RESUMO
In acute promyelocytic leukemia (APL), the promyelocytic leukemia-retinoic acid receptor alpha (PML/RARα) fusion protein destroys PML nuclear bodies (NBs), leading to the formation of microspeckles. However, our understanding, largely learned from morphological observations, lacks insight into the mechanisms behind PML/RARα-mediated microspeckle formation and its role in APL leukemogenesis. This study presents evidence uncovering liquid-liquid phase separation (LLPS) as a key mechanism in the formation of PML/RARα-mediated microspeckles. This process is facilitated by the intrinsically disordered region containing a large portion of PML and a smaller segment of RARα. We demonstrate the coassembly of bromodomain-containing protein 4 (BRD4) within PML/RARα-mediated condensates, differing from wild-type PML-formed NBs. In the absence of PML/RARα, PML NBs and BRD4 puncta exist as two independent phases, but the presence of PML/RARα disrupts PML NBs and redistributes PML and BRD4 into a distinct phase, forming PML/RARα-assembled microspeckles. Genome-wide profiling reveals a PML/RARα-induced BRD4 redistribution across the genome, with preferential binding to super-enhancers and broad-promoters (SEBPs). Mechanistically, BRD4 is recruited by PML/RARα into nuclear condensates, facilitating BRD4 chromatin binding to exert transcriptional activation essential for APL survival. Perturbing LLPS through chemical inhibition (1, 6-hexanediol) significantly reduces chromatin co-occupancy of PML/RARα and BRD4, attenuating their target gene activation. Finally, a series of experimental validations in primary APL patient samples confirm that PML/RARα forms microspeckles through condensates, recruits BRD4 to coassemble condensates, and co-occupies SEBP regions. Our findings elucidate the biophysical, pathological, and transcriptional dynamics of PML/RARα-assembled microspeckles, underscoring the importance of BRD4 in mediating transcriptional activation that enables PML/RARα to initiate APL.
Assuntos
Proteínas de Ciclo Celular , Leucemia Promielocítica Aguda , Proteínas de Fusão Oncogênica , Fatores de Transcrição , Humanos , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/patologia , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Fusão Oncogênica/metabolismo , Proteínas de Fusão Oncogênica/genética , Linhagem Celular Tumoral , Regulação Leucêmica da Expressão Gênica , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Proteína da Leucemia Promielocítica/metabolismo , Proteína da Leucemia Promielocítica/genética , Separação de Fases , Proteínas que Contêm BromodomínioRESUMO
Acute promyelocytic leukemia (APL) represents a paradigm for targeted differentiation therapy, with a minority of patients experiencing treatment failure and even early death. We here report a comprehensive single-cell analysis of 16 APL patients, uncovering cellular compositions and their impact on all-trans retinoic acid (ATRA) response in vivo and early death. We unveil a cellular differentiation hierarchy within APL blasts, rooted in leukemic stem-like cells. The oncogenic PML/RARα fusion protein exerts branch-specific regulation in the APL trajectory, including stem-like cells. APL cohort analysis establishes an association of leukemic stemness with elevated white blood cell counts and FLT3-ITD mutations. Furthermore, we construct an APL-specific stemness score, which proves effective in assessing early death risk. Finally, we show that ATRA induces differentiation of primitive blasts and patients with early death exhibit distinct stemness-associated transcriptional programs. Our work provides a thorough survey of APL cellular hierarchies, offering insights into cellular dynamics during targeted therapy.
