RESUMO
Venetoclax (VEN) combined with hypomethylating agents (HMA) decitabine or azacitidine is used for adult acute myeloid leukaemia (AML), but its application in paediatric, adolescent and young adult (AYA) AML lacks prospective studies. We performed a retrospective chart review of paediatric and AYA AML patients treated with HMA + VEN at Cincinnati Children's Hospital Medical Centre. Twenty-seven patients received 30 HMA + VEN treatment courses for relapsed/refractory (R/R, n = 21) or newly diagnosed (n = 9) AML due to ineligibility for intensive chemotherapy. The R/R cohort had high-risk cytomolecular genetic alterations and prior extensive treatments, with 50% (n = 9) of relapse patients (n = 18) having undergone haematopoietic stem cell transplantation (HSCT). Venetoclax treatment using the 400 mg adult exposure-equivelant dosing (AED) had a median duration of 21 days (range 7-30 days). Grade 3-4 toxicities included neutropenia (90%), anaemia (64%), thrombocytopenia (64%) and febrile neutropenia (44%). The overall complete remission (CR)/CR with incomplete blood count recovery (CRi) rate was 73% (77% minimal residual disease [MRD] negativity <0.1%), with 60% undergoing HSCT. Among newly diagnosed patients (n = 9), 89% achieved CR/CRi (78% MRD negativity) and 78% proceeded to HSCT. The R/R cohort (n = 21) showed a 67% CR/CRi rate (71% MRD negativity), with 52% undergoing HSCT. These findings support the safety and efficacy of HMA + VEN in paediatric/AYA AML, indicating it as a viable option for patients unfit for intensive chemotherapy. Further studies are necessary to determine optimal venetoclax dosing, chemotherapy combinations and pharmacokinetics in this population.
RESUMO
Multiagent immunochemotherapy affords excellent outcomes in pediatric non-Hodgkin lymphoma (NHL); however, scarce data exist for patients unfit for intensive treatment. Rituximab, gemcitabine, and oxaliplatin (R-GemOx) is well tolerated and efficacious in elderly adults with NHL; however, its use has not been described in pediatrics. In this retrospective, single-center study, six children with mature B-cell NHL and significant comorbidities received anti-CD20 therapy with GemOx (rituximab or obinutuzumab or ofatumumab with gemcitabine and oxaliplatin [R/O-GemOx]). R/O-GemOx was well tolerated and resulted in complete response in two of three patients with newly diagnosed NHL and one of three patients with primary refractory NHL. R/O-GemOx is a viable treatment option for children with NHL who cannot tolerate intensive therapy.
Assuntos
Gencitabina , Linfoma não Hodgkin , Adulto , Humanos , Criança , Adolescente , Idoso , Rituximab , Oxaliplatina , Estudos Retrospectivos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma não Hodgkin/tratamento farmacológico , Desoxicitidina , Resultado do TratamentoRESUMO
No guidelines exist for which intensive chemotherapy regimen is best in pediatric or young adult patients with high-risk posttransplant lymphoproliferative disorder (PTLD). We retrospectively reviewed patients with PTLD who received interval-compressed short-course etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin (SC-EPOCH) regimens at our institution. Eight patients were included with median age of 12 years. All patients achieved a complete response with a manageable toxicity profile. Two patients developed second, clonally unrelated, EBV-positive PTLD and one patient had recurrence at 6 months off therapy. No graft rejection occurred during therapy. All eight patients are alive with median follow-up of 29 months.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Transtornos Linfoproliferativos , Transplante de Órgãos/efeitos adversos , Criança , Ciclofosfamida/uso terapêutico , Doxorrubicina/uso terapêutico , Etoposídeo/uso terapêutico , Humanos , Transtornos Linfoproliferativos/tratamento farmacológico , Transtornos Linfoproliferativos/etiologia , Complicações Pós-Operatórias , Prednisona/uso terapêutico , Prognóstico , Estudos Retrospectivos , Vincristina/uso terapêutico , Adulto JovemRESUMO
Risk stratification and appropriate treatment selection for children with precursor B-acute lymphoblastic leukemia (B-ALL) have improved outcomes. We report the case of a 4-year-old male with a lymphomatous cavernous sinus mass, a previously undescribed presentation of newly diagnosed hyperdiploid B-ALL. Few case reports in the literature describe lymphomatous involvement in this region, but none are associated with pediatric B-ALL. This case presented unique treatment and risk assignment challenges given the intracranial location of this tumor and proximity to the central nervous system.
