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1.
Nat Immunol ; 22(2): 240-253, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33432228

RESUMEN

During the germinal center (GC) reaction, B cells undergo extensive redistribution of cohesin complex and three-dimensional reorganization of their genomes. Yet, the significance of cohesin and architectural programming in the humoral immune response is unknown. Herein we report that homozygous deletion of Smc3, encoding the cohesin ATPase subunit, abrogated GC formation, while, in marked contrast, Smc3 haploinsufficiency resulted in GC hyperplasia, skewing of GC polarity and impaired plasma cell (PC) differentiation. Genome-wide chromosomal conformation and transcriptional profiling revealed defects in GC B cell terminal differentiation programs controlled by the lymphoma epigenetic tumor suppressors Tet2 and Kmt2d and failure of Smc3-haploinsufficient GC B cells to switch from B cell- to PC-defining transcription factors. Smc3 haploinsufficiency preferentially impaired the connectivity of enhancer elements controlling various lymphoma tumor suppressor genes, and, accordingly, Smc3 haploinsufficiency accelerated lymphomagenesis in mice with constitutive Bcl6 expression. Collectively, our data indicate a dose-dependent function for cohesin in humoral immunity to facilitate the B cell to PC phenotypic switch while restricting malignant transformation.


Asunto(s)
Linfocitos B/metabolismo , Proteínas de Ciclo Celular/deficiencia , Proteínas de Ciclo Celular/genética , Transformación Celular Neoplásica/genética , Proteoglicanos Tipo Condroitín Sulfato/genética , Proteínas Cromosómicas no Histona/deficiencia , Proteínas Cromosómicas no Histona/genética , Dosificación de Gen , Centro Germinal/metabolismo , Inmunidad Humoral , Linfoma de Células B/genética , Animales , Linfocitos B/inmunología , Linfocitos B/patología , Proteínas de Ciclo Celular/metabolismo , Diferenciación Celular , Proliferación Celular , Transformación Celular Neoplásica/inmunología , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/patología , Células Cultivadas , Proteoglicanos Tipo Condroitín Sulfato/deficiencia , Proteoglicanos Tipo Condroitín Sulfato/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Dioxigenasas , Eliminación de Gen , Regulación Neoplásica de la Expresión Génica , Centro Germinal/inmunología , Centro Germinal/patología , Haploinsuficiencia , N-Metiltransferasa de Histona-Lisina/genética , N-Metiltransferasa de Histona-Lisina/metabolismo , Humanos , Linfoma de Células B/inmunología , Linfoma de Células B/metabolismo , Linfoma de Células B/patología , Linfoma de Células B Grandes Difuso/genética , Linfoma de Células B Grandes Difuso/inmunología , Linfoma de Células B Grandes Difuso/metabolismo , Linfoma de Células B Grandes Difuso/patología , Ratones Endogámicos C57BL , Ratones Noqueados , Proteína de la Leucemia Mieloide-Linfoide/genética , Proteína de la Leucemia Mieloide-Linfoide/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Transducción de Señal , Cohesinas
2.
Nat Biotechnol ; 42(3): 437-447, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37563300

RESUMEN

Although single-nucleotide variants (SNVs) make up the majority of cancer-associated genetic changes and have been comprehensively catalogued, little is known about their impact on tumor initiation and progression. To enable the functional interrogation of cancer-associated SNVs, we developed a mouse system for temporal and regulatable in vivo base editing. The inducible base editing (iBE) mouse carries a single expression-optimized cytosine base editor transgene under the control of a tetracycline response element and enables robust, doxycycline-dependent expression across a broad range of tissues in vivo. Combined with plasmid-based or synthetic guide RNAs, iBE drives efficient engineering of individual or multiple SNVs in intestinal, lung and pancreatic organoids. Temporal regulation of base editor activity allows controlled sequential genome editing ex vivo and in vivo, and delivery of sgRNAs directly to target tissues facilitates generation of in situ preclinical cancer models.


Asunto(s)
Edición Génica , Neoplasias , Ratones , Animales , Sistemas CRISPR-Cas/genética , ARN Guía de Sistemas CRISPR-Cas , Neoplasias/genética , Neoplasias/terapia , Pulmón
3.
Cancer Discov ; 10(11): 1654-1671, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32792368

RESUMEN

KRAS is the most frequently mutated oncogene in cancer, yet there is little understanding of how specific KRAS amino acid changes affect tumor initiation, progression, or therapy response. Using high-fidelity CRISPR-based engineering, we created an allelic series of new LSL-Kras mutant mice, reflecting codon 12 and 13 mutations that are highly prevalent in lung (KRASG12C), pancreas (KRASG12R), and colon (KRASG13D) cancers. Induction of each allele in either the murine colon or pancreas revealed striking quantitative and qualitative differences between KRAS mutants in driving the early stages of transformation. Furthermore, using pancreatic organoid models, we show that KRASG13D mutants are sensitive to EGFR inhibition, whereas KRASG12C-mutant organoids are selectively responsive to covalent G12C inhibitors only when EGFR is suppressed. Together, these new mouse strains provide an ideal platform for investigating KRAS biology in vivo and for developing preclinical precision oncology models of KRAS-mutant pancreas, colon, and lung cancers. SIGNIFICANCE: KRAS is the most frequently mutated oncogene. Here, we describe new preclinical models that mimic tissue-selective KRAS mutations and show that each mutation has distinct cellular consequences in vivo and carries differential sensitivity to targeted therapeutic agents.See related commentary by Kostyrko and Sweet-Cordero, p. 1626.This article is highlighted in the In This Issue feature, p. 1611.


Asunto(s)
Alelos , Oncogenes/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Línea Celular Tumoral , Humanos , Fenotipo
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