24 research outputs found
Hormonal regulation of mammary gland stem cells: differential role of progesterone receptor isoforms
No full textEn esta tesis se plantearon distintas estrategias para estudiar el papel de las isoformas del receptor de progesterona sobre la población de células madre de la glándula mamaria normal y tumoral. Para ello se utilizaron dos modelos: ratones transgénicos que sobre expresan la isoforma A (PR A) o B (PR B) del receptor de progesterona (PR), y la línea celular de cáncer de mama humano, T47D, y sus derivados T47D YA y T47D YB que expresan PR A y PR B respectivamente. Demostramos que tanto las glándulas mamarias de ratones transgénicos, como células de cáncer de mama humano T47D que sobre expresan PR B presentan mayor porcentaje de células positivas para marcadores de células madre. En los ratones, la ovariectomía llevó a una disminución en el porcentaje de células progenitoras luminales tanto en glándulas mamarias de ratones wild type como de transgénicos PR A, sin afectar a la población madre/progenitora basal. Por otra parte, ensayos con los anti estrógenos Fulvestran y Tamoxifeno demostraron que las células que sobre expresan PR B presentan resistencia a ambos tratamientos, mientras que aquellas con un incremento en la expresión de PR A son sensibles a los mismos. En el modelo tumoral la expresión de PR B se asoció a un fenotipo más maligno evaluado por la formación de mamoesferas de mayor tamaño, más irregulares, con mayor capacidad clonogénica y resistentes a terapias endocrinas. Los resultados obtenidos en este trabajo revelan que el balance adecuado en la expresión de las isoformas del PR es indispensable para mantener la homeostasis de la población de células madre mamarias, y que impacta también a esta población celular en el contexto tumoral. En particular, PR B jugaría un papel fundamental, indicando la relevancia de conocer si hay alteraciones en las cantidades relativas de PR A y PR B como factor de riesgo, o pronóstico al momento de una biopsia o decisión sobre una eventual terapia endocrina.In this thesis different strategies were proposed to study the role of progesterone receptor isoforms on the population of stem cells of the normal and tumor mammary gland. For this, two models were used: transgenic mice that overexpress the A (PR A) or B (PR B) isoforms of the progesterone receptor (PR), and the human breast cancer cell line, T47D, and its derivatives T47D YA and T47D YB expressing PR A and PR B respectively. We show that both the mammary glands of transgenic mice and T47D human breast cancer cells that overexpress PR B present a higher percentage of cells positive for stem cell markers. In mice, ovariectomy led to a decrease in the percentage of luminal progenitor cells in both mammary glands of wild type and transgenic PR A mice, without affecting the basal progenitor/stem cell population. On the other hand, the antiestrogens Fulvestran and Tamoxifen demonstrated that the cells that over-express PR B present resistance to both treatments, while those with an increase in the expression of PR A are sensitive to them. In the tumor model, the expression of PR B was associated with a more malignant phenotype evaluated by the formation of irregular mammospheres of larger size, with greater clonogenic capacity and resistant to endocrine therapies. The results obtained in this work reveal that the adequate balance in the expression of PR isoforms is essential to maintain the homeostasis of the mammary stem cell population, and that it also impacts this cell population in tumor contexts. In particular, PR B would play a fundamental role, indicating the relevance of knowing if there are alterations in the relative amounts of PR A and PR B as a risk factor, or prognostic factor, at the time of a biopsy or decision on an eventual endocrine therapy.Fil: Recouvreux, María Sol. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Hormonal regulation of mammary gland stem cells: differential role of progesterone receptor isoforms
