RESUMEN
The expression of four transcription variant of peroxisome proliferator-activated receptor gamma gene (PPARG) (XM_015292931.1; XM_015292932.1; XM_015292933.1 and NM_001001460.1) in the liver of broilers was measured and its correlation with abdominal fat weight and relative abdominal fat content was investigated. The study was conducted with 92 slow-growing crossbred chickens (Cobb males x indigenous Green-legged Partridge female chickens) divided into fat and lean groups, according to their abdominal fat yield. The NM_001001460.1 transcriptwas upregulated with ratio of means 4.26 (p0.01) in the fat group in relation to the lean group. Expression of this transcript was highly correlated with relative abdominal fat content (0.71, p0.01) and abdominal fat weight (0.59, p0.01). Two SNPs are located in putative transcription factor binding sites. Mutation -991C>A disrupts PPAR while mutation -884C>T disrupts C/EBP putative binding site. The gene expression analysis of PPARg showed that the expression of the transcripts (NM_001001460.1) was more than four times higher in fat than in lean chickens. These results point out that the peroxisome proliferator-activated receptor gamma NM_001001460.1 transcript could be candidate gene for determination of abdominal fat deposition in the chickens.
Asunto(s)
Animales , Hígado , Pollos/crecimiento & desarrollo , Grasa Abdominal , PPAR gamma/análisis , Polimorfismo de Nucleótido Simple , Expresión GénicaRESUMEN
The expression of four transcription variant of peroxisome proliferator-activated receptor gamma gene (PPARG) (XM_015292931.1; XM_015292932.1; XM_015292933.1 and NM_001001460.1) in the liver of broilers was measured and its correlation with abdominal fat weight and relative abdominal fat content was investigated. The study was conducted with 92 slow-growing crossbred chickens (Cobb males x indigenous Green-legged Partridge female chickens) divided into fat and lean groups, according to their abdominal fat yield. The NM_001001460.1 transcriptwas upregulated with ratio of means 4.26 (p0.01) in the fat group in relation to the lean group. Expression of this transcript was highly correlated with relative abdominal fat content (0.71, p0.01) and abdominal fat weight (0.59, p0.01). Two SNPs are located in putative transcription factor binding sites. Mutation -991C>A disrupts PPAR while mutation -884C>T disrupts C/EBP putative binding site. The gene expression analysis of PPARg showed that the expression of the transcripts (NM_001001460.1) was more than four times higher in fat than in lean chickens. These results point out that the peroxisome proliferator-activated receptor gamma NM_001001460.1 transcript could be candidate gene for determination of abdominal fat deposition in the chickens.(AU)
Asunto(s)
Animales , Pollos/crecimiento & desarrollo , PPAR gamma/análisis , Hígado , Polimorfismo de Nucleótido Simple , Grasa Abdominal , Expresión GénicaRESUMEN
Citral is a small molecule present in various citrus species, with reported anti-hyperlipidemic and anti-inflammation effects. Here, the effect of intraperitoneal (IP) administration of citral is evaluated in a mouse model of non-alcoholic steatosis. Male NMRI mice were divided into the following groups (n = 12): normal control group (NC) receiving a normal diet; high-fat emulsion group (HF) receiving high fat diet for four weeks; positive control group (C+) receiving HF diet for four weeks and then shifted to normal diet with IP-administered silymarin (80 mg/kg) for four weeks; sham group receiving HF diet for four weeks and then shifted to normal diet for four weeks; and EC1, EC2, and EC3 groups receiving HF diet for four weeks and then shifted to normal diet with IP-administered citral doses of 5, 10, and 20 mg/kg, respectively. HF diet resulted in steatohepatitis with impaired lipid profile, high glucose levels and insulin resistance, impaired liver enzymes, antioxidants, adiponectin and leptin levels, decreased PPARα level, and fibrosis in the liver tissue. Upon treatment with citral, improvement in condition was observed in a dose-dependent manner-both at histological level and in the serum of treated animals. and the PPARα level was also increased.
