RESUMO
Essential for cell survival, the 90 kD Heat Shock Proteins (HSP90) are molecular chaperons required for conformational stabilization and trafficking of numerous client proteins. Functional HSP90 is required for the stability of AKT, a serine-threonine kinase phosphorylated in response to growth factor stimulation. AKT plays a crucial regulatory role in differentiation, cell cycle, transcription, translation, metabolism and apoptosis. Acute promyelocytic leukaemia (APL) is characterized by the presence of the promyelocytic leukaemia/retinoic acid receptor alpha (PML/RARA) fusion protein, which deregulates expression of several genes involved in differentiation and apoptosis. Here, we report inhibition of HSP90AA1 and HSP90AB1 isomer transcription in blasts isolated from patients with APL, associated with reduction of HSP90 protein expression and loss of control on AKT protein phosphorylation. We show that in vitro treatment of PML/RARA expressing cells with all-trans retinoic acid (ATRA) up-regulates HSP90 expression and stabilizes AKT. Addition of the HSP90-inhibitor 17-(allylamino)-17-demethoxygeldanamycin in combination with ATRA, blocks upregulation of AKT protein, indicating that HSP90 is necessary for ATRA action on AKT. This is the first report proving that expression of HSP90 isomers are directly and differentially repressed by PML/RARA, with critical results on cellular homeostasis of target proteins, such as AKT, in APL blasts.
Assuntos
Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Leucemia Promielocítica Aguda/tratamento farmacológico , Proteínas de Fusão Oncogênica/metabolismo , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Benzoquinonas/farmacologia , Células HEK293 , Proteínas de Choque Térmico HSP90/biossíntese , Proteínas de Choque Térmico HSP90/genética , Histonas/genética , Histonas/metabolismo , Humanos , Lactamas Macrocíclicas/farmacologia , Leucemia Promielocítica Aguda/patologia , Proteínas de Fusão Oncogênica/biossíntese , Proteínas de Fusão Oncogênica/genética , Regiões Promotoras Genéticas , Proteína da Leucemia Promielocítica/biossíntese , Proteína da Leucemia Promielocítica/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Receptor alfa de Ácido Retinoico/biossíntese , Receptor alfa de Ácido Retinoico/genética , Transfecção , Tretinoína/farmacologia , Células Tumorais Cultivadas , Regulação para Cima/efeitos dos fármacosRESUMO
The effect of high doses of intravenous (sodium) ascorbate (ASC) in the treatment of cancer has been controversial although there is growing evidence that ASC in high (pharmacologic) concentrations induces dose-dependent pro-apoptotic death of tumor cells, in vitro. Very few data are available on the role of ASC in the treatment of acute myeloid leukemia (AML). Ascorbate behaves as an antioxidant at low (physiologic), and as pro-oxidant at pharmacologic, concentrations, and this may account for the differences reported in different experimental settings, when human myeloid cell lines, such as HL60, were treated with ASC. Considering the myeloid origin of HL60 cells, and previous literature reports showing that some cell lines belonging to the myeloid lineage could be sensitive to the pro-apoptotic effects of high concentrations of ASC, we investigated in more details the effects of high doses (0.5 to 7 mM) of ASC in vitro, on a variety of human myeloid cell lines including the following: HL60, U937, NB4, NB4-R4 (retinoic acid [RA]-resistant), NB4/AsR (ATO-resistant) acute promyelocytic leukemia (APL)-derived cell lines, and K562 as well as on normal CD34+ progenitors derived from human cord blood. Our results indicate that all analyzed cell lines including all-trans retinoic acid (ATRA)- and arsenic trioxide (ATO)-resistant ones are highly sensitive to the cytotoxic, pro-oxidant effects of high doses of ASC, with an average 50 % lethal concentration (LC50) of 3 mM, depending on cell type, ASC concentration, and time of exposure. Conversely, high doses of ASC neither did exert significant cytotoxic effects nor impaired the differentiation potential in cord blood (CB) CD34+ normal cells. Since plasma ASC concentrations within the millimolar (mM) range can be easily and safely reached by intravenous administration, we conclude that phase I/II clinical trials using high doses of ASC should be designed for patients with advanced/refractory AML and APL.