No full textEn esta tesis se plantearon distintas estrategias para estudiar el papel de las isoformas del receptor de progesterona sobre la población de células madre de la glándula mamaria normal y tumoral. Para ello se utilizaron dos modelos: ratones transgénicos que sobre expresan la isoforma A (PR A) o B (PR B) del receptor de progesterona (PR), y la línea celular de cáncer de mama humano, T47D, y sus derivados T47D YA y T47D YB que expresan PR A y PR B respectivamente. Demostramos que tanto las glándulas mamarias de ratones transgénicos, como células de cáncer de mama humano T47D que sobre expresan PR B presentan mayor porcentaje de células positivas para marcadores de células madre. En los ratones, la ovariectomía llevó a una disminución en el porcentaje de células progenitoras luminales tanto en glándulas mamarias de ratones wild type como de transgénicos PR A, sin afectar a la población madre/progenitora basal. Por otra parte, ensayos con los anti estrógenos Fulvestran y Tamoxifeno demostraron que las células que sobre expresan PR B presentan resistencia a ambos tratamientos, mientras que aquellas con un incremento en la expresión de PR A son sensibles a los mismos. En el modelo tumoral la expresión de PR B se asoció a un fenotipo más maligno evaluado por la formación de mamoesferas de mayor tamaño, más irregulares, con mayor capacidad clonogénica y resistentes a terapias endocrinas. Los resultados obtenidos en este trabajo revelan que el balance adecuado en la expresión de las isoformas del PR es indispensable para mantener la homeostasis de la población de células madre mamarias, y que impacta también a esta población celular en el contexto tumoral. En particular, PR B jugaría un papel fundamental, indicando la relevancia de conocer si hay alteraciones en las cantidades relativas de PR A y PR B como factor de riesgo, o pronóstico al momento de una biopsia o decisión sobre una eventual terapia endocrina.In this thesis different strategies were proposed to study the role of progesterone receptor isoforms on the population of stem cells of the normal and tumor mammary gland. For this, two models were used: transgenic mice that overexpress the A (PR A) or B (PR B) isoforms of the progesterone receptor (PR), and the human breast cancer cell line, T47D, and its derivatives T47D YA and T47D YB expressing PR A and PR B respectively. We show that both the mammary glands of transgenic mice and T47D human breast cancer cells that overexpress PR B present a higher percentage of cells positive for stem cell markers. In mice, ovariectomy led to a decrease in the percentage of luminal progenitor cells in both mammary glands of wild type and transgenic PR A mice, without affecting the basal progenitor/stem cell population. On the other hand, the antiestrogens Fulvestran and Tamoxifen demonstrated that the cells that over-express PR B present resistance to both treatments, while those with an increase in the expression of PR A are sensitive to them. In the tumor model, the expression of PR B was associated with a more malignant phenotype evaluated by the formation of irregular mammospheres of larger size, with greater clonogenic capacity and resistant to endocrine therapies. The results obtained in this work reveal that the adequate balance in the expression of PR isoforms is essential to maintain the homeostasis of the mammary stem cell population, and that it also impacts this cell population in tumor contexts. In particular, PR B would play a fundamental role, indicating the relevance of knowing if there are alterations in the relative amounts of PR A and PR B as a risk factor, or prognostic factor, at the time of a biopsy or decision on an eventual endocrine therapy.Fil: Recouvreux, María Sol. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
The hyperplastic phenotype in PR-A and PR-B transgenic mice: lessons on the role of estrogen and progesterone receptors in the mouse mammary gland and breast cancer.
No full textProgesterone receptor (PR) belongs to the superfamily of steroid receptors and mediates the action of progesterone in its target tissues. In the mammary gland, in particular, PR expression is restricted to the luminal epithelial cell compartment. The generation of estrogen receptor-a (ER) and PR knockout mice allowed the specific characterization of the roles of each of these in mammary gland development: ER is critical for ductal morphogenesis, whereas PR has a key role in lobuloalveolar differentiation. To further study the role PR isoforms have in mammary gland biology, transgenic mice overexpressing either the ?A? (PR-A) or the ?B? (PR-B) isoforms of PR were generated. Overexpression ofthe A isoform of PR led to increased side branching, multilayered ducts, loss of basement membrane integrity, and alterations in matrix metalloproteinase activation in the mammary gland. Moreover, levels of TGFb1 and p21 were diminished and those of cyclin D1 increased. Interestingly, the phenotype was counteracted by antiestrogens, suggesting that ER is essential for the manifestation of the hyperplasias. Mice overexpressing the B isoform of PR had limited ductal growth but retained the ability to differentiate during pregnancy. Levels of latent and active TGFb1 were increased compared to PR-A transgenics.