Asunto(s)
Animales , Masculino , Ratas , Expresión Génica/fisiología , PPAR gamma/análisis , Enfermedad Hepática en Estado Terminal/diagnóstico , Silimarina/farmacología , Citrus , Enfermedad del Hígado Graso no Alcohólico/diagnósticoRESUMEN
BACKGROUND: From ancient times, marine algae have emerged as alternative medicine and foods, contains the rich source of natural products like proteins, vitamins, and secondary metabolites, especially Chlorella vulgaris (C. vulgaris) contains numerous anti-inflammatory, antioxidants and wound healing substances. Type 2 diabetes mellitus is closely associated with adipogenesis and their factors. Hence, we aimed to investigate the chemical constituents and adipogenic modulatory properties of C. vulgaris in 3T3-L1 pre-adipocytes. RESULTS: We analysed chemical constituents in ethanolic extract of C. vulgaris (EECV) by LC-MS. Results revealed that the EECV contains few triterpenoids and saponin compounds. Further, the effect of EECV on lipid accumulation along with genes and proteins expressions which are associated with adipogenesis and lipogenesis were evaluated using oil red O staining, qPCR and western blot techniques. The data indicated that that EECV treatment increased differentiation and lipid accumulation in 3T3-L1 cells, which indicates positive regulation of adipogenic and lipogenic activity. These increases were associated with up-regulation of PPAR-γ2, C/EBP-α, adiponectin, FAS, and leptin mRNA and protein expressions. Also, EECV treatments increased the concentration of glycerol releases as compared with control cells. Troglitazone is a PPAR-γ agonist that stimulates the PPAR-γ2, adiponectin, and GLUT-4 expressions. Similarly, EECV treatments significantly upregulated PPAR-γ2, adiponectin, GLUT-4 expressions and glucose utilization. Further, EECV treatment decreased AMPK-α expression as compared with control and metformin treated cells. CONCLUSION: The present research findings confirmed that the EECV effectively modulates the lipid accumulation and differentiation in 3T3-L1 cells through AMPK-α mediated signalling pathway.
Asunto(s)
Células 3T3-L1/efectos de los fármacos , Chlorella vulgaris/química , Extractos Vegetales/farmacología , Algas Marinas/química , Células 3T3-L1/fisiología , Proteínas Quinasas Activadas por AMP/análisis , Proteínas Quinasas Activadas por AMP/efectos de los fármacos , Proteínas Quinasas Activadas por AMP/metabolismo , Adipocitos/citología , Adipocitos/efectos de los fármacos , Adipocitos/metabolismo , Adiponectina/análisis , Adiponectina/metabolismo , Animales , Diferenciación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Diabetes Mellitus Tipo 2/metabolismo , Regulación hacia Abajo , Expresión Génica , Glucosa/metabolismo , Transportador de Glucosa de Tipo 4/análisis , Transportador de Glucosa de Tipo 4/efectos de los fármacos , Transportador de Glucosa de Tipo 4/metabolismo , Ratones , PPAR gamma/análisis , PPAR gamma/efectos de los fármacos , PPAR gamma/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Tiempo , Regulación hacia ArribaRESUMEN
BACKGROUND: From ancient times, marine algae have emerged as alternative medicine and foods, contains the rich source of natural products like proteins, vitamins, and secondary metabolites, especially Chlorella vulgaris (C. vulgaris) contains numerous anti-inflammatory, antioxidants and wound healing substances. Type 2 diabetes mellitus is closely associated with adipogenesis and their factors. Hence, we aimed to investigate the chemical constituents and adipo-genic modulatory properties of C. vulgaris in 3T3-L1 pre-adipocytes. RESULTS: We analysed chemical constituents in ethanolic extract of C. vulgaris (EECV) by LC-MS. Results revealed that the EECV contains few triterpenoids and saponin compounds. Further, the effect of EECV on lipid accumulation along with genes and proteins expressions which are associated with adipogenesis and lipogenesis were evaluated using oil red O staining, qPCR and western blot techniques. The data indicated that that EECV treatment increased differentiation and lipid accumulation in 3T3-L1 cells, which indicates positive regulation of adipogenic and lipogenic activity. These increases were associated with up-regulation of PPAR-γ2, C/EBP-α, adiponectin, FAS, and leptin mRNA and protein expressions. Also, EECV treatments increased the concentration of glycerol releases as compared with control cells. Troglitazone is a PPAR-γ agonist that stimulates the PPAR-y2, adiponectin, and GLUT-4 expressions. Similarly, EECV treatments significantly upregulated PPAR-γ, adiponectin, GLUT-4 expressions and glucose utilization. Further, EECV treatment decreased AMPK-α expression as compared with control and metformin treated cells. CONCLUSION: The present research findings confirmed that the EECV effectively modulates the lipid accumulation and differentiation in 3T3-L1 cells through AMPK-α mediated signalling pathway.
