Conjugated linoleic acid, unlike other unsaturated fatty acids, strongly induces glutathione synthesis without any lipoperoxidation

International audienc

Mammary tumour microenvironment response to vitamin D and exercise in aged mice fed by high fat diet

International audienceBoth vitamin D (VD) and exercice (Ex) with their anti-carcinogenic and immunomodulatory properties can reduce the incidence of obesity-related breast cancer in post-menopausal situation. This study aimed to investigate the impact of VD supplementation and imposed exercise on the tumour microenvironment (TM) in a mouse breast cancer model.Old ovariectomized C57BL/6 mice under a high-fat diet were randomized into 4 groups (n=10/group) supplemented with VD (1250 vs 125 UI; 450 kcal / 100g) and/or submitted to an exercise (Ex) (treadmill 12m/mn from 30 to 45mn, 5d/W, moderate intensity). Syngenic EO771 cells were implanted at W8 and the protocol ended at W14. TM immune cell infiltrates, cellular expression of VD metabolism actors in cancer cells, liver and kidney, and tissue oxidative stress markers were analysed. Mean SEM, Anova two ways + Tukey test.No effect was observed in the immune cell found in the TM. Ex alone increases the expression of specific immune cells genes such as Cd8a, Eomes, and Nos2. Together, Ex and VD increase the expression of various genes such as Tnfr and Dx5 (p<0.01). In addition, both VD and Ex decreases the Tnfr/Foxp3 ratio, and the Cd8a/Foxp3 ratio (p<0.05). Finally, they modulate VD metabolism enzymes by enhancing the expression of VD receptor, Cyp24a1 involved in the catabolism of VD (p<0.01) while VD alone stimulates the gene expression of CYP27B1 transforming 25-OHD to the active VDR ligand, 1,25-D-OHD, (p=0.02).In our conditions, VD and Ex do not affect the tumour immune infiltrates but they modulated the expression of some immune subpopulation’s genes. Due to the overexpression of Cyp24a1 and high spontaneous activity, expected VD and Ex effects are masked, such as immunomodulatory and direct anti-proliferative effects. Further studies should be carried out to adjust VD supplementation and/or Ex to prevent or slow down tumor growth

Long-term high-fat diet limits exercice benefits on mammary tumor growth in mice

International audienceIn postmenopausal condition, body fatness, inducing metabolic and hormonal stresses, promotes the risk of breast cancer. Physical activity (PA), a central component of weight management, limits it by reducing inflammation, insulin resistance, and oxidative stress. We measure the impact of high-fat diet duration on the PA’s beneficial effects during tumor development.Old ovariectomized C57BL/6 mice were fed by a high-fat diet. After 42 days (short lipid impregnation, SLI) or 88 days (long LI, LLI) of high-fat diet, EO771 syngeneic cells were implanted and the tumor was allowed to grow for 5 weeks. In SLI, one group was placed in a standard environment (SE, spontaneous physical activity) and the second in an enriched environment (EE). Under LLI, both groups were in an EE and one was subjected to a moderate PA (treadmill 12m/mn from 30 to 45mn, 5d/W, EEI). At sacrifice, tissue immune cell infiltrate and metabolic parameters were explored. n=10-12/group, mean SEM, Mann-Whitney test.Under SLI, tumour growth is reduced in the EE (p<0.05 vs SE). Under LLI, tumour growth is similar to that of the SLI-SE group, and the imposed PA does not impact it. Mice under SLI significantly lost weight between implantation and sacrifice (SE or EE, p<0.05) but not under LLI. Total adipose tissue and hind leg muscle mass are respectively higher and lower in mice on LLI compared to those on SLI, without effect of PA. In the LLI vs SLI condition, the tumor Th1 and Treg infiltrated cell ratio are higher whereas TCD8+ and NK are the same. In this model, LLI promotes tumour growth and counteracts the benefits of PA by establishing a tolerogenic environment, regardless of the rupture of a sedentary lifestyle by the EE or its reinforcement by the EEI. Future explorations of skeletal muscle, adipose tissue, their metabolism and inter-organ exchanges will provide insights into the mechanisms involved

IMMUNOMODULATION DU MICRO-ENVIRONNEMENT TUMORAL MAMMAIRE : L'EXERCICE PHYSIQUE CONTREBALANCE L'EFFET TOLÉROGÈNE DE LA VITAMINE D

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Caractérisation de l’infiltrat immunitaire tumoral mammaire chez la souris C57BL/6 obèse

