Crescimento do câncer de mama receptor de hormônio dependente: contribuições de um modelo experimental

Si bien los estrógenos han demostrado tener un rol protagónico en el cáncer de mama, hoy se sabe que la progesterona, así como sus derivados sintéticos, ejercen roles proliferativos tanto en la glándula mamaria normal como neoplásica. Utilizando un modelo experimental de cáncer mamario murino, iniciado en la Academia Nacional de Medicina y trasladado al IBYME en el año 1995, demostramos la importancia de los fibroblastos asociados a tumor en la provisión de factores de crecimiento que activan en forma ligando-independiente a los receptores de progesterona (RPs) en las células tumorales. En este artículo mencionamos la importancia por un lado de la proporción de isoformas del RP en la determinación de la respuesta al tratamiento hormonal, y por otro, los mecanismos por los cuales el factor de crecimiento fibroblástico 2 (FGF2) estromal participaría en el crecimiento tumoral imitando la acción de la hormonaIt is well known that estrogens are key players regulating breast cancer growth. In addition, there is compelling evidence pointing out that progestins induce proliferative effects in normal and in neoplastic mammary glands. Using a murine breast cancer model, first developed in the National Academy of Medicine in Buenos Aires, and then moved to the IBYME in 1995, we demonstrated that carcinoma associated fibroblasts provide growth factors such as fibroblast growth factor 2 (FGF2), which are involved in the ligand independent activation of progesterone receptors (PR) of tumor cells. This article briefly describes, on one hand, the relevance of the evaluation of the PR isoform ratio to predict hormone responsiveness, and on the other hand, the mechanisms by which stromal FGF2 mimics the effects of progesterone to stimulate tumor growth.Embora os estrógenos tenham demonstrado ter um papel protagônico no câncer de mama, hoje se sabe que a progesterona, bem como seus derivados sintéticos, exerce papéis proliferativos tanto na glândula mamária normal quanto neoplá- sica. Utilizando um modelo experimental de câncer mamário murino, iniciado na Academia Nacional de Medicina e trasladado ao IBYME no ano 1995, demonstramos a importância dos fibroblastos associados a tumor na provisão de fatores de crescimento que ativam em forma ligando-independente os receptores de progesterona (RPs) nas células tumorais. Neste artigo mencionamos a importância, de um lado, da proporção de isoformas do RP na determinação da resposta ao tratamento hormonal, e do outro, dos mecanismos pelos quais o fator de crescimento fibroblástico 2 (FGF2) estromal participaria no crescimento tumoral imitando a ação do hormônio.Fil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Novaro, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Lamb, Caroline Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Fabris, Victoria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Rojas, Paola Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Giulianelli, Sebastian Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Gorostiaga, Maria Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Wargon, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Guillardoy, Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Polo, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Riggio, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Sequeira, Gonzalo Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Sahores, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Pampena, María Betina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentin

Expression of common fragile sites in two Ceboidea species: Saimiri boliviensis and Alouatta caraya (Primates: Platyrrhini)

Fragile sites are points of preferential breakage that may be involved in chromosome rearrangements. Induction of common fragile sites (c-fra) and spontaneous breakage were analyzed in two New World Monkeys species: Saimiri boliviensis (SBO) and Alouatta caraya (ACA). Spontaneous chromosome aberrations were analyzed on untreated lymphocyte cultures with Brögger´s formula (1977). SBO presented a low level of spontaneous breakage, while higher frequencies were detected in ACA in which bands 1q23; 2q13 and 11q19 were significantly affected (p<0.01). The populational distribution of c-fra was analyzed by the Chi2 test in FUdR plus caffeine treated cultures. A total of 21 c-fra was identified in SBO and 24 in ACA. Fragile sites A1q33, B1p21, B4p14, C3q23 and C5q22 were identified in all analyzed SBO specimens. The most frequent c-fra identified in ACA specimens were 1q23, 1q31, 1q33, 2q22, 8q14, 12q31, 13q22, 14q15 and Xq22. Fragile sites A1q31, A1q33, B1q14, B3q13, B4q21 and Xq22 identified in SBO and 1q31, 1q33, 2q22, 4q21, 6q13, 13q22 and Xq22 from ACA were the most conserved sites. A low coincidence between the location of c-fra and that of heterochromatin and breakpoints involved in euchromatic rearrangements known for these genera, was established.Fil: Fundia, Ariela Freya. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas "Mariano R. Castex"; ArgentinaFil: Gorostiaga, Maria Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Mudry, Marta Dolores. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentin

Functional attractors in microbial community assembly

For microbiome biology to become a more predictive science, we must identify which descriptive features of microbial communities are reproducible and predictable, which are not, and why. We address this question by experimentally studying parallelism and convergence in microbial community assembly in replicate glucose-limited habitats. Here, we show that the previously observed family-level convergence in these habitats reflects a reproducible metabolic organization, where the ratio of the dominant metabolic groups can be explained from a simple resource-partitioning model. In turn, taxonomic divergence among replicate communities arises from multistability in population dynamics. Multistability can also lead to alternative functional states in closed ecosystems but not in metacommunities. Our findings empirically illustrate how the evolutionary conservation of quantitative metabolic traits, multistability, and the inherent stochasticity of population dynamics, may all conspire to generate the patterns of reproducibility and variability at different levels of organization that are commonplace in microbial community assembly

Progestin and antiprogestin responsiveness in breast cancer is driven by the PRA/PRB ratio via AIB1 or SMRT recruitment to the CCND1 and MYC promoters

There is emerging interest in understanding the role of progesterone receptors (PRs) in breast cancer. The aim of this study was to investigate the proliferative effect of progestins and antiprogestins depending on the relative expression of the A (PRA) and B (PRB) isoforms of PR. In mifepristone (MFP)-resistant murine carcinomas antiprogestin responsiveness was restored by re-expressing PRA using demethylating agents and histone deacetylase inhibitors. Consistently, in two human breast cancer xenograft models, one manipulated to overexpress PRA or PRB (IBH-6 cells), and the other expressing only PRA (T47D-YA) or PRB (T47D-YB), MFP selectively inhibited the growth of PRA-overexpressing tumors and stimulated IBH-6-PRB xenograft growth. Furthermore, in cells with high or equimolar PRA/PRB ratios, which are stimulated to proliferate in vitro by progestins, and are inhibited by MFP, MPA increased the interaction between PR and the coactivator AIB1, and MFP favored the interaction between PR and the corepressor SMRT. In a PRB-dominant context in which MFP stimulates and MPA inhibits cell proliferation, the opposite interactions were observed. Chromatin immunoprecipitation assays in T47D cells in the presence of MPA or MFP confirmed the interactions between PR and the coregulators at the CCND1 and MYC promoters. SMRT downregulation by siRNA abolished the inhibitory effect of MFP on MYC expression and cell proliferation. Our results indicate that antiprogestins are therapeutic tools that selectively inhibit PRA-overexpressing tumors by increasing the SMRT/AIB1 balance at the CCND1 and MYC promoters.Fil: Wargon, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Riggio, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Giulianelli, Sebastian Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Sequeira, Gonzalo Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Rojas, Paola Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: May, Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Polo, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Gorostiaga, Maria Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Jacobsen, Britta. University of Colorado Anschutz Medical Campus; Estados UnidosFil: Molinolo, Alfredo. Oral and Pharyngeal Cancer Branch; Estados UnidosFil: Novaro, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

Classical membrane progesterone receptors in murine mammary carcinomas: agonistic effects of progestins and RU-486 mediating rapid non-genomic effects.

In this article, we demonstrate the expression of functional progesterone binding sites at the cell membrane in murine mammary carcinomas that are stimulated by progestins and inhibited by antiprogestins. Using confocal immunofluorescence, ligand binding and cell compartment-specific western blots, we were able to identify the presence of the classical progesterone receptors. Medroxyprogesterone acetate (MPA) and RU-486 (1 × 10(-11) and 1 × 10(-8) M) behaved as agonists activating extracellular signal-regulated kinases (ERKs) and progestin-regulated proteins, except for Cyclin D1 and Tissue factor which failed to increase with 1 × 10(-8) M RU-486, an experimental condition that allows PR to bind DNA. These results predicted a full agonist effect at low concentrations of RU-486. Accordingly, at concentrations lower than 1 × 10(-11) M, RU-486 increased cell proliferation in vitro. This effect was abolished by incubation with the ERK kinase inhibitor PD 98059 or by OH-tamoxifen. In vivo, at a daily dose of 1.2 μg/kg body weight RU-486 increased tumor growth, whereas at 12 mg/kg induces tumor regression. Our results indicate that low concentrations of MPA and RU-486 induce similar agonistic non-genomic effects, whereas RU-486 at higher concentrations may inhibit cell proliferation by genomic-induced effects. This suggests that RU-486 should be therapeutically administered at doses high enough to guarantee its genomic inhibitory effect.Fil: Bottino, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; ArgentinaFil: Cerliani, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; ArgentinaFil: Rojas, Paola Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; ArgentinaFil: Giulianelli, Sebastian Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; ArgentinaFil: Soldati, Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; ArgentinaFil: Mondillo, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; ArgentinaFil: Gorostiaga, Maria Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; ArgentinaFil: Pignataro, Omar Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Calvo, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Gutkind, Silvio J.. National Institutes of Health. National Institute of Dental and Craniofacial Reasearch; Estados UnidosFil: Amornphimoltham, Panomwat. National Institutes of Health. National Institute of Dental and Craniofacial Reasearch; Estados UnidosFil: Molinolo, Alfredo A.. National Institutes of Health. National Institute of Dental and Craniofacial Reasearch; Estados UnidosFil: Luthy, Isabel Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; ArgentinaFil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; Argentin

Inhibition of mammary tumor growth by estrogens: Is there a specific role for estrogen receptors alpha and beta?