Asunto(s)
Animales , Ratones , Algas Marinas/química , Extractos Vegetales/farmacología , Células 3T3-L1/efectos de los fármacos , Chlorella vulgaris/química , Factores de Tiempo , Regulación hacia Abajo , Expresión Génica , Diferenciación Celular/efectos de los fármacos , Regulación hacia Arriba , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Adipocitos/citología , Adipocitos/efectos de los fármacos , Adipocitos/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células 3T3-L1/fisiología , PPAR gamma/análisis , PPAR gamma/efectos de los fármacos , PPAR gamma/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Adiponectina/análisis , Adiponectina/metabolismo , Transportador de Glucosa de Tipo 4/análisis , Transportador de Glucosa de Tipo 4/efectos de los fármacos , Transportador de Glucosa de Tipo 4/metabolismo , Proteínas Quinasas Activadas por AMP/análisis , Proteínas Quinasas Activadas por AMP/efectos de los fármacos , Proteínas Quinasas Activadas por AMP/metabolismo , Glucosa/metabolismoRESUMEN
OBJECTIVE: To determine peroxisome proliferator activated receptor α and γ mRNA expression in liver tissue of hepatitis C virus-infected patients with and without human immunodeficiency virus and its possible contribution to an acceleration of liver disease progression. METHODS: We measured peroxisome proliferator-activated receptor α and γ mRNA expression by real-time polymerase chain reaction in liver tissues from 40 subjects infected only with hepatitis C virus, 36 subjects co-infected with hepatitis C virus and human immunodeficiency virus and 11 normal adults. RESULTS: Hepatic mRNA expression of both peroxisome proliferator-activated receptors was significantly lower in hepatitis C virus-infected subjects with and without human immunodeficiency virus co-infection compared to the controls. Non-black race was also identified as a predictor of lower peroxisome receptor α and γ mRNA expression. Compared to subjects infected only with hepatitis C virus, liver peroxisome receptor γ mRNA expression was significantly lower in hepatitis C virus/human immunodeficiency virus-co-infected subjects (0.0092 in hepatitis C virus/human immunodeficiency virus-co-infection vs. 0.0120 in hepatitis C virus-only; p=0.004). Hepatic peroxisome receptor α mRNA expression in the hepatitis C virus-infected patients was lower in the presence of human immunodeficiency virus co-infection in non-black subjects (0.0769 vs. 0.1061; p=0.02), whereas the levels did not vary based on human immunodeficiency virus status among black subjects. CONCLUSION: mRNA expression of both peroxisome proliferator-activated receptors is impaired in hepatitis C virus-infected liver and further reduced by human immunodeficiency virus co-infection, although the suppressive effects of the viruses are substantially mitigated in black patients.
