RESUMEN
Leukemias expressing constitutively activated mutants of ABL1 tyrosine kinase (BCR-ABL1, TEL-ABL1, NUP214-ABL1) usually contain at least 1 normal ABL1 allele. Because oncogenic and normal ABL1 kinases may exert opposite effects on cell behavior, we examined the role of normal ABL1 in leukemias induced by oncogenic ABL1 kinases. BCR-ABL1-Abl1(-/-) cells generated highly aggressive chronic myeloid leukemia (CML)-blast phase-like disease in mice compared with less malignant CML-chronic phase-like disease from BCR-ABL1-Abl1(+/+) cells. Additionally, loss of ABL1 stimulated proliferation and expansion of BCR-ABL1 murine leukemia stem cells, arrested myeloid differentiation, inhibited genotoxic stress-induced apoptosis, and facilitated accumulation of chromosomal aberrations. Conversely, allosteric stimulation of ABL1 kinase activity enhanced the antileukemia effect of ABL1 tyrosine kinase inhibitors (imatinib and ponatinib) in human and murine leukemias expressing BCR-ABL1, TEL-ABL1, and NUP214-ABL1. Therefore, we postulate that normal ABL1 kinase behaves like a tumor suppressor and therapeutic target in leukemias expressing oncogenic forms of the kinase.
Asunto(s)
Crisis Blástica/genética , Genes Supresores de Tumor , Genes abl , Leucemia Experimental/genética , Leucemia Mieloide de Fase Crónica/genética , Proteínas Oncogénicas v-abl/fisiología , Proteínas de Fusión Oncogénica/fisiología , Proteínas Proto-Oncogénicas c-abl/fisiología , Proteínas Supresoras de Tumor/fisiología , Animales , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Crisis Blástica/tratamiento farmacológico , Crisis Blástica/enzimología , Crisis Blástica/patología , División Celular/efectos de los fármacos , Línea Celular Tumoral , Citostáticos/farmacología , Regulación Leucémica de la Expresión Génica/efectos de los fármacos , Inestabilidad Genómica , Humanos , Mesilato de Imatinib/farmacología , Mesilato de Imatinib/uso terapéutico , Imidazoles/farmacología , Imidazoles/uso terapéutico , Leucemia Experimental/tratamiento farmacológico , Leucemia Experimental/enzimología , Leucemia Experimental/patología , Leucemia Mieloide de Fase Crónica/tratamiento farmacológico , Leucemia Mieloide de Fase Crónica/enzimología , Leucemia Mieloide de Fase Crónica/patología , Ratones , Ratones Endogámicos NOD , Ratones SCID , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/fisiología , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/enzimología , Proteínas Oncogénicas v-abl/antagonistas & inhibidores , Proteínas Oncogénicas v-abl/genética , Proteínas de Fusión Oncogénica/antagonistas & inhibidores , Proteínas de Fusión Oncogénica/genética , Estrés Oxidativo , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Proto-Oncogénicas c-abl/genética , Piridazinas/farmacología , Piridazinas/uso terapéutico , Proteínas Supresoras de Tumor/antagonistas & inhibidores , Proteínas Supresoras de Tumor/genéticaRESUMEN
Genomic instability is a hallmark of chronic myeloid leukemia in chronic phase (CML-CP) resulting in BCR-ABL1 mutations encoding resistance to tyrosine kinase inhibitors (TKIs) and/or additional chromosomal aberrations leading to disease relapse and/or malignant progression. TKI-naive and TKI-treated leukemia stem cells (LSCs) and leukemia progenitor cells (LPCs) accumulate high levels of reactive oxygen species (ROS) and oxidative DNA damage. To determine the role of TKI-refractory LSCs in genomic instability, we used a murine model of CML-CP where ROS-induced oxidative DNA damage was elevated in LSCs, including quiescent LSCs, but not in LPCs. ROS-induced oxidative DNA damage in LSCs caused clinically relevant genomic instability in CML-CP-like mice, such as TKI-resistant BCR-ABL1 mutations (E255K, T315I, H396P), deletions in Ikzf1 and Trp53, and additions in Zfp423 and Idh1. Despite inhibition of BCR-ABL1 kinase, imatinib did not downregulate ROS and oxidative DNA damage in TKI-refractory LSCs to the levels detected in normal cells, and CML-CP-like mice treated with imatinib continued to accumulate clinically relevant genetic aberrations. Inhibition of class I p21-activated protein kinases by IPA3 downregulated ROS in TKI-naive and TKI-treated LSCs. Altogether, we postulate that genomic instability may originate in the most primitive TKI-refractory LSCs in TKI-naive and TKI-treated patients.