Assuntos
Ácido Ascórbico/farmacologia , Citotoxinas/farmacologia , Células Mieloides/efeitos dos fármacos , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular , Relação Dose-Resposta a Droga , Células HL-60 , Humanos , Peróxido de Hidrogênio/metabolismo , Células K562 , Células Mieloides/fisiologia , Oxirredução/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Células U937Assuntos
Antineoplásicos/uso terapêutico , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Mieloide Aguda/tratamento farmacológico , Neoplasias Primárias Múltiplas/tratamento farmacológico , Sulfonamidas/uso terapêutico , Idoso , Feminino , Humanos , Leucemia Linfocítica Crônica de Células B/diagnóstico , Leucemia Mieloide Aguda/diagnóstico , Síndromes Mielodisplásicas/diagnóstico , Neoplasias Primárias Múltiplas/diagnóstico , Indução de RemissãoRESUMO
CONTEXT: We have previously reported that benznidazole (BZL), known for its trypanocidal action, has anti-proliferative activity against different cell lines like HeLa and Raw 264.7 among others. At the moment, it has not been reported if the anti-proliferative effect of BZL is similar for non-adherent hematopoietic cells like was reported for adherent cancer cell lines. OBJECTIVE: We aimed to investigate the efficacy of BZL on the growth of the leukemic cell lines THP-1 and OCI/AML3. MATERIALS AND METHODS: We evaluated cell proliferation by [³H]-thymidine incorporation and MTT reduction as well as cell death by lactate dehydrogenase (LDH) activity. We assessed apoptosis by flow cytometry for detection of annexin V-positive and propidium iodide-negative cells, along with nuclear morphology by diamidino-2-phenolindole (DAPI) staining. Western blot studies were performed to evaluate changes in cell cycle proteins in BZL-treated cells. RESULTS: BZL significantly reduced proliferation of both cell lines without inducing cell death. Likewise it produced no significant differences in apoptosis between treated cells and controls. In addition, flow cytometry analysis indicated that BZL caused a larger number of THP-1 cells in G0/G1 phase and a smaller number of cells in S phase than controls. This was accompanied with an increase in the expression of the CDK inhibitor p27 and of cyclin D1, with no significant differences in the protein levels of CDK1, CDK2, CDK4, cyclins E, A and B as compared to controls. CONCLUSION: BZL inhibits the proliferation of leukemic non-adherent cells by controlling cell cycle at G0/G1 cell phase through up-regulation of p27.
Assuntos
Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Leucemia Monocítica Aguda/metabolismo , Nitroimidazóis/farmacologia , Tripanossomicidas/farmacologia , Morte Celular/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p27/biossíntese , Quinases Ciclina-Dependentes/biossíntese , Ciclinas/biossíntese , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Células HeLa , Humanos , Leucemia Monocítica Aguda/patologia , Proteínas de Neoplasias/biossínteseRESUMO
Neutral lipid storage disease type M (NLSD-M) is an ultra-rare, autosomal recessive disorder that causes severe skeletal and cardiac muscle damage and lipid accumulation in all body tissues. In this hereditary pathology, the defective action of the adipose triglyceride lipase (ATGL) enzyme induces the enlargement of cytoplasmic lipid droplets and reduction in the detachment of mono- (MG) and diglycerides (DG). Although the pathogenesis of muscle fiber necrosis is unknown, some studies have shown alterations in cellular energy production, probably because MG and DG, the substrates of Krebs cycle, are less available. No tests have been tried with medium-chain fatty acid molecules to evaluate the anaplerotic effect in NLSD cells. In this study, we evaluated the in vitro effect of triheptanoin (Dojolvi®), a highly purified chemical triglyceride with seven carbon atoms, in fibroblasts obtained from five NLSD-M patients. Glycolytic and mitochondrial functions were determined by Seahorse XF Agylent Technology, and cellular viability and triglyceride content were measured through colorimetric assays. After the addition of triheptanoin, we observed an increase in glycolysis and mitochondrial respiration in all patients compared with healthy controls. These preliminary results show that triheptanoin is able to induce an anaplerotic effect in NLSD-M fibroblasts, paving the way towards new therapeutic strategies.