Asunto(s)
Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Coinfección/patología , Infecciones por VIH/patología , Hepatitis C Crónica/patología , PPAR alfa/análisis , PPAR gamma/análisis , ARN Mensajero/análisis , Análisis de Varianza , Biopsia , Estudios Transversales , Coinfección/complicaciones , Coinfección/etnología , Infecciones por VIH/complicaciones , Infecciones por VIH/etnología , Hepatitis C Crónica/complicaciones , Hepatitis C Crónica/etnología , Modelos Lineales , Cirrosis Hepática/etiología , Cirrosis Hepática/patología , Hígado/patología , PPAR alfa/genética , PPAR gamma/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Valores de Referencia , Índice de Severidad de la EnfermedadRESUMEN
Background There is little information on the effects of diets containing high α-linolenic acid (C18:3n-3) on liver lipid composition and lipogenic gene expressions. In this study fourteen goats (Capra aegagrus hircus) were fed either a flaxseed oil (FSO) supplemented diet containing high α-linolenic acid or a control diet without added flaxseed oil (CON) for 100-d to evaluate the effects on liver lipid composition and the gene expression of peroxisome proliferator-activated receptors (PPAR-α) and stearoyl-CoA-desaturase (SCD) in the liver. Results An increase in the levels of C18:3n-3 and C20:5n-3, C22:5n-3, C22:6n-3 was observed in the liver of FSO-treated goats. There was a significant (P < 0.05) up-regulation of PPAR-α gene expression and downregulation of SCD gene in the liver of goats fed the high α-linolenic acid diet. Conclusions In conclusion, genes associated with the control of fatty acid (FA) conversion (SCD and PPAR) were affected by the α-linolenic acid supplementation in the goat diet. It is suggested that PPAR-α is the key messenger responsible for the translation of nutritional stimuli into changes in hepatic gene expression.
Asunto(s)
Animales , Cabras , Ácido alfa-Linolénico/administración & dosificación , PPAR gamma/análisis , PPAR gamma/genética , Estearoil-CoA Desaturasa/análisis , Estearoil-CoA Desaturasa/genética , Ácidos Grasos Omega-3/administración & dosificación , Expresión Génica , HígadoRESUMEN
OBJECTIVE: To determine peroxisome proliferator activated receptor α and γ mRNA expression in liver tissue of hepatitis C virus-infected patients with and without human immunodeficiency virus and its possible contribution to an acceleration of liver disease progression. METHODS: We measured peroxisome proliferator-activated receptor α and γ mRNA expression by real-time polymerase chain reaction in liver tissues from 40 subjects infected only with hepatitis C virus, 36 subjects co-infected with hepatitis C virus and human immunodeficiency virus and 11 normal adults. RESULTS: Hepatic mRNA expression of both peroxisome proliferator-activated receptors was significantly lower in hepatitis C virus-infected subjects with and without human immunodeficiency virus co-infection compared to the controls. Non-black race was also identified as a predictor of lower peroxisome receptor α and γ mRNA expression. Compared to subjects infected only with hepatitis C virus, liver peroxisome receptor γ mRNA expression was significantly lower in hepatitis C virus/human immunodeficiency virus-co-infected subjects (0.0092 in hepatitis C virus/human immunodeficiency virus-co-infection vs. 0.0120 in hepatitis C virus-only; p=0.004). Hepatic peroxisome receptor α mRNA expression in the hepatitis C virus-infected patients was lower in the presence of human immunodeficiency virus co-infection in non-black subjects (0.0769 vs. 0.1061; p=0.02), whereas the levels did not vary based on human immunodeficiency virus status among black subjects. CONCLUSION: mRNA expression of both peroxisome proliferator-activated receptors is impaired in hepatitis C virus-infected liver and further reduced by human immunodeficiency virus co-infection, although the suppressive effects of the viruses are substantially mitigated in black patients.