Assuntos
Leucemia Promielocítica Aguda , Humanos , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/metabolismo , Tretinoína/farmacologia , Diferenciação Celular , Linhagem Celular Tumoral , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismoRESUMO
Patients with primary refractory acute myeloid leukemia (AML) have a dismal long-term prognosis. Elucidating the resistance mechanisms to induction chemotherapy could help identify strategies to improve AML patient outcomes. Herein, we retrospectively analyzed the multiomics data of more than 1,500 AML cases and found that patients with spliceosome mutations had a higher risk of developing refractory disease. RNA splicing analysis revealed that the mis-spliced genes in refractory patients converged on translation-associated pathways, promoted mainly by U2AF1 mutations. Integrative analyses of binding and splicing in AML cell lines substantiated that the splicing perturbations of mRNA translation genes originated from both the loss and gain of mutant U2AF1 binding. In particular, the U2AF1S34F and U2AF1Q157R mutants orchestrated the inclusion of exon 11 (encoding a premature termination codon) in the eukaryotic translation initiation factor 4A2 (EIF4A2). This aberrant inclusion led to reduced eIF4A2 protein expression via nonsense-mediated mRNA decay. Consequently, U2AF1 mutations caused a net decrease in global mRNA translation that induced the integrated stress response (ISR) in AML cells, which was confirmed by single-cell RNA sequencing. The induction of ISR enhanced the ability of AML cells to respond and adapt to stress, contributing to chemoresistance. A pharmacologic inhibitor of ISR, ISRIB, sensitized U2AF1 mutant cells to chemotherapy. These findings highlight a resistance mechanism by which U2AF1 mutations drive chemoresistance and provide a therapeutic approach for AML through targeting the ISR pathway. SIGNIFICANCE: U2AF1 mutations induce the integrated stress response by disrupting splicing of mRNA translation genes that improves AML cell fitness to enable resistance to chemotherapy, which can be targeted to improve AML treatment.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Leucemia Mieloide Aguda , Mutação , Fator de Processamento U2AF , Humanos , Fator de Processamento U2AF/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/patologia , Resistencia a Medicamentos Antineoplásicos/genética , Biossíntese de Proteínas/efeitos dos fármacos , RNA Mensageiro/genética , Splicing de RNA/genética , Animais , Estudos Retrospectivos , Camundongos , Linhagem Celular Tumoral , Fator de Iniciação 4A em Eucariotos/genética , Fator de Iniciação 4A em Eucariotos/metabolismoRESUMO
The bone marrow microenvironment (BMM) can regulate leukemia stem cells (LSCs) via secreted factors. Increasing evidence suggests that dissecting the mechanisms by which the BMM maintains LSCs may lead to the development of effective therapies for the eradication of leukemia. Inhibitor of DNA binding 1 (ID1), a key transcriptional regulator in LSCs, previously identified by us, controls cytokine production in the BMM, but the role of ID1 in acute myeloid leukemia (AML) BMM remains obscure. Here, we report that ID1 is highly expressed in the BMM of patients with AML, especially in BM mesenchymal stem cells, and that the high expression of ID1 in the AML BMM is induced by BMP6, secreted from AML cells. Knocking out ID1 in mesenchymal cells significantly suppresses the proliferation of cocultured AML cells. Loss of Id1 in the BMM results in impaired AML progression in AML mouse models. Mechanistically, we found that Id1 deficiency significantly reduces SP1 protein levels in mesenchymal cells cocultured with AML cells. Using ID1-interactome analysis, we found that ID1 interacts with RNF4, an E3 ubiquitin ligase, and causes a decrease in SP1 ubiquitination. Disrupting the ID1-RNF4 interaction via truncation in mesenchymal cells significantly reduces SP1 protein levels and delays AML cell proliferation. We identify that the target of Sp1, Angptl7, is the primary differentially expression protein factor in Id1-deficient BM supernatant fluid to regulate AML progression in mice. Our study highlights the critical role of ID1 in the AML BMM and aids the development of therapeutic strategies for AML.
Assuntos
Proteína 7 Semelhante a Angiopoietina , Proteína 1 Inibidora de Diferenciação , Leucemia Mieloide Aguda , Animais , Camundongos , Proteína 7 Semelhante a Angiopoietina/genética , Proteína 7 Semelhante a Angiopoietina/metabolismo , Medula Óssea/metabolismo , Modelos Animais de Doenças , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Microambiente Tumoral , Humanos , Proteína 1 Inibidora de Diferenciação/metabolismoRESUMO
Vanadium is a transition metal that naturally occurs in the environment and has a variety of biological and physiological impacts on humans. Sodium orthovanadate (SOV), a well-known chemical compound of vanadium, has shown notable anti-cancer activity in various types of human malignancies. However, the effect of SOV on stomach cancer is yet undetermined. Furthermore, only a few studies have investigated the association of SOV and radiosensitivity with stomach cancer. Our study has investigated the ability of SOV to increase the sensitivity of gastric cancer cells to radiation. To detect autophagy triggered by ionizing radiation and the influence of SOV on cell radiosensitivity, the Cell Counting Kit-8 (CCK8) test, EDU staining experiment, colony formation assay, and immunofluorescence were performed. The possible synergistic effects of SOV and irradiation were examined in vivo using a xenograft mouse model of stomach cancer cells. Both in vitro and in vivo studies showed that SOV markedly reduced the growth of stomach cancer cells and improved their radiosensitivity. Our results showed that SOV increased gastric cancer cells' radiosensitivity, thereby blocking the radiation-induced autophagy-related protein, ATG10. Thus, SOV can be considered a potential agent for radiosensitizing gastric cancer.