Assuntos
Seio Cavernoso/patologia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Seio Cavernoso/efeitos dos fármacos , Seio Cavernoso/efeitos da radiação , Pré-Escolar , Humanos , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/radioterapia , Doses de Radiação , Resultado do TratamentoRESUMO
As a central regulator of cell polarity, the activity of CDC42 GTPase is tightly controlled in maintaining normal hematopoietic stem and progenitor cell (HSC/P) functions. We found that transformation of HSC/P to acute myeloid leukemia (AML) is associated with increased CDC42 expression and activity in leukemia cells. In a mouse model of AML, the loss of Cdc42 abrogates MLL-AF9-induced AML development. Furthermore, genetic ablation of CDC42 in both murine and human MLL-AF9 (MA9) cells decreased survival and induced differentiation of the clonogenic leukemia-initiating cells. We show that MLL-AF9 leukemia cells maintain cell polarity in the context of elevated Cdc42-guanosine triphosphate activity, similar to nonmalignant, young HSC/Ps. The loss of Cdc42 resulted in a shift to depolarized AML cells that is associated with a decrease in the frequency of symmetric and asymmetric cell divisions producing daughter cells capable of self-renewal. Importantly, we demonstrate that inducible CDC42 suppression in primary human AML cells blocks leukemia progression in a xenograft model. Thus, CDC42 loss suppresses AML cell polarity and division asymmetry, and CDC42 constitutes a useful target to alter leukemia-initiating cell fate for differentiation therapy.
Assuntos
Diferenciação Celular , Divisão Celular , Polaridade Celular , Leucemia Mieloide Aguda/patologia , Proteína cdc42 de Ligação ao GTP/metabolismo , Animais , Carcinogênese/genética , Carcinogênese/patologia , Diferenciação Celular/genética , Divisão Celular/genética , Linhagem Celular Tumoral , Polaridade Celular/genética , Transformação Celular Neoplásica/patologia , Células Clonais , Análise Citogenética , Teste em Amostras de Sangue Seco , GTP Fosfo-Hidrolases/metabolismo , Deleção de Genes , Regulação Leucêmica da Expressão Gênica , Células-Tronco Hematopoéticas/metabolismo , Humanos , Leucemia Mieloide Aguda/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Células-Tronco Neoplásicas/patologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Proteína cdc42 de Ligação ao GTP/genéticaRESUMO
Hemophagocytic lymphohistiocytosis (HLH) is characterized by dysregulated immune activation. Primary HLH involves hereditary deficits in cytotoxic lymphocytes while secondary HLH is triggered by extrinsic factors. The HLH-2004 criteria are widely used for clinical diagnosis, yet their specificity for HLH or their ability to differentiate primary from secondary disease is unclear, potentially leading to inappropriate treatment. We describe several cases where fulfillment of HLH-2004 criteria obscured the diagnoses of underlying malignancies and delayed curative management. These issues are remedied without waiting for genetic testing results through an alternative diagnostic approach using flow cytometry-based immunologic assays and a thorough investigation for malignancy.
