RESUMEN
Treating refractory pediatric acute lymphoblastic leukemia (ALL) remains a challenge despite impressive remission rates (>90%) achieved in the last decade. The use of innovative immunotherapeutic approaches such as anti-CD19 chimeric antigen receptor T cells does not ensure durable remissions, because leukemia-propagating cells (LPCs) that lack expression of CD19 can cause relapse, which signifies the need to identify new markers of ALL. Here we investigated expression of CD58, CD97, and CD200, which were previously shown to be overexpressed in B-cell precursor ALL (BCP-ALL) in CD34+/CD19+, CD34+/CD19-, CD34-/CD19+, and CD34-/CD19- LPCs, to assess their potential as therapeutic targets. Whole-genome microarray and flow cytometric analyses showed significant overexpression of these molecules compared with normal controls. CD58 and CD97 were mainly co-expressed with CD19 and were not a prerequisite for leukemia engraftment in immune deficient mice. In contrast, expression of CD200 was essential for engraftment and serial transplantation of cells in measurable residual disease (MRD) low-risk patients. Moreover, these CD200+ LPCs could be targeted by using the monoclonal antibody TTI-CD200 in vitro and in vivo. Treating mice with established disease significantly reduced disease burden and extended survival. These findings demonstrate that CD200 could be an attractive target for treating low-risk ALL, with minimal off-tumor effects that beset current immunotherapeutic approaches.
Asunto(s)
Leucemia-Linfoma Linfoblástico de Células Precursoras B , Leucemia-Linfoma Linfoblástico de Células Precursoras , Animales , Antígenos CD19 , Niño , Citometría de Flujo , Humanos , Ratones , Neoplasia Residual , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológicoRESUMEN
Relapse of paediatric acute lymphoblastic leukaemia (ALL) may occur due to persistence of resistant cells with leukaemia-propagating ability (LPC). In leukaemia, the balance of B-cell lymphoma-2 (BCL-2) family proteins is disrupted, promoting survival of malignant cells and possibly LPC. A direct comparison of BCL-2 inhibitors, navitoclax and venetoclax, was undertaken on LPC subpopulations from B-cell precursor (BCP) and T-cell ALL (T-ALL) cases in vitro and in vivo. Responses were compared to BCL-2 levels detected by microarray analyses and Western blotting. In vitro, both drugs were effective against most BCP-ALL LPC, except CD34- /CD19- cells. In contrast, only navitoclax was effective in T-ALL and CD34- /CD7- LPC were resistant to both drugs. In vivo, navitoclax was more effective than venetoclax, significantly improving survival of mice engrafted with BCP- and T-ALL samples. Venetoclax was not particularly effective against T-ALL cases in vivo. The proportions of CD34+ /CD19- , CD34- /CD19- BCP-ALL cells and CD34- /CD7- T-ALL cells increased significantly following in vivo treatment. Expression of pro-apoptotic BCL-2 genes was lower in these subpopulations, which may explain the lack of sensitivity. These data demonstrate that some LPC were resistant to BCL-2 inhibitors and sustained remission will require their use in combination with other therapeutics.
Asunto(s)
Compuestos de Anilina/uso terapéutico , Antineoplásicos/uso terapéutico , Compuestos Bicíclicos Heterocíclicos con Puentes/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamiento farmacológico , Proteínas Proto-Oncogénicas c-bcl-2/antagonistas & inhibidores , Sulfonamidas/uso terapéutico , Adolescente , Niño , Preescolar , Femenino , Humanos , Masculino , Proteínas Proto-Oncogénicas c-bcl-2/análisis , Resultado del TratamientoRESUMEN
There have been sporadic reports of the development of delayed disease recurrence after bone marrow transplantation for severe aplastic anemia despite sustained majority or full donor chimerism. This is termed "donor-type aplasia" (DTA). We describe the management and outcome of 11 pediatric patients from 8 institutions in Europe, the United States, and the Middle East who developed DTA at a mean of 35 months post-transplant. These patients were initially transplanted at a mean age of 10.0 years (range, 5.8 to 16.0 years), 9 from matched sibling donors and 2 from matched unrelated donors. Attempts to treat DTA with varying combinations of additional immunosuppression (including intravenous immunoglobulin, donor lymphocyte infusions, stem cell boosts, and other therapies) failed. Ten patients have received a conditioned second transplant, 9 from the same donor and 1 from a new matched unrelated donor. Aplasia has resolved in the remaining patient in response to ongoing eltrombopag therapy. All patients were alive at a mean of 92 months (range, 26 to 195) after a second transplant; 6 are in complete remission, but 4 suffered from second/recurrent DTA at 16 to 129 months after retransplant and required further transplant therapy.