Assuntos
Glicólise , Lipase , Humanos , Lipase/metabolismo , Triglicerídeos , Fibroblastos/metabolismoRESUMO
In this study we analyzed the expression of Yin and Yang 1 protein (YY1), a member of the noncanonical PcG complexes, in AML patient samples and AML cell lines and the effect of YY1 downregulation on the AML differentiation block. Our results show that YY1 is significantly overexpressed in AML patient samples and AML cell lines and that YY1 knockdown relieves the differentiation block. YY1 downregulation in two AML cell lines (HL-60 and OCI-AML3) and one AML patient sample restored the expression of members of the CEBP protein family, increased the expression of extrinsic growth factors/receptors and surface antigenic markers, induced morphological cell characteristics typical of myeloid differentiation, and sensitized cells to retinoic acid treatment and to apoptosis. Overall, our data show that YY1 is not a secondary regulator of myeloid differentiation but that, if overexpressed, it can play a predominant role in myeloid differentiation block.
RESUMO
We characterize the metabolic background in distinct Acute Myeloid Leukemias (AMLs), by comparing the metabolism of primary AML blasts isolated at diagnosis with that of normal hematopoietic maturing progenitors, using the Seahorse XF Agilent. Leukemic cells feature lower spare respiratory (SRC) and glycolytic capacities as compared to hematopoietic precursors (i.e. day 7, promyelocytes). According with Proton Leak (PL) values, AML blasts can be grouped in two well defined populations. The AML group with blasts presenting high PL or high basal OXPHOS plus high SRC levels had shorter overall survival time and significantly overexpressed myeloid cell leukemia 1 (MCL1) protein. We demonstrate that MCL1 directly binds to Hexokinase 2 (HK2) on the outer mitochondrial membrane (OMM). Overall, these results suggest that high PL and high SRC plus high basal OXPHOS levels at disease onset, arguably with the concourse of MCL1/HK2 action, are significantly linked with shorter overall survival time in AML. Our data describe a new function for MCL1 protein in AMLs' cells: by forming a complex with HK2, MCL1 co-localizes to VDAC on the OMM, thus inducing glycolysis and OXPHOS, ultimately conferring metabolic plasticity and promoting resistance to therapy.
Assuntos
Hexoquinase , Leucemia Mieloide Aguda , Humanos , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismoAssuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Decitabina/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Terapia de Salvação/métodos , Idoso , Quimioterapia Adjuvante , Humanos , Quimioterapia de Indução , Quimioterapia de Manutenção , Masculino , Terapia Neoadjuvante , Indução de Remissão , Falha de TratamentoAssuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Decitabina/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Neoplasias Primárias Múltiplas/tratamento farmacológico , Trombocitemia Essencial/patologia , Adulto , Feminino , Humanos , Janus Quinase 2/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Neoplasias Primárias Múltiplas/genética , Neoplasias Primárias Múltiplas/patologia , Trombocitemia Essencial/genética , Resultado do TratamentoRESUMO
In the present study, we characterized the metabolic background of different Acute Myeloid Leukemias' (AMLs) cells and described a heterogeneous and highly flexible energetic metabolism. Using the Seahorse XF Agilent, we compared the metabolism of normal hematopoietic progenitors with that of primary AML blasts and five different AML cell lines. We assessed the efficacy and mechanism of action of the association of high doses of ascorbate, a powerful oxidant, with the metabolic inhibitor buformin, which inhibits mitochondrial complex I and completely shuts down mitochondrial contributions in ATP production. Primary blasts from seventeen AML patients, assayed for annexin V and live/dead exclusion by flow cytometry, showed an increase in the apoptotic effect using the drug combination, as compared with ascorbate alone. We show that ascorbate inhibits glycolysis through interfering with HK1/2 and GLUT1 functions in hematopoietic cells. Ascorbate combined with buformin decreases mitochondrial respiration and ATP production and downregulates glycolysis, enhancing the apoptotic effect of ascorbate in primary blasts from AMLs and sparing normal CD34+ bone marrow progenitors. In conclusion, our data have therapeutic implications especially in fragile patients since both agents have an excellent safety profile, and the data also support the clinical evaluation of ascorbate-buformin in association with different mechanism drugs for the treatment of refractory/relapsing AML patients with no other therapeutic options.