The phenotypes of these transgenic mice are further discussed in the context of the impact of progesterone on mammary stem cells and breast cancer. We conclude that an adequate balance between the A and B isoforms of PR is critical for tissue homeostasis. Future work to further understand the biology of PR in breast biology will hopefully lead to new and effective preventive and therapeutic alternatives for patients.Fil: Sampayo, Rocío Guadalupe. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Recouvreux, Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología; ArgentinaFil: Simian, Marina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin
Microenvironment and endocrine resistance in breast cancer: Friend or foe?
No full textBreast cancer affects one in eight women around the world. Seventy five percent of these patients have tumors that are estrogen receptor positive and as a consequence receive endocrine therapy. However, about one third eventually develop resistance and cancer reappears. In the last decade our vision of cancer has evolved to consider it more of a tissuerelated disease than a cell-centered one. This editorial argues that we are only starting to understand the role the tumor microenvironment plays in therapy resistance in breast cancer. The development of new therapeutic strategies that target the microenvironment will come when we clearly understand this extremely complicated scenario. As such, and as a scientific community, we have extremely challenging work ahead. We share our views regarding these matters.Fil: Recouvreux, Sol. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; ArgentinaFil: Sampayo, Rocío Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; ArgentinaFil: Díaz Bessone, María Inés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; ArgentinaFil: Simian, Marina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Universidad Nacional de San Martin. Instituto de Nanosistemas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
RUNX1 and FOXP3 interplay regulates expression of breast cancer related genes
No full textAbstract Runx1 participation in epithelial mammary cells is still under review. Emerging data indicates that Runx1 could be relevant for breast tumor promotion. However, to date no studies have specifically evaluated the functional contribution of Runx1 to control gene expression in mammary epithelial tumor cells. It has been described that Runx1 activity is defined by protein context interaction. Interestingly, Foxp3 is a breast tumor suppressor gene. Here we show that endogenous Runx1 and Foxp3 physically interact in normal mammary cells and this interaction blocks Runx1 transcriptional activity. Furthermore we demonstrate that Runx1 is able to bind to R-spondin 3 (RSPO3) and Gap Junction protein Alpha 1 (GJA1) promoters. This binding upregulates Rspo3 oncogene expression and downregulates GJA1 tumor suppressor gene expression in a Foxp3-dependent manner. Moreover, reduced Runx1 transcriptional activity decreases tumor cell migration properties. Collectively, these data provide evidence of a new mechanism for breast tumor gene expression regulation, in which Runx1 and Foxp3 physically interact to control mammary epithelial cell gene expression fate. Our work suggests for the first time that Runx1 could be involved in breast tumor progression depending on Foxp3 availability.Fil: Recouvreux, Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Grasso, Esteban Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Echeverria, Pablo Christian. Universidad de Ginebra; Suiza. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rocha Viegas, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Castilla, Lucio Hernán. University Of Massachussets. Medical School; Estados UnidosFil: Schere Levy, Carolina Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Tocci, Johanna Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Kordon, Edith Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Rubinstein, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin
Alterations in Progesterone Receptor Isoform Balance in Normal and Neoplastic Breast Cells Modulates the Stem Cell Population
