RESUMEN
Myelodysplastic syndrome (MDS) is a refractory cancer that arises from hematopoietic stem cells and predominantly affects elderly adults. In addition to driver gene mutations, which are also found in clonal hematopoiesis in healthy elderly people, systemic inflammation caused by infection or collagen disease has long been known as an extracellular factor in the pathogenesis of MDS. Wild-type HSCs have an "innate immune memory" that functions in response to infection and inflammatory stress, and my colleagues and I used an infection stress model to demonstrate that the innate immune response by the TLR-TRIF-PLK-ELF1 pathway is similarly critical in impairment of hematopoiesis and dysregulation of chromatin in MDS stem cells. This revealed that not only are MDS stem cells expanded by the TRAF6-NF-kB pathway, the innate immune response is also involved in generating MDS stem cells. In this review, I will present research findings related to "innate immune memory," one of the pathogenic mechanisms of blood cancer, and discuss future directions for basic pathological research and potential therapeutic development.
Asunto(s)
Transformación Celular Neoplásica , Neoplasias Hematológicas , Mutación , Humanos , Neoplasias Hematológicas/genética , Transformación Celular Neoplásica/genética , Infecciones , Inmunidad Innata , Síndromes Mielodisplásicos/genética , Animales , Estrés FisiológicoRESUMEN
Leukemia stem cells (LSCs) are widely believed to reside in well-characterized bone marrow (BM) niches; however, the capacity of the BM niches to accommodate LSCs is insufficient, and a significant proportion of LSCs are instead maintained in regions outside the BM. The molecular basis for this niche-independent behavior of LSCs remains elusive. Here, we show that integrin-α9 overexpression (ITGA9 OE) plays a pivotal role in the extramedullary maintenance of LSCs by molecularly mimicking the niche-interacting status, through the binding with its soluble ligand, osteopontin (OPN). Retroviral insertional mutagenesis conducted on leukemia-prone Runx-deficient mice identified Itga9 OE as a novel leukemogenic event. Itga9 OE activates Akt and p38MAPK signaling pathways. The elevated Myc expression subsequently enhances ribosomal biogenesis to overcome the cell integrity defect caused by the preexisting Runx alteration. The Itga9-Myc axis, originally discovered in mice, was further confirmed in multiple human acute myeloid leukemia (AML) subtypes, other than RUNX leukemias. In addition, ITGA9 was shown to be a functional LSC marker of the best prognostic value among 14 known LSC markers tested. Notably, the binding of ITGA9 with soluble OPN, a known negative regulator against HSC activation, induced LSC dormancy, while the disruption of ITGA9-soluble OPN interaction caused rapid cell propagation. These findings suggest that the ITGA9 OE increases both actively proliferating leukemia cells and dormant LSCs in a well-balanced manner, thereby maintaining LSCs. The ITGA9 OE would serve as a novel therapeutic target in AML.
Asunto(s)
Leucemia Mieloide Aguda , Células Madre Neoplásicas , Animales , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patología , Humanos , Ratones , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Osteopontina/genética , Osteopontina/metabolismo , Nicho de Células Madre , Cadenas alfa de Integrinas/metabolismo , Cadenas alfa de Integrinas/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Regulación Leucémica de la Expresión Génica , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , Ratones Endogámicos C57BL , Transducción de SeñalRESUMEN
TIF1ß/KAP1/TRIM28, a chromatin modulator, both represses and activates the transcription of genes in normal and malignant cells. Analyses of datasets on leukemia patients revealed that the expression level of TIF1ß was increased in patients with chronic myeloid leukemia at the blast crisis and acute myeloid leukemia. We generated a BCR::ABL1 conditional knock-in (KI) mouse model, which developed aggressive myeloid leukemia, and demonstrated that the deletion of the Tif1ß gene inhibited the progression of myeloid leukemia and showed longer survival than that in BCR::ABL1 KI mice, suggesting that Tif1ß drove the progression of BCR::ABL1-induced leukemia. In addition, the deletion of Tif1ß sensitized BCR::ABL1 KI leukemic cells to dasatinib. The deletion of Tif1ß decreased the expression levels of TIF1ß-target genes and chromatin accessibility peaks enriched with the Fosl1-binding motif in BCR::ABL1 KI stem cells. TIF1ß directly bound to the promoters of proliferation genes, such as FOSL1, in human BCR::ABL1 cells, in which TIF1ß and FOSL1 bound to adjacent regions of chromatin. Since the expression of Fosl1 was critical for the enhanced growth of BCR::ABL1 KI cells, Tif1ß and Fosl1 interacted to activate the leukemic transcriptional program in and cellular function of BCR::ABL1 KI stem cells and drove the progression of myeloid leukemia.
Asunto(s)
Proteínas de Fusión bcr-abl , Leucemia Mielógena Crónica BCR-ABL Positiva , Animales , Ratones , Humanos , Proteínas de Fusión bcr-abl/genética , Proteínas de Fusión bcr-abl/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Leucemia Mielógena Crónica BCR-ABL Positiva/metabolismo , Regulación Leucémica de la Expresión Génica , Proteína 28 que Contiene Motivos Tripartito/metabolismo , Proteína 28 que Contiene Motivos Tripartito/genética , Transcripción GenéticaRESUMEN
The molecular mechanisms governing the response of hematopoietic stem cells (HSCs) to stress insults remain poorly defined. Here, we investigated effects of conditional knock-out or overexpression of Hmga2 (High mobility group AT-hook 2), a transcriptional activator of stem cell genes in fetal HSCs. While Hmga2 overexpression did not affect adult hematopoiesis under homeostasis, it accelerated HSC expansion in response to injection with 5-fluorouracil (5-FU) or in vitro treatment with TNF-α. In contrast, HSC and megakaryocyte progenitor cell numbers were decreased in Hmga2 KO animals. Transcription of inflammatory genes was repressed in Hmga2-overexpressing mice injected with 5-FU, and Hmga2 bound to distinct regions and chromatin accessibility was decreased in HSCs upon stress. Mechanistically, we found that casein kinase 2 (CK2) phosphorylates the Hmga2 acidic domain, promoting its access and binding to chromatin, transcription of anti-inflammatory target genes, and the expansion of HSCs under stress conditions. Notably, the identified stress-regulated Hmga2 gene signature is activated in hematopoietic stem progenitor cells of human myelodysplastic syndrome patients. In sum, these results reveal a TNF-α/CK2/phospho-Hmga2 axis controlling adult stress hematopoiesis.
Asunto(s)
Quinasa de la Caseína II , Cromatina , Proteína HMGA2 , Células Madre Hematopoyéticas , Ratones Noqueados , Proteína HMGA2/metabolismo , Proteína HMGA2/genética , Animales , Células Madre Hematopoyéticas/metabolismo , Ratones , Humanos , Quinasa de la Caseína II/metabolismo , Quinasa de la Caseína II/genética , Cromatina/metabolismo , Cromatina/genética , Factor de Necrosis Tumoral alfa/metabolismo , Hematopoyesis , Estrés Fisiológico , Fluorouracilo/farmacología , Regeneración , Fosforilación , Síndromes Mielodisplásicos/patología , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/metabolismo , Ratones Endogámicos C57BLRESUMEN
In this issue of PIH, we asked four researchers to write about basic research on the molecular mechanisms of the development of myeloid malignancies, in particular two epigenetic regulation and two space- and time-dependent factors. Regarding epigenomic regulation, Dr. Yang reviewed ASXL1, a polycomb modifier gene that is often mutated in myeloid malignancies, but also in clonal hematopoiesis in healthy elderly people, and Dr. Vu reviewed RNA modifications, which are critical for development and tissue homeostasis, and are now recognized as an important driver for cancer development. Regarding spatiotemporal factors, Dr. Inoue reviewed the role of extracellular vesicles in leukemic stem cell niches. As some cancers develop preferentially in infancy or old age, Dr. Osato discussed the time-specific development of leukemia involving the RUNX1-ETO mutation, which is often found in leukemia in adolescents and young adults. Recent studies on hematopoietic development have shown that hematopoietic stem cells do not generate multipotent progenitor cells, but that these cells develop in parallel. We hope that reconsideration of the definition of leukemic stem cells and their origin will help us understand the regulatory mechanisms of these cells, but also enable us to develop future therapies by targeting factors that regulate the leukemic stem cell and the niche.
Asunto(s)
Leucemia , Trastornos Mieloproliferativos , Humanos , Anciano , Adolescente , Epigénesis Genética , Trastornos Mieloproliferativos/genética , Leucemia/patología , Células Madre Hematopoyéticas/patología , Hematopoyesis/genéticaRESUMEN
Aberrant innate immune signaling in myelodysplastic syndrome (MDS) hematopoietic stem/progenitor cells (HSPCs) has been implicated as a driver of the development of MDS. We herein demonstrated that a prior stimulation with bacterial and viral products followed by loss of the Tet2 gene facilitated the development of MDS via up-regulating the target genes of the Elf1 transcription factor and remodeling the epigenome in hematopoietic stem cells (HSCs) in a manner that was dependent on Polo-like kinases (Plk) downstream of Tlr3/4-Trif signaling but did not increase genomic mutations. The pharmacological inhibition of Plk function or the knockdown of Elf1 expression was sufficient to prevent the epigenetic remodeling in HSCs and diminish the enhanced clonogenicity and the impaired erythropoiesis. Moreover, this Elf1-target signature was significantly enriched in MDS HSPCs in humans. Therefore, prior infection stress and the acquisition of a driver mutation remodeled the transcriptional and epigenetic landscapes and cellular functions in HSCs via the Trif-Plk-Elf1 axis, which promoted the development of MDS.
Asunto(s)
Dioxigenasas , Síndromes Mielodisplásicos , Humanos , Células Madre Hematopoyéticas/metabolismo , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Regulación de la Expresión Génica , Proteínas Adaptadoras del Transporte Vesicular/genética , Proteínas Adaptadoras del Transporte Vesicular/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Dioxigenasas/genética , Dioxigenasas/metabolismoRESUMEN
MicroRNAs (miRNAs) play a crucial role in regulating gene expression. MicroRNA expression levels fluctuate, and point mutations and methylation occur in cancer cells; however, to date, there have been no reports of carcinogenic point mutations in miRNAs. MicroRNA 142 (miR-142) is frequently mutated in patients with follicular lymphoma, diffuse large B-cell lymphoma, chronic lymphocytic leukemia (CLL), and acute myeloid leukemia/myelodysplastic syndrome (AML/MDS). To understand the role of miR-142 mutation in blood cancers, the CRISPR-Cas9 system was utilized to successfully generate miR-142-55A>G mutant knock-in (Ki) mice, simulating the most frequent mutation in patients with miR-142 mutated AML/MDS. Bone marrow cells from miR-142 mutant heterozygous Ki mice were transplanted, and we found that the miR-142 mutant/wild-type cells were sufficient for the development of CD8+ T-cell leukemia in mice post-transplantation. RNA-sequencing analysis in hematopoietic stem/progenitor cells and CD8+ T-cells revealed that miR-142-Ki/+ cells had increased expression of the mTORC1 activator, a potential target of wild-type miR-142-3p. Notably, the expression of genes involved in apoptosis, differentiation, and the inhibition of the Akt-mTOR pathway was suppressed in miR-142-55A>G heterozygous cells, indicating that these genes are repressed by the mutant miR-142-3p. Thus, in addition to the loss of function due to the halving of wild-type miR-142-3p alleles, mutated miR-142-3p gained the function to suppress the expression of distinct target genes, sufficient to cause leukemogenesis in mice.
Asunto(s)
Leucemia Mieloide Aguda , MicroARNs , Síndromes Mielodisplásicos , Animales , Ratones , Carcinogénesis , Linfocitos T CD8-positivos/metabolismo , Mutación con Ganancia de Función , Leucemia Mieloide Aguda/genética , MicroARNs/genética , MicroARNs/metabolismo , Síndromes Mielodisplásicos/genéticaRESUMEN
Adult T-cell leukemia/lymphoma (ATL) is caused by human T-cell leukemia virus type 1 (HTLV-1). In addition to HTLV-1 bZIP factor (HBZ), a leukemogenic antisense transcript of HTLV-1, abnormalities of genes involved in TCR-NF-κB signaling, such as CARD11, are detected in about 90% of patients. Utilizing mice expressing CD4+ T cell-specific CARD11(E626K) and/or CD4+ T cell-specific HBZ, namely CARD11(E626K)CD4-Cre mice, HBZ transgenic (Tg) mice, and CARD11(E626K)CD4-Cre;HBZ Tg double transgenic mice, we clarify these genes' pathogenetic effects. CARD11(E626K)CD4-Cre and HBZ Tg mice exhibit lymphocytic invasion to many organs, including the lungs, and double transgenic mice develop lymphoproliferative disease and increase CD4+ T cells in vivo. CARD11(E626K) and HBZ cooperatively activate the non-canonical NF-κB pathway, IRF4 targets, BATF3/IRF4/HBZ transcriptional network, MYC targets, and E2F targets. Most KEGG and HALLMARK gene sets enriched in acute-type ATL are also enriched in double transgenic mice, indicating that these genes cooperatively contribute to ATL development.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico , Leucemia-Linfoma de Células T del Adulto , Linfoma , Adulto , Animales , Humanos , Ratones , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Proteínas Adaptadoras de Señalización CARD , Guanilato Ciclasa , Leucemia-Linfoma de Células T del Adulto/genética , Ratones Transgénicos , Mutación , FN-kappa B/genética , Proteínas de los RetroviridaeRESUMEN
High mobility group nucleosome-binding protein 3 (HMGN3), a member of the HMGN family, modulates the structure of chromatin and regulates transcription through transcription factors. HMGN3 has been implicated in the development of various cancers; however, the underlying mechanisms remain unclear. We herein demonstrated that the high expression of HMGN3 correlated with the metastasis of liver fluke infection-induced cholangiocarcinoma (CCA) in patients in northeastern Thailand. The knockdown of HMGN3 in CCA cells significantly impaired the oncogenic properties of colony formation, migration, and invasion. HMGN3 inhibited the expression of and blocked the intracellular polarities of epithelial regulator genes, such as the CDH1/E-cadherin and TJAP1 genes in CCA cells. A chromatin immunoprecipitation sequencing analysis revealed that HMGN3 required the transcription factor SNAI2 to bind to and repress the expression of epithelial regulator genes, at least in part, due to histone deacetylases (HDACs), the pharmacological inhibition of which reactivated these epithelial regulators in CCA, leading to impairing the cell migration capacity. Therefore, the overexpression of HMGN3 represses the transcription of and blocks the polarities of epithelial regulators in CCA cells in a manner that is dependent on the SNAI2 gene and HDACs.
Asunto(s)
Neoplasias de los Conductos Biliares , Colangiocarcinoma , Neoplasias de los Conductos Biliares/genética , Neoplasias de los Conductos Biliares/patología , Conductos Biliares Intrahepáticos/metabolismo , Conductos Biliares Intrahepáticos/patología , Colangiocarcinoma/genética , Colangiocarcinoma/patología , Regulación de la Expresión Génica , Proteínas HMGN/genética , Proteínas HMGN/metabolismo , Humanos , Factores de Transcripción de la Familia Snail/genética , Factores de Transcripción de la Familia Snail/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
In order to support bone marrow regeneration after myeloablation, hematopoietic stem cells (HSCs) actively divide to provide both stem and progenitor cells. However, the mechanisms regulating HSC function and cell fate choice during hematopoietic recovery remain unclear. We herein provide novel insights into HSC regulation during regeneration by focusing on mitochondrial metabolism and ATP citrate lyase (ACLY). After 5-fluorouracil-induced myeloablation, HSCs highly expressing endothelial protein C receptor (EPCRhigh ) were enriched within the stem cell fraction at the expense of more proliferative EPCRLow HSCs. These EPCRHigh HSCs were initially more primitive than EPCRLow HSCs and enabled stem cell expansion by enhancing histone acetylation, due to increased activity of ACLY in the early phase of hematopoietic regeneration. In the late phase of recovery, HSCs enhanced differentiation potential by increasing the accessibility of cis-regulatory elements in progenitor cell-related genes, such as CD48. In conditions of reduced mitochondrial metabolism and ACLY activity, these HSCs maintained stem cell phenotypes, while ACLY-dependent histone acetylation promoted differentiation into CD48+ progenitor cells. Collectively, these results indicate that the dynamic control of ACLY-dependent metabolism and epigenetic alterations is essential for HSC regulation during hematopoietic regeneration.