RESUMO
The translocation t(16;21) involving RUNX1 (AML1) and resulting in the RUNX1-CBFA2T3 fusion is a rare but recurrent abnormality mostly found in therapy-related acute myeloid leukemia (t-AML) associated with agents targeting topoisomerase II (topo II). We characterized, at the genomic level, the t(16;21) translocation in a patient who developed t-AML after treatment of multiple sclerosis with mitoxantrone (MTZ). Long template nested PCR of genomic DNA followed by direct sequencing enabled the localization of RUNX1 and CBFA2T3 (ETO2) breakpoints in introns 5 and 3, respectively. Sequencing of the cDNA with specific primers showed the presence of the expected RUNX1-CBFA2T3 fusion transcript in leukemic cells. The RUNX1 intron 5 breakpoint was located at nucleotide position 24,785. This region contained an ATGCCCCAG nucleotide sequence showing approximately 90% homology to a "hotspot" DNA region ATGCCCTAG present in intron 6 of PML previously identified in therapy-related acute promyelocytic leukemia cases arising following treatment with MTZ. This study suggests a wider distribution in the human genome, and particularly at genes involved in chromosome translocations observed in t-AML, of DNA regions (hotspot) targeted by specific topo II drugs.
Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Leucemia Mieloide Aguda/genética , Mitoxantrona/efeitos adversos , Translocação Genética , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Análise Citogenética , Bases de Dados Genéticas , Regulação Neoplásica da Expressão Gênica , Humanos , Hibridização in Situ Fluorescente , Leucemia Mieloide Aguda/induzido quimicamente , Leucemia Mieloide Aguda/diagnóstico , Masculino , Pessoa de Meia-Idade , Mitoxantrona/uso terapêutico , Esclerose Múltipla/complicações , Esclerose Múltipla/tratamento farmacológico , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Análise de Sequência de DNA , Inibidores da Topoisomerase II , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
Acute promyelocytic leukemia (APL) is a hematological disease characterized by a balanced reciprocal translocation that leads to the synthesis of the oncogenic fusion protein PML-RARα. APL is mainly managed by a differentiation therapy based on the administration of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). However, therapy resistance, differentiation syndrome, and relapses require the development of new low-toxicity therapies based on the induction of blasts differentiation. In keeping with this, we reasoned that a better understanding of the molecular mechanisms pivotal for ATRA-driven differentiation could definitely bolster the identification of new therapeutic strategies in APL patients. We thus performed an in-depth high-throughput transcriptional profile analysis and metabolic characterization of a well-established APL experimental model based on NB4 cells that represent an unevaluable tool to dissect the complex mechanism associated with ATRA-induced granulocytic differentiation. Pathway-reconstruction analysis using genome-wide transcriptional data has allowed us to identify the activation/inhibition of several cancer signaling pathways (e.g., inflammation, immune cell response, DNA repair, and cell proliferation) and master regulators (e.g., transcription factors, epigenetic regulators, and ligand-dependent nuclear receptors). Furthermore, we provide evidence of the regulation of a considerable set of metabolic genes involved in cancer metabolic reprogramming. Consistently, we found that ATRA treatment of NB4 cells drives the activation of aerobic glycolysis pathway and the reduction of OXPHOS-dependent ATP production. Overall, this study represents an important resource in understanding the molecular "portfolio" pivotal for APL differentiation, which can be explored for developing new therapeutic strategies.