No full textTo investigate the role of PR isoforms on the homeostasis of stem cells in the normal and neoplastic mammary gland, we used PRA and PRB transgenic mice and the T47D human breast cancer cell line and its derivatives, T47D YA and YB (manipulated to express only PRA or PRB, respectively). Flow cytometry and mammosphere assays revealed that in murine breast, overexpression of PRB leads to an increase in luminal and basal progenitor/stem cells. Ovariectomy had a negative impact on the luminal compartment and induced an increase in mammosphere-forming capacity in cells derived from WT and PRA mice only. Treatment with ICI 182,780 augmented the mammosphere-forming capacity of cells isolated from WT and PRA mice, whilst those from PRB remained unaltered. T47D YB cells showed an increase in the CD44+/CD24Low/- subpopulation; however, the number of tumorspheres did not vary relative to T47D and YA, even though they were larger, more irregular, and had increased clonogenic capacity. T47D and YA tumorspheres were modulated by estrogen/antiestrogens, whereas YB spheres remained unchanged in size and number. Our results show that alterations in PR isoform balance have an impact on normal and tumorigenic breast progenitor/stem cells and suggest a key role for the B isoform, with implications in response to antiestrogens.Fil: Recouvreux, María Sol. University of California at Los Angeles. School of Medicine; Estados Unidos. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Díaz Bessone, María Inés. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Taruselli, María Agustina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; ArgentinaFil: Todaro, Laura Beatriz. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Lago Huvelle, María Amparo. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Sampayo, Rocío Guadalupe. University of California at Berkeley; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Bissell, Mina J.. Lawrence Berkeley National Laboratory; Estados UnidosFil: Simian, Marina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Universidad Nacional de San Martín; Argentin
Nanocompósito esférico de celulose bacteriana/dióxido de titânio para aplicações em fotocatálise
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Programa de Pós-Graduação em Engenharia e Ciências Mecânicas, Joinville, 2017.A celulose bacteriana (CB) é um biopolímero com propriedades interessantes, tais como, biocompatibilidade, alta resistência à tração, alta capacidade de absorção, retenção de água e alta cristalinidade. A celulose é o polímero mais abundante da terra, podendo ser produzida por plantas e por vários microrganismos. Bactérias do gênero Komagataeibacter, que foram usadas neste estudo, têm carácter não patogênico e mantém a capacidade de sintetizar nanofibras de celulose em meio estático e em condições dinâmicas, na qual há uma tendência para a formação de geometrias membranosas e corpos tridimensionais de formas esféricas, respectivamente. Na primeira etapa deste trabalho, o objetivo principal foi avaliar e caracterizar a produção de esferas de CB produzidas com a bactéria Komagataeibacter hansenii ATCC 23769, sob cultivo agitado e diferentes condições de operação. Para isto, utilizou-se um planejamento experimental envolvendo as variáveis correspondentes a fonte de carbono, concentração de inóculo, volume do meio de cultura, volume do frasco Erlenmeyer e a velocidade de agitação. Os resultados experimentais mostraram que o rendimento mais elevado de celulose bacteriana na forma de hidrogel foi obtido sob condições em que a fonte de carbono utilizada foi o glicerol, na temperatura controlada de 25 °C e com a velocidade de agitação de 125 rpm. Nanopartículas de dióxido de titânio (TiO2) são extremamente importantes em aplicações elétricas, fotocatalíticas e biomédicas. Materiais multifuncionais com propriedades diferenciadas, baseados em celulose bacteriana, podem ser concebidos a partir de nanocompósitos de CB/TiO2 pelo método ex-situ de imersão sol-gel. Deste modo, a segunda etapa do trabalho foi composta pela fabricação de nanocompósito constituído de hidrogel CB/TiO2. As caracterizações foram realizadas por microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva (EDS) e espectroscopia no infravermelho por transformada de Fourier (FTIR). A análise morfológica do nanocompósito revelou a existência de interação molecular e adesão entre as nanopartículas de TiO2 e a matriz de nanofibras de celulose, onde a presença de picos de Ti no espectro EDS foram encontrados, provando a incorporação bem sucedida das nanopartículas. O FTIR revelou a modificação dos grupos funcionais, o que