Asunto(s)
Coinfección/patología , Infecciones por VIH/patología , Hepatitis C Crónica/patología , PPAR alfa/análisis , PPAR gamma/análisis , ARN Mensajero/análisis , Adulto , Anciano , Análisis de Varianza , Biopsia , Coinfección/complicaciones , Coinfección/etnología , Estudios Transversales , Femenino , Infecciones por VIH/complicaciones , Infecciones por VIH/etnología , Hepatitis C Crónica/complicaciones , Hepatitis C Crónica/etnología , Humanos , Modelos Lineales , Hígado/patología , Cirrosis Hepática/etiología , Cirrosis Hepática/patología , Masculino , Persona de Mediana Edad , PPAR alfa/genética , PPAR gamma/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Valores de Referencia , Índice de Severidad de la EnfermedadRESUMEN
Background: Corpora lutea (CL) are transient organs, essentials for the pregnancy to be successful, that results from the ovulatory follicle rupture. If pregnancy fails to occur, the CL undergo luteolysis, a dynamic regression process that ends with their complete functional and structural demise. The life span of CL is characterized by luteal development, maintenance, and regression regulated by complex interactions between luteotropic and luteolytic mediators. The life-span of bovine CL is regulated by a multifactorial system that includes various hormonal regulators that up to date are not yet well studied, therefore the aim of the present study was to evaluate the immunohistochemical presence of receptors for adrenocorticotropic hormone (melanocortin-2 receptor, MC2R), dopamine (DR1-5), gonadotropin-releasing hormone (GnRHR), and peroxisome proliferators-activated receptor γ (PPARγ) in early, mid, late and regressive CL during diestrous cycle of bovine. Materials, Methods & Results: Ovaries from 24 clinically healthy cyclic cows were collected from licensed abattoirs. The animals had undergone a general veterinary assessment of their reproductive tract and ovaries before slaughter to exclude any apparent abnormalities and early pregnancy. Corpora lutea were separated by blunt dissection from the surrounding ovarian tissues and classified into four groups, covering the entire diestrous cycle length: early, mid, late and regressive. Tissue specimens were immediately processed for immunohistochemical investigation. The slides were incubated with the following primary antibodies: rabbit polyclonal anti-GnRHR, rabbit polyclonal anti-MC2R, rabbit polyclonal anti-DRD1-DR5, and mouse monoclonal anti-PPARγ. The slides were incubated with the specific biotinylated secondary antibody exposed to avidin-biotin complex and the peroxidase activity sites were visualized using the DAB kit as chromogen. Tissue sections in which the primary antibody was omitted or substituted by the specific IgG were used as negative controls of non-specific staining. The intensity of receptor immunostaining in CL was assessed and comparated microdensitometrically. The data of the densitometric analysis were examined by Levene's test and one-way ANOVA followed by Student-Newman-Keuls t-test. Differences were considered significant at P < 0.01. GnRHR, PPARγ, and DR2 immunostained the cytoplasm of luteal cells in early, mid and late stages, whereas they did not react in regressive CL. The immunostaining of MC2R was strong in the cytoplasm and nucleus of luteal cells during early, mid and late CL, and decreased (P < 0.01) in regressive ones. PPARγ immunostained the cytoplasm of luteal cells in early, mid and late stages, whereas they did not react in regressive CL. DR2 immunosignals were only found in early, mid and late stages, whereas DR5 was evidenced strongly in the cytoplasm of early and mid CL, and weakly (P < 0.01) in late and regressive ones. DR1, -3, and -4 were immunonegative in all CL types. Discussion: The present study showed that in bovine CL GnRHR, MC2R, PPARγ, DR2 and DR5 are variously present throughout the different luteal phases of the diestrous cycle. These preliminary data confirm the multifactorial complexity of the bovine CL life span regulation, in particular the fine tuning of the mediators that balance the CL luteotropic and luteolytic condition.