Assuntos
Linfo-Histiocitose Hemofagocítica/diagnóstico , Linfo-Histiocitose Hemofagocítica/etiologia , Linfoma/complicações , Linfoma/diagnóstico , Síndromes Paraneoplásicas/diagnóstico , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Adulto JovemRESUMO
Treatment with dose-adjusted EPOCH (etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone) chemotherapy and rituximab (DA-EPOCH-R) has become the standard of care for primary mediastinal B-cell lymphoma (PMBCL) at many institutions despite limited data in the multi-centre setting. We report a large, multi-centre retrospective analysis of children and adults with PMBCL treated with DA-EPOCH-R to characterize outcomes and evaluate prognostic factors. We assessed 156 patients with PMBCL treated with DA-EPOCH-R across 24 academic centres, including 38 children and 118 adults. All patients received at least one cycle of DA-EPOCH-R. Radiation therapy was administered in 14·9% of patients. With median follow-up of 22·6 months, the estimated 3-year event-free survival (EFS) was 85·9% [95% confidence interval (CI) 80·3-91·5] and overall survival was 95·4% (95% CI 91·8-99·0). Outcomes were not statistically different between paediatric and adult patients. Thrombotic complications were reported in 28·2% of patients and were more common in paediatric patients (45·9% vs. 22·9%, P = 0·011). Seventy-five per cent of patients had a negative fluorodeoxyglucose positron emission tomography (FDG-PET) scan at the completion of DA-EPOCH-R, defined as Deauville score 1-3. Negative FDG-PET at end-of-therapy was associated with improved EFS (95·4% vs. 54·9%, P < 0·001). Our data support the use of DA-EPOCH-R for the treatment of PMBCL in children and adults. Patients with a positive end-of-therapy FDG-PET scan have an inferior outcome.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Neoplasias do Mediastino/tratamento farmacológico , Adolescente , Adulto , Fatores Etários , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Criança , Ciclofosfamida/administração & dosagem , Ciclofosfamida/efeitos adversos , Doxorrubicina/administração & dosagem , Doxorrubicina/efeitos adversos , Esquema de Medicação , Etoposídeo/administração & dosagem , Etoposídeo/efeitos adversos , Feminino , Humanos , Estimativa de Kaplan-Meier , Linfoma Difuso de Grandes Células B/diagnóstico por imagem , Linfoma Difuso de Grandes Células B/patologia , Linfoma Difuso de Grandes Células B/radioterapia , Masculino , Neoplasias do Mediastino/diagnóstico por imagem , Neoplasias do Mediastino/patologia , Neoplasias do Mediastino/radioterapia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons , Prednisona/administração & dosagem , Prednisona/efeitos adversos , Prognóstico , Radioterapia Adjuvante , Estudos Retrospectivos , Rituximab/administração & dosagem , Rituximab/efeitos adversos , Trombose/induzido quimicamente , Resultado do Tratamento , Vincristina/administração & dosagem , Vincristina/efeitos adversos , Adulto JovemRESUMO
Hematopoietic stem and progenitor cells (HSPCs) reside in a specialized niche that regulates their proliferative capacity and their fate. There is increasing evidence for similar roles of marrow niches on controlling the behavior of leukemic cells; however, whether normal hematopoietic stem cell (HSC) and leukemic cells reside in or functionally compete for the same marrow niche is unclear. We used the mixed lineage leukemia-AF9 (MLL-AF9) murine acute myeloid leukemia (AML) in a competitive repopulation model to investigate whether normal HSPC and leukemic cells functionally compete for the same marrow niches. Irradiated recipient mice were transplanted with fixed numbers of MLL-AF9 cells mixed with increasing doses of normal syngeneic whole bone marrow (WBM) or with purified HSPC (LSK). Survival was significantly increased and leukemic progression was delayed proportional to increasing doses of normal WBM or normal LSK cells in multiple independent experiments, with all doses of WBM or LSK cells studied above the threshold for rapid and complete hematopoietic reconstitution in the absence of leukemia. Confocal microscopy demonstrated nests of either leukemic cells or normal hematopoietic cells but not both in the marrow adjacent to endosteum. Early following transplantation, leukemic cells from animals receiving lower LSK doses were cycling more actively than in those receiving higher doses. These results suggest that normal HSPC and AML cells compete for the same functional niche. Manipulation of the niche could impact on response to antileukemic therapies, and the numbers of normal HSPC could impact on leukemia outcome, informing approaches to cell dose in the context of stem cell transplantation.
