Activación inmune por productos finales de glicación avanzada

Con el objetivo de revisar los avances recientes en la biología de los productos de glicación avanzada y su papel en diversas patologías de alta relevancia en salud pública, se realizó una búsqueda dirigida de la bibliografía entre los años 2000 y 2021 en la base de datos PubMed (NCBI) y se usaron como palabras clave “advanced glycation end products”. Se ha demostrado que el receptor de productos de glicación avanzada induce una activación sostenida del factor de transcripción proinflamatorio NF-kB y suprime una serie de funciones autorreguladoras endógenas. Este efecto influye negativamente en una gran variedad de patologías como diabetes, autoinmunidad, neurodegeneración y enfermedades infecciosas. La acumulación tisular de productos de glicación avanzada está relacionada con procesos de inflamación crónica y disfunción celular, y constituye un blanco prometedor para el diseño de tratamientos enfocados en esta vía de señalización. Actualmente se realizan múltiples ensayos clínicos para determinar su utilidad como marcador de lesiones pulmonares en COVID-19.

Abstract PR04: Epigenetic silencing of CDR1as drives IGF2BP3-mediated melanoma invasion and metastasis

Metastasis is the primary cause of death of cancer patients. Dissecting mechanisms governing metastatic spread may uncover new biology and/or yield promising therapeutic insights. Here we investigated the role of circular RNAs (circRNAs), a class of noncoding RNAs lacking characterized functions, in metastasis, using melanoma as a model aggressive tumor. We analyzed RNA-seq of melanocytes and melanoma short-term cultures to characterize the landscape of circRNA in melanocytic cells. We observed silencing of Cerebellar Degeneration Related 1 (CDR1as), a neuronal-enriched circRNA and known regulator of the microRNA miR-7, in melanoma cell lines and short-term cultures compared to cultured melanocytes, and progressive loss from primary to metastatic disease in melanoma patient samples. Moreover, low CDR1as expression in primary tumors associates with poor prognostic histopathologic indicators and patient outcomes. We find that CDR1as loss results from H3K27me3-mediated silencing of its originating lincRNA LINC00632. We observed abundant H3K27me3, the repressive chromatin mark deposited by the PRC2 complex, in regulatory regions of LINC00632 in cell lines lacking CDR1as expression, and pharmacologic inhibition of EZH2 restored expression of both transcripts. Phenotypically, CDR1as depletion in vitro and in vivo enhances melanoma invasion and metastasis, with limited effect on cell proliferation or tumor growth. Surprisingly, we did not observe miR-7 regulation to be a catalyst of the proinvasive effects of CDR1as depletion in our models. Instead, we identified IGF2BP3 as a novel interactor of CDR1as and critical mediator downstream of CDR1as silencing. Finally, we find that CDR1as abundance associates with previously defined cellular states that engender distinct therapeutic responses to MAPK and GPX4 inhibitors. Collectively, our study reveals CDR1as silencing as a hallmark of melanoma progression; documents novel functional, prognostic and predictive roles for CDR1as; and exposes circRNAs as key players in metastasis.

This abstract is also being presented as Poster A29.

Citation Format: Douglas Hanniford, Alejandro Ulloa-Morales, Beatriz Sánchez-Sendra, Alcida Karz, Rana Moubarak, Tommaso Tabaglio, Maria Gabriela Berzoti-Coelho, Veronica Davalos, Pamela Wu, Varshini Vasudevaraja, Andreas Kloetgen, Karin Lilja, Jochen Imig, Carlos Monteagudo, Ernesto Guccione, Aristotelis Tsirigos, Iman Osman, Iannis Aifantis, Eva Hernando. Epigenetic silencing of CDR1as drives IGF2BP3-mediated melanoma invasion and metastasis [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr PR04.

Epigenetic Silencing of CDR1as Drives IGF2BP3-Mediated Melanoma Invasion and Metastasis

Metastasis is the primary cause of death of cancer patients. Dissecting mechanisms governing metastatic spread may uncover important tumor biology and/or yield promising therapeutic insights. Here, we investigated the role of circular RNAs (circRNA) in metastasis, using melanoma as a model aggressive tumor. We identified silencing of cerebellar degeneration-related 1 antisense (CDR1as), a regulator of miR-7, as a hallmark of melanoma progression. CDR1as depletion results from epigenetic silencing of LINC00632, its originating long non-coding RNA (lncRNA) and promotes invasion in vitro and metastasis in vivo through a miR-7-independent, IGF2BP3-mediated mechanism. Moreover, CDR1as levels reflect cellular states associated with distinct therapeutic responses. Our study reveals functional, prognostic, and predictive roles for CDR1as and expose circRNAs as key players in metastasis.

Functional analysis of RPS27 mutations and expression in melanoma

Next-generation sequencing has enabled genetic and genomic characterization of melanoma to an unprecedent depth. However, the high mutational background plus the limited depth of coverage of whole-genome sequencing performed on cutaneous melanoma samples make the identification of novel driver mutations difficult. We sought to explore the somatic mutation portfolio in exonic and gene regulatory regions in human melanoma samples, for which we performed targeted sequencing of tumors and matched germline DNA samples from 89 melanoma patients, identifying known and novel recurrent mutations. Two recurrent mutations found in the RPS27 promoter associated with decreased RPS27 mRNA levels in vitro. Data mining and IHC analyses revealed a bimodal pattern of RPS27 expression in melanoma, with RPS27-low patients displaying worse prognosis. In vitro characterization of RPS27-high and RPS27-low melanoma cell lines, as well as loss-of-function experiments, demonstrated that high RPS27 status provides increased proliferative and invasive capacities, while low RPS27 confers survival advantage in low attachment and resistance to therapy. Additionally, we demonstrate that 10 other cancer types harbor bimodal RPS27 expression, and in those, similarly to melanoma, RPS27-low expression associates with worse clinical outcomes. RPS27 promoter mutation could thus represent a mechanism of gene expression modulation in melanoma patients, which may have prognostic and predictive implications.