Everolimus in combination with Imatinib overcomes resistance in Chronic myeloid leukaemia.

Although Imatinib and other tyrosine kinase inhibitors (TKIs) have excellent results, the appearance of resistance is a problem in chronic myeloid leukaemia (CML). PI3K/AKT/mTOR pathway is activated by BCR-ABL playing a crucial rule in CML. This study aimed to evaluate the therapeutic potential of Everolimus, in CML models sensitive and resistant to Imatinib. We used one CML cell line sensitive to Imatinib (K562) and two resistant (K562-RC and K56-RD). Cell lines were treated with Everolimus alone and in combination with Imatinib. Cell viability was analysed by resazurin assay. Cell death and cell cycle were analysed by flow cytometry. Additionally, we also studied peripheral blood samples obtained from 52 patients under TKI treatment. Everolimus reduced cell line viability in sensitive (IC50 = 20 µM) and resistant models (K562-RC, IC50 = 25 µM; K562-RD, IC50 = 30 µM). This drug induced cell death by apoptosis and cell cycle arrest in G0/G1 phase. Everolimus also reduced cell viability by increasing apoptosis of haematopoietic stem cells (CD34+ cells) with low cytotoxicity to lymphocytes. Everolimus at 25 µM increased apoptotic cells 18.7% in CD34+ cells and only 8% in lymphocytes. The response to Everolimus was influenced by TKI treatment, with a better response in samples from patients under 2nd and 3rd generation TKI and with less toxicity to lymphocytes. Our results reveal that Everolimus induce cell death in CML cells sensitive and resistant to Imatinib, with low cytotoxicity to normal cells, suggesting that Everolimus could be an alternative targeted therapeutic approach in CML patients, even in cases of Imatinib resistance.

[Serum Erythropoietin as Prognostic Marker in Myelodysplastic Syndromes]. / Eritropoietina Sérica como Marcador Prognóstico em Síndrome Mielodisplásica.

INTRODUCTION: This myelodysplastic syndromes are a heterogeneous entity characterized by dysplasia, hypercellular bone marrow, cytopenias and risk of transformation to acute leukaemia. Prognostic factors, such as bone marrow fibrosis, lactate dehydrogenase and 2-microglobulin elevation have been described, but treatment is mainly based in the International Prognostic Scoring System. MATERIAL AND METHODS: Our aim was to analyze serum's erythropoietin at diagnosis in de novo myelodysplastic syndromes patients, through its impact in overall survival and possible implementation as prognostic marker. Clinical and laboratorial data from 102 patients with de novo myelodysplastic syndromes diagnosed between October/2009 and March/2014 were collected. Survival analysis was performed according to serum erythropoietin level stratification, using Kaplan-Meier methodology. RESULTS: Our 102 patients had a median age of 74 years, with a male:female ratio of 0.8. Mean erythropoietin was significantly lower in refractory cytopenia with unilineage dysplasia patients in contrast with the higher values observed in 5q- syndrome (p < 0.05). Eleven patients progressed to acute leukaemia; these have higher mean erythropoietin values (p < 0.05). In addition, elevated serum erythropoietin was associated with lower survival rates (p = 0.0336). Predictive value of serum erythropoietin was maintained after Cox regression adjustment. In multivariate analysis, serum erythropoietin is an independent survival predictor (p < 0.001). DISCUSSION: Serum erythropoietin is a predictive factor for response to therapy with subcutaneous erythropoietin, and patients with myelodysplastic syndromes with higher values of erythropoietin have poorer response to administration of erythropoietin even at higher doses. Our sample shows that serum erythropoietin also has prognostic value, and in all myelodysplastic syndromes subtypes. Moreover, alone or in combination with other factors or prognostic indices, erythropoietin may enhance the prognostic indices such as the International Prognostic Scoring System, since high levels are associated with progression to acute leukemia and hence lower survival. CONCLUSION: This study suggests that increased erythropoietin levels at diagnosis can by itself be a poor prognosis factor inmyelodysplastic syndromes patients, with higher values in patients with progression to acute leukaemia and decreased overall survival.

