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1.
Nat Commun ; 11(1): 4980, 2020 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-33020477

RESUMO

The functions of the proto-oncoprotein c-Myc and the tumor suppressor p53 in controlling cell survival and proliferation are inextricably linked as "Yin and Yang" partners in normal cells to maintain tissue homeostasis: c-Myc induces the expression of ARF tumor suppressor (p14ARF in human and p19ARF in mouse) that binds to and inhibits mouse double minute 2 homolog (MDM2) leading to p53 activation, whereas p53 suppresses c-Myc through a combination of mechanisms involving transcriptional inactivation and microRNA-mediated repression. Nonetheless, the regulatory interactions between c-Myc and p53 are not retained by cancer cells as is evident from the often-imbalanced expression of c-Myc over wildtype p53. Although p53 repression in cancer cells is frequently associated with the loss of ARF, we disclose here an alternate mechanism whereby c-Myc inactivates p53 through the actions of the c-Myc-Inducible Long noncoding RNA Inactivating P53 (MILIP). MILIP functions to promote p53 polyubiquitination and turnover by reducing p53 SUMOylation through suppressing tripartite-motif family-like 2 (TRIML2). MILIP upregulation is observed amongst diverse cancer types and is shown to support cell survival, division and tumourigenicity. Thus our results uncover an inhibitory axis targeting p53 through a pan-cancer expressed RNA accomplice that links c-Myc to suppression of p53.


Assuntos
Neoplasias/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Longo não Codificante/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Carcinogênese , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias/genética , Neoplasias/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Proteínas Proto-Oncogênicas c-myc/genética , RNA Longo não Codificante/genética , Sumoilação , Proteína Supressora de Tumor p53/genética , Ubiquitinação
2.
Nat Commun ; 11(1): 4153, 2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32814769

RESUMO

The histone methyltransferase DOT1L methylates lysine 79 (K79) on histone H3 and is involved in Mixed Lineage Leukemia (MLL) fusion leukemogenesis; however, its role in prostate cancer (PCa) is undefined. Here we show that DOT1L is overexpressed in PCa and is associated with poor outcome. Genetic and chemical inhibition of DOT1L selectively impaired the viability of androgen receptor (AR)-positive PCa cells and organoids, including castration-resistant and enzalutamide-resistant cells. The sensitivity of AR-positive cells is due to a distal K79 methylation-marked enhancer in the MYC gene bound by AR and DOT1L not present in AR-negative cells. DOT1L inhibition leads to reduced MYC expression and upregulation of MYC-regulated E3 ubiquitin ligases HECTD4 and MYCBP2, which promote AR and MYC degradation. This leads to further repression of MYC in a negative feed forward manner. Thus DOT1L selectively regulates the tumorigenicity of AR-positive prostate cancer cells and is a promising therapeutic target for PCa.


Assuntos
Histona-Lisina N-Metiltransferase/genética , Neoplasias da Próstata/genética , Proteínas Proto-Oncogênicas c-myc/genética , Receptores Androgênicos/genética , Adenosina/análogos & derivados , Adenosina/farmacologia , Animais , Linhagem Celular Tumoral , Intervalo Livre de Doença , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Histona-Lisina N-Metiltransferase/antagonistas & inibidores , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Masculino , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Compostos de Fenilureia/farmacologia , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/terapia , Estabilidade Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-myc/metabolismo , Interferência de RNA , Terapêutica com RNAi/métodos , Receptores Androgênicos/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
3.
Life Sci ; 258: 118252, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32791149

RESUMO

AIMS: This study aimed to analyze the impact of four synthesized benzoxazinone derivatives as screening drugs on c-Myc-overexpressed cancer cells (H7402, HeLa, SK-RC-42, SGC7901, and A549) and to explore their interaction mechanisms in detail. MATERIALS AND METHODS: Using morphological analysis, real-time cytotoxicity analysis, wound healing assay, reverse transcription PCR, electrophoretic mobility shift assay, and circular dichroism spectroscopy techniques. KEY FINDINGS: Results revealed that these four compounds could inhibit proliferation of SK-RC-42, SGC7901, and A549 cells in five cancer cell lines to varying degrees and significantly hinder migration. More importantly, the RT-PCR assay showed that the compounds could surprisingly downregulate the expression of c-Myc mRNA in a dose-dependent manner in the five cancer cells, which may be one of the causes of cancer cell proliferation in vitro inhibition. Further EMSA assays demonstrated that at the molecular level of DNA, four compounds can induce the formation of G-quadruplexes (G4-DNAs) in the c-Myc gene promoter. In addition, the CD result of compound 1 clearly indicates that it specifically induces a c-Myc GC-rich 36mer double-stranded DNA in the c-Myc promoter to form a G-quadruplex hybrid configuration. In conclusion, the compounds studied could dose-dependently inhibit the growth and migration of the cancer cells being investigated. This is positively associated with the reduction of overexpression of the c-Myc gene, which may be significantly regulated by the association of compounds with the G-quadruplexes produced in the c-Myc gene promoter region. SIGNIFICANCE: We conclude that three compounds merit further study, particularly against non-small-cell lung cancer, as leading compounds of anticancer drugs.


