate that physical exhaustion was responsible for an alteration in T-cells in the moderately trained rat. This alteration was in part enhanced by dex.

Animals↗
PubMed1992

Effect of moderate exercise on rat T-cells.

The aim of this study was a detailed examination of the effects of moderate exercise on T-cells in adult male Wistar rats. The T-cell populations were compared in sedentary rats (C, n = 5) and in rats trained for 4 weeks on a treadmill (30-60 min.day-1, 6 days.week-1, 20-30 m.min-1) and sacrificed at rest (T-rest, n = 5). In the T-rest rats, there were higher percentages of CD4+CD8-, CD4-CD8+ and CD4-CD8- thymocytes (P < 0.05, P < 0.05 and P < 0.01 respectively) and of CD4-CD8+ splenocytes (P < 0.01), and a lower percentage of CD4-CD8+ cells in the lymph nodes (P < 0.01). Compared with T-rest or C rats, trained rats (n = 5) or untrained rats (n = 5) sacrificed immediately after a running session (60 min, 30 m.min-1) had a higher percentage of mononucleated cells CD4+CD8- in the blood (P < 0.05 and P < 0.01). Lastly, compared with C rats, rats (n = 5) sacrificed immediately after their 5th day of training (30-60 min.day-1) presented a higher total splenocyte population (P < 0.05) and greater in vitro production of T-cell growth factor (interleukin 2 + Interleukin 4) by splenocytes in response to a mitogen (P < 0.01). These results would indicate that moderate endurance training modifies the cellular composition of lymphoid organs, without impairing the in vitro functions of T-cells.

Animals↗
PubMed1991

Immunomodulations of thymocytes and splenocytes in trained rats.

The aim of this study was to describe the effects of training (running) on thymus and spleen cells in the rat. Young Wistar control rats (n = 6), rats trained for 4 wk (n = 5), and rats trained for 4 wk followed by 1 wk of intensive training (3 h/day, n = 6) were studied. Various lymphocyte surface and nuclear markers were determined by immunocytochemistry. The results show that 4 wk of training 1) decreased the percentage of bromodeoxyuridine (BrdU+) thymocytes (cell in phase S of the cycle, immature thymocytes; P less than 0.05) and the viability of thymocytes stimulated with concanavalin A (Con A; P less than 0.05) and 2) increased the absolute number of CD8+ (suppressor/cytotoxic T cells; 29%) and the percentage of CD8+ splenocytes (P less than 0.01). An additional week of intensive training in the 4-wk trained rats induced 1) a decrease in the absolute number of thymocytes (25%, P less than 0.05), TCR+ thymocytes, splenocytes (28%, P less than 0.01), T, CD4+ (helper T cells; 34%), and CD8+ (31%) splenocytes (P less than 0.01) and 2) an increase in the viability of splenocytes after stimulation with Con A for 72 h (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