Assuntos
Neoplasias Gástricas , Humanos , Camundongos , Animais , Neoplasias Gástricas/radioterapia , Vanadatos/farmacologia , Vanádio/farmacologia , Apoptose , Autofagia , Linhagem Celular TumoralRESUMO
Acute promyelocytic leukemia (APL) is characterized by the balanced translocation of chromosomes 15 and 17, resulting in the formation of PML-RARA fusion gene. More than 98% of APL have PML-RARA fusion, and less than 2% have other types of RARA gene partners, which named variant APL (vAPL). In the present study, we reported a vAPL with BCOR-RARA, which was the third case of BCOR-RARA APL published. The patient achieved complete remission (CR) with all-trans retinoic acid (ATRA) monotherapy, and molecular CR with ATRA plus standard chemotherapy. After that, he underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) and ATRA maintenance and maintained a molecular CR status. This case provided valuable insights into the accurate identification of vAPL. Moreover, ATRA combined with chemotherapy followed by allo-HSCT was suggested as an optimal choice for those vAPL patients who had a high risk of relapse.
RESUMO
In patients with acute promyelocytic leukemia (APL), intracranial hemorrhage (ICH), if not identified promptly, could be fatal. It is the leading cause of failure of induction and early death. Thus, biomarkers that could promptly predict severe complications are critical. Here, cytokine differences between patients with APL with and without ICH were investigated to develop predictive models for this complication. The initial cytokine profiling using plasma samples from 39 patients and 18 healthy donors found a series of cytokines that were remarkedly different between patients with APL and healthy controls. The APL patients were subsequently divided into high and low white blood cell count groups. Results showed that tumor necrosis factor a and interleukin 8 (IL-8) were vital in distinguishing patients with APL who did or did not develop ICH. In addition, verification in 81 patients with APL demonstrated that the two cytokines were positively correlated with the cumulative incidence of ICH. Finally, in-vitro and in-vivo experimental evidence were provided to show that IL-8 influenced the migration of APL-derived NB4 cells and impaired the blood-brain barrier in PML/RARα positive blast-transplanted FVB/NJ mice. These assessments may facilitate the early warning of ICH and reduce future mortality levels in APL.
Assuntos
Leucemia Promielocítica Aguda , Camundongos , Animais , Leucemia Promielocítica Aguda/complicações , Tretinoína/farmacologia , Interleucina-8 , Fator de Necrose Tumoral alfa , Citocinas , Hemorragias Intracranianas/etiologia , Proteínas de Fusão OncogênicaRESUMO
PURPOSE: The molecular complexity of acute myeloid leukemia (AML) presents a considerable challenge to implementation of clinical genetic testing for accurate risk stratification. Identification of better biomarkers therefore remains a high priority to enable improving established stratification and guiding risk-adapted therapy decisions. EXPERIMENTAL DESIGN: We systematically integrated and analyzed the genome-wide CRISPR-Cas9 data from more than 1,000 in vitro and in vivo knockout screens to identify the AML-specific fitness genes. A prognostic fitness score was developed using the sparse regression analysis in a training cohort of 618 cases and validated in five publicly available independent cohorts (n = 1,570) and our RJAML cohort (n = 157) with matched RNA sequencing and targeted gene sequencing performed. RESULTS: A total of 280 genes were identified as AML fitness genes and a 16-gene AML fitness (AFG16) score was further generated and displayed highly prognostic power in more than 2,300 patients with AML. The AFG16 score was able to distill downstream consequences of several genetic abnormalities and can substantially improve the European LeukemiaNet classification. The multi-omics data from the RJAML cohort further demonstrated its clinical applicability. Patients with high AFG16 scores had significantly poor response to induction chemotherapy. Ex vivo drug screening indicated that patients with high AFG16 scores were more sensitive to the cell-cycle inhibitors flavopiridol and SNS-032, and exhibited strongly activated cell-cycle signaling. CONCLUSIONS: Our findings demonstrated the utility of the AFG16 score as a powerful tool for better risk stratification and selecting patients most likely to benefit from chemotherapy and alternative experimental therapies.