Assuntos
Antineoplásicos/administração & dosagem , Benzoxazinas/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Quadruplex G/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-myc/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-myc/metabolismo , Células A549 , Células HT29 , Células HeLa , Células Hep G2 , Humanos , Células MCF-7
4.
PLoS One ; 15(7): e0235573, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32609742

RESUMO

Diabetes mellitus is a well-known risk factor for pancreatic cancer. We focused on hyperglycemia, a main feature of diabetes mellitus, and uncovered its effect on precancerous pancreatic intraepithelial neoplasia (PanIN) progression. In vivo induction of hyperglycemia with 100 mg/kg streptozotocin in KrasLSL G12D Pdx1Cre (KP) mice promoted the PanIN formation and progression. Preconditioning with a high- or low-glucose medium for 28 days showed that a high-glucose environment increased cell viability and sphere formation in PANC-1, a Kras-mutant human pancreatic ductal adenocarcinoma cell line, and mPKC1, a Kras-mutant murine pancreatic cancer cell line. In contrast, no changes were observed in BxPC3, a Kras-wild-type human pancreatic cancer cell line. Orthotopic injection of mPKC1 into the pancreatic tails of BL6/J mice showed that cells maintained in high-glucose medium grew into larger tumors than did those maintained in low-glucose medium. Hyperglycemia strengthened the STAT3 phosphorylation, which was accompanied by elevated MYC expression in Kras-mutant cells. Immunohistochemistry showed stronger phosphorylated STAT3 (pSTAT3) and MYC staining in PanINs from diabetic KP mice than in those from euglycemic counterparts. STAT3 inhibition with 1 µM STAT3 inhibitor STATTIC in Kras-mutant pancreatic cell lines blocked the cell viability- and sphere formation-enhancing effects of the hyperglycemic environment and reversed the elevated pSTAT3 and MYC expression. MYC knockdown did not affect cell viability but did reduce sphere formation. No decrease in pSTAT3 expression was observed upon siMYC treatment. In conclusion, hyperglycemia, on a Kras-mutant background, aggravates the PanIN progression, which is accompanied by elevated pSTAT3 and MYC expression.


Assuntos
Progressão da Doença , Hiperglicemia/complicações , Neoplasias Pancreáticas/complicações , Neoplasias Pancreáticas/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Fator de Transcrição STAT3/metabolismo , Animais , Linhagem Celular Tumoral , Sobrevivência Celular , Regulação Neoplásica da Expressão Gênica , Glucose/metabolismo , Humanos , Camundongos , Mutação , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Fosforilação , Proteínas Proto-Oncogênicas p21(ras)/genética
5.
Mol Immunol ; 125: 115-122, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32659596

RESUMO

Genome-wide association studies have established that human REL is a susceptibility gene for lymphoid cancers and inflammatory diseases. REL is the hematopoietic member of the nuclear factor-κB (NF-κB) family and is frequently amplified in human lymphomas. However, the mechanism through which REL and its encoded protein c-Rel affect human lymphoma is largely unknown. Using both loss-of-function and gain-of-function approaches, we studied the roles of REL gene in human Jurkat leukemia cells. Compared with control Jurkat cells, REL knockout cells exhibited significant defects in cell growth and mitochondrial respiration. Genome-wide transcriptome analyses revealed that T cells lacking c-Rel had selective defects in the expression of inflammatory and metabolic genes including c-Myc. We found that c-Rel controlled the expression of c-Myc through its promotor, and expressing c-Myc in c-Rel-deficient lymphoma cells rescued their proliferative and metabolic defects. Thus, the human c-Rel-c-Myc axis controls lymphoma growth and metabolism and could be a therapeutic target for lymphomas.