sugeriu a interação entre os componentes. Devido ao grande potencial fotocatalítico das nanopartículas de TiO2 e pela possibilidade de confecção de hidrogéis esféricos de CB, contendo elevada área superficial, a terceira etapa do projeto foi composta pelo desenvolvimento de nanocompósitos esféricos de CB/TiO2 confeccionados via imersão sol-gel e via síntese direta de nanopartículas de TiO2. O objetivo da confecção dos nanocompósitos em duas vias é a comparação de eficiência do efeito fotocatalítico. As caracterizações morfológicas foram realizadas via MEV e a avaliação da atividade fotocatalítica foi conduzida em um reator fotocatalítico de baixa potência (UV-C 15W), por fim, a análise quantitativa foi via a degradação de um corante medida por espectroscopia visível. Como resultado final os materiais alcançaram uma capacidade de remoção do corante de 89,58 e 70,83% através da fotocatálise dos nanocompósitos de CB/TiO2 confecionados via a adição das nanopartículas pelos métodos ex-situ e in-situ, respectivamente. Estes bons resultados possibilitarão a utilização deste material no tratamento de efluentes industriais.Abstract : Bacterial cellulose (BC) is a biopolymer with interesting properties, such as biocompatibility, high tensile strength, high absorption capacity, water retention and high crystallinity. Cellulose is the most abundant polymer of the earth, it can be produced by plants and by various microorganisms. Bacteria of the Komagataeibacter genus, which were used in the experiments have non-pathogenic character and hold the ability to synthesize cellulose nanofibers in static medium and in dynamic conditions, where there is a tendency in the formation of membranous geometries and three-dimensional bodies of spherical shapes, respectively. The first step of this work was to evaluate and characterize the production of spherical BC produced with Komagataeibacter hansenii ATCC 23769 bacteria under agitated culture and different operating conditions. A design of experiments was used to evaluate the parameters corresponding to a carbon source, inoculum concentration, the volume of the culture medium, the volume of the Erlenmeyer flask and stirring speed. The experimental results showed that the highest yield of bacterial cellulose as hydrogel was obtained with the utilization of glycerol, temperature controlled at 25 °C and agitation speed of 125 rpm. Nanoparticles of titanium dioxide (TiO2) are extremely important in electrical applications, photocatalysis, sensors and biomedical areas. Multifunctional materials, based on bacterial cellulose, with differentiated properties can be designed from the CB/TiO2 nanocomposite by ex situ method of sol-gel immersion. It was manufactured as a nanocomposite consisting of CB/TiO2 hydrogel. The characterizations were carried out by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). The morphological analysis of nanocomposite revealed the existence of molecular interaction and adhesion between TiO2 nanoparticles and cellulosic nanofibers matrix, where the presence of Ti peaks in EDS spectra was discovered, proving the successful incorporation of nanoparticles. The FTIR showed modification on the functional groups, suggesting an interaction between the components. Due to the large photocatalytic activity of TiO2 nanoparticles and the possibility to produce spherical hydrogels of BC with high surface area, the third step of the project will consist of the development of spherical nanocomposites BC/TiO2 prepared by immersion sol-gel and by direct synthesis of TiO2 nanoparticles. Both nanocomposites will be compared for the photocatalytic effect. Morphological characterizations will be performed through SEM and the evaluation of the photocatalytic activity will be conducted at a low power photocatalytic reactor (15W UV-C). Finally, the quantitative analysis will be measured by degradation of a dye at visible spectroscopy. As final results materials achieved a dye removal capacity of 89.58 and 70.83% by photocatalysis of the CB/TiO2 nanocomposites produced by addition of the nanoparticles via ex-situ and in-situ methods, respectively. These good results will enable the use of this material in the treatment of industrial effluents
RUNX1 is regulated by androgen receptor to promote cancer stem markers and chemotherapy resistance in triple negative breast cancer