To evaluate the extent to which each estrogen receptor (ER) subtype contributes to the stimulation or to the inhibition of mammary tumor growth, we evaluated the effects of specific agonists in MC4-L2 cells, which are stimulated by 17β-estradiol (E 2), and in mammary carcinomas of the MPA mouse breast cancer model, which are inhibited by E 2. Both express ERα and ERβ. In MC4-L2 cells, 4,4,4-(4-propyl-(1H)-pyrazole-1,3,5- Triyl)trisphenol (PPT; ERα agonist) and (4-hydroxy-phenyl)-propionitrile (DPN; ERβ agonist) stimulated cell proliferation, whereas the opposite occurred in C4-HI primary cultures. The inhibitory effect was associated with a decrease in ERa and cyclin D1 expression and an increase in progesterone receptor (PR) expression as well as in the Bax/Bcl-xl ratio. In vivo, mice carrying C4-HI or 32-2-HI tumors were treated with E 2, PPT or DPN (3 mg/kg/day) or with vehicle. PPT and DPN inhibited tumor size, as did E 2, during the first 72 h. After a few days, DPN-Treated tumors started to grow again, while PPT-Treated tumors remained quiescent for a longer period of time. A pronounced decrease in the mitotic index and an increase in the apoptotic index was associated with tumor regresion. All treated tumors showed: (a) an increase in integrin α6 and Bax expression, (b) an increased stromal laminin redistribution, and (c) a decrease in ERα, Bcl-xl and Bcl-2 expression (P<0.001). Apoptosis-inducing factor (Aif) expression was increased in DPN-Treated tumors, while active caspase 9 was upregulated in PPT-Treated mice, demonstrating the involvement of the intrinsic apoptotic pathway in estrogen-induced regression in this model. In conclusion, our data indicate that although there may be some preferences for activation pathways by the different agonists, the stimulatory or inhibitory effects triggered by estrogens are cell-context dependent rather than ER isoform dependent. © Springer Science+Business Media, LLC. 2009.Fil: Soldati, Rocío Cinthia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Wargon, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Cerliani, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Giulianelli, Sebastian Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Vanzulli, Silvia Inés. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Gorostiaga, Maria Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Bolado, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Do Campo, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Molinolo, Alfredo. National Institute of Dental and Craniofacial Research; Estados UnidosFil: Vollmer, Günter. Technische Universitat Dresden; AlemaniaFil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

A randomized trial of planned cesarean or vaginal delivery for twin pregnancy

Background: Twin birth is associated with a higher risk of adverse perinatal outcomes than singleton birth. It is unclear whether planned cesarean section results in a lower risk of adverse outcomes than planned vaginal delivery in twin pregnancy.\ud \ud Methods: We randomly assigned women between 32 weeks 0 days and 38 weeks 6 days of gestation with twin pregnancy and with the first twin in the cephalic presentation to planned cesarean section or planned vaginal delivery with cesarean only if indicated. Elective delivery was planned between 37 weeks 5 days and 38 weeks 6 days of gestation. The primary outcome was a composite of fetal or neonatal death or serious neonatal morbidity, with the fetus or infant as the unit of analysis for the statistical comparison.\ud \ud Results: A total of 1398 women (2795 fetuses) were randomly assigned to planned cesarean delivery and 1406 women (2812 fetuses) to planned vaginal delivery. The rate of cesarean delivery was 90.7% in the planned-cesarean-delivery group and 43.8% in the planned-vaginal-delivery group. Women in the planned-cesarean-delivery group delivered earlier than did those in the planned-vaginal-delivery group (mean number of days from randomization to delivery, 12.4 vs. 13.3; P = 0.04). There was no significant difference in the composite primary outcome between the planned-cesarean-delivery group and the planned-vaginal-delivery group (2.2% and 1.9%, respectively; odds ratio with planned cesarean delivery, 1.16; 95% confidence interval, 0.77 to 1.74; P = 0.49).\ud \ud Conclusion: In twin pregnancy between 32 weeks 0 days and 38 weeks 6 days of gestation, with the first twin in the cephalic presentation, planned cesarean delivery did not significantly decrease or increase the risk of fetal or neonatal death or serious neonatal morbidity, as compared with planned vaginal delivery