Assuntos
Diferenciação Celular/genética , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/metabolismo , Transcrição Gênica , Tretinoína/farmacologia , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Linhagem da Célula/efeitos dos fármacos , Estudos de Coortes , Perfilação da Expressão Gênica , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Glicólise/genética , Humanos , Leucemia Promielocítica Aguda/patologia , Células Mieloides/efeitos dos fármacos , Células Mieloides/metabolismo , Células Mieloides/patologia , Fosforilação Oxidativa/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacosRESUMO
Breakpoint cluster region - Abelson (BCR-ABL1) chimeric protein and mutated Nucleophosmin (NPM1) are often present in hematological cancers, but they rarely coexist in the same disease. Both anomalies are considered founder mutations that inhibit differentiation and apoptosis, but BCR-ABL1 could act as a secondary mutation conferring a proliferative advantage to a pre-neoplastic clone. The 2016 World Health Organization (WHO) classification lists the provisional acute myeloid leukemia (AML) with BCR-ABL1, which must be diagnosed differentially from the rare blast phase (BP) onset of chronic myeloid leukemia (CML), mainly because of the different therapeutic approach in the use of tyrosine kinase inhibitors (TKI). Here we review the BCR/ABL1 plus NPMc+ published cases since 1975 and describe a case from our institution in order to discuss the clinical and molecular features of this rare combination, and report the latest acquisition about an occurrence that could pertain either to the rare AML BCR-ABL1 positive or the even rarer CML-BP with mutated NPM1 at the onset. Differential diagnosis is based on careful analysis of genotypic and phenotypic features and anamnestic, clinical evolution, and background data. Therapeutic decisions must consider the broader clinical aspects, the comparatively mild effects of TKI therapy versus the great benefit that might bring to most of the patients, as may be incidentally demonstrated by our case history.
RESUMO
OBJECTIVES: Mutations in the C-terminal region of the nucleophosmin (NPM1) gene occur in approximately 60% of acute myeloid leukemia (AML) cases with normal karyotype and represent the most common genetic lesion presently known in this disease. Because of their frequency and favorable impact on prognostic outcome, screening for this aberration is currently recommended in routine diagnostic characterization of AML. Several techniques enabling to detect NPM1 mutation have been reported, but all require sophisticated equipment, which represent an obstacle particularly in countries with limited resources. METHODS: We designed an RT-PCR strategy to amplify NPM1 exon 12 followed by electrophoresis and fragment visualization on polyacrylamide gels to discriminate a 4-5 bp size difference resulting from mutations in this gene. A hemi-nested method was designed to increase sensitivity for the study of minimal residual disease (MRD). RESULTS: The assay enabled specific detection of NPM1 mutations in 12/36 patients. A 10(-2) sensitivity level was obtained using one amplification round, while the hemi-nested PCR approach yielded a 10(-5) sensitivity level, therefore proving useful to assess MRD in patients carrying the mutation. The results were independently validated in 24 AML cases by sequencing analysis. CONCLUSIONS: This simple and low-cost assay may integrate diagnostic work-up of AML and could be used for assessment of response to therapy in patients with NPM1 mutations.
Assuntos
Eletroforese em Gel de Poliacrilamida/métodos , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Proteínas Nucleares/análise , Proteínas Nucleares/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Sequência de Bases , Éxons/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutação/genética , Neoplasia Residual/diagnóstico , Neoplasia Residual/genética , NucleofosminaRESUMO
Forkhead box (FOX) genes encode transcription factors, which regulate embryogenesis and play an important role in hematopoietic differentiation and in mesenchymal niche maintenance. Overexpression of the family member FOXC1 has been reported in solid tumors and acute myeloid leukemia (AML). We studied FOXC1 expression and function in acute promyelocytic leukemia (APL) and normal hematopoietic progenitors. FOXC1 mRNA and protein levels were significantly lower in primary marrow samples from 27 APL patients, as compared to samples obtained from 27 patients with other AML subtypes, and 5 normal CD34+ hematopoietic cells. FOXC1 expression significantly increased in APL samples at the time of remission following consolidation treatment. In cell lines overexpressing PML-RARA, and in the NB4 t(15;17)-positive cell line, FOXC1 expression was lower than in other non-APL cell lines, and increased following treatment with all-trans retinoic acid (ATRA), due to functional binding of ATRA to the FOXC1 promoter region. Reduced FOXC1 expression was also associated to DNA hypermethylation of the +354 to +568 FOXC1 region, both in primary APL, and in NB4 cells. Treatment of NB4 cells with decitabine demethylated FOXC1 and upregulated its expression. Our findings indicate that FOXC1 is consistently repressed in APL due to hypermethylation and the presence of the PML-RARA rearrangement. A potential role of hypomethylating treatment in advanced APL remains to be established.