Assuntos
Proliferação de Células/fisiologia , Leucemia de Células T/metabolismo , Leucemia de Células T/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-rel/metabolismo , Técnicas de Inativação de Genes , Humanos , Células Jurkat
6.
Mol Pharmacol ; 98(2): 130-142, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32487733

RESUMO

Aberrant cellular Myc (c-Myc) is a common feature in the majority of human cancers and has been linked to oncogenic malignancies. Here, we developed a novel c-Myc-targeting compound, N, N-bis (5-ethyl-2-hydroxybenzyl) methylamine (EMD), and present evidence demonstrating its effectiveness in targeting c-Myc for degradation in human lung carcinoma. EMD exhibited strong cytotoxicity toward various human lung cancer cell lines, as well as chemotherapeutic-resistant patient-derived lung cancer cells, through apoptosis induction in comparison with chemotherapeutic drugs. The IC50 of EMD against lung cancer cells was approximately 60 µM. Mechanistically, EMD eliminated c-Myc in the cells and initiated caspase-dependent apoptosis cascade. Cycloheximide chase assay revealed that EMD tended to shorten the half-life of c-Myc by approximately half. The cotreatment of EMD with the proteasome inhibitor MG132 reversed its c-Myc-targeting effect, suggesting the involvement of ubiquitin-mediated proteasomal degradation in the process. We further verified that EMD strongly induced the ubiquitination of c-Myc and promoted protein degradation. c-Myc inhibition and apoptosis induction were additionally shown in hematologic malignant K562 cells, indicating the generality of the observed EMD effects. Altogether, we identified EMD as a novel potent compound targeting oncogenic c-Myc that may offer new opportunities for lung cancer treatment. SIGNIFICANCE STATEMENT: The deregulation of c-Myc is frequently associated with cancer progression. This study examined the effect of a new compound, N, N-bis (5-ethyl-2-hydroxybenzyl) methylamine (EMD), in targeting c-Myc in several lung cancer cell lines and drug-resistant primary lung cancer cells. EMD induced dramatic c-Myc degradation through a ubiquitin-proteasomal mechanism. The promising anticancer and c-Myc-targeted activities of EMD support its use in potential new approaches to treat c-Myc-driven cancer.


Assuntos
Antineoplásicos/síntese química , Neoplasias Pulmonares/metabolismo , Metilaminas/síntese química , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Humanos , Células K562 , Neoplasias Pulmonares/tratamento farmacológico , Metilaminas/química , Metilaminas/farmacologia , Estrutura Molecular , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Proteínas Proto-Oncogênicas c-myc/efeitos dos fármacos , Ubiquitina/metabolismo
7.
Nat Commun ; 11(1): 3243, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32591507

RESUMO

Dysregulation of polyamine metabolism has been linked to the development of colorectal cancer (CRC), but the underlying mechanism is incompletely characterized. Here, we report that spermine synthase (SMS), a polyamine biosynthetic enzyme, is overexpressed in CRC. Targeted disruption of SMS in CRC cells results in spermidine accumulation, which inhibits FOXO3a acetylation and allows subsequent translocation to the nucleus to transcriptionally induce expression of the proapoptotic protein Bim. However, this induction is blunted by MYC-driven expression of miR-19a and miR-19b that repress Bim production. Pharmacological or genetic inhibition of MYC activity in SMS-depleted CRC cells dramatically induces Bim expression and apoptosis and causes tumor regression, but these effects are profoundly attenuated by silencing Bim. These findings uncover a key survival signal in CRC through convergent repression of Bim expression by distinct SMS- and MYC-mediated signaling pathways. Thus, combined inhibition of SMS and MYC signaling may be an effective therapy for CRC.


Assuntos
Proteína 11 Semelhante a Bcl-2/metabolismo , Neoplasias Colorretais/enzimologia , Neoplasias Colorretais/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Espermina Sintase/metabolismo , Acetilação/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Azepinas/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Colorretais/genética , Regulação para Baixo/efeitos dos fármacos , Feminino , Proteína Forkhead Box O3/metabolismo , Deleção de Genes , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Camundongos Nus , MicroRNAs/genética , MicroRNAs/metabolismo , Modelos Biológicos , Poliaminas/metabolismo , Triazóis/farmacologia , Regulação para Cima/efeitos dos fármacos
8.
Nucleic Acids Res ; 48(13): 7439-7453, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32501500

RESUMO

Despite two decades of study, the full scope of RNAi in mammalian cells has remained obscure. Here we combine: (i) Knockout of argonaute (AGO) variants; (ii) RNA sequencing analysis of gene expression changes and (iii) Enhanced Crosslinking Immunoprecipitation Sequencing (eCLIP-seq) using anti-AGO2 antibody to identify potential microRNA (miRNA) binding sites. We find that knocking out AGO1, AGO2 and AGO3 together are necessary to achieve full impact on steady state levels of mRNA. eCLIP-seq located AGO2 protein associations within 3'-untranslated regions. The standard mechanism of miRNA action would suggest that these associations should repress gene expression. Contrary to this expectation, associations between AGO and RNA are poorly correlated with gene repression in wild-type versus knockout cells. Many clusters are associated with increased steady state levels of mRNA in wild-type versus knock out cells, including the strongest cluster within the MYC 3'-UTR. Our results suggest that assumptions about miRNA action should be re-examined.


Assuntos
Regiões 3' não Traduzidas , Proteínas Argonauta/metabolismo , Inativação Gênica , Proteínas Argonauta/química , Proteínas Argonauta/genética , Sítios de Ligação , Células HCT116 , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Ligação Proteica , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo
9.
Proc Natl Acad Sci U S A ; 117(24): 13447-13456, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32482854

RESUMO

Precisely controlling the activation of transcription factors is crucial for physiology. After a transcription factor is activated and carries out its transcriptional activity, it also needs to be properly deactivated. Here, we report a deactivation mechanism of HIF-1 and several other oncogenic transcription factors. HIF-1 promotes the transcription of an ADP ribosyltransferase, TiPARP, which serves to deactivate HIF-1. Mechanistically, TiPARP forms distinct nuclear condensates or nuclear bodies in an ADP ribosylation-dependent manner. The TiPARP nuclear bodies recruit both HIF-1α and an E3 ubiquitin ligase HUWE1, which promotes the ubiquitination and degradation of HIF-1α. Similarly, TiPARP promotes the degradation of c-Myc and estrogen receptor. By suppressing HIF-1α and other oncogenic transcription factors, TiPARP exerts strong antitumor effects both in cell culture and in mouse xenograft models. Our work reveals TiPARP as a negative-feedback regulator for multiple oncogenic transcription factors, provides insights into the functions of protein ADP-ribosylation, and suggests activating TiPARP as an anticancer strategy.


Assuntos
Núcleo Celular/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas Supressoras de Tumor/metabolismo , ADP-Ribosilação , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Receptor alfa de Estrogênio/metabolismo , Retroalimentação Fisiológica , Regulação Neoplásica da Expressão Gênica , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Camundongos , Poli(ADP-Ribose) Polimerases/química , Poli(ADP-Ribose) Polimerases/genética , Domínios e Motivos de Interação entre Proteínas , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
10.
Proc Natl Acad Sci U S A ; 117(24): 13457-13467, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32482868

RESUMO

The protooncogene MYC regulates a variety of cellular processes, including proliferation and metabolism. Maintaining MYC at homeostatic levels is critical to normal cell function; overexpression drives many cancers. MYC stability is regulated through phosphorylation: phosphorylation at Thr58 signals degradation while Ser62 phosphorylation leads to its stabilization and functional activation. The bromodomain protein 4 (BRD4) is a transcriptional and epigenetic regulator with intrinsic kinase and histone acetyltransferase (HAT) activities that activates transcription of key protooncogenes, including MYC We report that BRD4 phosphorylates MYC at Thr58, leading to MYC ubiquitination and degradation, thereby regulating MYC target genes. Importantly, BRD4 degradation, but not inhibition, results in increased levels of MYC protein. Conversely, MYC inhibits BRD4's HAT activity, suggesting that MYC regulates its own transcription by limiting BRD4-mediated chromatin remodeling of its locus. The MYC stabilizing kinase, ERK1, regulates MYC levels directly and indirectly by inhibiting BRD4 kinase activity. These findings demonstrate that BRD4 negatively regulates MYC levels, which is counteracted by ERK1 activation.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Fatores de Transcrição/metabolismo , Acetilação , Núcleo Celular/metabolismo , Cromatina/metabolismo , Dipeptídeos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Células HeLa , Compostos Heterocíclicos com 3 Anéis/farmacologia , Histonas/metabolismo , Humanos , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fosforilação , Ligação Proteica , Estabilidade Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-myc/genética , Ubiquitinação
11.
PLoS One ; 15(6): e0232068, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32559187

RESUMO

Cyclin Dependent Kinase 9 (CDK9) associates with Bromodomain and Extra-Terminal Domain (BET) proteins to promote transcriptional elongation by phosphorylation of serine 2 of RNAP II C-terminal domain. We examined the therapeutic potential of selective CDK9 inhibitors (AZD 4573 and MC180295) against human multiple myeloma cells in vitro. Short-hairpin RNA silencing of CDK9 in Multiple Myeloma (MM) cell lines reduced cell viability compared to control cells showing the dependency of MM cells on CDK9. In order to explore synergy with the CDK9 inhibitor, proteolysis targeting chimeric molecule (PROTAC) ARV 825 was added. This latter drug causes ubiquitination of BET proteins resulting in their rapid and efficient degradation. Combination treatment of MM cells with ARV 825 and AZD 4573 markedly reduced their protein expression of BRD 2, BRD 4, MYC and phosphorylated RNA pol II as compared to each single agent alone. Combination treatment synergistically inhibited multiple myeloma cells both in vitro and in vivo with insignificant weight loss. The combination also resulted in marked increase of apoptotic cells at low dose compared to single agent alone. Taken together, our studies show for the first time that the combination of a BET PROTAC (ARV 825) plus AZD 4573 (CDK9 inhibitor) is effective against MM cells.


Assuntos
Quinase 9 Dependente de Ciclina/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Proteínas/metabolismo , Proteólise/efeitos dos fármacos , Animais , Azepinas/farmacologia , Azepinas/uso terapêutico , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quinase 9 Dependente de Ciclina/genética , Quinase 9 Dependente de Ciclina/metabolismo , Regulação para Baixo/efeitos dos fármacos , Sinergismo Farmacológico , Humanos , Camundongos , Camundongos SCID , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/patologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas/genética , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Interferência de RNA , RNA Polimerase II/metabolismo , RNA Interferente Pequeno/metabolismo , Talidomida/análogos & derivados , Talidomida/farmacologia , Talidomida/uso terapêutico , Transplante Heterólogo
12.
Nat Commun ; 11(1): 2860, 2020 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-32503978

RESUMO

The MYC oncogene drives T- and B- lymphoid malignancies, including Burkitt's lymphoma (BL) and Acute Lymphoblastic Leukemia (ALL). Here, we demonstrate a systemic reduction in natural killer (NK) cell numbers in SRα-tTA/Tet-O-MYCON mice bearing MYC-driven T-lymphomas. Residual mNK cells in spleens of MYCON T-lymphoma-bearing mice exhibit perturbations in the terminal NK effector differentiation pathway. Lymphoma-intrinsic MYC arrests NK maturation by transcriptionally repressing STAT1/2 and secretion of Type I Interferons (IFNs). Treating T-lymphoma-bearing mice with Type I IFN improves survival by rescuing NK cell maturation. Adoptive transfer of mature NK cells is sufficient to delay both T-lymphoma growth and recurrence post MYC inactivation. In MYC-driven BL patients, low expression of both STAT1 and STAT2 correlates significantly with the absence of activated NK cells and predicts unfavorable clinical outcomes. Our studies thus provide a rationale for developing NK cell-based therapies to effectively treat MYC-driven lymphomas in the future.


Assuntos
Linfoma de Burkitt/imunologia , Células Matadoras Naturais/imunologia , Linfoma de Células T/imunologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transferência Adotiva , Animais , Linfoma de Burkitt/mortalidade , Linhagem Celular Tumoral/transplante , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica/imunologia , Humanos , Vigilância Imunológica/genética , Interferon Tipo I/farmacologia , Interferon Tipo I/uso terapêutico , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/transplante , Linfoma de Células T/tratamento farmacológico , Linfoma de Células T/genética , Linfoma de Células T/patologia , Masculino , Camundongos , Cultura Primária de Células , Proteínas Proto-Oncogênicas c-myc/genética , Fator de Transcrição STAT1/metabolismo , Fator de Transcrição STAT2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transdução de Sinais/imunologia
13.
Nucleic Acids Res ; 48(11): 6340-6352, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32383752

RESUMO

API5 (APoptosis Inhibitor 5) and nuclear FGF2 (Fibroblast Growth Factor 2) are upregulated in various human cancers and are correlated with poor prognosis. Although their physical interaction has been identified, the function related to the resulting complex is unknown. Here, we determined the crystal structure of the API5-FGF2 complex and identified critical residues driving the protein interaction. These findings provided a structural basis for the nuclear localization of the FGF2 isoform lacking a canonical nuclear localization signal and identified a cryptic nuclear localization sequence in FGF2. The interaction between API5 and FGF2 was important for mRNA nuclear export through both the TREX and eIF4E/LRPPRC mRNA export complexes, thus regulating the export of bulk mRNA and specific mRNAs containing eIF4E sensitivity elements, such as c-MYC and cyclin D1. These data show the newly identified molecular function of API5 and nuclear FGF2, and provide a clue to understanding the dynamic regulation of mRNA export.


Assuntos
Proteínas Reguladoras de Apoptose/química , Proteínas Reguladoras de Apoptose/metabolismo , Fator 2 de Crescimento de Fibroblastos/química , Fator 2 de Crescimento de Fibroblastos/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Transporte de RNA , RNA Mensageiro/metabolismo , Transporte Ativo do Núcleo Celular , Núcleo Celular/metabolismo , Cristalografia por Raios X , Ciclina D1/metabolismo , RNA Helicases DEAD-box/metabolismo , Fator de Iniciação 4E em Eucariotos/metabolismo , Humanos , Modelos Moleculares , Proteínas de Neoplasias/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo
14.
Cancer Sci ; 111(7): 2336-2348, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32437590

RESUMO

Dietary fat consumption during accelerated stages of mammary gland development, such as peripubertal maturation or pregnancy, is known to increase the risk for breast cancer. However, the underlying molecular mechanisms are not fully understood. Here we examined the gene expression profile of mouse mammary epithelial cells (MMECs) on exposure to a high-fat diet (HFD) or control diet (CD). Trp53-/- female mice were fed with the experimental diets for 5 weeks during the peripubertal period (3-8 weeks of age). The treatment showed no significant difference in body weight between the HFD-fed mice and CD-fed mice. However, gene set enrichment analysis predicted a significant enrichment of c-Myc target genes in animals fed HFD. Furthermore, we detected enhanced activity and stabilization of c-Myc protein in MMECs exposed to a HFD. This was accompanied by augmented c-Myc phosphorylation at S62 with a concomitant increase in ERK phosphorylation. Moreover, MMECs derived from HFD-fed Trp53-/- mouse showed increased colony- and sphere-forming potential that was dependent on c-Myc. Further, oleic acid, a major fatty acid constituent of the HFD, and TAK-875, an agonist to G protein-coupled receptor 40 (a receptor for oleic acid), enhanced c-Myc stabilization and MMEC proliferation. Overall, our data indicate that HFD influences MMECs by stabilizing an oncoprotein, pointing to a novel mechanism underlying dietary fat-mediated mammary carcinogenesis.


Assuntos
Dieta Hiperlipídica , Epitélio/metabolismo , Glândulas Mamárias Animais/metabolismo , Glândulas Mamárias Animais/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Maturidade Sexual , Animais , Linhagem Celular Tumoral , Feminino , Genes p53 , Humanos , Camundongos , Camundongos Knockout , Obesidade/etiologia , Obesidade/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Puberdade , Células Tumorais Cultivadas
15.
Clin Sci (Lond) ; 134(10): 1151-1166, 2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32420596

RESUMO

A percentage of celiac disease (CD) patients develop refractory type-2 disease (RCD2), a condition associated with increased risk of enteropathy-associated T-cell-lymphoma (EATL) and without therapeutic option. Therefore, we profiled the miRNome in series of peripheral T-cell lymphomas (PTCLs), CD, RCD1 or 2 and in the murine interleukin-15 (IL15)-transgenic (TG) model of RCD. The transcriptome was analyzed in 18 intestinal T-cell lymphomas (ITLs). Bioinformatics pipelines provided significant microRNA (miRNA) lists and predicted targets that were confirmed in a second set of patients. Our data show that ITLs have a unique miRNA profile with respect to other PTCLs. The c-MYC regulated miR-17/92 cluster distinguishes monomorphic epitheliotropic ITL (MEITL) from EATL and prognosticates EATL outcome. These miRNAs are decreased in IL15-TG mice upon Janus kinase (JAK) inhibition. The random forest algorithm identified a signature of 38 classifier miRNAs, among which, the miR-200 and miR-192/215 families were progressively lost in RCD2 and ITL-CD, whereas miR-17/92 and C19MC miRNAs were up-regulated. Accordingly, SMAD3, MDM2, c-Myc and activated-STAT3 were increased in RCD2 and EATL tissues while JAK inhibition in IL15-TG mice restored their levels to baseline. Our data suggest that miRNAs circuit supports activation of STAT3 and c-Myc oncogenic signaling in RCD2, thus contributing to lymphomagenesis. This novel understanding might pave the way to personalized medicine approaches for RCD and EATL.


