RESUMO
This study investigates the potential utility of IKZF1 deletion as an additional high-risk marker for paediatric acute lymphoblastic leukaemia (ALL). The prognostic impact of IKZF1 status, in conjunction with minimal/measurable residual disease (MRD), was evaluated within the MRD-guided TPOG-ALL-2013 protocol using 412 newly diagnosed B-ALL patients aged 1-18. IKZF1 status was determined using multiplex ligation-dependent probe amplification. IKZF1 deletions, when co-occurring with CDKN2A, CDKN2B, PAX5 or PAR1 region deletions in the absence of ERG deletions, were termed IKZF1plus. Both IKZF1 deletion (14.6%) and IKZF1plus (7.8%) independently predicted poorer outcomes in B-ALL. IKZF1plus was observed in 4.1% of Philadelphia-negative ALL, with a significantly lower 5-year event-free survival (53.9%) compared to IKZF1 deletion alone (83.8%) and wild-type IKZF1 (91.3%) (p < 0.0001). Among patients with Day 15 MRD ≥0.01%, provisional high-risk patients with IKZF1plus exhibited the worst outcomes in event-free survival (42.0%), relapse-free survival (48.0%) and overall survival (72.7%) compared to other groups (p < 0.0001). Integration of IKZF1plus and positive Day 15 MRD identified a subgroup of Philadelphia-negative B-ALL with a 50% risk of relapse. This study highlights the importance of assessing IKZF1plus alongside Day 15 MRD positivity to identify patients at increased risk of adverse outcomes, potentially minimizing overtreatment.
Assuntos
Leucemia-Linfoma Linfoblástico de Células Precursoras B , Leucemia-Linfoma Linfoblástico de Células Precursoras , Criança , Humanos , Deleção de Genes , Fator de Transcrição Ikaros/genética , Recidiva Local de Neoplasia , Neoplasia Residual/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Prognóstico , Medição de Risco , Fatores de Transcrição , Lactente , Pré-Escolar , AdolescenteRESUMO
INTRODUCTION: Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in the western countries and is very rare in Asia. METHODS: Peripheral blood or bone marrow mononuclear cells obtained at initial diagnosis from 215 patients with CLL were analyzed by using next-generation sequencing to investigate the ethnic differences in genetic abnormalities. RESULTS: Whole-genome sequencing and whole-exome sequencing analyses on 30 cases showed that 9 genes, including IGLL5, MYD88, TCHH, DSCAM, AXDND1, BICRA, KMT2D, MYT1L, RBM43 were more frequently mutated in our Taiwanese cohort compared with those of the western cohorts. IGLL5, MYD88, and KMT2D genes were further analyzed by targeted sequencing in another 185 CLL patients, unravelling frequencies of 29.3%, 20.9%, and 15.0%, respectively. The most frequent positional mutation of MYD88 was V217F (26/45, 57.8%), followed by L265P (9/45, 20.0%). MYD88 mutations were significantly associated with IGLL5 mutations (P = 0.0004), mutated IGHV (P < 0.0001) and 13q deletion (P = 0.0164). CLL patients with co-occurrence of MYD88 mutations with KMT2D or/and IGLL5 mutations were associated with a significantly inferior survival compared to those with MYD88 mutation alone (not reached vs. 131.8 months, P = 0.007). In multivariate analysis, MYD88 mutation without KMT2D or IGLL5 mutations was an independently favorable predictor. CONCLUSIONS: IGLL5, MYD88, and KMT2D mutations were enriched in Taiwanese CLL, and co-occurrence of MYD88 mutations with KMT2D or/and IGLL5 mutations was associated with a poorer prognosis.
RESUMO
BACKGROUND: IKZF1deletion is an unfavorable factor in Philadelphia negative (Ph -) B-cell acute lymphoblastic leukemia. However, the effects of IKZF1 deletions co-existing genetic alterations in Ph (-) ALL have not been extensively studied. METHODS: Bone marrow samples from 368 children with Ph (-) ALL were analyzed by using multiplex ligation-dependent probe amplification kit for detection of gene deletions and Sanger sequencing for mutational analysis of RAS pathway genes. The outcome was analyzed on 215 patients treated with Taiwan Pediatric Oncology Group-ALL-2002 protocol. RESULTS: IKZF1 deletions were present in 12.8% and IKZF1plus in 6.3% of patients. Mutations of RAS pathway genes were detected in 25.0% of IKZF1-deleted patients. The 10-year event-free survival (EFS) of IKZF1-undeleted patients was significantly better compared with IKZF1-deleted patients (80.0% vs. 47.8%, p = 0.001). Compared with outcome of patients harboring IKZF1 deletion alone, no difference in EFS was observed in patients with IKZF1plus , whereas three patients carried both IKZF1 and ERG deletions had a superior 10-year EFS (100%). The 10-year EFS of patients with any gene mutation of RAS pathway was worse than that of patients with wild-type genes (79.1% vs. 61.6%, p = 0.033). In multivariate analysis, RAS pathway mutations and IKZF1 deletion were independent predictors of inferior EFS. Co-existence of IKZF1 deletion with RAS pathway mutations had a worst 10-year EFS (11.1 ± 10.5%) and 10-year OS (53.3 ± 17.6%). CONCLUSIONS: Our results showed that RAS pathway mutation is an added-value biomarker in pediatric IKZF1-deleted Ph (-) ALL patients.
