Antiapoptotic proteins Bcl2 and BclX do not protect chronic myeloid leukemia cells from imatinib-mediated growth arrest

Imatinib (Glivec, Gleevec, STI571), a Bcr-Abl kinase inhibitor, is the most used drug in chronic myeloid leukemia. Imatinib induces apoptosis in a number of CML-derived cell lines, including K562. However, in order to achieve hematological remissions it is required chronic treatment with the drug, a fact inconsistent with a cytotoxic mechanism of imatinib in vivo. In this work we have analysed the effects of imatinib on the proliferation and apoptosis of K562-derived cell lines with constitutive expression of the anti-apoptotic genes Bcl2 and BclX. We found that imatinib-mediated apoptosis was completely abrogated in both Bcl2- and BclX-cell lines. However, imatinib inhibited proliferation, although growth rate was higher than in parental K562. We conclude that, besides its apoptotic effect, imatinib acts through an apoptosis-independent mechanism to arrest cell growth.The work was supported by grant PM98-0109 and SAF2002-04193 from Spanish Ministry of Science and Technology to J.L.Peer Reviewe

Las proteínas antiapoptóticas Bcl2 y BclX no protegen a las células de leucemia mieloide crónica de la parada proliferativa inducida por imatinib

Imatinib (Glivec, Gleevec, STI571), a Bcr-Abl kinase inhibitor, is the most used drug in chronic myeloid leukemia. Imatinib induces apoptosis in a number of CML-derived cell lines, including K562. However, in order to achieve hematological remissions it is required chronic treatment with the drug, a fact inconsistent with a cytotoxic mechanism of imatinib in vivo. In this work we have analysed the effects of imatinib on the proliferation and apoptosis of K562-derived cell lines with constitutive expression of the anti-apoptotic genes Bcl2 and BclX. We found that imatinib-mediated apoptosis was completely abrogated in both Bcl2- and BclXcell lines. However, imatinib inhibited proliferation, although growth rate was higher than in parental K562. We conclude that, besides its apoptotic effect, imatinib acts through an apoptosis-independent mechanism to arrest cell growth.El imatinib (Glivec, Gleevec, STI571) es un inhibidor de la quinasa Bcr-Abl, y es el fármaco de más uso en leucemia mieloide crónica (LMC). El imatinib induce apoptosis en varias líneas celulares derivadas de LMC, entre ellas K562. Sin embargo, para obtener remisión hematológica es necesario el tratamiento continuado con imatinib, un hecho no consistente con un mecanismo de acción citotóxico in vivo del fármaco in vivo. En este trabajo hemos analizado un los efectos del imatinib en la proliferación y apoptosis de líneas celulares derivadas de K562 con expresión constitutiva de las proteínas antiapoptóticas Bcl2 y BclX. Hemos encontrado que la apoptosis mediada por imatinib era completamente abolida en las líneas celulares con expresión de Bcl2 y BclX. Sin embargo, el imatinib inhibía la proliferación, aunque este efecto fue menos severo que en las células parentales K562. Concluimos que, además de su efecto apoptótico, el imatinib actúa a través de un mecanismo independiente de la apoptosis para detener la proliferación

Guidelines for diagnosis and treatment of Hunter Syndrome for clinicians in Latin America

This review aims to provide clinicians in Latin America with the most current information on the clinical aspects, diagnosis, and management of Hunter syndrome, a serious and progressive disease for which specific treatment is available. Hunter syndrome is a genetic disorder where iduronate-2-sulfatase (I2S), an enzyme that degrades glycosaminoglycans, is absent or deficient. Clinical manifestations vary widely in severity and involve multiple organs and tissues. An attenuated and a severe phenotype are recognized depending on the degree of cognitive impairment. Early diagnosis is vital for disease management. Clinical signs common to children with Hunter syndrome include inguinal hernia, frequent ear and respiratory infections, facial dysmorphisms, macrocephaly, bone dysplasia, short stature, sleep apnea, and behavior problems. Diagnosis is based on screening urinary glycosaminoglycans and confirmation by measuring I2S activity and analyzing I2S gene mutations. Idursulfase (recombinant I2S) (Elaprase®, Shire) enzyme replacement therapy (ERT), designed to address the underlying enzyme deficiency, is approved treatment and improves walking capacity and respiratory function, and reduces spleen and liver size and urinary glycosaminoglycan levels. Additional measures, responding to the multi-organ manifestations, such as abdominal/inguinal hernia repair, carpal tunnel surgery, and cardiac valve replacement, should also be considered. Investigational treatment options such as intrathecal ERT are active areas of research, and bone marrow transplantation is in clinical practice. Communication among care providers, social workers, patients and families is essential to inform and guide their decisions, establish realistic expectations, and assess patients' responses.Hospital de Clinicas de Porto Alegre Serviço de Génetica MédicaUniversidade Federal do Rio Grande do Sul Departamento de GéneticaInstituto Nacional de Genética Médica PopulacionalAsociación Colombiana de Neurología InfantilInstituto Mexicano del Seguro SocialInstituto de Estudios AvanzadosHospital de NiñosLa Misericordia University HospitalUniversidade Federal de São Paulo (UNIFESP) Centro de Referência em Erros Inatos do MetabolismoUniversidade Federal de BahiaUniversidad de Chile Instituto de Nutrición y Tecnología de los AlimentosHospital Italiano Instituto de Genética MédicaHospital Pequeno Príncipe Departamento de NeuropediatraHospital Universitario AustralUNIFESP, Centro de Referência em Erros Inatos do MetabolismoSciEL