Assuntos
Sistemas CRISPR-Cas , Leucemia Mieloide Aguda , Estudos de Coortes , Humanos , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Prognóstico , Medição de RiscoRESUMO
Drug resistance is an important factor for treatment failure of gastric cancer. N6 -methyladenosine (m6 A) is the predominant mRNA internal modification in eukaryotes. The roles of m6 A modification in drug resistance of gastric cancer remains unclear. In the present study, the m6 A methylated RNA level was significantly decreased while the expression of m6 A demethylase fat mass and obesity-associated protein (FTO) was obviously elevated in cisplatin-resistant (SGC-7901/DDP) gastric cancer cells. Knockdown of FTO reversed cisplatin resistance of SGC-7901/DDP cells both in vitro and in vivo, which was attributed to the inhibition of Unc-51-like kinase 1 (ULK1)-mediated autophagy. Mechanistically, ULK1 expression was regulated in an FTO-m6 A-dependent and YTHDF2-mediated manner. Collectively, our findings indicate that the FTO/ULK1 axis exerts crucial roles in cisplatin resistance of gastric cancer.
Assuntos
Cisplatino , Neoplasias Gástricas , Dioxigenase FTO Dependente de alfa-Cetoglutarato/genética , Dioxigenase FTO Dependente de alfa-Cetoglutarato/metabolismo , Apoptose , Autofagia/genética , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/genética , Cisplatino/farmacologia , Cisplatino/uso terapêutico , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/uso terapêutico , Obesidade/genética , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/genéticaRESUMO
BACKGROUND: The epidemiology of Gram-negative bacteria in patients with febrile neutropenia (FN) and their susceptibility to initial empirical antibiotic therapy is key to successful treatment during the treatment of hematologic malignancies. METHODS: A retrospective study was conducted. Patients with FN and confirmed laboratory results of Gram-negative bacteria infections were included. If no direct sensitivity of the identified pathogen to the initially prescribed antibiotic regimen was confirmed, it was defined as inappropriate initial antibiotic treatment (IIAT). RESULTS: A total of 247 patients with FN were proven to be infected with Gram-negative bacteria, and 200 were diagnosed with acute leukemia. The most commonly detected bacteria were Escherichia coli (40%), Klebsiella pneumoniae (20%), and Pseudomonas aeruginosa (11%). In sum, 176 patients were classified as IIAT. The mortality rate in the IIAT group was significantly higher (37.7% vs 23.9%, P=0.038). With monotherapy as empirical treatment, high possibility of IIAT with fluoroquinolones (52%) and cephalosporins (35%) was detected, while more sensitivity to carbapenems (16%) and glycopeptides antibiotics (19%) was noticed. With combined treatment, cephalosporins/carbapenems had with the lowest percentage of IIAT (18%). CONCLUSION: In conclusion, inappropriate initial empirical antibiotic treatments were associated with higher mortality in patients with hematologic malignancies. The current empirical antibiotic regimen needs to be further optimized.
RESUMO
Previous studies have demonstrated an association between high body mass index (BMI) and acute myeloid leukemias (AML), particularly acute promyelocytic leukemia (APL). However, the effect of obesity and overweight on the incidence of AML is not supported by all studies, and the relationship between obesity and prognosis of AML and APL has not been established. Thus, we conducted a meta-analysis to determine the role of BMI on the risk and clinical outcome of AML, including APL. Twenty-six eligible studies enrolling 12,971 AML (including 866 APL) patients were retrieved and analyzed. Overweight and obesity was associated with an increased incidence of AML (relative risk [RR], 1.23; 95% confidence interval [CI], 1.12-1.35; P < 0.001). High BMI did not significantly affect overall survival (OS) (hazard ratio [HR], 0.97; 95% CI, 0.92-1.03; P = 0.323) or disease-free survival (HR, 0.98; 95% CI, 0.88-1.10; P = 0.755) in patients with non-APL AML. By contrast, APL patients with high BMI had shorter OS (HR, 1.77; 95% CI, 1.26-2.48; P = 0.001) and a higher risk of differentiation syndrome (HR, 1.53; 95% CI, 1.03-2.27, P = 0.04). Overall, our findings suggest that patients with overweight or obesity have a higher incidence of AML, and high BMI is a predictor of adverse clinical outcomes in APL.