Asunto(s)
Animales , Femenino , Bovinos , Diestro , Dopamina/análisis , Receptores de Corticotropina/análisis , Hormonas del Cuerpo Lúteo/análisis , PPAR gamma/análisis , Gonadotropinas/análisisRESUMEN
Objectives were to determine adipose tissue mRNA expression of peroxisome proliferator-activated receptor (PPAR)γ co-regulators, target enzymes and transcription regulators, inflammation-related genes, and adipokines in response to dietary long-chain fatty acids (LCFA). From -21 through 10 d relative to parturition cows were fed no supplemental LCFA (control), saturated LCFA (SFAT; mainly 16:0 and 18:0), or fish oil (FO). Lipid was fed at 250 g/d prepartum or approximately 1.5 to 1.9% of the previous day's dry matter intake postpartum. Transcript profiling of 35 genes via quantitative PCR was conducted on biopsies (n=5 cows/diet) collected at -14 and 11 d from parturition. Despite lower dry matter intake with FO, pre- and postpartal blood nonesterified fatty acids, ß-hydroxybutyrate, and liver triacylglycerol were unaffected by treatment but increased after calving regardless of diet. Prepartal expression of adipogenic/lipogenic transcription regulators [CEBPA, CEBPB, RXRA, KLF5, and MLXIPL (formerly ChREBP)] and co-regulators (CARM1, EP300, NCOA1, MED1, NCOR2, and NRIP1) was upregulated by FO and SFAT versus control, whereas most enzymes involved in lipogenesis/triacylglycerol synthesis (FASN, SCD, DGAT2, and LPIN1) had greater expression only with FO. Expression of most adipogenic/lipogenic genes decreased after parturition, but feeding SFAT led to sustained upregulation of CEBPA, CEBPB, RXRA, several PPAR-co-activators, and DGAT2 and SCD, suggesting maintenance of a pro-adipogenic/pro-lipogenic state with SFAT. The co-activator CREBBP was greater in cows fed lipid and did not decrease after parturition, suggesting ligand activation of PPARγ. The greater peripartal expression of NFKB1 and TBK1 due to dietary lipid was suggestive of a local inflammatory response. At amounts fed prepartum, both FO and SFAT were effective in upregulating the adipose tissue PPARγ-gene network. In contrast, only SFAT led to sustaining that response. Overall, the observed expression patterns are suggestive of an adipogenic regulatory mechanism particularly responsive to SFAT.
Asunto(s)
Dieta/veterinaria , Grasas de la Dieta/farmacología , PPAR gamma/análisis , Grasa Subcutánea/química , Adipoquinas/análisis , Animales , Bovinos , Ácidos Grasos/sangre , Ácidos Grasos/farmacología , Femenino , Aceites de Pescado/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Lactancia/efectos de los fármacos , Hígado/química , PPAR gamma/metabolismo , Embarazo , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Grasa Subcutánea/efectos de los fármacos , Grasa Subcutánea/metabolismo , Factores de Transcripción/análisisRESUMEN
Prenatal testosterone (T) excess increases ovarian follicular recruitment, follicular persistence, insulin resistance, and compensatory hyperinsulinemia. Considering the importance of insulin in ovarian physiology, in this study, using prenatal T- and dihydrotestosterone (DHT, a nonaromatizable androgen)-treated female sheep, we tested the hypothesis that prenatal androgen excess alters the intraovarian insulin signaling cascade and metabolic mediators that have an impact on insulin signaling. Changes in ovarian insulin receptor (INSRB), insulin receptor substrate 1 (IRS1), mammalian target of rapamycin (MTOR), phosphatidylinositol 3-kinase (PIK3), peroxisome proliferator-activated receptor-gamma (PPARG), and adiponectin proteins were determined at fetal (Days 90 and 140), postpubertal (10 mo), and adult (21 mo) ages by immunohistochemistry. Results indicated that these proteins were expressed in granulosa, theca, and stromal compartments, with INSRB, IRS1, PPARG, and adiponectin increasing in parallel with advanced follicular differentiation. Importantly, prenatal T excess induced age-specific changes in PPARG and adiponectin expression, with increased PPARG expression evident during fetal life and decreased antral follicular adiponectin expression during adult life. Comparison of developmental changes in prenatal T and DHT-treated females found that the effects on PPARG were programmed by androgenic actions of T, whereas the effects on adiponectin were likely by its estrogenic action. These results suggest a role for PPARG in the programming of ovarian disruptions by prenatal T excess, including a decrease in antral follicular adiponectin expression and a contributory role for adiponectin in follicular persistence and ovulatory failure.