Assuntos
Células-Tronco Hematopoéticas/metabolismo , Leucemia Mieloide Aguda/metabolismo , Microambiente Tumoral , Animais , Linhagem Celular Tumoral , Células-Tronco Hematopoéticas/patologia , Leucemia Mieloide Aguda/patologia , CamundongosRESUMO
Thymocyte development is regulated by complex signaling pathways. How these signaling cascades are coordinated remains elusive. RhoA of the Rho family small GTPases plays an important role in actin cytoskeleton organization, cell adhesion, migration, proliferation, and survival. Nonetheless, the physiological function of RhoA in thymocyte development is not clear. By characterizing a conditional gene targeting mouse model bearing T cell deletion of RhoA, we show that RhoA critically regulates thymocyte development by coordinating multiple developmental events. RhoA gene disruption caused a strong developmental block at the pre-TCR checkpoint and during positive selection. Ablation of RhoA led to reduced DNA synthesis in CD4(-)CD8(-), CD4(+)CD8(-), and CD4(-)CD8(+) thymocytes but not in CD4(+)CD8(+) thymocytes. Instead, RhoA-deficient CD4(+)CD8(+) thymocytes showed an impaired mitosis. Furthermore, we found that abrogation of RhoA led to an increased apoptosis in all thymocyte subpopulations. Importantly, we show that the increased apoptosis was resulted from reduced pre-TCR expression and increased production of reactive oxygen species (ROS), which may be because of an enhanced mitochondrial function, as manifested by increased oxidative phosphorylation, glycolysis, mitochondrial membrane potential, and mitochondrial biogenesis in RhoA-deficient thymocytes. Restoration of pre-TCR expression or treatment of RhoA-deficient mice with a ROS scavenger N-acetylcysteine partially restored thymocyte development. These results suggest that RhoA is required for thymocyte development and indicate, to our knowledge, for the first time that fine-tuning of ROS production by RhoA, through a delicate control of metabolic circuit, may contribute to thymopoiesis.
Assuntos
Marcação de Genes , Mitocôndrias/genética , Mitocôndrias/metabolismo , Timócitos/citologia , Timócitos/metabolismo , Proteína rhoA de Ligação ao GTP/genética , Animais , Antígenos de Superfície , Apoptose/genética , Apoptose/imunologia , Diferenciação Celular , Linhagem da Célula/genética , Linhagem da Célula/imunologia , Sobrevivência Celular/genética , Perfilação da Expressão Gênica , Imunofenotipagem , Camundongos , Camundongos Knockout , Fenótipo , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/metabolismo , Recombinação V(D)J , Proteína rhoA de Ligação ao GTP/deficiênciaRESUMO
As acute myeloid leukemia (AML) xenograft models improve, the potential for using them to evaluate novel therapeutic strategies becomes more appealing. Currently, there is little information on using standard chemotherapy regimens in AML xenografts. Here we have characterized the immunodeficient mouse response to combined Ara-C (cytarabine) and doxorubicin treatment. We observed significant toxicity associated with doxorubicin that required optimization of the route of injection as well as the maximum-tolerated dose for immunodeficient strains. Mice treated with an optimized 5-day induction protocol showed transient weight loss, short-term reduction of peripheral blood cell and platelet counts, and slight anemia. Considerable cytotoxicity was observed in the bone marrow (BM), with primitive LSK cells having a significant survival advantage relative to more mature cells, consistent with the idea of chemotherapy targeting actively growing cells. Treated leukemic mice demonstrated reduced disease burden and increased survival, demonstrating efficacy. AML cells showed significantly increased sensitivity to doxorubicin-containing therapy compared with murine BM cells. Although early treatment could result in some cures, mice with significant leukemia grafts were not cured by using induction therapy alone. Overall, the data show that this model system is useful for the evaluation of novel chemotherapies in combination with standard induction therapy.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Leucemia Mieloide Aguda/tratamento farmacológico , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Linhagem Celular Tumoral , Citarabina/administração & dosagem , Doxorrubicina/administração & dosagem , Vias de Administração de Medicamentos , Resistencia a Medicamentos Antineoplásicos/fisiologia , Hematopoese/efeitos dos fármacos , Humanos , Leucemia Mieloide Aguda/sangue , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos SCID , Camundongos Transgênicos , Resultado do TratamentoRESUMO
AML1-ETO (AE) is a fusion product of translocation (8;21) that accounts for 40% of M2 type acute myeloid leukemia (AML). In addition to its role in promoting preleukemic hematopoietic cell self-renewal, AE represses DNA repair genes, which leads to DNA damage and increased mutation frequency. Although this latter function may promote leukemogenesis, concurrent p53 activation also leads to an increased baseline apoptotic rate. It is unclear how AE expression is able to counterbalance this intrinsic apoptotic conditioning by p53 to promote survival and self-renewal. In this report, we show that Bcl-xL is up-regulated in AE cells and plays an essential role in their survival and self-renewal. Further investigation revealed that Bcl-xL expression is regulated by thrombopoietin (THPO)/MPL-signaling induced by AE expression. THPO/MPL-signaling also controls cell cycle reentry and mediates AE-induced self-renewal. Analysis of primary AML patient samples revealed a correlation between MPL and Bcl-xL expression specifically in t(8;21) blasts. Taken together, we propose that survival signaling through Bcl-xL is a critical and intrinsic component of a broader self-renewal signaling pathway downstream of AML1-ETO-induced MPL.
Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Leucemia Mieloide Aguda/patologia , Proteínas de Fusão Oncogênica/metabolismo , Pré-Leucemia/metabolismo , Pré-Leucemia/patologia , Receptores de Trombopoetina/metabolismo , Trombopoetina/metabolismo , Proteína bcl-X/metabolismo , Animais , Apoptose , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Western Blotting , Ciclo Celular , Diferenciação Celular , Proliferação de Células , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Sangue Fetal/citologia , Sangue Fetal/metabolismo , Feto/citologia , Feto/metabolismo , Citometria de Fluxo , Perfilação da Expressão Gênica , Humanos , Técnicas Imunoenzimáticas , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Fígado/citologia , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos SCID , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas de Fusão Oncogênica/genética , RNA Mensageiro/genética , Proteína 1 Parceira de Translocação de RUNX1 , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Trombopoetina/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Trombopoetina/genética , Proteína bcl-X/genéticaRESUMO
Monocytic acute myeloid leukemia (AML) responds poorly to current treatments, including venetoclax-based therapy. We conducted in vivo and in vitro CRISPR-Cas9 library screenings using a mouse monocytic AML model and identified SETDB1 and its binding partners (ATF7IP and TRIM33) as crucial tumor promoters in vivo. The growth-inhibitory effect of Setdb1 depletion in vivo is dependent mainly on natural killer (NK) cell-mediated cytotoxicity. Mechanistically, SETDB1 depletion upregulates interferon-stimulated genes and NKG2D ligands through the demethylation of histone H3 Lys9 at the enhancer regions, thereby enhancing their immunogenicity to NK cells and intrinsic apoptosis. Importantly, these effects are not observed in non-monocytic leukemia cells. We also identified the expression of myeloid cell nuclear differentiation antigen (MNDA) and its murine counterpart Ifi203 as biomarkers to predict the sensitivity of AML to SETDB1 depletion. Our study highlights the critical and selective role of SETDB1 in AML with granulo-monocytic differentiation and underscores its potential as a therapeutic target for current unmet needs.
Assuntos
Diferenciação Celular , Histona-Lisina N-Metiltransferase , Células Matadoras Naturais , Leucemia Mieloide Aguda , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/imunologia , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/genética , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Animais , Camundongos , Histona-Lisina N-Metiltransferase/metabolismo , Histona-Lisina N-Metiltransferase/genética , Humanos , Camundongos Endogâmicos C57BL , Linhagem Celular Tumoral , Vigilância Imunológica , Monócitos/metabolismo , Monócitos/imunologia , ApoptoseRESUMO
The Rac family of small Rho GTPases coordinates diverse cellular functions in hematopoietic cells including adhesion, migration, cytoskeleton rearrangements, gene transcription, proliferation, and survival. The integrity of Rac signaling has also been found to critically regulate cellular functions in the initiation and maintenance of hematopoietic malignancies. Using an in vivo gene targeting approach, we demonstrate that Rac2, but not Rac1, is critical to the initiation of acute myeloid leukemia in a retroviral expression model of MLL-AF9 leukemogenesis. However, loss of either Rac1 or Rac2 is sufficient to impair survival and growth of the transformed MLL-AF9 leukemia. Rac2 is known to positively regulate expression of Bcl-2 family proteins toward a prosurvival balance. We demonstrate that disruption of downstream survival signaling through antiapoptotic Bcl-2 proteins is implicated in mediating the effects of Rac2 deficiency in MLL-AF9 leukemia. Indeed, overexpression of Bcl-xL is able to rescue the effects of Rac2 deficiency and MLL-AF9 cells are exquisitely sensitive to direct inhibition of Bcl-2 family proteins by the BH3-mimetic, ABT-737. Furthermore, concurrent exposure to NSC23766, a small-molecule inhibitor of Rac activation, increases the apoptotic effect of ABT-737, indicating the Rac/Bcl-2 survival pathway may be targeted synergistically.