Asunto(s)
Anemia Aplásica , Enfermedad Injerto contra Huésped , Trasplante de Células Madre Hematopoyéticas , Adolescente , Anemia Aplásica/terapia , Trasplante de Médula Ósea/efectos adversos , Niño , Preescolar , Quimerismo , Europa (Continente) , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Humanos , RecurrenciaRESUMEN
Current therapies for childhood T-cell acute lymphoblastic leukemia have increased survival rates to above 85% in developed countries. Unfortunately, some patients fail to respond to therapy and many suffer from serious side effects, highlighting the need to investigate other agents to treat this disease. Parthenolide, a nuclear factor kappa (κ)B inhibitor and reactive oxygen species inducer, has been shown to have excellent anti-cancer activity in pediatric leukemia xenografts, with minimal effects on normal hemopoietic cells. However, some leukemia initiating cell populations remain resistant to parthenolide. This study examined mechanisms for this resistance, including protective effects conferred by bone marrow stromal components. T-cell acute leukemia cells co-cultured with mesenchymal stem cells demonstrated significantly enhanced survival against parthenolide (73±11%) compared to cells treated without mesenchymal stem cell support (11±9%). Direct cell contact between mesenchymal cells and leukemia cells was not required to afford protection from parthenolide. Mesenchymal stem cells released thiols and protected leukemia cells from reactive oxygen species stress, which is associated with parthenolide cytotoxicity. Blocking cystine uptake by mesenchymal stem cells, using a small molecule inhibitor, prevented thiol release and significantly reduced leukemia cell resistance to parthenolide. These data indicate it may be possible to achieve greater toxicity to childhood T-cell acute lymphoblastic leukemia by combining parthenolide with inhibitors of cystine uptake.
Asunto(s)
Resistencia a Antineoplásicos/efectos de los fármacos , Sesquiterpenos/farmacología , Adolescente , Biomarcadores , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Niño , Preescolar , Técnicas de Cocultivo , Relación Dosis-Respuesta a Droga , Femenino , Glutatión/metabolismo , Humanos , Masculino , Células Madre Mesenquimatosas/efectos de los fármacos , Células Madre Mesenquimatosas/metabolismo , Estrés Oxidativo/efectos de los fármacos , Leucemia-Linfoma Linfoblástico de Células T Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Sesquiterpenos/uso terapéuticoAsunto(s)
Proteínas HSP90 de Choque Térmico/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Benzoquinonas/farmacología , Supervivencia Celular/efectos de los fármacos , Niño , Relación Dosis-Respuesta a Droga , Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Humanos , Lactamas Macrocíclicas/farmacología , Terapia Molecular Dirigida , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Transducción de Señal/efectos de los fármacosRESUMEN
A significant number of children with T-lineage acute lymphoblastic leukemia (T-ALL) fail to respond to therapy and experience early relapse. CD99 has been shown to be overexpressed on T-ALL cells and is considered to be a reliable detector of the disease. However, the relevance of CD99 overexpression in ALL has not been investigated in a functional context. The aim of this study was to investigate the functional capacity of CD99+ cells in childhood ALL and determine the suitability of CD99 as a therapeutic target. Flow cytometric analyses confirmed higher expression of CD99 in ALL blasts (81.5±22.7%) compared to normal hemopoietic stem cells (27.5±21.9%) and T cells (3.1±5.2%, P≤0.004). When ALL cells were sorted and assessed in functional assays, all 4 subpopulations (CD34+/CD99+, CD34+/CD99-, CD34-/CD99+ and CD34-/CD99-) could proliferate in vitro and establish leukemia in NSG mice. Leukemia propagating cell frequencies ranged from 1 in 300 to 1 in 7.4x104 but were highest in the CD34+/CD99- subpopulation. In addition, all four subpopulations had self-renewal ability in secondary NSG mice. Cells in each subpopulation contained patient specific TCR rearrangements and karyotypic changes that were preserved with passage through serial NSG transplants. Despite high levels of CD99 antigen on the majority of blast cells, leukemia initiating capacity in vivo was not restricted to cells that express this protein. Consequently, targeting CD99 alone would not eliminate all T-ALL cells with the ability to maintain the disease. The challenge remains to develop therapeutic strategies that can eliminate all leukemia cells with self-renewal capacity in vivo.
