Identificación de genes supresores tumorales regulados por CDC42 en cáncer colorrectal

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina. Departamento Bioquímica. Fecha de lectura: 19 de Diciembre del 200

Clinical relevance of the transcriptional signature regulated by CDC42 in colorectal cancer

CDC42 is an oncogenic Rho GTPase overexpressed in colorectal cancer (CRC). Although CDC42 has been shown to regulate gene transcription, the specific molecular mechanisms regulating the oncogenic ability of CDC42 remain unknown. Here, we have characterized the transcriptional networks governed by CDC42 in the CRC SW620 cell line using gene expression analysis. Our results establish that several cancer-related signaling pathways, including cell migration and cell proliferation, are regulated by CDC42. This transcriptional signature was validated in two large cohorts of CRC patients and its clinical relevance was also studied. We demonstrate that three CDC42-regulated genes offered a better prognostic value when combined with CDC42 compared to CDC42 alone. In particular, the concordant overexpression of CDC42 and silencing of the putative tumor suppressor gene CACNA2D2 dramatically improved the prognostic value. The CACNA2D2/CDC42 prognostic classifier was further validated in a third CRC cohort as well as in vitro and in vivo CRC models. Altogether, we show that CDC42 has an active oncogenic role in CRC via the transcriptional regulation of multiple cancer-related pathways and that CDC42-mediated silencing of CACNA2D2 is clinically relevant. Our results further support the use of CDC42 specific inhibitors for the treatment of the most aggressive types of CRCThis work has been supported by grants to JCL from Ministerio de Ciencia e Innovación (SAF2008- 03750, RD06-0020-0016 and RD12/0036/0019) and to DGO Cancer Institute New South Wales (2017/CDF625). FVM is a National Breast Cancer Foundation/Cure Cancer Australia Foundation Postdoctoral Training Fellow

A Read/Write Mechanism Connects p300 Bromodomain Function to H2A.Z Acetylation

Acetylation of the histone variant H2A.Z (H2A.Zac) occurs at active regulatory regions associated with gene expression. Although the Tip60 complex is proposed to acetylate H2A.Z, functional studies suggest additional enzymes are involved. Here, we show that p300 acetylates H2A.Z at multiple lysines. In contrast, we found that although Tip60 does not efficiently acetylate H2A.Z in vitro, genetic inhibition of Tip60 reduces H2A.Zac in cells. Importantly, we found that interaction between the p300-bromodomain and H4 acetylation (H4ac) enhances p300-driven H2A.Zac. Indeed, H2A.Zac and H4ac show high genomic overlap, especially at active promoters. We also reveal unique chromatin features and transcriptional states at enhancers correlating with co-occurrence or exclusivity of H4ac and H2A.Zac. We propose that differential H4 and H2A.Z acetylation signatures can also define the enhancer state. In conclusion, we show both Tip60 and p300 contribute to H2A.Zac and reveal molecular mechanisms of writer/reader crosstalk between H2A.Z and H4 acetylation through p300

Transient exposure to miR-203 expands the differentiation capacity of pluripotent stem cells

Full differentiation potential along with self‐renewal capacity is a major property of pluripotent stem cells (PSCs). However, the differentiation capacity frequently decreases during expansion of PSCs in vitro . We show here that transient exposure to a single microRNA, expressed at early stages during normal development, improves the differentiation capacity of already‐established murine and human PSCs. Short exposure to miR‐203 in PSCs (mi PSCs) induces a transient expression of 2C markers that later results in expanded differentiation potency to multiple lineages, as well as improved efficiency in tetraploid complementation and human–mouse interspecies chimerism assays. Mechanistically, these effects are at least partially mediated by direct repression of de novo DNA methyltransferases Dnmt3a and Dnmt3b, leading to transient and reversible erasure of DNA methylation. These data support the use of transient exposure to miR‐203 as a versatile method to reset the epigenetic memory in PSCs, and improve their effectiveness in regenerative medicine

Single-cell transcriptomics reveals involution mimicry during the specification of the basal breast cancer subtype

Basal breast cancer is associated with younger age, early relapse, and a high mortality rate. Here, we use unbiased droplet-based single-cell RNA sequencing (RNA-seq) to elucidate the cellular basis of tumor progression during the specification of the basal breast cancer subtype from the luminal progenitor population in the MMTV-PyMT (mouse mammary tumor virus-polyoma middle tumor-antigen) mammary tumor model. We find that basal-like cancer cells resemble the alveolar lineage that is specified upon pregnancy and encompass the acquisition of an aberrant post-lactation developmental program of involution that triggers remodeling of the tumor microenvironment and metastatic dissemination. This involution mimicry is characterized by a highly interactive multicellular network, with involution cancer-associated fibroblasts playing a pivotal role in extracellular matrix remodeling and immunosuppression. Our results may partially explain the increased risk and poor prognosis of breast cancer associated with childbirth.</p