Assuntos
Leucemia Aguda Bifenotípica/tratamento farmacológico , Leucemia Aguda Bifenotípica/metabolismo , Neuropeptídeos/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas rac de Ligação ao GTP/antagonistas & inibidores , Aminoquinolinas/farmacologia , Animais , Compostos de Bifenilo/farmacologia , Linhagem Celular Tumoral , Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Leucemia Aguda Bifenotípica/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Camundongos Transgênicos , Neuropeptídeos/deficiência , Neuropeptídeos/genética , Nitrofenóis/farmacologia , Piperazinas/farmacologia , Pirimidinas/farmacologia , Transdução de Sinais , Sulfonamidas/farmacologia , Transplante Heterólogo , Proteína bcl-X/genética , Proteínas rac de Ligação ao GTP/deficiência , Proteínas rac de Ligação ao GTP/genética , Proteínas rac1 de Ligação ao GTP , Proteína RAC2 de Ligação ao GTPRESUMO
Inosine monophosphate dehydrogenase (IMPDH) is a rate-limiting enzyme in de novo guanine nucleotide synthesis pathway. Although IMPDH inhibitors are widely used as effective immunosuppressants, their antitumor effects have not been proven in the clinical setting. Here, we found that acute myeloid leukemias (AMLs) with MLL-fusions are susceptible to IMPDH inhibitors in vitro. We also showed that alternate-day administration of IMPDH inhibitors suppressed the development of MLL-AF9-driven AML in vivo without having a devastating effect on immune function. Mechanistically, IMPDH inhibition induced overactivation of Toll-like receptor (TLR)-TRAF6-NF-κB signaling and upregulation of an adhesion molecule VCAM1, which contribute to the antileukemia effect of IMPDH inhibitors. Consequently, combined treatment with IMPDH inhibitors and the TLR1/2 agonist effectively inhibited the development of MLL-fusion AML. These findings provide a rational basis for clinical testing of IMPDH inhibitors against MLL-fusion AMLs and potentially other aggressive tumors with active TLR signaling.
Assuntos
Leucemia Mieloide Aguda , Proteína de Leucina Linfoide-Mieloide , Humanos , Proteína de Leucina Linfoide-Mieloide/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/patologia , Inibidores Enzimáticos/farmacologia , NF-kappa B , Imunossupressores/uso terapêuticoRESUMO
Aberrant RHO guanine nucleotide exchange factor (RhoGEF) activation is chief mechanism driving abnormal activation of their GTPase targets in transformation and tumorigenesis. Consequently, a small-molecule inhibitor of RhoGEF can make an anti-cancer drug. We used cellular, mouse, and humanized models of RAC-dependent BCR-ABL1-driven and Ph-like acute lymphoblastic leukemia to identify VAV3, a tyrosine phosphorylation-dependent RacGEF, as the target of the small molecule IODVA1. We show that through binding to VAV3, IODVA1 inhibits RAC activation and signaling and increases pro-apoptotic activity in BCR-ABL1-transformed cells. Consistent with this mechanism of action, cellular and animal models of BCR-ABL1-induced leukemia in Vav3-null background do not respond to IODVA1. By durably decreasing in vivo RAC signaling, IODVA1 eradicates leukemic propagating activity of TKI-resistant BCR-ABL1(T315I) B-ALL cells after treatment withdrawal. Importantly, IODVA1 suppresses the leukemic burden in the treatment refractory pediatric Ph+ and TKI-resistant Ph+ B-ALL patient-derived xenograft models better than standard-of-care dasatinib or ponatinib and provides a more durable response after treatment withdrawal. Pediatric leukemia samples with diverse genetic lesions show high sensitivity to IODVA1 ex vivo and this sensitivity is VAV3 dependent. IODVA1 thus spearheads a novel class of drugs that inhibits a RacGEF and holds promise as an anti-tumor therapy.
Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-vav/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Animais , Antineoplásicos/uso terapêutico , Feminino , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos SCID , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas c-vav/metabolismo , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/uso terapêutico , Células Tumorais CultivadasRESUMO
We report a novel glucose-6-phosphate dehydrogenase (G6PD) mutation, which we propose to name G6PD Cincinnati (c.1037A > T, p.N346I), found in combination with G6PD Gastonia (c.637G > T, p.V213L) in an infant who presented with neonatal cholestasis. The G6PD Cincinnati mutation results in a non-conservative amino acid substitution at the tetramer interface disturbing its formation, as seen by native gel electrophoresis and immunoblotting. G6PD Gastonia disrupts dimerization of the enzyme and by itself causes chronic non-spherocytic hemolytic anemia. The G6PD Cincinnati mutation may have aggravated the clinical picture of G6PD Gastonia with the result of severe perinatal hemolysis causing cholestasis and associated liver injury.
Assuntos
Colestase/etiologia , Deficiência de Glucosefosfato Desidrogenase/genética , Glucosefosfato Desidrogenase/genética , Hiperbilirrubinemia Neonatal/etiologia , Mutação/genética , Sequência de Aminoácidos , Substituição de Aminoácidos , Colestase/enzimologia , Colestase/patologia , DNA/genética , Deficiência de Glucosefosfato Desidrogenase/enzimologia , Humanos , Hiperbilirrubinemia Neonatal/enzimologia , Hiperbilirrubinemia Neonatal/patologia , Recém-Nascido , Masculino , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Homologia de Sequência de AminoácidosRESUMO
Immune therapies such as blinatumomab, CD19-directed bispecific CD3 T-cell Engager (BiTE), have resulted in significant improvements in outcomes for relapsed B-cell acute lymphoblastic leukemia (B-ALL). However, up to half of blinatumomab treated patients do not respond completely or relapse after therapy. As a result, there is a need to identify potential strategies to improve the efficacy of BiTE therapy. The anti-PD-1 antibody pembrolizumab has been shown to successfully activate T cells against a wide range of cancer types. Here, we tested the ability of umbilical cord blood (UCB) reconstituted mice to respond to blinatumomab therapy with or without concurrent pembrolizumab treatment. Humanized mice were engrafted with patient-derived xenograft (PDX) cells derived from pediatric and adolescent/young adult (AYA) B-ALL patients who had either failed to achieve remission with negative minimum residual disease (MRD negative) or experienced a relapse. Mock-treated humanized mice engrafted with PDX cells efficiently developed overt disease within 30 days of engraftment of B-ALL. However, single agent therapy with either blinatumomab or pembrolizumab reduced disease burden in engrafted mice, with some mice observed to be MRD negative after the 28-day treatment course. Combination therapy significantly improved the percentage of MRD negative mice and improved long-term survival and cure rates as compared to mice that were given blinatumomab alone. Importantly, no benefits were observed in treated mice that lacked human immune cell reconstitution. These results indicate that UCB-humanized NRGS mice develop activatable immune function, and UCB-humanized PDX leukemia models can be used in preclinical studies to evaluate specificity, efficacy, and cooperativity of immune therapies in B-ALL.