Asunto(s)
Antígeno 12E7/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patología , Adolescente , Animales , Antígenos CD34/metabolismo , Células de la Médula Ósea/citología , Células de la Médula Ósea/metabolismo , Proliferación Celular , Células Cultivadas , Niño , Preescolar , Femenino , Citometría de Flujo , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Humanos , Hibridación Fluorescente in Situ , Cariotipo , Masculino , Ratones , Ratones Endogámicos NOD , Leucemia-Linfoma Linfoblástico de Células T Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/metabolismo , Linfocitos T/citología , Linfocitos T/metabolismoRESUMEN
Hyperglycemia during induction chemotherapy for childhood acute lymphoblastic leukemia (ALL) has been inconsistently associated with risk of infection. We investigated the incidence of hyperglycemia during induction for childhood ALL in a retrospective cohort study of 144 patients treated on a single national protocol (UKALL2003) and explored its association with infection. All patients received dexamethasone. Overt hyperglycemia was seen in 36% and proven bacterial or fungal infection was most common in this group (OR 4.1 (1.1-15.6), P = 0.039). Both hyperglycaemia and infection were particularly common in patients with Down Syndrome.
Asunto(s)
Infecciones Bacterianas/etiología , Hiperglucemia/etiología , Quimioterapia de Inducción/efectos adversos , Micosis/etiología , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Infecciones Bacterianas/epidemiología , Niño , Preescolar , Femenino , Humanos , Hiperglucemia/epidemiología , Incidencia , Masculino , Micosis/epidemiología , Factores de RiesgoRESUMEN
Approximately 20% of children with acute lymphoblastic leukemia (ALL) relapse because of failure to eradicate the disease. Current drug efficacy studies focus on reducing leukemia cell burden. However, if drugs have limited effects on leukemia-initiating cells (LICs), then these cells may expand and eventually cause relapse. Parthenolide (PTL) has been shown to cause apoptosis of LIC in acute myeloid leukemia. In the present study, we assessed the effects of PTL on LIC populations in childhood ALL. Apoptosis assays demonstrated that PTL was effective against bulk B- and T-ALL cells, whereas the CD34(+)/CD19(-), CD34(+)/CD7(-), and CD34(-) subpopulations were more resistant. However, functional analyses revealed that PTL treatment prevented engraftment of multiple LIC populations in NOD/LtSz-scid IL-2Rγ(c)-null mice. PTL treatment of mice with established leukemias from low- and high-risk patients resulted in survival and restoration of normal murine hemopoiesis. In only 3 cases, disease progression was significantly slowed in mice engrafted with CD34(+)/CD19(-) or CD34(+)/CD7(-) and CD34(-) cells, but was not prevented, demonstrating that individual LIC populations within patients have different responses to therapy. These observations indicate that PTL may have therapeutic potential in childhood ALL and provide a basis for developing effective therapies that eradicate all LIC populations to prevent disease progression and reduce relapse.