Assuntos
Carcinogênese/genética , Doença Celíaca/genética , Regulação Neoplásica da Expressão Gênica , Linfoma/genética , MicroRNAs/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Algoritmos , Animais , Biomarcadores Tumorais/metabolismo , Feminino , Intestinos/patologia , Linfoma/patologia , Masculino , Camundongos Transgênicos , MicroRNAs/metabolismo , Modelos Biológicos , Prognóstico , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteína Smad3/metabolismo , Regulação para Cima/genética
16.
Life Sci ; 253: 117736, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32360571

RESUMO

AIMS: Recently, studies indicated that inflammation could exacerbate the development of BC. Karyopherin α-2 (KPNA2) is a molecule which modulates nucleocytoplasmic transport and is involved in malignant cellular behavior and carcinogenesis. Our study aims to elucidate the role of KPNA2 in BC pathogenesis and explore the mechanism of KPNA2 in regulating inflammation-induced BC exacerbations. MAIN METHODS: We measured the expression of KPNA2 in BC cells. Through loss-of-function experiments, the functional role of KPNA2 in MCF-7 and MDA-MB-468 cells was evaluated. SK-BR-3 cells were treated with IL-6 as an inflammatory in vitro model of BC. ELISA determination exhibited the contents of cytokines. RANKL and leptomycin B treatments activated NF-κB signaling and inhibited the nuclear translocation of c-Myc, respectively. KEY FINDINGS: The results showed that KPNA2 was significantly up-regulated in BC and silencing KPNA2 inhibited the proliferation, migration and invasion of BC cells, while the cycle arrest was induced, via blocking NF-κB signaling and c-Myc nuclear translocation. IL-6 stimulated the secretions of IL-8 and IL-17 in BC cells, and elevated KPNA2 expression. However, KPNA2 knockdown suppressed the inflammatory responses and malignant progression of BC induced by IL-6. SIGNIFICANCE: In conclusion, our study illustrated that KPNA2 regulated BC development, as well as IL-6-induced inflammation and exacerbation, via NF-κB signaling and c-Myc nuclear translocation. This may provide a novel target for BC therapy.


Assuntos
Neoplasias da Mama/patologia , Inflamação/patologia , Interleucina-6/metabolismo , alfa Carioferinas/genética , Neoplasias da Mama/genética , Linhagem Celular , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Proliferação de Células/genética , Feminino , Técnicas de Silenciamento de Genes , Inativação Gênica , Humanos , Células MCF-7 , NF-kappa B/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transdução de Sinais , Regulação para Cima
17.
Cancer Sci ; 111(7): 2423-2430, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32350965

RESUMO

The transmembrane receptors integrins are the bridges for cell-cell or cell-ECM interaction, which is strictly correlated to cancer development in several tumor types. Here, we revealed that integrin ß8 serves as a driver to mediate sustained growth of bladder cancer and development of drug resistance. The elevated expression of integrin ß8 was observed in highly malignant bladder tumor tissues from patients. The in vitro and in vivo results further indicated that integrin ß8 overexpression in Biu87/T24 bladder cancer could mediate and strengthen cell proliferation and resistance to mitomycin C and hydroxycamptothecin. Mechanistically, integrin ß8 on the cellular surface might recruit phosphorylated Y-box binding protein 1, leading to the activation of c-Myc and nuclear factor-κB signals. Pharmacological targeting of integrin ß8 by Arg-Gly-Asp-Ser efficiently suppressed sustained growth and drug resistance in bladder cancer cells. Our findings identified integrin ß8 as a marker of bladder cancer diagnosis and development, and provides an innovative approach for clinical bladder cancer therapy.


Assuntos
Resistencia a Medicamentos Antineoplásicos , Cadeias beta de Integrinas/metabolismo , Transdução de Sinais , Neoplasias da Bexiga Urinária/metabolismo , Proteína 1 de Ligação a Y-Box/metabolismo , Animais , Linhagem Celular Tumoral , Proliferação de Células , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Cadeias beta de Integrinas/genética , Camundongos , NF-kappa B/metabolismo , Ligação Proteica , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Neoplasias da Bexiga Urinária/tratamento farmacológico , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/patologia , Proteína 1 de Ligação a Y-Box/genética
18.
Mol Cell ; 78(4): 653-669.e8, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32315601

