RESUMO
The N6-methyladenosine (m6A) RNA modification is used widely to alter the fate of mRNAs. Here we demonstrate that the C. elegans writer METT-10 (the ortholog of mouse METTL16) deposits an m6A mark on the 3' splice site (AG) of the S-adenosylmethionine (SAM) synthetase pre-mRNA, which inhibits its proper splicing and protein production. The mechanism is triggered by a rich diet and acts as an m6A-mediated switch to stop SAM production and regulate its homeostasis. Although the mammalian SAM synthetase pre-mRNA is not regulated via this mechanism, we show that splicing inhibition by 3' splice site m6A is conserved in mammals. The modification functions by physically preventing the essential splicing factor U2AF35 from recognizing the 3' splice site. We propose that use of splice-site m6A is an ancient mechanism for splicing regulation.
Assuntos
Adenosina/análogos & derivados , Sítios de Splice de RNA/genética , Splicing de RNA/genética , Fator de Processamento U2AF/metabolismo , Adenosina/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Caenorhabditis elegans/genética , Sequência Conservada/genética , Dieta , Células HeLa , Humanos , Íntrons/genética , Metionina Adenosiltransferase , Metilação , Metiltransferases/química , Camundongos , Mutação/genética , Conformação de Ácido Nucleico , Ligação Proteica , Precursores de RNA/química , Precursores de RNA/genética , Precursores de RNA/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Nuclear Pequeno , S-Adenosilmetionina , Transcriptoma/genéticaRESUMO
The twenty-three Fanconi anemia (FA) proteins cooperate in the FA/BRCA pathway to repair DNA interstrand cross-links (ICLs). The cell division cycle and apoptosis regulator 1 (CCAR1) protein is also a regulator of ICL repair, though its possible function in the FA/BRCA pathway remains unknown. Here, we demonstrate that CCAR1 plays a unique upstream role in the FA/BRCA pathway and is required for FANCA protein expression in human cells. Interestingly, CCAR1 co-immunoprecipitates with FANCA pre-mRNA and is required for FANCA mRNA processing. Loss of CCAR1 results in retention of a poison exon in the FANCA transcript, thereby leading to reduced FANCA protein expression. A unique domain of CCAR1, the EF hand domain, is required for interaction with the U2AF heterodimer of the spliceosome and for excision of the poison exon. Taken together, CCAR1 is a splicing modulator required for normal splicing of the FANCA mRNA and other mRNAs involved in various cellular pathways.
Assuntos
Proteínas Reguladoras de Apoptose , Proteínas de Ciclo Celular , Proteína do Grupo de Complementação A da Anemia de Fanconi , Anemia de Fanconi , Splicing de RNA , Fator de Processamento U2AF , Humanos , Proteína BRCA1/metabolismo , Proteína BRCA1/genética , Proteína BRCA2/metabolismo , Proteína BRCA2/genética , Reparo do DNA , Endodesoxirribonucleases , Éxons , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteína do Grupo de Complementação A da Anemia de Fanconi/genética , Proteína do Grupo de Complementação A da Anemia de Fanconi/metabolismo , Células HEK293 , Células HeLa , Ligação Proteica , Precursores de RNA/metabolismo , Precursores de RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais , Spliceossomos/metabolismo , Spliceossomos/genética , Fator de Processamento U2AF/metabolismo , Fator de Processamento U2AF/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismoRESUMO
Somatic mutations in genes encoding components of the RNA splicing machinery occur frequently in multiple forms of cancer. The most frequently mutated RNA splicing factors in cancer impact intronic branch site and 3' splice site recognition. These include mutations in the core RNA splicing factor SF3B1 as well as mutations in the U2AF1/2 heterodimeric complex, which recruits the SF3b complex to the 3' splice site. Additionally, mutations in splicing regulatory proteins SRSF2 and RBM10 are frequent in cancer, and there has been a recent suggestion that variant forms of small nuclear RNAs (snRNAs) may contribute to splicing dysregulation in cancer. Here, we describe molecular mechanisms by which mutations in these factors alter splice site recognition and how studies of this process have yielded new insights into cancer pathogenesis and the molecular regulation of splicing. We also discuss data linking mutant RNA splicing factors to RNA metabolism beyond splicing.
RESUMO
Transcription and splicing of pre-messenger RNA are closely coordinated, but how this functional coupling is disrupted in human diseases remains unexplored. Using isogenic cell lines, patient samples, and a mutant mouse model, we investigated how cancer-associated mutations in SF3B1 alter transcription. We found that these mutations reduce the elongation rate of RNA polymerase II (RNAPII) along gene bodies and its density at promoters. The elongation defect results from disrupted pre-spliceosome assembly due to impaired protein-protein interactions of mutant SF3B1. The decreased promoter-proximal RNAPII density reduces both chromatin accessibility and H3K4me3 marks at promoters. Through an unbiased screen, we identified epigenetic factors in the Sin3/HDAC/H3K4me pathway, which, when modulated, reverse both transcription and chromatin changes. Our findings reveal how splicing factor mutant states behave functionally as epigenetic disorders through impaired transcription-related changes to the chromatin landscape. We also present a rationale for targeting the Sin3/HDAC complex as a therapeutic strategy.
Assuntos
Cromatina , Neoplasias , Animais , Humanos , Camundongos , Cromatina/genética , Mutação , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , Splicing de RNA/genética , Fatores de Processamento de RNA/genética , Fatores de Processamento de RNA/metabolismoRESUMO
Specialized enzymes add methyl groups to the nitrogens of the amino acid histidine, altering the chemical properties of its imidazole ring and, in turn, the function of the modified (poly)peptide. In this issue of Genes & Development, Shimazu and colleagues (pp. 724-742) make the remarkable discovery that CARNMT1 acts as a dual-specificity histidine methyltransferase, modifying both the small-molecule dipeptide carnosine and a set of proteins, predominantly within RNA-binding C3H zinc finger (C3H ZF) motifs. As a result, CARNMT1 modulates the activity of its protein targets to affect RNA processing and metabolism, ultimately contributing an essential function during mammalian development.
Assuntos
Aminoácidos , Histidina , Animais , Metilação , Metiltransferases , Organogênese , MamíferosRESUMO
Histidine (His) residues are methylated in various proteins, but their roles and regulation mechanisms remain unknown. Here, we show that carnosine N-methyltransferase 1 (CARNMT1), a known His methyltransferase of dipeptide carnosine (ßAla-His), is a major His N1-position-specific methyltransferase. We found that 52 His sites in 20 proteins underwent CARNMT1-mediated methylation. The consensus methylation site for CARNMT1 was identified as Cx(F/Y)xH, a C3H zinc finger (C3H ZF) motif. CARNMT1-deficient and catalytically inactive mutant mice showed embryonic lethality. Among the CARNMT1 target C3H ZF proteins, RNA degradation mediated by Roquin and tristetraprolin (TTP) was affected by CARNMT1 and its enzymatic activity. Furthermore, the recognition of the 3' splice site of the CARNMT1 target C3H ZF protein U2AF1 was perturbed, and pre-mRNA alternative splicing (AS) was affected by CARNMT1 deficiency. These findings indicate that CARNMT1-mediated protein His methylation, which is essential for embryogenesis, plays roles in diverse aspects of RNA metabolism by targeting C3H ZF-type RNA-binding proteins and modulating their functions, including pre-mRNA AS and mRNA degradation regulation.
Assuntos
Carnosina , Animais , Camundongos , Camundongos Endogâmicos C3H , Histidina/genética , Precursores de RNA , Metiltransferases/genética , Sítios de Splice de RNA , Dedos de ZincoRESUMO
Splicing factor mutations are common among cancers, recently emerging as drivers of myeloid malignancies. U2AF1 carries hotspot mutations in its RNA-binding motifs; however, how they affect splicing and promote cancer remain unclear. The U2AF1/U2AF2 heterodimer is critical for 3' splice site (3'SS) definition. To specifically unmask changes in U2AF1 function in vivo, we developed a crosslinking and immunoprecipitation procedure that detects contacts between U2AF1 and the 3'SS AG at single-nucleotide resolution. Our data reveal that the U2AF1 S34F and Q157R mutants establish new 3'SS contacts at -3 and +1 nucleotides, respectively. These effects compromise U2AF2-RNA interactions, resulting predominantly in intron retention and exon exclusion. Integrating RNA binding, splicing, and turnover data, we predicted that U2AF1 mutations directly affect stress granule components, which was corroborated by single-cell RNA-seq. Remarkably, U2AF1-mutant cell lines and patient-derived MDS/AML blasts displayed a heightened stress granule response, pointing to a novel role for biomolecular condensates in adaptive oncogenic strategies.
Assuntos
Leucemia Mieloide Aguda , Síndromes Mielodisplásicas , Fator de Processamento U2AF , Grânulos de Estresse , Humanos , Leucemia Mieloide Aguda/genética , Mutação , Síndromes Mielodisplásicas/genética , Sítios de Splice de RNA , Splicing de RNA/genética , Proteínas de Ligação a RNA/genética , Fator de Processamento U2AF/genética , Fator de Processamento U2AF/metabolismo , Grânulos de Estresse/metabolismoRESUMO
Long introns with short exons in vertebrate genes are thought to require spliceosome assembly across exons (exon definition), rather than introns, thereby requiring transcription of an exon to splice an upstream intron. Here, we developed CoLa-seq (co-transcriptional lariat sequencing) to investigate the timing and determinants of co-transcriptional splicing genome wide. Unexpectedly, 90% of all introns, including long introns, can splice before transcription of a downstream exon, indicating that exon definition is not obligatory for most human introns. Still, splicing timing varies dramatically across introns, and various genetic elements determine this variation. Strong U2AF2 binding to the polypyrimidine tract predicts early splicing, explaining exon definition-independent splicing. Together, our findings question the essentiality of exon definition and reveal features beyond intron and exon length that are determinative for splicing timing.
Assuntos
Processamento Alternativo , Splicing de RNA , Humanos , Sequência de Bases , Íntrons/genética , Éxons/genéticaRESUMO
The differentiation of embryonic stem cells (ESCs) into a lineage-committed state is a dynamic process involving changes in cellular metabolism, epigenetic modifications, post-translational modifications, gene expression, and RNA processing. Here we integrated data from metabolomic, proteomic, and transcriptomic assays to characterize how alterations in NAD+ metabolism during the differentiation of mouse ESCs lead to alteration of the PARP1-mediated ADP-ribosylated (ADPRylated) proteome and mRNA isoform specialization. Our metabolomic analyses indicate that mESCs use distinct NAD+ biosynthetic pathways in different cell states: the de novo pathway in the pluripotent state, and the salvage and Preiss-Handler pathways as differentiation progresses. We observed a dramatic induction of PARP1 catalytic activity driven by enhanced nuclear NAD+ biosynthesis during the early stages of mESC differentiation (e.g., within 12 h of LIF removal). PARP1-modified proteins in mESCs are enriched for biological processes related to stem cell maintenance, transcriptional regulation, and RNA processing. The PARP1 substrates include core spliceosome components, such as U2AF35 and U2AF65, whose splicing functions are modulated by PARP1-mediated site-specific ADP-ribosylation. Finally, we observed that splicing is dysregulated genome-wide in Parp1 knockout mESCs. Together, these results demonstrate a role for the NAD+-PARP1 axis in the maintenance of mESC state, specifically in the splicing program during differentiation.
Assuntos
NAD , Poli(ADP-Ribose) Polimerases , ADP-Ribosilação , Animais , Células-Tronco Embrionárias/metabolismo , Camundongos , NAD/metabolismo , Poli(ADP-Ribose) Polimerase-1/genética , Poli(ADP-Ribose) Polimerase-1/metabolismo , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , ProteômicaRESUMO
SF3B1, which encodes an essential spliceosomal protein, is frequently mutated in myelodysplastic syndromes (MDS) and many cancers. However, the defect of mutant SF3B1 is unknown. Here, we analyzed RNA sequencing data from MDS patients and confirmed that SF3B1 mutants use aberrant 3' splice sites. To elucidate the underlying mechanism, we purified complexes containing either wild-type or the hotspot K700E mutant SF3B1 and found that levels of a poorly studied spliceosomal protein, SUGP1, were reduced in mutant spliceosomes. Strikingly, SUGP1 knockdown completely recapitulated the splicing errors, whereas SUGP1 overexpression drove the protein, which our data suggest plays an important role in branchsite recognition, into the mutant spliceosome and partially rescued splicing. Other hotspot SF3B1 mutants showed similar altered splicing and diminished interaction with SUGP1. Our study demonstrates that SUGP1 loss is a common defect of spliceosomes with disease-causing SF3B1 mutations and, because this defect can be rescued, suggests possibilities for therapeutic intervention.
Assuntos
Leucemia Eritroblástica Aguda/metabolismo , Mutação , Síndromes Mielodisplásicas/metabolismo , Fosfoproteínas/metabolismo , Fatores de Processamento de RNA/metabolismo , Splicing de RNA , Spliceossomos/metabolismo , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença , Células HEK293 , Humanos , Células K562 , Leucemia Eritroblástica Aguda/genética , Leucemia Eritroblástica Aguda/patologia , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/patologia , Fenótipo , Fosfoproteínas/genética , Ligação Proteica , Fatores de Processamento de RNA/genética , Spliceossomos/genética , Spliceossomos/patologiaRESUMO
The molecular mechanisms leading to the establishment of immunological memory are inadequately understood, limiting the development of effective vaccines and durable antitumor immune therapies. Here, we show that ectopic OCA-B expression is sufficient to improve antiviral memory recall responses, while having minimal effects on primary effector responses. At peak viral response, short-lived effector T cell populations are expanded but show increased Gadd45b and Socs2 expression, while memory precursor effector cells show increased expression of Bcl2, Il7r, and Tcf7 on a per-cell basis. Using an OCA-B mCherry reporter mouse line, we observe high OCA-B expression in CD4+ central memory T cells. We show that early in viral infection, endogenously elevated OCA-B expression prospectively identifies memory precursor cells with increased survival capability and memory recall potential. Cumulatively, the results demonstrate that OCA-B is both necessary and sufficient to promote CD4 T cell memory in vivo and can be used to prospectively identify memory precursor cells.
Assuntos
Linfócitos T CD4-Positivos , Células T de Memória , Animais , Camundongos , Memória Imunológica , Memória , Receptores de Interleucina-7 , Transativadores , Proteínas GADD45 , Antígenos de DiferenciaçãoRESUMO
Somatic mutations in the genes encoding components of the spliceosome occur frequently in human neoplasms, including myeloid dysplasias and leukemias, and less often in solid tumors. One of the affected factors, U2AF1, is involved in splice site selection, and the most common change, S34F, alters a conserved nucleic acid-binding domain, recognition of the 3' splice site, and alternative splicing of many mRNAs. However, the role that this mutation plays in oncogenesis is still unknown. Here, we uncovered a noncanonical function of U2AF1, showing that it directly binds mature mRNA in the cytoplasm and negatively regulates mRNA translation. This splicing-independent role of U2AF1 is altered by the S34F mutation, and polysome profiling indicates that the mutation affects translation of hundreds of mRNA. One functional consequence is increased synthesis of the secreted chemokine interleukin 8, which contributes to metastasis, inflammation, and cancer progression in mice and humans.
Assuntos
Regulação Neoplásica da Expressão Gênica/genética , Neoplasias/fisiopatologia , Fator de Processamento U2AF/metabolismo , Linhagem Celular Tumoral , Citoplasma/patologia , Progressão da Doença , Células HEK293 , Humanos , Interleucina-8/genética , Interleucina-8/metabolismo , Células MCF-7 , Mutação/genética , Neoplasias/genética , Ligação Proteica , RNA Mensageiro/metabolismo , Fator de Processamento U2AF/genéticaRESUMO
The mixed-lineage leukemia (MLL)-AF10 fusion oncoprotein recruits DOT1L to the homeobox A (HOXA) gene cluster through its octapeptide motif leucine zipper (OM-LZ), thereby inducing and maintaining the MLL-AF10-associated leukemogenesis. However, the recognition mechanism between DOT1L and MLL-AF10 is unclear. Here, we present the crystal structures of both apo AF10OM-LZ and its complex with the coiled-coil domain of DOT1L. Disruption of the DOT1L-AF10 interface abrogates MLL-AF10-associated leukemic transformation. We further show that zinc stabilizes the DOT1L-AF10 complex and may be involved in the regulation of the HOXA gene expression. Our studies may also pave the way for the rational design of therapeutic drugs against MLL-rearranged leukemia.
Assuntos
Transformação Celular Neoplásica/patologia , Metiltransferases , Modelos Moleculares , Proteína de Leucina Linfoide-Mieloide , Fatores de Transcrição , Cristalização , Regulação Neoplásica da Expressão Gênica , Histona-Lisina N-Metiltransferase , Proteínas de Homeodomínio/genética , Humanos , Metiltransferases/química , Metiltransferases/metabolismo , Proteína de Leucina Linfoide-Mieloide/química , Proteína de Leucina Linfoide-Mieloide/metabolismo , Ligação Proteica , Domínios Proteicos , Estrutura Quaternária de Proteína , Relação Estrutura-Atividade , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Zinco/químicaRESUMO
Mixed lineage leukemia-fusion proteins (MLL-FPs) are believed to maintain gene activation and induce MLL through aberrantly stimulating transcriptional elongation, but the underlying mechanisms are incompletely understood. Here, we show that both MLL1 and AF9, one of the major fusion partners of MLL1, mainly occupy promoters and distal intergenic regions, exhibiting chromatin occupancy patterns resembling that of RNA polymerase II in HEL, a human erythroleukemia cell line without MLL1 rearrangement. MLL1 and AF9 only coregulate over a dozen genes despite of their co-occupancy on thousands of genes. They do not interact with each other, and their chromatin occupancy is also independent of each other. Moreover, AF9 deficiency in HEL cells decreases global TBP occupancy while decreases CDK9 occupancy on a small number of genes, suggesting an accessory role of AF9 in CDK9 recruitment and a possible major role in transcriptional initiation via initiation factor recruitment. Importantly, MLL1 and MLL-AF9 occupy promoters and distal intergenic regions, exhibiting identical chromatin occupancy patterns in MLL cells, and MLL-AF9 deficiency decreased occupancy of TBP and TFIIE on major target genes of MLL-AF9 in iMA9, a murine acute myeloid leukemia cell line inducibly expressing MLL-AF9, suggesting that it can also regulate initiation. These results suggest that there is no difference between MLL1 and MLL-AF9 with respect to location and size of occupancy sites, contrary to what people have believed, and that MLL-AF9 may also regulate transcriptional initiation in addition to widely believed elongation.
RESUMO
The core body temperature of all mammals oscillates with the time of the day. However, direct molecular consequences of small, physiological changes in body temperature remain largely elusive. Here we show that body temperature cycles drive rhythmic SR protein phosphorylation to control an alternative splicing (AS) program. A temperature change of 1°C is sufficient to induce a concerted splicing switch in a large group of functionally related genes, rendering this splicing-based thermometer much more sensitive than previously described temperature-sensing mechanisms. AS of two exons in the 5' UTR of the TATA-box binding protein (Tbp) highlights the general impact of this mechanism, as it results in rhythmic TBP protein levels with implications for global gene expression in vivo. Together our data establish body temperature-driven AS as a core clock-independent oscillator in mammalian peripheral clocks.
Assuntos
Processamento Alternativo , Regulação da Temperatura Corporal , Relógios Circadianos , Ritmo Circadiano , Proteína de Ligação a TATA-Box/metabolismo , Regiões 5' não Traduzidas , Animais , Linhagem Celular Tumoral , Éxons , Feminino , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Células NIH 3T3 , Fosforilação , Interferência de RNA , Fatores de Processamento de Serina-Arginina/genética , Fatores de Processamento de Serina-Arginina/metabolismo , Fator de Processamento U2AF/genética , Fator de Processamento U2AF/metabolismo , Proteína de Ligação a TATA-Box/genética , Fatores de Tempo , TransfecçãoRESUMO
Atrial fibrillation (AF), with its significant associated morbidity and mortality contributes to significant healthcare utilisation and expenditure. Given its progressively rising incidence, strategies to limit AF development and progression are urgently needed. Lifestyle modification is a potentially potent but underutilised weapon against the AF epidemic. The purpose of this article is to review the role of lifestyle factors as risk factors for AF, outline potential mechanisms of pathogenesis and examine the available evidence for lifestyle intervention in primary and secondary AF prevention. It will also highlight the need for investment by physicians, researchers, health services and governments in order to facilitate delivery of the comprehensive, multidisciplinary AF care that is required to manage this complex and multifactorial disease.
Assuntos
Fibrilação Atrial , Estilo de Vida , Fibrilação Atrial/epidemiologia , Fibrilação Atrial/etiologia , Fibrilação Atrial/terapia , Humanos , Fatores de RiscoRESUMO
BACKGROUND: Small nucleolar RNAs (snoRNAs) play key roles in ribosome biosynthesis. However, the mechanism by which snoRNAs regulate cancer stemness remains to be fully elucidated. METHODS: SNORA68 expression was evaluated in breast cancer tissues by in situ hybridization and qRTâPCR. Proliferation, migration, apoptosis and stemness analyses were used to determine the role of SNORA68 in carcinogenesis and stemness maintenance. Mechanistically, RNA pull-down, RNA immunoprecipitation (RIP), cell fractionation and coimmunoprecipitation assays were conducted. RESULTS: SNORA68 exhibited high expression in triple-negative breast cancer (TNBC) and was significantly correlated with tumor size (P = 0.048), ki-67 level (P = 0.037), and TNM stage (P = 0.015). The plasma SNORA68 concentration was significantly lower in patients who achieved clinical benefit. The SNORA68-high patients had significantly shorter disease-free survival (DFS) (P = 0.036). Functionally, SNORA68 was found to promote the cell stemness and carcinogenesis of TNBC in vitro and in vivo. Furthermore, elevated SNORA68 expression led to increased nucleolar RPL23 expression and retained RPL23 in the nucleolus by binding U2AF2. RPL23 in the nucleolus subsequently upregulated c-Myc expression. This pathway was validated using a xenograft model. CONCLUSION: U2AF2-SNORA68 promotes TNBC stemness by retaining RPL23 in the nucleolus and increasing c-Myc expression, which provides new insight into the regulatory mechanism of stemness.
Assuntos
Neoplasias de Mama Triplo Negativas , Humanos , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/patologia , Linhagem Celular Tumoral , RNA , Núcleo Celular , Regulação Neoplásica da Expressão Gênica , Carcinogênese/genética , Proliferação de Células/genética , Fator de Processamento U2AF/genéticaRESUMO
We intended to update human papillomavirus (HPV) prevalence and p16INK4a positivity in oropharyngeal squamous cell carcinomars (SCC), and calculate HPV attributable fraction (AF) for oropharyngeal SCC by geographic region. We searched Medline, Embase, and the Cochrane Library to identify published studies of HPV prevalence and p16INK4a positivity alone or together in oropharyngeal SCC before December 28, 2021. Studies that reported type-specific HPV DNA prevalence using broad-spectrum PCR-based testing methods were included. We estimated pooled HPV prevalence, type-specific HPV prevalence, and p16INK4a positivity. AF of HPV was calculated by geographic region. One hundred and thirty-four studies including 12 139 cases were included in our analysis. The pooled HPV prevalence estimate for oropharyngeal SCC was 48.1% (95% confidence interval [CI] 43.2-53.0). HPV prevalence varied significantly by geographic region, and the highest HPV prevalence in oropharyngeal SCC was noted in North America (72.6%, 95% CI 63.8-80.6). Among HPV positive cases, HPV 16 was the most common type with a prevalence of 40.2% (95% CI 35.7-44.7). The pooled p16INK4a positivity in HPV positive and HPV16 positive oropharyngeal SCC cases was 87.2% (95% CI 81.6-91.2) and 91.7% (84.3-97.2). The highest AFs of HPV and HPV16 were noted in North America at 69.6% (95% CI 53.0-91.5) and 63.0% (48.0-82.7). [Correction added on 31 October 2023, after first online publication: the percentage symbol (%) was missing and has been added to 63.0% (48.0-82.7) in the Abstract and Conclusion.] A significant proportion of oropharyngeal SCC was attributable to HPV. HPV16 accounts for the majority of HPV positive oropharyngeal SCC cases. These findings highlight the importance of HPV vaccination in the prevention of a substantial proportion of oropharyngeal SCC cases.
Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Orofaríngeas , Infecções por Papillomavirus , Humanos , Carcinoma de Células Escamosas/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/genética , DNA Viral/genética , DNA Viral/análise , Papillomavirus Humano 16/genética , Papillomavirus Humano 16/metabolismo , Papillomavirus Humano , Papillomaviridae/genética , Papillomaviridae/metabolismo , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/metabolismo , Carcinoma de Células Escamosas de Cabeça e PescoçoRESUMO
MLL-rearranged (MLL-r) leukaemia is observed in approximately 10% of acute myeloid leukaemia (AML) and is associated with a relatively poor prognosis, highlighting the need for new treatment regimens. MLL fusion proteins produced by MLL rearrangements recruit KDM4C to mediate epigenetic reprogramming, which is required for the maintenance of MLL-r leukaemia. In this study, we used a combinatorial drug screen to selectively identify synergistic treatment partners for the KDM4C inhibitor SD70. The results showed that the drug combination of SD70 and MI-503, a potent menin-MLL inhibitor, induced synergistically enhanced apoptosis in MLL::AF9 leukaemia cells without affecting normal CD34+ cells. In vivo treatment with SD70 and MI-503 significantly prolonged survival in AML xenograft models. Differential gene expression analysis by RNA-seq following combined pharmacological inhibition of SD70 and MI-503 revealed changes in numerous genes, with MYC target genes being the most significantly downregulated. Taken together, these data provide preclinical evidence that the combination of SD70 and MI-503 is a potential dual-targeted therapy for MLL::AF9 AML.
Assuntos
Sinergismo Farmacológico , Leucemia Mieloide Aguda , Proteína de Leucina Linfoide-Mieloide , Proteínas Proto-Oncogênicas , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Animais , Camundongos , Proteína de Leucina Linfoide-Mieloide/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Apoptose/efeitos dos fármacos , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/antagonistas & inibidores , Ensaios Antitumorais Modelo de Xenoenxerto , Linhagem Celular TumoralRESUMO
The afila (af) mutation causes the replacement of leaflets by a branched mass of tendrils in the compound leaves of pea - Pisum sativum L. This mutation was first described in 1953, and several reports of spontaneous af mutations and induced mutants with a similar phenotype exist. Despite widespread introgression into breeding material, the nature of af and the origin of the alleles used remain unknown. Here, we combine comparative genomics with reverse genetic approaches to elucidate the genetic determinants of af. We also investigate haplotype diversity using a set of AfAf and afaf cultivars and breeding lines and molecular markers linked to seven consecutive genes. Our results show that deletion of two tandemly arranged genes encoding Q-type Cys(2)His(2) zinc finger transcription factors, PsPALM1a and PsPALM1b, is responsible for the af phenotype in pea. Eight haplotypes were identified in the af-harbouring genomic region on chromosome 2. These haplotypes differ in the size of the deletion, covering more or less genes. Diversity at the af locus is valuable for crop improvement and sheds light on the history of pea breeding for improved standing ability. The results will be used to understand the function of PsPALM1a/b and to transfer the knowledge for innovation in related crops.