Assuntos
Fator de Transcrição Ikaros/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Proteínas ras/genética , Criança , Pré-Escolar , Feminino , Deleção de Genes , Humanos , Lactente , Masculino , Mutação , Cromossomo Filadélfia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Transdução de Sinais , Proteínas ras/metabolismoRESUMO
Chronic lymphocytic leukaemia (CLL) is the most common leukaemia in Western countries but very rare in Asia. Peripheral blood or bone marrow mononuclear cells obtained at initial diagnosis from 194 patients with CLL were analysed to determine the ethnic difference in genetic abnormalities. Mutated IGHV was detected in 71·2% of Taiwanese CLL and IGHV3-23 was the most frequently used gene. Stereotyped BCR was present in 18·3% with subset 8 being the most frequent. All cases with subset 8 belonged to IGHV 4-39 and were exclusively associated with un-mutated IGHV and poor outcome. Mutation frequencies of SF3B1 (9·7%), NOTCH1 (8·6%), BIRC3 (1·1%), ATM (16·9%) or TP53 (8·1%), and frequencies of cytogenetic abnormalities including trisomy 12 (18·6%), del(17p) (10·4%), del(13q) (43·7%) and IGH translocation (10·1%) were comparable to those reported from Western countries, except del(11q) (6·9%) which was lower in our patients. Patients with un-mutated IGHV, subset 8, disrupted TP53, trisomy 12, and SF3B1 mutations had a worse outcome compared to patients without these mutations. In conclusion, IGHV3-23 usage, stereotyped subset 8 and lower frequency of del(11q) show an ethnicity-dependent association in Taiwanese CLL patients.
Assuntos
Genes de Cadeia Pesada de Imunoglobulina/genética , Região Variável de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/genética , Mutação , Povo Asiático/genética , Aberrações Cromossômicas , Análise Mutacional de DNA/métodos , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Estimativa de Kaplan-Meier , Prognóstico , Proteínas Proto-Oncogênicas c-bcr/genética , Fatores de Risco , TaiwanRESUMO
BACKGROUND: The leukemogenesis of T-cell acute lymphoblastic leukemia (T-ALL) involves multistep processes of genetic alterations. We aimed to determine the genetic alterations including common fusion transcripts, overexpression of T-cell transcription factor oncogenes, and deletion or mutation of targeted genes in pediatric T-ALL in Taiwan as well as their impact on outcomes in those treated with the Taiwan Pediatric Oncology Group-ALL-2002 protocol. PROCEDURE: Between 1995 and 2015, bone marrow samples obtained from 102 children aged <18 years consecutively diagnosed with T-ALL were examined. Thirty-two genetic alterations were examined by reverse transcription polymerase chain reaction (PCR) assays-PCR-based assays-followed by direct sequencing, real time quantitative PCR with TaqMan assays, or multiplex ligase probe amplification. RESULTS: TAL1 overexpression, CDKN2A/2B deletions, and NOTCH1 mutation were the most frequent aberrations while none had NF1, SUZ12 deletion, JAK1 or JAK2 mutations, or NUP214-ABL1 fusion in our cohort. The most frequent cooperating occurrence of genetic alterations included CDKN2A/2B and MTAP, MTAP and CDKN2B, LEF1 and PTPN2, and HOX11L2 and PHF6 mutation/deletion. NOTCH1 mutations conferred a favorable overall survival, whereas SIL-TAL1 fusion, TAL overexpression, LEF1 deletion, and PHF6 deletion/mutation were associated with an inferior outcome. By multivariate analysis, PHF6 mutation/deletion was the only independent predictor for inferior overall survival. CONCLUSIONS: The present study showed that the frequencies of genetic alterations in Taiwanese children with T-ALL differed considerably from those reported in Western countries. PHF6 mutation/deletion was an independently adverse predictor.
Assuntos
Biomarcadores Tumorais/genética , Mutação , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/epidemiologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Adolescente , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Lactente , Masculino , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Prognóstico , Taxa de Sobrevida , Taiwan/epidemiologiaRESUMO
PTPN11 mutation, a RAS signaling pathway mutation, is associated with MLL translocations in acute leukemia. A girl with MLL/AF10 AML was found to carry PTPN11G503A . To study the impact of PTPN11G503A cooperating with MLL/AF10 on leukemogenesis, we established a retroviral transduction/transplantation mouse model. Compared to the MLL/AF10(OM-LZ) leukemia cells harboring PTPN11wt , the cells harboring PTPN11G503A were hypersensitive to GM-CSF and IL3, and more resistant to death upon treatment with daunorubicin but sensitive to cytarabine. The cells harboring PTPN11G503A autonomously differentiated into macrophages (1.8%) in the medium containing IL3. Further studies showed that the cells had an elevated (â¼2.9-fold) Csf1 transcription level and secreted more (â¼4.5-fold) M-CSF to the medium which can stimulate monocyte/macrophage differentiation of BM cells. Mice transplanted with the cells harboring PTPN11G503A had a higher concentration of M-CSF in plasma. When mixed with the MLL/AF10(OM-LZ) leukemia cells harboring PTPN11wt , the cells harboring PTPN11G503A had an increased competitive engraftment and clonal expansion in the BM and spleen of recipient mice, although no competitive growth advantage was observed in the in vitro co-culturing assays. The mice transplanted with the MLL/AF10(OM-LZ) cells harboring PTPN11wt developed myelomonocytic leukemia, while those transplanted with the cells harboring PTPN11G503A -induced monocytic leukemia in a shorter latency. Our results demonstrated that addition of PTPN11G503A to MLL/AF10 affected cell proliferation, chemo-resistance, differentiation, in vivo BM recruitment/clonal expansion and accelerated disease progression.
Assuntos
Transformação Celular Neoplásica/genética , Leucemia Monocítica Aguda/etiologia , Leucemia Mielomonocítica Aguda/etiologia , Mutação de Sentido Incorreto , Proteína de Leucina Linfoide-Mieloide/fisiologia , Proteínas de Fusão Oncogênica/fisiologia , Mutação Puntual , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Animais , Medula Óssea/patologia , Diferenciação Celular/efeitos dos fármacos , Técnicas de Cocultura , Citarabina/uso terapêutico , Daunorrubicina/uso terapêutico , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/genética , Ativação Enzimática/genética , Feminino , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Humanos , Lactente , Interleucina-3/farmacologia , Leucemia Monocítica Aguda/genética , Leucemia Mielomonocítica Aguda/genética , Fator Estimulador de Colônias de Macrófagos/sangue , Macrófagos/citologia , Camundongos , Camundongos Endogâmicos C57BL , Proteína de Leucina Linfoide-Mieloide/genética , Proteínas de Fusão Oncogênica/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/fisiologia , Quimera por Radiação , Transdução Genética , Células Tumorais Cultivadas/transplanteRESUMO
BACKGROUND/PURPOSE: Real-time quantitative polymerase chain reaction (RQ-PCR) for fusion transcripts and flow cytometry for leukemia-specific markers are widely used for minimal residual disease (MRD) detection in acute lymphoblastic leukemia, but the relation between the results of either method is unclear. METHODS: Mononucleated cells from 108 bone marrow samples collected from 55 B-precursor acute lymphoblastic leukemia patients (30 with t(12;21)/ETV6-RUNX1, 16 with t(9;22)/BCR-ABL1 and nine with t(1;19)/TCF3-PBX1) were examined in tandem by RQ-PCR and six-color flow cytometry. RESULTS: MRD results were concordant in 91 of the 108 paired samples (84.2%; K=0.690); 49 samples were MRD-negative while 42 were MRD-positive by both methods, with < 1 log difference in positive MRD estimates in 39 samples (92.9%). Of the 17 discordant samples, 16 were MRD-positive by RQ-PCR but MRD-negative by flow cytometry; the opposite was true in one sample. Kappa value/concordance was 0.690/85.0% (n = 60) for ETV6-RUNX1, 0.842/93.3% (n = 15) for TCF3-PBX1, and 0.535/78.8% (n = 33) for BCR-ABL1. Specific immunophenotypic abnormalities were more prevalent in each genetic subgroup, such as CD38 underexpression, CD58 overexpression, and CD34 overexpression in ETV6-RUNX1, TCF3-PBX1, and BCR-ABL1, respectively. CONCLUSION: In most follow-up samples, MRD estimates by two methods are in agreement, especially in patients with TCF3-PBX1.
Assuntos
Neoplasia Residual/patologia , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Doença Aguda , Medula Óssea/patologia , Citometria de Fluxo , Humanos , Imunofenotipagem , Reação em Cadeia da Polimerase , Análise de RegressãoRESUMO
In the Klebsiella pneumoniae CG43 genome, the divergently transcribed genes coding for PecS, the MarR-type transcription factor, and PecM, the drug metabolite transporter, are located between the type 1 and type 3 fimbrial gene clusters. The intergenic sequence pecO between pecS and pecM contains three putative PecS binding sites and a CpxR box. Electrophoretic mobility shift assay revealed that the recombinant PecS and CpxR could specifically bind to the pecO sequence, and the specific interaction of PecS and pecO could be attenuated by urate. The expression of pecS and pecM was negatively regulated by CpxAR and PecS, and was inducible by exogenous urate in the absence of cpxAR. Compared with CG43S3ΔcpxAR, the derived mutants CG43S3ΔcpxARΔpecS and CG43S3ΔcpxARΔpecSΔpecM exerted similar levels of sensitivity to H2O2 or paraquat, but higher levels of mannose-sensitive yeast agglutination activity and FimA production. The promoter activity and transcript levels of fimA in CG43S3ΔcpxAR were also increased by deleting pecS. However, no binding activity between PecS and the fimA promoter could be observed. Nevertheless, PecS deletion could reduce the expression of the global regulator HNS and release the negative effect of HNS on FimA expression. In CG43S3ΔcpxAR, the expression of FimA as well as PecS was inducible by urate, whilst urate-induced FimA expression was inhibited by the deletion of pecS. Taken together, we propose that K. pneumoniae PecS indirectly and negatively regulates the expression of type 1 fimbriae, and the regulation is urate-inducible in the absence of CpxAR.
Assuntos
Proteínas de Bactérias/metabolismo , Fímbrias Bacterianas/metabolismo , Regulação Bacteriana da Expressão Gênica , Klebsiella pneumoniae/metabolismo , Proteínas Repressoras/metabolismo , Ácido Úrico/metabolismo , Proteínas de Bactérias/genética , Fímbrias Bacterianas/genética , Klebsiella pneumoniae/genética , Regiões Promotoras Genéticas , Proteínas Repressoras/genéticaRESUMO
Gene mutations involving epigenetic regulators recently have been described in adult acute myeloid leukemia (AML). Similar studies are limited in children. We analyzed gene mutations and cooperation in pediatric AML with special reference on mutated epigenetic regulators. Nineteen gene mutations, including 8 class I genes, 4 class II genes, WT1 and TP53 (class III), and 5 epigenetic regulator genes (class IV), were analyzed in 206 children with de novo AML. Mutational analysis was performed with polymerase chain reaction-based assay followed by direct sequencing. One hundred seventeen of 206 patients (56.8%) had at least one mutation: 51% class I, 13% class II, 6.8% class III, and 5.6% class IV. FLT3-internal tandem duplication was most frequent, and 29% of patients had more than one gene mutation. Two patients carried ASXL1 mutations, both with t(8;21), 2 had DNMT3A mutations, 2 had IDH1 mutations, 1 had IDH2 mutation, and 3 had TET2 mutations. Both patients with IDH1 mutations had AML-M0 subtype and MLL-partial tandem duplication. Cooperating mutations with mutated epigenetic regulators were observed in 8 of 10 patients. We conclude that mutated epigenetic regulators were much less than those in adult AML but with frequent cooperating mutations. ASXL1, TET2, and IDH1 mutations were associated with specific genetic subtypes.
Assuntos
DNA (Citosina-5-)-Metiltransferases/genética , Proteínas de Ligação a DNA/genética , Isocitrato Desidrogenase/genética , Leucemia Mieloide/genética , Mutação , Proteínas Proto-Oncogênicas/genética , Proteínas Repressoras/genética , Doença Aguda , Adolescente , Criança , Pré-Escolar , DNA Metiltransferase 3A , Análise Mutacional de DNA , Dioxigenases , Intervalo Livre de Doença , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Taxa de Mutação , Prognóstico , Adulto JovemRESUMO
The use of next-generation sequencing (NGS) for monitoring measurable residual disease (MRD) in acute lymphoblastic leukaemia (ALL) has been gaining traction. This study aimed to investigate the utility of NGS in MRD monitoring for the three major fusion transcript (FT) subtypes of B-precursor ALL (B-ALL). The MRD results for 104 bone marrow samples from 56 patients were analysed through NGS and real time quantitative reverse transcription PCR (RT-qPCR) for the three major FTs: BCR::ABL1, TCF3::PBX1, and ETV6::RUNX1. To validate the NGS approach, NGS-MRD was initially compared with allele-specific oligonucleotide-qPCR-MRD, and the coefficient of determination was good (R2=0.8158). A subsequent comparison of NGS-MRD with FT-MRD yielded a good coefficient of determination (R2=0.7690), but the coefficient varied by subtype. Specifically, the R2 was excellent for TCF3::PBX1 ALL (R2=0.9157), good for ETV6::RUNX1 ALL (R2=0.8606), and subpar for BCR::ABL1 ALL (R2=0.5763). The overall concordance between the two methods was 83.7%, and an excellent concordance rate of 95.8% was achieved for TCF3::PBX1 ALL. Major discordance, which was defined as a >1 log difference between discordant NGS-MRD and FT-MRD, occurred in 6.7% of the samples, with all but one sample being BCR::ABL1 ALL. Among the four non-transplanted patients with BCR::ABL1-MRD (+)/NGS-MRD (-), three did not relapse after long-term follow-up. Our finding indicates that NGS-MRD has a better prognostic impact than RT-qPCR-MRD in ETV6::RUNX1 and BCR::ABL1 ALL, whereas in TCF3::PBX1 ALL, both methods exhibit comparable efficacy.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Neoplasia Residual , Proteínas de Fusão Oncogênica , Leucemia-Linfoma Linfoblástico de Células Precursoras B , Humanos , Neoplasia Residual/genética , Neoplasia Residual/diagnóstico , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patologia , Feminino , Masculino , Adolescente , Adulto , Criança , Pessoa de Meia-Idade , Adulto Jovem , Pré-Escolar , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Proteínas de Fusão bcr-abl/genéticaRESUMO
Oncogenic N-/KRAS mutations were frequently associated with MLL/AF10 in acute myeloid leukemia with myeloid sarcoma (MS). To study the cooperating leukemogenesis by MLL/AF10 and KRAS mutation, we retrovirally transduced MLL/AF10(OM-LZ) and KRASG12C into mouse bone marrow cells and generated two immortalized cell lines. The cells carrying cooperating MLL/AF10(OM-LZ) and KRASG12C had immature myelomonocytic phenotypes. Compared to a previously established cell line carrying MLL/AF10(OM-LZ) alone, cooperation of MLL/AF10(OM-LZ) with KRASG12C blocked the cells at a more immature myelomonocytic stage with reduced expression of monocyte/macrophage markers. The mice transplanted with the cells carrying cooperating MLL/AF10(OM-LZ) and KRASG12C, liked those transplanted with the cells carrying MLL/AF10(OM-LZ) alone, induced myeloproliferative disease-like myeloid leukemia, but in a shorter latency and formed multiple MS at the adipose tissues of skin, peritoneum and intraperitoneal cavity. Cooperation of MLL/AF10(OM-LZ) with KRASG12C increased cell adhesion via upregulation of an adhesion G-protein-coupled receptor Gpr125. Knockdown of Gpr125 in the cells by short hairpin RNA reduced cell aggregation and diminished MS formation in the transplanted mice. Our results indicated that upregulation of Gpr125 by cooperating MLL/AF10(OM-LZ) and KRASG12C promoted cell adhesion and contributed to the MS formation.
Assuntos
Histona-Lisina N-Metiltransferase/metabolismo , Proteína de Leucina Linfoide-Mieloide/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Sarcoma Mieloide/metabolismo , Fatores de Transcrição/metabolismo , Adolescente , Adulto , Animais , Transplante de Medula Óssea , Adesão Celular/genética , Linhagem Celular Tumoral , Linhagem da Célula , Criança , Pré-Escolar , Modelos Animais de Doenças , Feminino , Histona-Lisina N-Metiltransferase/genética , Humanos , Lactente , Leucemia Mieloide Aguda/metabolismo , Masculino , Camundongos , Pessoa de Meia-Idade , Mutação , Proteína de Leucina Linfoide-Mieloide/genética , Transplante de Neoplasias , Neoplasias Lipomatosas , Proteínas Proto-Oncogênicas p21(ras)/genética , Interferência de RNA , RNA Interferente Pequeno , Receptores Acoplados a Proteínas G/biossíntese , Receptores Acoplados a Proteínas G/genética , Fatores de Transcrição/genética , Regulação para Cima , Adulto JovemRESUMO
Klebsiella pneumoniae CG43, a heavy encapsulated liver abscess isolate, mainly expresses type 3 fimbriae. Type 1 fimbriae expression was only apparent in CG43S3ΔmrkA (the type 3 fimbriae-deficient strain). The expression of type 1 fimbriae in CG43S3ΔmrkA was reduced by deleting the fimK gene, but was unaffected by removing the 3' end of fimK encoding the C-terminal EIL domain (EILfimK). Quantitative RT-PCR and promoter activity analysis showed that the putative DNA-binding region at the N terminus, but not the C-terminal EIL domain, of FimK positively affects transcription of the type 1 fimbrial major subunit, fimA. An electrophoretic mobility shift assay demonstrated that the recombinant FimK could specifically bind to fimS, which is located upstream of fimA and contains a vegetative promoter for the fim operon, also reflecting possible transcriptional regulation. EILfimK was shown to encode a functional phosphodiesterase (PDE) via enhancing motility in Escherichia coli JM109 and in vitro using PDE activity assays. Moreover, EILfimK exhibited higher PDE activity than FimK, implying that the N-terminal DNA-binding domain may negatively affect the PDE activity of FimK. FimA expression was detected in CG43S3 expressing EILfimK or AILfimK, suggesting that FimA expression is not directly influenced by the c-di-GMP level. In summary, FimK influences type 1 fimbriation by binding to fimS at the N-terminal domain, and thereafter, the altered protein structure may activate C-terminal PDE activity to reduce the intracellular c-di-GMP level.
Assuntos
Proteínas de Fímbrias/metabolismo , Fímbrias Bacterianas/metabolismo , Regulação Bacteriana da Expressão Gênica , Klebsiella pneumoniae/metabolismo , Diester Fosfórico Hidrolases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , GMP Cíclico/análogos & derivados , GMP Cíclico/metabolismo , Proteínas de Fímbrias/química , Proteínas de Fímbrias/genética , Fímbrias Bacterianas/genética , Humanos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/fisiologia , Óperon , Diester Fosfórico Hidrolases/genéticaRESUMO
OBJECTIVES: The clinical presentations of essential thrombocythemia (ET) may be quite similar to early/prefibrotic primary myelofibrosis (pre-PMF), especially in pre-PMF presenting with thrombocytosis (pre-PMF-T), but may be associated with a different outcome. It is very important to distinguish these two entities. The aim of this study was to address the clinical and prognostic relevance of distinguishing pre-PMF-T from ET. METHODS: All patients, including 258 with ET and 105 with pre-PMF-T, received JAK2V617F, MPL (exon 10), and CALR (exon 9) mutation analysis and allele burden measurement for JAK2V617F and CALR mutants. RESULTS: Patients with pre-PMF-T had an older age and higher leukocyte and platelet counts but lower hemoglobin levels than patients with ET. Patients with pre-PMF-T had a shorter overall, leukemia-free, and thrombosis-free survival compared with patients with ET. Patients with ET had a higher rate of cerebral ischemic stroke, whereas patients with pre-PMF-T tended to have splanchnic vein thrombosis. The frequencies of JAK2V617F, CALR, and MPL mutations and CALR allele burden were no different, but JAK2V617F allele burden was significantly higher in pre-PMF-T. Patients with pre-PMF-T with the JAK2V617F mutation had an inferior overall survival and thrombosis-free survival, whereas the status of driver gene mutations did not influence the outcomes of patients with ET. CONCLUSIONS: ET and pre-PMF-T were two distinct disease entities and exhibited different clinical phenotype, genotype, and outcomes.
Assuntos
Mielofibrose Primária , Trombocitemia Essencial , Humanos , Trombocitemia Essencial/genética , Taiwan , Mutação , Contagem de Plaquetas , Janus Quinase 2/genética , Calreticulina/genéticaRESUMO
The Klebsiella pneumoniae type 3 fimbriae are mainly composed of MrkA pilins that assemble into a helixlike filament. This study determined the biomechanical properties of the fimbriae and analyzed 11 site-directed MrkA mutants to identify domains that are critical for the properties. Escherichia coli strains expressing type 3 fimbriae with an Ala substitution at either F34, V45, C87, G189, T196, or Y197 resulted in a significant reduction in biofilm formation. The E. coli strain expressing MrkAG189A remained capable of producing a normal number of fimbriae. Although F34A, V45A, T196A, and Y197A substitutions expressed on E. coli strains produced sparse quantities of fimbriae, no fimbriae were observed on the cells expressing MrkAC87A. Further investigations of the mechanical properties of the MrkAG189A fimbriae with optical tweezers revealed that, unlike the wild-type fimbriae, the uncoiling force for MrkAG189A fimbriae was not constant. The MrkAG189A fimbriae also exhibited a lower enthalpy in the differential scanning calorimetry analysis. Together, these findings indicate that the mutant fimbriae are less stable than the wild-type. This study has demonstrated that the C-terminal ß strands of MrkA are required for the assembly and structural stability of fimbriae.
Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Fímbrias/metabolismo , Klebsiella pneumoniae/metabolismo , Proteínas de Bactérias/química , Biofilmes , Proteínas de Fímbrias/química , Estrutura Terciária de ProteínaRESUMO
Locked nucleic acid quantitative Real-Time PCR (LNA-qPCR) for IDH1/2 mutations in AML measurable residual disease (MRD) detection is rarely reported. LNA-qPCR was applied to quantify IDH1/2 mutants MRD kinetics in bone marrow from 88 IDH1/2-mutated AML patients, and correlated with NPM1-MRD, clinical characteristics, and outcomes. The median normalized copy number (NCN) of IDH1/2 mutants decreased significantly from 53,228 (range 87−980,686)/ALB × 106 at diagnosis to 773 (range 1.5−103,600)/ALB × 106 at first complete remission (CR). IDH1/2 LNA-qPCR MRD was concordant with remission status or NPM1-MRD in 79.5% (70/88) of patients. Younger patients and patients with FLT3 mutations had higher concordance. The Spearman correlation coefficient (rs) and concordance rate between the log reduction of IDH1/2 LNA-qPCR and NPM1-MRD were 0.68 and 81% (K = 0.63, 95% CI 0.50−0.74), respectively. IDH1/2-MRD > 2 log reduction at first CR predicted significantly better relapse-free survival (3-year RFS rates 52.9% vs. 31.9%, p = 0.007) and cumulative incidence of relapse (3-year CIR rates 44.5% vs. 64.5%, p = 0.012) compared to IDH1/2-MRD ≤ 2 log reduction. IDH1/2-MRD > 2 log reduction during consolidation is also associated with a significantly lower CIR rate than IDH1/2-MRD ≤ 2 log reduction (3-year CIR rates 42.3% vs. 68.8%, p = 0.019). LNA-qPCR for IDH1/2 mutation is a potential MRD technique to predict relapse in IDH1/2-mutated AML patients, especially for those with IDH1/2 MRD > 2 log reduction at first CR or a concurrent FLT3 mutation.
RESUMO
This study investigated the structural and mechanical properties of Klebsiella pneumoniae type 3 fimbriae, which constitute a known virulence factor for the bacterium. Transmission electron microscopy and optical tweezers were used to understand the ability of the bacterium to survive flushes. An individual K. pneumoniae type 3 fimbria exhibited a helix-like structure with a pitch of 4.1 nm and a three-phase force-extension curve. The fimbria was first nonlinearly stretched with increasing force. Then, it started to uncoil and extended several micrometers at a fixed force of 66 ± 4 pN (n = 22). Finally, the extension of the fimbria shifted to the third phase, with a characteristic force of 102 ± 9 pN (n = 14) at the inflection point. Compared with the P fimbriae and type 1 fimbriae of uropathogenic Escherichia coli, K. pneumoniae type 3 fimbriae have a larger pitch in the helix-like structure and stronger uncoiling and characteristic forces.
Assuntos
Proteínas de Fímbrias/metabolismo , Fímbrias Bacterianas/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Proteínas de Fímbrias/química , Proteínas de Fímbrias/genética , Fímbrias Bacterianas/química , Fímbrias Bacterianas/genética , Mecânica , Microscopia Eletrônica de Varredura , Conformação Proteica , Escherichia coli Uropatogênica/metabolismo , Fatores de VirulênciaRESUMO
Two quantitative PCR (qPCR)-based methods, for clonal immunoglobulin or T-cell receptor gene (Ig/TCR) rearrangements and for fusion transcripts, are widely used for the measurement of minimal residual disease (MRD) in patients with B-precursor acute lymphoblastic leukemia (ALL). MRD of bone marrow samples from 165 patients carrying the three major fusion transcripts, including 74 BCR-ABL1, 54 ETV6-RUNX1, and 37 TCF3-PBX1, was analyzed by using the two qPCR-based methods. The correlation coefficient of both methods was good for TCF3-PBX1 (R2 = 0.8088) and BCR-ABL1 (R2 = 0.8094) ALL and moderate for ETV6-RUNX1 (R2 = 0.5972). The concordance was perfect for TCF3-PBX1 ALL (97.2%), substantially concordant for ETV6-RUNX1 ALL (87.1%), and only moderate for BCR-ABL1 ALL (70.6%). The discordant MRD, positive for only one method with a difference greater than one log, was found in 4 of 93 samples (4.3%) with ETV6-RUNX1, 31 of 245 samples (12.7%) with BCR-ABL1, and none of TCF3-PBX1 ALL. None of the eight non-transplanted patients with BCR-ABL1-MRD (+)/Ig/TCR-MRD (-) with a median follow-up time of 73.5 months had hematologic relapses. Our study showed an excellent MRD concordance between the two qPCR-based methods in TCF3-PBX1 ALL, whereas qPCR for Ig/TCR is more reliable in BCR-ABL1 ALL.
Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Proteínas de Fusão bcr-abl/genética , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Seguimentos , Rearranjo Gênico do Linfócito T/genética , Humanos , Imunoglobulinas/genética , Neoplasia Residual , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patologia , Recidiva , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Blast crisis (BC) predicts dismal outcomes in patients with chronic myeloid leukaemia (CML). Although additional genetic alterations play a central role in BC, the landscape and prognostic impact of these alterations remain elusive. Here, we comprehensively investigate genetic abnormalities in 136 BC and 148 chronic phase (CP) samples obtained from 216 CML patients using exome and targeted sequencing. One or more genetic abnormalities are found in 126 (92.6%) out of the 136 BC patients, including the RUNX1-ETS2 fusion and NBEAL2 mutations. The number of genetic alterations increase during the transition from CP to BC, which is markedly suppressed by tyrosine kinase inhibitors (TKIs). The lineage of the BC and prior use of TKIs correlate with distinct molecular profiles. Notably, genetic alterations, rather than clinical variables, contribute to a better prediction of BC prognosis. In conclusion, genetic abnormalities can help predict clinical outcomes and can guide clinical decisions in CML.
Assuntos
Crise Blástica/genética , Evolução Clonal/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Crise Blástica/tratamento farmacológico , Crise Blástica/patologia , Proteínas Sanguíneas/genética , Estudos de Coortes , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Feminino , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Leucemia Mieloide de Fase Crônica/genética , Leucemia Mieloide de Fase Crônica/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Proteínas de Fusão Oncogênica/genética , Prognóstico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteína Proto-Oncogênica c-ets-2/genética , Sequenciamento do Exoma , Adulto JovemRESUMO
In the genome of Klebsiella pneumoniae NTUH-K2044, nine fimbrial gene clusters were identified. Besides type 1 and type 3 fimbriae, the others are novel and were named Kpa, Kpb, Kpc, Kpd, Kpe, Kpf and Kpg fimbriae. Prevalence analysis among 105 K. pneumoniae clinical isolates revealed that the kpc genes were highly associated with the K1 serotype isolates. Induced expression of the recombinant kpcABCD genes in Escherichia coli resulted in Kpc fimbriation and increased biofilm formation. A putative site-specific recombinase encoding gene kpcI and a 302 bp intergenic DNA flanked by 11 bp inverted repeats, namely kpcS, were identified in the upstream region of the kpcABCD genes. Using LacZ as the reporter, a dramatic difference in promoter activity of kpcS in two different orientations was observed and accordingly assigned as ON and OFF phase. kpcI expression was found to be able to invert kpcS in trans from phase ON to OFF and vice versa. Using the two-plasmid system, expression of kpcA, encoding the major component of the Kpc fimbriae, could be observed upon the induced expression of kpcI. These results indicate that KpcI is involved in the regulation of Kpc fimbriation in a phase-variable manner.
Assuntos
Fímbrias Bacterianas/metabolismo , Regulação Bacteriana da Expressão Gênica , Klebsiella pneumoniae/metabolismo , Recombinases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Fímbrias Bacterianas/genética , Humanos , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Dados de Sequência MolecularRESUMO
Acute myeloid leukemia (AML) with partial tandem duplication of histone-lysine N-methyltransferase 2A (KMT2A-PTD) is a subtype of AML and is associated with adverse survival, yet the molecular pathogenesis of KMT2A-PTD is not fully understood. DNA methyltransferase 3A (DNMT3A) is mutated in various myeloid neoplasms including AML, especially at the Arg882. Recently, it has been found that DNMT3A mutations frequently coexisted with KMT2A-PTD and are associated with inferior outcomes. We aimed to understand the biological role of DNMT3A mutation in KMT2A-PTD-positive cells. Herein, we found that overexpression of DNMT3A mutants (MT) in KMT2A-PTD-positive EOL-1 cells augmented cell proliferation and clonogenicity. Serial colony replating assays indicated that DNMT3A-MT increased the self-renewal ability of Kmt2a-PTD-expressing mouse bone marrow cells with immature morphology. At 10 months post bone marrow transplantation, mice with the combined Kmt2a-PTD and DNMT3A-MT showed hepatosplenomegaly and leukocytosis with a shorter latency compared to control and DNMT3A-wild-type. Gene expression microarray analyses of bone marrow samples from human AML with KMT2A-PTD/DNMT3A-MT showed a stem cell signature and myeloid hematopoietic lineage with dysregulation of HOXB gene expression. In addition, human bone marrow AML cells carrying KMT2A-PTD/DNMT3A-MT showed abnormal growth and augmented self-renewal activity in primary cell culture. The present study provides information underlying the pathogenic role of DNMT3A-MT with KMT2A-PTD in proliferating advantage with augmentation of self-renewal activity in human leukemia, which may help to better understand the disease and to design better therapy for AML patients with these mutations.