Introdução: A síndrome mielodisplásica é uma doença heterogénea caracterizada por displasia, medula hipercelular, citopenias e risco de evolução para leucemia aguda. Outros factores de prognóstico, nomeadamente, fibrose medular, elevação da enzima desidrogenase do lactato e 2-microglobulina têm sido descritos, contudo, a decisão terapêutica baseia-se no score do International Prognostic Scoring System. Material e Métodos: Este trabalho teve como objectivo analisar a relevãncia da eritropoietina sérica ao diagnóstico, em doentes com síndrome mielodisplásica de novo, avaliando o seu impacto na sobrevivência global e a sua implementação como factor de prognóstico. Recolhemos dados clínicos e laboratoriais de 102 doentes com síndrome mielodisplásica de novo diagnosticada entre outubro/2009 e março/2014. A análise de sobrevivência foi efectuada recorrendo à metodologia de Kaplan-Meier, de acordo com os valores de eritropoietina. Resultados: A amostra, de 102 doentes, apresenta uma mediana de idades de 74 anos e relação masculino/feminino igual a 0,8. Os doentes com o subtipo citopenia refratária com displasia unilinha apresentam, em média, valores de eritropoietina significativamente mais baixos, em oposição aos doentes com o subtipo 5q- que apresentam a média de eritropoietina sérica mais elevada (p < 0,05). Onze doentes evoluíram para leucemia aguda; estes têm, em média, eritropoietina sérica superior (p < 0,05). Adicionalmente, a eritropoietina sérica acima do limite superior da normalidade associa-se a menor sobrevivência (p = 0,0336). Após ajuste do modelo de regressão de Cox, o valor preditivo da eritropoietina para a sobrevivência global manteve-se (p < 0,001). Em análise multivariada, a eritropoietina sérica demonstrou ser um factor de prognóstico independente (p < 0,001). Discussão: A eritropoietina sérica é um factor preditivo de resposta à terapêutica com eritropoietina subcut'nea, sendo que os doentes com síndrome mielodisplásica com valores mais elevados de eritropoietina apresentam uma pior resposta à administração de eritropoietina, mesmo com doses mais elevadas. A nossa amostra demonstra que a eritropoietina sérica apresenta também valor prognóstico, e em todos os subtipos de síndrome mielodisplásica. Além disso, isoladamente ou em associação com outros factores ou índices de prognóstico, poderá melhorar o valor prognóstico de índices como o International Prognostic Scoring System, uma vez que valores elevados de eritropoietina estão associados a progressão para leucemia aguda e, consequentemente, a menor sobrevivência.Conclusão: Os resultados sugerem que o aumento dos níveis séricos de eritropoietina ao diagnóstico pode constituir um factor de mau prognóstico em doentes com síndrome mielodisplásica, associando-se a maior risco de evolução para leucemia aguda e menor sobrevivência global.

Farnesyltransferase inhibitors: molecular evidence of therapeutic efficacy in acute lymphoblastic leukemia through cyclin D1 inhibition.

BACKGROUND: Farnesyltransferase inhibitors have the ability to interfere with various intracellular pathways, reducing cell survival and proliferation. They have become an attractive tool for cancer therapy, namely acute leukemias. In this work, we have studied the efficacy of α-hydroxyfarnesylphosphonic acid (α-HFPA) in CEM (acute T-cell lymphoblastic leukemia) in culture. MATERIALS AND METHODS: CEM cells were incubated with α-HFPA at different concentrations; viability and proliferation studies were performed using the trypan blue exclusion assay and cell morphological analysis. Expression of lamin A/C, cyclin D1 and BAD were analyzed by flow cytometry. RESULTS: Our results show that α-HFPA significantly decreases Farnesyltransferase activity, reduces cell proliferation and induces cell death through apoptosis in CEM cells, which is correlated with a reduction of cyclin D1 levels. CONCLUSION: This study suggests that α-HFPA blocks the cell cycle and induces cell death through apoptosis in CEM cells and may be a therapeutic approach in ALL.