RESUMO

Epstein-Barr virus (EBV) is associated with multiple human malignancies. To evade immune detection, EBV switches between latent and lytic programs. How viral latency is maintained in tumors or in memory B cells, the reservoir for lifelong EBV infection, remains incompletely understood. To gain insights, we performed a human genome-wide CRISPR/Cas9 screen in Burkitt lymphoma B cells. Our analyses identified a network of host factors that repress lytic reactivation, centered on the transcription factor MYC, including cohesins, FACT, STAGA, and Mediator. Depletion of MYC or factors important for MYC expression reactivated the lytic cycle, including in Burkitt xenografts. MYC bound the EBV genome origin of lytic replication and suppressed its looping to the lytic cycle initiator BZLF1 promoter. Notably, MYC abundance decreases with plasma cell differentiation, a key lytic reactivation trigger. Our results suggest that EBV senses MYC abundance as a readout of B cell state and highlights Burkitt latency reversal therapeutic targets.


Assuntos
Linfoma de Burkitt/patologia , Infecções por Vírus Epstein-Barr/virologia , Herpesvirus Humano 4/fisiologia , Interações Hospedeiro-Patógeno , Proteínas Proto-Oncogênicas c-myc/metabolismo , Ativação Viral , Latência Viral , Animais , Linfócitos B/metabolismo , Linfócitos B/patologia , Linfócitos B/virologia , Linfoma de Burkitt/metabolismo , Linfoma de Burkitt/virologia , Proliferação de Células , Infecções por Vírus Epstein-Barr/genética , Infecções por Vírus Epstein-Barr/metabolismo , Feminino , Regulação Viral da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-myc/genética , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Nat Commun ; 11(1): 1833, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32286255

RESUMO

Small molecule inhibitor of the bromodomain and extraterminal domain (BET) family proteins is a promising option for cancer treatment. However, current BET inhibitors are limited by their potency or oral bioavailability. Here we report the discovery and characterization of NHWD-870, a BET inhibitor that is more potent than three major clinical stage BET inhibitors BMS-986158, OTX-015, and GSK-525762. NHWD-870 causes tumor shrinkage or significantly suppresses tumor growth in nine xenograft or syngeneic models. In addition to its ability to downregulate c-MYC and directly inhibit tumor cell proliferation, NHWD-870 blocks the proliferation of tumor associated macrophages (TAMs) through multiple mechanisms, partly by reducing the expression and secretion of macrophage colony-stimulating factor CSF1 by tumor cells. NHWD-870 inhibits CSF1 expression through suppressing BRD4 and its target HIF1α. Taken together, these results reveal a mechanism by which BRD4 inhibition suppresses tumor growth, and support further development of NHWD-870 to treat solid tumors.


Assuntos
Comunicação Celular , Proteínas de Ciclo Celular/antagonistas & inibidores , Macrófagos/patologia , Neoplasias/patologia , Fatores de Transcrição/antagonistas & inibidores , Administração Oral , Animais , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Modelos Animais de Doenças , Regulação para Baixo , Desenho de Fármacos , Feminino , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Fator Estimulador de Colônias de Macrófagos/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Nus , Fosforilação , Proteínas Proto-Oncogênicas c-myc/metabolismo , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Resultado do Tratamento
20.
Nat Commun ; 11(1): 1827, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32286286

RESUMO

It is unclear why some tissues are refractory to the mitogenic effects of the oncogene Myc. Here we show that Myc activation induces rapid transcriptional responses followed by proliferation in some, but not all, organs. Despite such disparities in proliferative response, Myc is bound to DNA at open elements in responsive (liver) and non-responsive (heart) tissues, but fails to induce a robust transcriptional and proliferative response in the heart. Using heart as an exemplar of a non-responsive tissue, we show that Myc-driven transcription is re-engaged in mature cardiomyocytes by elevating levels of the positive transcription elongation factor (P-TEFb), instating a large proliferative response. Hence, P-TEFb activity is a key limiting determinant of whether the heart is permissive for Myc transcriptional activation. These data provide a greater understanding of how Myc transcriptional activity is determined and indicate modification of P-TEFb levels could be utilised to drive regeneration of adult cardiomyocytes for the treatment of heart myopathies.


Assuntos
Miocárdio/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Transcrição Genética , Animais , Proliferação de Células/genética , Cromatina/metabolismo , Ciclina T/metabolismo , Camundongos , Miócitos Cardíacos/metabolismo , Especificidade de Órgãos , Fosforilação , Fator B de Elongação Transcricional Positiva/metabolismo , Ligação Proteica , Proteínas Proto-Oncogênicas c-myc/metabolismo , Ativação Transcricional/genética
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