Cell heterogeneity in human breast cancer

Dos objetivos principales fueron planteados en este trabajo: 1) investigar la heterogeneidad celular en carcinomas mamarios humanos, caracterizando distintas subpoblaciones celulares respecto a proliferación y expresión de diversos marcadores tumorales; 2) obtener anticuerpos monoclonales (AMC) contra estos tumores, con propiedades citotóxicas, que reconozcan células indiferenciadas, de alto potencial proliferativo. Los estudios de heterogeneidad celular fueron realizados utilizando muestras tumorales humanas, la proliferación evaluada mediante incorporación de [3H]Timidina y marcadores por inmunohistoquímica. Los resultados permitieron establecer una secuencia de expresión de marcadores a medida que progresa la diferenciación celular y disminuye la capacidad proliferativa. Pudieron identificarse marcadores asociados a distintas etapas de la diferenciación (NCA90, receptor estroncio, receptor de progesterona, TAG72, CaMBr1, CEA) y otros que comienzan a expresarse en células indiferenciadas, altamente proliferativas, y continuarían durante todo el proceso de diferenciación (Ag2.15, PEM). Se investigaron también las propiedades del AMC FC-2.15 (anti-Ag2.15) desarrollado utilizando como inmunogeno un carcinoma mamario humano indiferenciado. FC-2.15 presento una potente citotoxicidad contra células Ag2.15+ mediando lisis por complemento humano, reconocio un antígeno presente en membrana plasmática en alta densidad (2,8x10 6 /célula) y fue lentamente internalizado. Los resultados presentados en este trabajo sugieren que FC-2.15 podría ser útil en inmunoterapia de pacientes con neoplasias Ag2.15+.The main purposes of this study were: 1) to investigate the cell heterogeneity in human breast cancer and characterize the different cell subpopulations with regard to proliferation and expression of tumor markers; 2) to obtain monoclonal antibodies (MAb) against these tumors which recognize highly undifferentiated (stem) cells, and mediate specific cytotoxicity. Cell heterogeneity was studied in human tumor samples, proliferation was evaluated by [3H]thymidine incorporation and markers by immunohistochemistry. According to the results, it could be defined a regular sequence of marker expression as cell differentiation proceeds and proliferation decreases. Some markers were identified which are expressed in different stages of the differentiation pathway (NCA90, estrogen receptor, progesterone receptor, TAG72, CaMBr1, CEA). Conversely, the expression of other markers (Ag2.15, PEM) would start in undifferentiated-highly proliferative cells and remain throughout the whole differentiation process. It was also investigated the properties of MAb FC-2.15 (anti-Ag2.15) generated using an undifferentiated human breast carcinoma as immunogen. Results showed that FC-2.15 exhibits strong human complement-mediated cytotoxicity against Ag2.15+ cells. It recognizes a high-density antigen (2.8x10 6/cell) in the cell membrane and is slowly internalized. The results obtained in this study suggest that FC-2.15 could be a useful agent for passive immuntherapy.Fil:Ballaré, Cecilia J.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

The Dynamic Regulatory Genome of Capsaspora and the Origin of Animal Multicellularity

The unicellular ancestor of animals had a complex repertoire of genes linked to multicellular processes. This suggests that changes in the regulatory genome, rather than in gene innovation, were key to the origin of animals. Here, we carry out multiple functional genomic assays in Capsaspora owczarzaki, the unicellular relative of animals with the largest known gene repertoire for transcriptional regulation. We show that changing chromatin states, differential lincRNA expression, and dynamic cis-regulatory sites are associated with life cycle transitions in Capsaspora. Moreover, we demonstrate conservation of animal developmental transcription-factor networks and extensive network interconnection in this premetazoan organism. In contrast, however, Capsaspora lacks animal promoter types, and its regulatory sites are small, proximal, and lack signatures of animal enhancers. Overall, our results indicate that the emergence of animal multicellularity was linked to a major shift in genome cis-regulatory complexity, most notably the appearance of distal enhancer regulation.This work was supported by an Institució Catalana de Recerca i Estudis Avançats contract, a European Research Council Consolidator Grant (ERC-2012-Co-616960), and a grant from Ministerio de Economía y Competitividad (MINECO) (BFU-2011-23434) (to I.R.-T.). We also acknowledge financial support from Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya (project 2014 SGR 619). The work in L.D.’s laboratory was supported by grants from the Spanish “Ministerio de Educación y Ciencia” (SAF2013-48926-P), AGAUR, and the European Commission’s 7th Framework Program 4DCellFate (277899). A.S.-P. is supported by an EMBO Long-Term Fellowship (ALTF 841-2014). J.L.G.-S. was funded by grants from Ministerio de Economía y Competitividad (BFU2013-41322-P) and the Andalusian Government (BIO-396). J.J.T. has a postdoctoral grant from the University Pablo de Olavide. The CRG/UPF Proteomics Unit is part of the “Plataforma de Recursos Biomoleculares y Bioinformáticos (ProteoRed)” supported by a grant from Instituto de Salud Carlos III (ISCIII) (PT13/0001). We thank Guadalupe Espadas for her support with the histone derivatization protocol and Núria Ros and Meritxell Antó for technical support. Finally, we thank the CRG Genomics Unit for helping with ChIP-seq and RNA-seq sequencing