Acetylation of H2A.Z is a key epigenetic modification associated with gene deregulation and epigenetic remodeling in cancer

Histone H2A.Z (H2A.Z) is an evolutionarily conserved H2A variant implicated in the regulation of gene expression; however, its role in transcriptional deregulation in cancer remains poorly understood. Using genome-wide studies, we investigated the role of promoter-associated H2A.Z and acetylated H2A.Z (acH2A.Z) in gene deregulation and its relationship with DNA methylation and H3K27me3 in prostate cancer. Our results reconcile the conflicting reports of positive and negative roles for histone H2A.Z and gene expression states. We find that H2A.Z is enriched in a bimodal distribution at nucleosomes, surrounding the transcription start sites (TSSs) of both active and poised gene promoters. In addition, H2A.Z spreads across the entire promoter of inactive genes in a deacetylated state. In contrast, acH2A.Z is only localized at the TSSs of active genes. Gene deregulation in cancer is also associated with a reorganization of acH2A.Z and H2A.Z nucleosome occupancy across the promoter region and TSS of genes. Notably, in cancer cells we find that a gain of acH2A.Z at the TSS occurs with an overall decrease of H2A.Z levels, in concert with oncogene activation. Furthermore, deacetylation of H2A.Z at TSSs is increased with silencing of tumor suppressor genes. We also demonstrate that acH2A.Z anti-correlates with promoter H3K27me3 and DNA methylation. We show for the first time, that acetylation of H2A.Z is a key modification associated with gene activity in normal cells and epigenetic gene deregulation in tumorigenesis

OncoChok. Validación de nuevos factores pronóstico e identificación de nuevas dianas terapéuticas en carcinogénesis humana

El consorcio OncoChok está integrado por el Laboratorio de Oncología Traslacional liderado por el Dr. Juan Carlos Lacal en el Instituto de Investigaciones Biomédicas de Madrid "Alberto Sols" (IIBM) del Consejo Superior de Investigaciones Cientificas (CSIC), y tres de los hospitales universitarios más importantes de la Comunidad de Madrid: Hospital Clínico, Hospital Doce de Octubre y Hospital La Paz y la empresa Translational Cancer Drugs Pharma (TCD Pharma).-- Más información sobre el programa en: http://www.oncochok.com/.El Programa OncoChok investiga la implicación del enzima colino quinasa alfa (ChoKa) como marcador de diagnóstico, pronóstico o predictor de respuesta al tratamiento antitumoral, así como su utilidad como una nueva diana terapéutica en distintos tipos de cáncer (pulmón, mama, páncreas, colorrectal y vejiga). También propone identificar sus posibles reguladores y efectores, su participación en el proceso de carcinogénesis y dilucidar el mecanismo de acción de sus inhibidores. El estudio se completa con la posible implicación del enzima ChoKa y sus reguladores en el desarrollo y progresión del cáncer y el análisis de su posible relación con parámetros clínico-patológicos.OncoChok es un proyecto de investigación subvencionado por la Comunidad de Madrid (CAM).Peer reviewe

Jornadas sobre la carrera investigadora: Módulo I, primera sesión: Etapas de la carrera Investigadora (predoctoral y postdoctoral).

La Facultad de Veterinaria y la Sociedad Española de Bioquímica y Biología Molecular (SEBBM) organizan de manera conjunta unas I Jornadas sobre la carrera investigadora que comenzarán en Enero de 2021. En la organización se ha colaborado de manera conjunta con otras Facultades de la UCM con similitud en sus programas de doctorado como son la Facultad de CC. Biológicas, la Facultad de CC. Químicas, la Facultad de Medicina y la Facultad de Farmacia. Las jornadas están encuadradas dentro de las Actividades Formativas de la Escuela de Doctorado de la UCM y están orientadas principalmente a Estudiantes de Doctorado, pero también a Investigadores en distintas etapas de su carrera investigadora, en el área de Ciencias de la Salud y Experimentales principalmente. Asimismo, hay sesiones que pueden resultar de interés para otras disciplinas debido a su carácter transversal.Depto. de Producción AnimalSección Deptal. de Bioquímica y Biología Molecular (Veterinaria)Fac. de VeterinariaFALSEsubmitte