RESUMEN
The transcription factor PAX8 is critical for the development of the thyroid and urogenital system. Comprehensive genomic screens furthermore indicate an additional oncogenic role for PAX8 in renal and ovarian cancers. While a plethora of PAX8-regulated genes in different contexts have been proposed, we still lack a mechanistic understanding of how PAX8 engages molecular complexes to drive disease-relevant oncogenic transcriptional programs. Here we show that protein isoforms originating from the MECOM locus form a complex with PAX8. These include MDS1-EVI1 (also called PRDM3) for which we map its interaction with PAX8 in vitro and in vivo. We show that PAX8 binds a large number of genomic sites and forms transcriptional hubs. At a subset of these, PAX8 together with PRDM3 regulates a specific gene expression module involved in adhesion and extracellular matrix. This gene module correlates with PAX8 and MECOM expression in large scale profiling of cell lines, patient-derived xenografts (PDXs) and clinical cases and stratifies gynecological cancer cases with worse prognosis. PRDM3 is amplified in ovarian cancers and we show that the MECOM locus and PAX8 sustain in vivo tumor growth, further supporting that the identified function of the MECOM locus underlies PAX8-driven oncogenic functions in ovarian cancer.
Asunto(s)
Regulación Neoplásica de la Expresión Génica , Proteína del Locus del Complejo MDS1 y EV11/genética , Neoplasias Ováricas/genética , Factor de Transcripción PAX8/genética , Animales , Línea Celular Tumoral , Femenino , Células HEK293 , Humanos , Proteína del Locus del Complejo MDS1 y EV11/metabolismo , Ratones Desnudos , Neoplasias Ováricas/tratamiento farmacológico , Neoplasias Ováricas/metabolismo , Factor de Transcripción PAX8/metabolismo , Unión Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Carga Tumoral/genética , Ensayos Antitumor por Modelo de Xenoinjerto/métodosRESUMEN
Functionalized oligoribonucleotides are essential tools in RNA chemical biology. Various synthetic routes have been developed over recent years to conjugate functional groups to oligoribonucleotides. However, the presence of the functional group on the oligoribonucleotide backbone can lead to partial or total loss of biological function. The limited knowledge concerning the positioning of functional groups therefore represents a hurdle for the development of oligoribonucleotide chemical tools. Here we describe a systematic investigation of site-specific labeling of pre-miRNAs to identify positions for the incorporation of functional groups, in order not to hinder their processing into active mature miRNAs.