The Dynamic Regulatory Genome of Capsaspora and the Origin of Animal Multicellularity

The unicellular ancestor of animals had a complex repertoire of genes linked to multicellular processes. This suggests that changes in the regulatory genome, rather than in gene innovation, were key to the origin of animals. Here, we carry out multiple functional genomic assays in Capsaspora owczarzaki, the unicellular relative of animals with the largest known gene repertoire for transcriptional regulation. We show that changing chromatin states, differential lincRNA expression, and dynamic cis-regulatory sites are associated with life cycle transitions in Capsaspora. Moreover, we demonstrate conservation of animal developmental transcription-factor networks and extensive network interconnection in this premetazoan organism. In contrast, however, Capsaspora lacks animal promoter types, and its regulatory sites are small, proximal, and lack signatures of animal enhancers. Overall, our results indicate that the emergence of animal multicellularity was linked to a major shift in genome cis-regulatory complexity, most notably the appearance of distal enhancer regulation.This work was supported by an Institució Catalana de Recerca i Estudis Avançats contract, a European Research Council Consolidator Grant (ERC-2012-Co-616960), and a grant from Ministerio de Economía y Competitividad (MINECO) (BFU-2011-23434) (to I.R.-T.). We also acknowledge financial support from Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya (project 2014 SGR 619). The work in L.D.’s laboratory was supported by grants from the Spanish “Ministerio de Educación y Ciencia” (SAF2013-48926-P), AGAUR, and the European Commission’s 7th Framework Program 4DCellFate (277899). A.S.-P. is supported by an EMBO Long-Term Fellowship (ALTF 841-2014). J.L.G.-S. was funded by grants from Ministerio de Economía y Competitividad (BFU2013-41322-P) and the Andalusian Government (BIO-396). J.J.T. has a postdoctoral grant from the University Pablo de Olavide. The CRG/UPF Proteomics Unit is part of the “Plataforma de Recursos Biomoleculares y Bioinformáticos (ProteoRed)” supported by a grant from Instituto de Salud Carlos III (ISCIII) (PT13/0001). We thank Guadalupe Espadas for her support with the histone derivatization protocol and Núria Ros and Meritxell Antó for technical support. Finally, we thank the CRG Genomics Unit for helping with ChIP-seq and RNA-seq sequencing

RING1B recruits EWSR1-FLI1 and cooperates in the remodeling of chromatin necessary for Ewing sarcoma tumorigenesis

Ewing sarcoma (EwS) is an aggressive tumor that affects adolescents and young adults. EwS is defined by a chromosomal translocation, EWSR1-FLI1 being the most common, that causes genome reprogramming through remodeling of enhancers. Here, we describe an unexpected function of RING1B, which is highly expressed in EwS. While retaining its repressive activity at Polycomb developmental regulated genes, RING1B colocalizes with EWSR1-FLI1 at active enhancers. We demonstrate that RING1B is necessary for the expression of key EWSR1-FLI1 targets by facilitating oncogene recruitment to their enhancers. Knockdown of RING1B impairs growth of tumor xenografts and expression of genes regulated by EWSR1-FLI1 bound enhancers. Pharmacological inhibition of AURKB with AZD1152 increases H2Aub levels causing down-regulation of RING1B/EWSR1-FLI1 common targets. Our findings demonstrate that RING1B is a critical modulator of EWSR1-FLI1-induced chromatin remodeling, and its inhibition is a potential therapeutic strategy for the treatment of these tumors.S.S.-M. and the project were supported by the Spanish Association Against Cancer (AECC) consolidated groups grant (GCB13131578) consortium. The project also had the support from the Asociacion Pablo Ugarte (APU). E.F.-B. was supported by the Spanish government grant, Instituto de Salud Carlos III (PI16/00245) to J.M. The work in the Di Croce laboratory was supported by grants from the Spanish of Economy, Industry and Competitiveness (MEIC) (BFU2016-75008-P), and Fundacion Vencer El Cancer (VEC)