Asunto(s)
ATP Citrato (pro-S)-Liasa , Médula Ósea , ATP Citrato (pro-S)-Liasa/genética , ATP Citrato (pro-S)-Liasa/metabolismo , Receptor de Proteína C Endotelial/metabolismo , Células Madre Hematopoyéticas/fisiología , Histonas/metabolismoRESUMEN
High mobility group AT-hook 2 (Hmga2) is a chromatin modifier protein that plays a critical role in fetal development and leukemia propagation by binding to chromatin and DNA via its AT-hook domains. However, the molecular mechanisms by which Hmga2 activates the expression of target genes to drive the self-renewal of hematopoietic stem cells (HSCs) remain unclear. We generated Rosa26 locus Hmga2 conditional knock-in mice and found that overexpression of Hmga2 promoted self-renewal of normal HSCs, but maintained their fitness in bone marrow, and consequently was not sufficient to initiate malignancy. This result is consistent with previous findings showing that Hmga2 is a proto-oncogene. We also assessed the cellular functions of Hmga2 mutants lacking functional domains and demonstrated that the C-terminus acidic domain of Hmga2 and the domain's linker region were critical for activating genes involved in stem cell signatures, such as the Igf2bp2 gene, to drive proliferation of HSCs. In contrast, overexpression of Hmga1, a member of the Hmga family with a different linker region, did not drive proliferation of HSCs. Our results reveal a critical role for the acidic domain of Hmga2 and the domain's linker region in modulating the transcription and self-renewal functions of HSCs.
Asunto(s)
Células Madre Hematopoyéticas , Neoplasias , Animales , Células Madre Hematopoyéticas/metabolismo , Humanos , Ratones , Proteínas de Unión al ARNRESUMEN
Insufficiency of polycomb repressive complex 2 (PRC2), which trimethylates histone H3 at lysine 27, is frequently found in primary myelofibrosis and promotes the development of JAK2V617F-induced myelofibrosis in mice by enhancing the production of dysplastic megakaryocytes. Polycomb group ring finger protein 1 (Pcgf1) is a component of PRC1.1, a non-canonical PRC1 that monoubiquitylates H2A at lysine 119 (H2AK119ub1). We herein investigated the impact of PRC1.1 insufficiency on myelofibrosis. The deletion of Pcgf1 in JAK2V617F mice strongly promoted the development of lethal myelofibrosis accompanied by a block in erythroid differentiation. Transcriptome and chromatin immunoprecipitation sequence analyses showed the de-repression of PRC1.1 target genes in Pcgf1-deficient JAK2V617F hematopoietic progenitors and revealed Hoxa cluster genes as direct targets. The deletion of Pcgf1 in JAK2V617F hematopoietic stem and progenitor cells (HSPCs), as well as the overexpression of Hoxa9, restored the attenuated proliferation of JAK2V617F progenitors. The overexpression of Hoxa9 also enhanced JAK2V617F-mediated myelofibrosis. The expression of PRC2 target genes identified in PRC2-insufficient JAK2V617F HSPCs was not largely altered in Pcgf1-deleted JAK2V617F HSPCs. The present results revealed a tumor suppressor function for PRC1.1 in myelofibrosis and suggest that PRC1.1 insufficiency has a different impact from that of PRC2 insufficiency on the pathogenesis of myelofibrosis.
Asunto(s)
Diferenciación Celular , Janus Quinasa 2/genética , Mutación , Complejo Represivo Polycomb 1/fisiología , Mielofibrosis Primaria/patología , Animales , Femenino , Lisina , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mielofibrosis Primaria/etiología , Mielofibrosis Primaria/metabolismo , UbiquitinaciónAsunto(s)
Subunidad alfa 2 del Factor de Unión al Sitio Principal/fisiología , Proteínas de Unión al ADN/genética , Leucemia Mieloide/patología , Proteínas de Fusión Oncogénica , Proteínas Proto-Oncogénicas/genética , Proteína 1 Compañera de Translocación de RUNX1/fisiología , Factores de Transcripción/genética , Factores de Edad , Animales , Leucemia Mieloide/genética , Leucemia Mieloide/metabolismo , Ratones , Ratones Noqueados , Translocación GenéticaRESUMEN
Cholangiocarcinoma (CCA) is the second most common type of hepatic cancer. In east and southeast Asia, intrahepatic CCA is caused predominantly by infection of Opisthorchis viverrini and Clonorchis sinensis, two species of parasitic liver flukes. In this review, we present molecular evidence that liver fluke-associated CCAs have enhanced features of epithelial-mesenchymal transition (EMT) in bile duct epithelial cells (cholangiocytes) and that some of those features are associated with mis-regulation at the epigenetic level. We hypothesize that both direct and indirect mechanisms underlie parasitic infection-induced EMT in CCA.