RESUMO
PURPOSE: The US Food and Drug Administration-expanded access program (EAP) uses a single patient use (SPU) mechanism to provide patient access to investigational agents in situations where no satisfactory or comparable therapy is available. Genomic profiling of de novo and relapsed or refractory childhood cancer has led to increased identification of new drug targets in the last decade. The aim of this study is to examine the SPU experience for genomically targeted therapies in patients with pediatric cancer. PATIENTS AND METHODS: All genomically targeted therapeutic SPUs obtained over a 5-year period were evaluated at four large pediatric cancer programs. Data were collected on the type of neoplasm, agents requested, corresponding molecularly informed targets, and clinical outcomes. RESULTS: A total of 45 SPUs in 44 patients were identified. Requests were predominantly made for CNS and solid tumors (84.4%) compared with hematologic malignancies (15.6%). Lack of an available clinical trial was the main reason for SPU initiation (64.4%). The median time from US Food and Drug Administration submission to approval was 3 days (range, 0-12 days) and from Institutional Review Board submission to approval was 5 days (range, 0-50 days). Objective tumor response was seen in 39.5% (15 of 38) of all evaluable SPUs. Disease progression was the primary reason for discontinuation of drug (66.7%) followed by toxicity (13.3%). CONCLUSION: SPU requests remain an important mechanism for pediatric access to genomically targeted agents given the limited availability of targeted clinical trials for children with high-risk neoplasms. Furthermore, this subset of SPUs resulted in a substantial number of objective tumor responses. The development of a multi-institutional data registry of SPUs may enable systematic review of toxicity and clinical outcomes and provide evidence-based access to new drugs in rare pediatric cancers.
Assuntos
Genômica/métodos , Neoplasias/genética , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Adulto JovemRESUMO
FOXM1, a known transcription factor, promotes cell proliferation in a variety of cancer cells. Here we show that Foxm1 is required for survival, quiescence and self-renewal of MLL-AF9 (MA9)-transformed leukemia stem cells (LSCs) in vivo. Mechanistically, Foxm1 upregulation activates the Wnt/ß-catenin signaling pathways by directly binding to ß-catenin and stabilizing ß-catenin protein through inhibiting its degradation, thereby preserving LSC quiescence, and promoting LSC self-renewal in MLL-rearranged AML. More importantly, inhibition of FOXM1 markedly suppresses leukemogenic potential and induces apoptosis of primary LSCs from MLL-rearranged AML patients in vitro and in vivo in xenograft mice. Thus, our study shows a critical role and mechanisms of Foxm1 in MA9-LSCs, and indicates that FOXM1 is a potential therapeutic target for selectively eliminating LSCs in MLL-rearranged AML.
Assuntos
Proteína Forkhead Box M1/metabolismo , Regulação Leucêmica da Expressão Gênica , Leucemia Mieloide Aguda/genética , Células-Tronco Neoplásicas/patologia , Animais , Apoptose/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Proteína Forkhead Box M1/antagonistas & inibidores , Proteína Forkhead Box M1/genética , Rearranjo Gênico , Humanos , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Knockout , Proteína de Leucina Linfoide-Mieloide/genética , Proteínas de Fusão Oncogênica/genética , Cultura Primária de Células , RNA-Seq , Regulação para Cima , Via de Sinalização Wnt/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Our previous study revealed that expression of G protein-coupled receptor 68 (GPR68) was upregulated in MDSL cells, a cell line representing myelodysplastic syndromes (MDS), in response to lenalidomide (LEN), and mediated a calcium/calpain proapoptotic pathway. Isx, a GPR68 agonist, enhanced the sensitivity to LEN in MDSL cells. The fact that Isx is not a U.S. Food and Drug Administration-approved drug prompts us to look for alternative candidates that could enhance the sensitivity of LEN in MDS as well as other hematologic malignancies, such as acute myeloid leukemia (AML). In the study described here, we found that regulator of calcineurin 1 (RCAN1), an endogenous inhibitor of calcineurin (CaN), was upregulated in MDSL cells in response to LEN, possibly through degradation of IKZF1. Consistently, cyclosporin (Cys), a pharmacological inhibitor of CaN, inhibited the activity of CaN and induced apoptosis in MDSL cells, indicating that CaN provided a prosurvival signal in MDSL cells. In addition, Cys enhanced the cytotoxic effect of LEN in MDS/AML cell lines as well as primary bone marrow cells from MDS patients and AML patient-derived xenograft models. Intriguingly, pretreatment with LEN reversed the suppressive effect of Cys on T-cell activation. Our study suggests a novel mechanism of action of LEN in mediating cytotoxicity in MDS/AML via upregulation of RCAN1, thus inhibiting the CaN prosurvival pathway. Our study also suggests that Cys enhances the sensitivity to LEN in MDS/AML cells without compromising T-cell activation.