RESUMO
BACKGROUND: Elevated levels of glutathione (GSH) have been reported to play an important role in mediating chemoresistance in tumor cells. The regulation of gamma-glutamylcysteine synthetase (gamma-GCS) is one of the major determinants of GSH homeostasis. The aim of our study was to investigate gamma-GCS gene expression in patients affected by acute myeloid leukemia (AML). METHODS: A total of 64 AML samples, including 23 acute promyelocytic leukemia (APL or M3) cases, were included in the study. gamma-GCS mRNA levels were determined by real-time quantitative RT-PCR. All patients were evaluated at diagnosis, whereas post-treatment gamma-GCS mRNA levels were assessed at the end of the consolidation therapy in 16 cases. RESULTS: Our data showed that variable degrees of gamma-GCS expression were detectable in AML, likely reflecting disease heterogeneity; in particular, APL cases, compared to the other AML subsets, showed both significantly lower basal levels of gamma-GCS mRNA at presentation and significantly increased mRNA levels after treatment. CONCLUSIONS: Decreased levels of gamma-GCS leading to reduced GSH may at least in part explain the higher sensitivity of APL to chemotherapy.
Assuntos
Antineoplásicos/uso terapêutico , Expressão Gênica , Glutamato-Cisteína Ligase/genética , Leucemia Mieloide/tratamento farmacológico , Doença Aguda , Humanos , Leucemia Mieloide/enzimologia , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Acute promyelocitic leukemia (APL) is characterized by the pathognomonic presence in leukemic blasts of the hybrid protein PML/RARA, that acts as a transcriptional repressor impairing the expression of genes that are critical to myeloid differentiation. Here, we show that primary blasts from APL patients express lower levels of the oncosuppressor protein PTEN, as compared to blast cells from other AML subtypes or normal bone marrow, and demonstrate that PML-RARA directly inhibits PTEN expression. We show that All-Trans Retinoic Acid (ATRA) triggers in APL cells an active chromatin status at the core regulatory region of the PTEN promoter, that allows the binding of the myeloid-regulating transcription factor PU.1, and, in turn, the transcriptional induction of PTEN. ATRA, via PML/RARA degradation, also promotes PTEN nuclear re-localization and decreases expression of the PTEN target Aurora A kinase. In conclusion, our findings support the notion that PTEN is one of the primary targets of PML/RARA in APL.
Assuntos
Regulação Neoplásica da Expressão Gênica/fisiologia , Leucemia Promielocítica Aguda/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , PTEN Fosfo-Hidrolase/biossíntese , Proteínas Proto-Oncogênicas/metabolismo , Transativadores/metabolismo , Humanos , Leucemia Promielocítica Aguda/genética , Ativação Transcricional/fisiologiaRESUMO
BACKGROUND AND OBJECTIVES: Front line treatment of acute promyelocytic leukemia (APL) with all-trans retinoic acid (ATRA) and chemotherapy (CHT) results in molecular remission in approximately 95% of patients tested after consolidation. The small fraction of patients with persistence of molecular disease (i.e. those in whom polymerase chain reaction (PCR) is positive for PML/RARalpha) after such therapy are thought to have a dismal prognosis but has not yet been investigated in detail. DESIGN AND METHODS: We analyzed the clinico-biological features at presentation of APL patients who showed PCR-detectable residual disease and compared them to those of patients achieving molecular remission after AIDA induction and consolidation. Furthermore, we report the outcome of patients with molecularly persistent disease treated with salvage therapy. RESULTS: Patients attaining molecular remission (n=650) and patients who tested PCR+ve at the end of consolidation (n=23) were not statistically significantly different as regards median age, white cell and platelet counts, morphologic subtype (M3 or M3v), fibrinogen levels or PML/RARalpha transcript type. As to treatment outcome after salvage therapy, 7 patients were treated before morphologic relapse [3 with chemotherapy and autologous stem cell transplantation (SCT) and 4 with allogeneic SCT], and are alive after 64-118 months. Of 16 patients treated at the time of morphologic relapse, only 2 patients are alive, both of whom received an allogeneic SCT. INTERPRETATION AND CONCLUSIONS: Our findings indicate that APL patients who are molecularly resistant to the AIDA protocol have no distinguishing features at presentation. Their outcome suggests the need for early therapeutic intervention with aggressive treatment prior to the occurrence of hematologic relapse.