RESUMEN
RUNX3, a transcription factor, has been implicated as a tumor suppressor in various cancers, including hematological malignancies; however, recent studies revealed an oncogenic function of RUNX3 in the pathogenesis of myeloid malignancies, such as myelodysplastic syndrome and acute myeloid leukemia. In contrast to the high frequency of mutations in the RUNX1 gene, deletion of and loss-of-function mutations in RUNX3 are rarely detected in patients with hematopoietic malignancies. Although RUNX3 is expressed in normal hematopoietic stem and progenitor cells, its expression decreases with aging in humans. The loss of Runx3 did not result in the development of lethal hematological diseases in mice despite the expansion of myeloid cells. Therefore, RUNX3 does not appear to initiate the transformation of normal hematopoietic stem cells. However, the overexpression of RUNX3 inhibits the expression and transcriptional function of the RUNX1 gene, but activates the expression of key oncogenic pathways, such as MYC, resulting in the transformation of premalignant stem cells harboring a driver genetic mutation. We herein discuss the mechanisms by which RUNX3 is activated and how RUNX3 exerts oncogenic effects on the cellular function of and transcriptional program in premalignant stem cells to drive myeloid transformation.
Asunto(s)
Transformación Celular Neoplásica , Subunidad alfa 3 del Factor de Unión al Sitio Principal/genética , Leucemia Mieloide/genética , Síndromes Mielodisplásicos/genética , Células Mieloides/patología , Animales , Subunidad alfa 3 del Factor de Unión al Sitio Principal/metabolismo , Regulación Neoplásica de la Expresión Génica , Hematopoyesis , Humanos , Leucemia Mieloide/metabolismo , Leucemia Mieloide/patología , Síndromes Mielodisplásicos/metabolismo , Síndromes Mielodisplásicos/patología , Células Mieloides/metabolismoRESUMEN
In the tumor microenvironment, senescent non-malignant cells, including cancer-associated fibroblasts (CAFs), exhibit a secretory profile under stress conditions; this senescence-associated secretory phenotype (SASP) leads to cancer progression and chemoresistance. However, the role of senescent CAFs in metastatic lesions and the molecular mechanism of inflammation-related SASP induction are not well understood. We show that pro-inflammatory cytokine-driven EZH2 downregulation maintains the SASP by demethylating H3K27me3 marks in CAFs and enhances peritoneal tumor formation of gastric cancer (GC) through JAK/STAT3 signaling in a mouse model. A JAK/STAT3 inhibitor blocks the increase in GC cell viability induced by senescent CAFs and peritoneal tumor formation. Single-cell mass cytometry revealed that fibroblasts exist in the ascites of GC patients with peritoneal dissemination, and the fibroblast population shows p16 expression and SASP factors at high levels. These findings provide insights into the inflammation-related SASP maintenance by histone modification and the role of senescent CAFs in GC peritoneal dissemination.
Asunto(s)
Fibroblastos Asociados al Cáncer/enzimología , Citocinas/metabolismo , Mediadores de Inflamación/metabolismo , Neoplasias Peritoneales/metabolismo , Fenotipo Secretor Asociado a la Senescencia , Neoplasias Gástricas/metabolismo , Anciano , Animales , Antineoplásicos/farmacología , Fibroblastos Asociados al Cáncer/patología , Línea Celular Tumoral , Citocinas/genética , Proteína Potenciadora del Homólogo Zeste 2/genética , Proteína Potenciadora del Homólogo Zeste 2/metabolismo , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Inhibidores de las Cinasas Janus/farmacología , Quinasas Janus/metabolismo , Masculino , Ratones Endogámicos BALB C , Ratones Desnudos , Persona de Mediana Edad , Neoplasias Peritoneales/tratamiento farmacológico , Neoplasias Peritoneales/genética , Neoplasias Peritoneales/secundario , Piridinas/farmacología , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismo , Transducción de Señal , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Microambiente Tumoral , Tirfostinos/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
High Mobility Group AT-hook 2 (HMGA2) is a chromatin modifier and its overexpression has been found in patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Level of Hmga2 expression is fine-tuned by Lin28b-Let-7 axis and Polycomb Repressive Complex 2, in which deletion of Ezh2 leads to activation of Hmga2 expression in hematopoietic stem cells. To elucidate the mechanisms by which the overexpression of HMGA2 helps transformation of stem cells harboring a driver mutation of TET2, we generated an Hmga2-expressing Tet2-deficient mouse model showing the progressive phenotypes of MDS and AML. The overexpression of Hmga2 remodeled the transcriptional program of Tet2-deficient stem and progenitor cells, leading to the impaired differentiation of myeloid cells. Furthermore, Hmga2 was bound to a proximal region of Igf2bp2 oncogene, and activated its transcription, leading to enhancing self-renewal of Tet2-deficient stem cells that was suppressed by inhibition of the DNA binding of Hmga2. These combinatory effects on the transcriptional program and cellular function were not redundant to those in Tet2-deficient cells. The present results elucidate that Hmga2 targets key oncogenic pathways during the transformation and highlight the Hmga2-Igf2bp2 axis as a potential target for therapeutic intervention.