Asunto(s)
Antineoplásicos/uso terapéutico , Benzamidas/uso terapéutico , Resistencia a Antineoplásicos/genética , Inestabilidad Genómica , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Células Madre Neoplásicas/fisiología , Piperazinas/uso terapéutico , Pirimidinas/uso terapéutico , Animales , Células Cultivadas , Daño del ADN/efectos de los fármacos , Inestabilidad Genómica/efectos de los fármacos , Inestabilidad Genómica/fisiología , Humanos , Mesilato de Imatinib , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Ratones , Ratones Transgénicos , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/genética , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Especies Reactivas de Oxígeno/metabolismoRESUMEN
PARP inhibitors (PARPis) have been used to induce synthetic lethality in BRCA-deficient tumors in clinical trials with limited success. We hypothesized that RAD52-mediated DNA repair remains active in PARPi-treated BRCA-deficient tumor cells and that targeting RAD52 should enhance the synthetic lethal effect of PARPi. We show that RAD52 inhibitors (RAD52is) attenuated single-strand annealing (SSA) and residual homologous recombination (HR) in BRCA-deficient cells. Simultaneous targeting of PARP1 and RAD52 with inhibitors or dominant-negative mutants caused synergistic accumulation of DSBs and eradication of BRCA-deficient but not BRCA-proficient tumor cells. Remarkably, Parp1-/-;Rad52-/- mice are normal and display prolonged latency of BRCA1-deficient leukemia compared with Parp1-/- and Rad52-/- counterparts. Finally, PARPi+RAD52i exerted synergistic activity against BRCA1-deficient tumors in immunodeficient mice with minimal toxicity to normal cells and tissues. In conclusion, our data indicate that addition of RAD52i will improve therapeutic outcome of BRCA-deficient malignancies treated with PARPi.
Asunto(s)
Proteína BRCA1/genética , Proteína BRCA2/genética , Poli(ADP-Ribosa) Polimerasa-1/genética , Proteína Recombinante y Reparadora de ADN Rad52/genética , Animales , Proteína BRCA1/deficiencia , Proteína BRCA2/deficiencia , Reparación del ADN/efectos de los fármacos , Femenino , Proteínas de Fusión bcr-abl/genética , Proteínas de Fusión bcr-abl/metabolismo , Recombinación Homóloga/efectos de los fármacos , Humanos , Mesilato de Imatinib/farmacología , Estimación de Kaplan-Meier , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/mortalidad , Leucemia Mieloide Aguda/patología , Masculino , Ratones , Ratones Endogámicos NOD , Ratones Noqueados , Ftalazinas/farmacología , Piperazinas/farmacología , Poli(ADP-Ribosa) Polimerasa-1/antagonistas & inhibidores , Poli(ADP-Ribosa) Polimerasa-1/deficiencia , Proteína Recombinante y Reparadora de ADN Rad52/antagonistas & inhibidores , Proteína Recombinante y Reparadora de ADN Rad52/deficiencia , Mutaciones Letales Sintéticas , Proteína 1 de Unión al Supresor Tumoral P53/deficiencia , Proteína 1 de Unión al Supresor Tumoral P53/genéticaRESUMEN
Prolonged exit from quiescence by hematopoietic stem cells (HSCs) progressively impairs their homeostasis in the bone marrow through an unidentified mechanism. We show that Rb proteins, which are major enforcers of quiescence, maintain HSC homeostasis by positively regulating thrombopoietin (Tpo)-mediated Jak2 signaling. Rb family protein inactivation triggers the progressive E2f-mediated transactivation of Socs3, a potent inhibitor of Jak2 signaling, in cycling HSCs. Aberrant activation of Socs3 impairs Tpo signaling and leads to impaired HSC homeostasis. Therefore, Rb proteins act as a central hub of quiescence and homeostasis by coordinating the regulation of both cell cycle and Jak2 signaling in HSCs.
Asunto(s)
Células Madre Hematopoyéticas/metabolismo , Homeostasis/genética , Proteína de Retinoblastoma/genética , Proteína p107 Similar a la del Retinoblastoma/genética , Proteína p130 Similar a la del Retinoblastoma/genética , Proteína 3 Supresora de la Señalización de Citocinas/genética , Animales , Ciclo Celular/genética , División Celular/genética , Proliferación Celular/genética , Factores de Transcripción E2F/genética , Factores de Transcripción E2F/metabolismo , Perfilación de la Expresión Génica/métodos , Immunoblotting , Janus Quinasa 2/genética , Janus Quinasa 2/metabolismo , Ratones Noqueados , Ratones Transgénicos , Fosforilación/efectos de los fármacos , Interferencia de ARN , Proteína de Retinoblastoma/metabolismo , Proteína p107 Similar a la del Retinoblastoma/metabolismo , Proteína p130 Similar a la del Retinoblastoma/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Proteína 3 Supresora de la Señalización de Citocinas/metabolismo , Trombopoyetina/farmacología , Activación TranscripcionalRESUMEN
Quiescent and proliferating leukemia cells accumulate highly lethal DNA double-strand breaks that are repaired by 2 major mechanisms: BRCA-dependent homologous recombination and DNA-dependent protein kinase-mediated (DNA-PK-mediated) nonhomologous end-joining, whereas DNA repair pathways mediated by poly(ADP)ribose polymerase 1 (PARP1) serve as backups. Here we have designed a personalized medicine approach called gene expression and mutation analysis (GEMA) to identify BRCA- and DNA-PK-deficient leukemias either directly, using reverse transcription-quantitative PCR, microarrays, and flow cytometry, or indirectly, by the presence of oncogenes such as BCR-ABL1. DNA-PK-deficient quiescent leukemia cells and BRCA/DNA-PK-deficient proliferating leukemia cells were sensitive to PARP1 inhibitors that were administered alone or in combination with current antileukemic drugs. In conclusion, GEMA-guided targeting of PARP1 resulted in dual cellular synthetic lethality in quiescent and proliferating immature leukemia cells, and is thus a potential approach to eradicate leukemia stem and progenitor cells that are responsible for initiation and manifestation of the disease. Further, an analysis of The Cancer Genome Atlas database indicated that this personalized medicine approach could also be applied to treat numerous solid tumors from individual patients.