No full textBackground: Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype for which no effective targeted therapies are available. Growing evidence suggests that chemotherapy-resistant cancer cells with stem-like properties (CSC) may repopulate the tumor. Androgen receptor (AR) is expressed in up to 50% of TNBC, and AR inhibition decreases CSC and tumor initiation. Runt-related transcription factor 1 (RUNX1) correlates with poor prognosis in TNBC and is regulated by AR in prostate cancer. Our group has shown that RUNX1 promotes TNBC cell migration and regulates tumor gene expression. We hypothesized that RUNX1 is regulated by AR and that both may work together in TNBC CSC to promote disease recurrence following chemotherapy. Results and methods: Chromatin immunoprecipitation DNA-sequencing (ChIP-seq) experiments in MDA-MB-453 revealed AR binding to RUNX1 regulatory regions. RUNX1 expression is upregulated by dihydrotestosterone (DHT) in MDA-MB-453 and in HCI-009 patient-derived xenograft (PDX) tumors (p<0.05). RUNX1 is increased in a CSC-like experimental model in MDA-MB-453 and SUM-159PT cells (p<0.05). Inhibition of RUNX1 transcriptional activity reduced the expression of CSC markers. Interestingly, RUNX1 inhibition reduced cell viability and enhanced paclitaxel and enzalutamide sensitivity. Conclusion: Targeting RUNX1 may be an attractive strategy to potentiate the anti-tumor effects of AR inhibition, specifically in the slow growing CSC-like populations that resist chemotherapy leading to metastatic disease.Fil: Fernández, Natalia Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biociencias, Biotecnología y Biología Traslacional.; ArgentinaFil: Sosa, Sofía María. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biociencias, Biotecnología y Biología Traslacional.; ArgentinaFil: Roberts, Justin T.. University Of South Alabama; Estados UnidosFil: Recouvreux, María Sol. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biociencias, Biotecnología y Biología Traslacional.; Argentina. University of California; Estados UnidosFil: Rocha Viegas, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Christenson, Jessica. University of Colorado; Estados UnidosFil: Spoelstra, Nicole. University of Colorado; Estados UnidosFil: Couto, Facundo Luis. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biociencias, Biotecnología y Biología Traslacional.; ArgentinaFil: Raimondi, Ana Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Richer, Jennifer K.. University of Colorado; Estados UnidosFil: Rubinstein, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biociencias, Biotecnología y Biología Traslacional.; Argentin
Chimera proteins with affinity for membranes and microtubule tips polarize in the membrane of fission yeast cells
No full textCell polarity refers to a functional spatial organization of proteins that is crucial for the control of essential cellular processes such as growth and division. To establish polarity, cells rely on elaborate regulation networks that control the distribution of proteins at the cell membrane. In fission yeast cells, a microtubule-dependent network has been identified that polarizes the distribution of signaling proteins that restricts growth to cell ends and targets the cytokinetic machinery to the middle of the cell. Although many molecular components have been shown to play a role in this network, it remains unknown which molecular functionalities are minimally required to establish a polarized protein distribution in this system. Here we show that a membrane-binding protein fragment, which distributes homogeneously in wild-type fission yeast cells, can be made to concentrate at cell ends by attaching it to a cytoplasmic microtubule end-binding protein. This concentration results in a polarized pattern of chimera proteins with a spatial extension that is very reminiscent of natural polarity patterns in fission yeast. However, chimera levels fluctuate in response to microtubule dynamics, and disruption of microtubules leads to disappearance of the pattern. Numerical simulations confirm that the combined functionality of membrane anchoring and microtubule tip affinity is in principle sufficient to create polarized patterns. Our chimera protein may thus represent a simple molecular functionality that is able to polarize the membrane, onto which additional layers of molecular complexity may be built to provide the temporal robustness that is typical of natural polarity patterns.</p