c-myc expression in cell lines derived from chronic myeloid leukemia

Letter to the Editor.-- Open AccessWe analyzed proliferation and c-myc expression in three chronic myeloid leukemia (CML)-derived cell lines treated with interferon-α, hydroxyurea, busulfan and imatinib. We found that c-Myc levels did not universally correlate with CML cell proliferation and that c-Myc down-regulation correlated to imatinib activity but not to imatinib-induced apoptosis.This study was supported by grants SAF2002-04193 from Spanish Ministry of Science and Technology to J.L., and FIS01-1129 from Spanish Ministry of Health to M.D.D.Peer Reviewe

Positive Impact of Eculizumab Therapy on Surgery for Budd- Chiari Syndrome in a Patient with Paroxysmal Nocturnal Hemoglobinuria and a Longterm History of Thrombosis

Paroxysmal nocturnal hemoglobinuria (PNH) is associated with severe end-organ damage and a high risk of thrombosis. Budd- Chiari syndrome, which develops after thrombotic occlusion of major hepatic blood vessels, is relatively common in PNH and has been associated with increased mortality. We report the case of a 46-year-old male with PNH who presented with Budd-Chiari syndrome associated with portal cavernoma, portal hypertension and hypersplenism. In September 2010, the patient suffered gastrointestinal bleeding, hematuria, and elevated plasma lactate dehydrogenase; he started eculizumab therapy with a good response. In October 2012, he developed upper gastrointestinal variceal bleeding and a splenorenal shunt was placed. At the time of writing, the patient remains stable and eculizumab continues to be effective. There is limited data on the use of eculizumab for prevention of hemolysis and its consequences in PNH patients undergoing surgery. Our findings provide evidence for the efficacy and safety of eculizumab in this setting

Financial indicators to evaluate the economic performance of feedlot steers with different slaughter weights

ABSTRACT: The objective of this study was to evaluate various financial indicators, estimated deterministically (considering historical quotes twelve consecutive years - 2003 to 2014), on the economic feasibility of finishing steers commercialized with different weights, using the simulation technique. Performance data steers were simulated with average initial weight of 350kg, fed in feedlot and slaughtered with 410, 440, 470, 500, 530, 560 and 590kg. The feeding period varies from 46 to 185 days, respectively. Based in various economic indicators, the viability of the investment decreased linearly according to the increase in slaughter weight. The coefficient of simple linear regression and means from lowest to highest slaughter weight were, respectively: net present value (-0.538 and R$67.37, R$ 65.28, R$32.14, R$ -7.34, R$8.01, R$ -12.38, R$-23.41); index benefit: cost (-0.0003 and R$ 1.042, R$1.039, R$ 1.014, R$1.006, R$ 1.003, R$0.995, R$ 0.991); additional return on investment (-0.009 and 1.38, 1.29, 0.35, 0.11, 0.05, -0.08, -0.13% per month); internal rate of return (-0.009 and 2.21, 2.10, 1.28, 0.80, 0.93, 0.78, 0.73% per month). Feedlot use as termination option to obtain the direct benefits of this technology is an alternative investment with low economic return

Guidelines for diagnosis and treatment of Hunter Syndrome for clinicians in Latin America

This review aims to provide clinicians in Latin America with the most current information on the clinical aspects, diagnosis, and management of Hunter syndrome, a serious and progressive disease for which specific treatment is available. Hunter syndrome is a genetic disorder where iduronate-2-sulfatase (I2S), an enzyme that degrades glycosaminoglycans, is absent or deficient. Clinical manifestations vary widely in severity and involve multiple organs and tissues. An attenuated and a severe phenotype are recognized depending on the degree of cognitive impairment. Early diagnosis is vital for disease management. Clinical signs common to children with Hunter syndrome include inguinal hernia, frequent ear and respiratory infections, facial dysmorphisms, macrocephaly, bone dysplasia, short stature, sleep apnea, and behavior problems. Diagnosis is based on screening urinary glycosaminoglycans and confirmation by measuring I2S activity and analyzing I2S gene mutations. Idursulfase (recombinant I2S) (Elaprase®, Shire) enzyme replacement therapy (ERT), designed to address the underlying enzyme deficiency, is approved treatment and improves walking capacity and respiratory function, and reduces spleen and liver size and urinary glycosaminoglycan levels. Additional measures, responding to the multi-organ manifestations, such as abdominal/inguinal hernia repair, carpal tunnel surgery, and cardiac valve replacement, should also be considered. Investigational treatment options such as intrathecal ERT are active areas of research, and bone marrow transplantation is in clinical practice. Communication among care providers, social workers, patients and families is essential to inform and guide their decisions, establish realistic expectations, and assess patients' responses