Asunto(s)
Dihidrotestosterona/metabolismo , Insulina/metabolismo , Ovario/embriología , Síndrome del Ovario Poliquístico/metabolismo , Efectos Tardíos de la Exposición Prenatal/metabolismo , Ovinos/embriología , Testosterona/metabolismo , Adiponectina/análisis , Adiponectina/metabolismo , Animales , Dihidrotestosterona/farmacología , Femenino , Feto/metabolismo , Proteínas Sustrato del Receptor de Insulina/análisis , Proteínas Sustrato del Receptor de Insulina/metabolismo , Péptidos y Proteínas de Señalización Intracelular/análisis , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ovario/efectos de los fármacos , Ovario/metabolismo , PPAR gamma/análisis , PPAR gamma/metabolismo , Fosfatidilinositol 3-Quinasas/análisis , Fosfatidilinositol 3-Quinasas/metabolismo , Embarazo , Proteínas Serina-Treonina Quinasas/análisis , Proteínas Serina-Treonina Quinasas/metabolismo , Receptor de Insulina/análisis , Receptor de Insulina/metabolismo , Ovinos/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR , Testosterona/farmacologíaRESUMEN
BACKGROUND: Activation of peroxisome proliferator-activated receptors gamma (PPARgamma) induces diverse effects on cancer cells. The thiazolidinediones (TZDs), such as troglitazone and ciglitazone, are PPARgamma agonists exhibiting antitumor activities; however, the underlying mechanism remains inconclusive. Rosiglitazone (RGZ), a synthetic ligand of PPARgamma used in the treatment of Type 2 diabetes, inhibits growth of some tumor cells and is involved in other processes related to cancer progression. Opposing results have also been reported with different ligands on tumor cells. The purpose of this study was to determine if RGZ and 15d-PGJ2 induce antitumor effects in vivo and in vitro on the murine mammary tumor cell line LMM3. METHODS: The effect on LMM3 cell viability and nitric oxide (NO) production of different doses of RGZ, 15-dPGJ2, BADGE and GW9662 were determined using the MTS colorimetric assay and the Griess reaction respectively. In vivo effect of orally administration of RGZ on tumor progression was evaluated either on s.c. primary tumors as well as on experimental metastasis. Cell adhesion, migration (wound assay) and invasion in Transwells were performed. Metalloproteinase activity (MMP) was determined by zymography in conditioned media from RGZ treated tumor cells. PPARgamma expression was detected by inmunohistochemistry in formalin fixed tumors and by western blot in tumor cell lysates. RESULTS: RGZ orally administered to tumor-bearing mice decreased the number of experimental lung metastases without affecting primary s.c. tumor growth. Tumor cell adhesion and migration, as well as metalloproteinase MMP-9 activity, decreased in the presence of 1 muM RGZ (non-cytotoxic dose). RGZ induced PPARgamma protein expression in LMM3 tumors. Although metabolic activity -measured by MTS assay- diminished with 1-100 microM RGZ, 1 microM-treated cells recovered their proliferating capacity while 100 microM treated cells died. The PPARgamma antagonist Biphenol A diglicydyl ether (BADGE) did not affect RGZ activity. On the contrary, the specific antagonist GW9662 completely abrogated RGZ-induced decrease in cell viability. A decrease in NO levels was detected in the presence of either 1 or 100 microM RGZ. The natural ligand 15d-PGJ2 did not affect metabolic activity although it induced a significant decrease in NO production. CONCLUSION: A significant decrease in the number of experimental LMM3 lung metastasis, but not on primary tumor growth, after oral RGZ administration was observed. In vitro, 100 microMRGZ also reduced cell viability and NO production, while no changes were observed in the presence of 15d-PGJ2. BADGE did not reverse RGZ effect while the antagonist GW9662 completely abrogated it, suggesting a PPARgamma- dependent mechanism. Inhibition of lung metastatic nodules by RGZ administered in vivo, might be associated with the observed decrease in MMP-9 expression, in cell adhesion, migration and invasion. RGZ augmented its expression. PPARgamma was detected in cell lysates by western blot and by immunohistochemistry in tumors from RGZ-treated mice. In summary we can suggest that RGZ or any other TZDs might be possible future approaches in the treatment of metastasis of PPARgamma-expressing cells.