Asunto(s)
Proteínas de Unión al ADN/genética , Proteína HMGA2/genética , Leucemia Mieloide Aguda/genética , Síndromes Mielodisplásicos/genética , Proteínas Proto-Oncogénicas/genética , Proteínas de Unión al ARN/genética , Animales , Diferenciación Celular/genética , Dioxigenasas , Proteína Potenciadora del Homólogo Zeste 2/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Leucemia Mieloide Aguda/patología , Ratones , MicroARNs/genética , Síndromes Mielodisplásicos/patología , Células Mieloides/metabolismo , Células Mieloides/patología , Complejo Represivo Polycomb 2/genéticaRESUMEN
EZH1 and EZH2 are enzymatic components of polycomb repressive complex (PRC) 2, which catalyzes histone H3K27 tri-methylation (H3K27me3) to repress the transcription of PRC2 target genes. We previously reported that the hematopoietic cell-specific Ezh2 deletion (Ezh2Δ/Δ) induced a myelodysplastic syndrome (MDS)-like disease in mice. We herein demonstrated that severe PRC2 insufficiency induced by the deletion of one allele Ezh1 in Ezh2-deficient mice (Ezh1+/-Ezh2Δ/Δ) caused advanced dyserythropoiesis accompanied by a differentiation block and enhanced apoptosis in erythroblasts. p53, which is activated by impaired ribosome biogenesis in del(5q) MDS, was specifically activated in erythroblasts, but not in hematopoietic stem or progenitor cells in Ezh1+/-Ezh2Δ/Δ mice. Cdkn2a, a major PRC2 target encoding p19Arf, which activates p53 by inhibiting MDM2 E3 ubiquitin ligase, was de-repressed in Ezh1+/-Ezh2Δ/Δ erythroblasts. The deletion of Cdkn2a as well as p53 rescued dyserythropoiesis in Ezh1+/-Ezh2Δ/Δ mice, indicating that PRC2 insufficiency caused p53-dependent dyserythropoiesis via the de-repression of Cdkn2a. Since PRC2 insufficiency is often involved in the pathogenesis of MDS, the present results suggest that p53-dependent dyserythropoiesis manifests in MDS in the setting of PRC2 insufficiency.
Asunto(s)
Susceptibilidad a Enfermedades , Eritropoyesis/genética , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/metabolismo , Complejo Represivo Polycomb 2/genética , Proteína p53 Supresora de Tumor/metabolismo , Animales , Biomarcadores , Secuenciación de Inmunoprecipitación de Cromatina , Modelos Animales de Enfermedad , Eritroblastos/metabolismo , Eritroblastos/patología , Citometría de Flujo , Histonas/metabolismo , Humanos , Ratones , Ratones Transgénicos , Modelos Biológicos , Mutación , Síndromes Mielodisplásicos/diagnóstico , Síndromes Mielodisplásicos/terapia , Unión ProteicaRESUMEN
Random gene trapping is the application of insertional mutagenesis techniques that are conventionally used to inactivate protein-coding genes in mouse embryonic stem (ES) cells. Transcriptionally silent genes are not effectively targeted by conventional random gene trapping techniques, thus we herein developed an unbiased poly (A) trap (UPATrap) method using a Tol2 transposon, which preferentially integrated into active genes rather than silent genes in ES cells. To achieve efficient trapping at transcriptionally silent genes using random insertional mutagenesis in ES cells, we generated a new diphtheria toxin (DT)-mediated trapping vector, DTrap that removed cells, through the expression of DT that was induced by the promoter activity of the trapped genes, and selected trapped clones using the neomycin-resistance gene of the vector. We found that a double-DT, the dDT vector, dominantly induced the disruption of silent genes, but not active genes, and showed more stable integration in ES cells than the UPATrap vector. The dDT vector disrupted differentiated cell lineage genes, which were silent in ES cells, and labeled trapped clone cells by the expression of EGFP upon differentiation. Thus, the dDT vector provides a systematic approach to disrupt silent genes and examine the cellular functions of trapped genes in the differentiation of target cells and development.