National audienceLa réponse immunitaire systémique et tissulaire joue un rôle-clé dans la prévention du développement tumoral. Notre objectif est d’évaluer les modifications de l’infiltrat immunitaire tumoral dans un modèle murin syngénique orthotopique de carcinogenèse mammaire en situation d’obésité. Des souris femelles C57BL/6 âgées (33 semaines) ovariectomisées, nourries avec un régime Hyperlipidique (HL) ou Standard (SD), ont reçu une injection de cellules tumorales (EO771) par la technique « fatpad ». Au sacrifice, un phénotypage des cellules immunitaires intra-tumorales a été réalisé par cytométrie en flux. Le phénotypage des cellules immunitaires intra-tumorales révèle, sous régime HL vs SD, une augmentation des populations immunosuppressives (MDSC : 278 ± 42 vs 57 ± 17 cellules (C) /mg tumeur (T), p=0,02 ; LTreg : 1,2 ± 0.3 vs 11,23 ± 17,4 C /mg T, p=0,013 ), associée à une modification de la répartition des sous-types de lymphocytes T (LTc / LTreg : 1,4 ± 0,1 vs 12 ± 6,8, p=0,05). De plus une tendance à l’augmentation des populations anti-tumorales est observée (NKT : 364 ± 70 vs 491 ± 113 C /mg T, p=0,13 ; NK : 7,4 ±1,41 vs 43 ± 16 C /mg T, p=0,013). Ainsi, le régime HL favorise la migration des cellules immunitaires depuis les organes lymphoïdes secondaires vers la tumeur, induisant une repolarisation de l’infiltrat immunitaire tumoral en faveur des cellules immunosuppressives impliquées dans le processus de carcinogenèse en dépit d’une immunosurveillance renforcé

Cell Cycle Synchronization of the Murine EO771 Cell Line Using Double Thymidine Block Treatment

International audienceThis study shows that double thymidine block treatment efficiently arrests the EO771 cells in the S-phase without altering cell growth or survival. A long-term analysis of cell behavior, using 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (CFSE) staining, show synchronization to be stable and consistent over time. The EO771 cell line is a medullary breast-adenocarcinoma cell line isolated from a spontaneous murine mammary tumor, and can be used to generate murine tumor implantation models. Different biological (serum or amino acid deprivation), physical (elutriation, mitotic shake-off), or chemical (colchicine, nocodazole, thymidine) treatments are widely used for cell synchronization. Of the different methods tested, the double thymidine block is the most efficient for synchronization of murine EO771 cells if a large quantity of highly synchronized cells is recommended to study functional and biochemical events occurring in specific points of cell cycle progression

Effects of Enriched Environment on COX-2, Leptin and Eicosanoids in a Mouse Model of Breast Cancer

Cyclooxygenase-2 (COX-2) and adipokines have been implicated in breast cancer. This study investigated a possible link between COX-2 and adipokines in the development of mammary tumors. A model of environmental enrichment (EE), known to reduce tumor growth was used for a syngeneic murine model of mammary carcinoma. 3-week-old, female C57BL/6 mice were housed in standard environment (SE) or EE cages for 9 weeks and transplanted orthotopically with syngeneic EO771 adenocarcinoma cells into the right inguinal mammary fat pad. EE housing influenced mammary gland development with a decrease in COX-2 expressing cells and enhanced side-branching and advanced development of alveolar structures of the mammary gland. Tumor volume and weight were decreased in EE housed mice and were associated with a reduction in COX-2 and Ki67 levels, and an increase in caspase-3 levels. In tumors of SE mice, high COX-2 expression correlated with enhanced leptin detection. Non-tumor-bearing EE mice showed a significant increase in adiponectin levels but no change in those of leptin, F2-isoprostanes, PGF2α, IL-6, TNF-α, PAI-1, and MCP-1 levels. Both tumor-bearing groups (SE and EE housing) had increased resistin, IL-6, TNF-α, PAI-1 and MCP-1 levels irrespective of the different housing environment demonstrating higher inflammatory response due to the presence of the tumor. This study demonstrates that EE housing influenced normal mammary gland development and inhibited mammary tumor growth resulting in a marked decrease in intratumoral COX-2 activity and an increase in the plasma ratio of adiponectin/leptin levels

Increased consumption of salmon during pregnancy partly prevents the decline of some plasma essential amino acid concentrations in pregnant women

International audienceBackground & aims: Oily fish is a good source of n-3 long-chain polyunsaturated fatty acids. Since these fatty acids may change efficiency of amino acid (AA) absorption, we determined whether increased salmon consumption influences plasma AA concentrations in pregnant women and their newborns. Methods: Pregnant women were randomly allocated to remain on their habitual diet (n = 61; control group) or to consume two 150 g farmed salmon portions per week from 20 weeks pregnancy until birth (n = 62; salmon group). Plasma AA concentrations were determined in women at w20, w34 and w38 of pregnancy and in umbilical cord at delivery. Results: Concentrations of arginine, valine, leucine and lysine were affected by both time of pregnancy and salmon intake (p 0.05). Conclusions: Two portions/wk of oily fish increased plasma essential AA concentrations during pregnancy and could contribute to a maternal health benefit. Two portions/wk of salmon did not affect plasma AA concentrations in the newborn. (C) 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved