Dysregulation of H/ACA ribonucleoprotein components in chronic lymphocytic leukemia

Telomeres are protective repeats of TTAGGG sequences located at the end of human chromosomes. They are essential to maintain chromosomal integrity and genome stability. Telomerase is a ribonucleoprotein complex containing an internal RNA template (hTR) and a catalytic subunit (hTERT). The human hTR gene consists of three major domains; among them the H/ACA domain is essential for telomere biogenesis. H/ACA ribonucleoprotein (RNP) complex is composed of four evolutionary conserved proteins, including dyskerin (encoded by DKC1 gene), NOP10, NHP2 and GAR1. In this study, we have evaluated the expression profile of the H/ACA RNP complex genes: DKC1, NOP10, NHP2 and GAR1, as well as hTERT and hTR mRNA levels, in patients with chronic lymphocytic leukemia (CLL). Results were correlated with the number and type of genetic alteration detected by conventional cytogenetics and FISH (fluorescence in situ hybridization), IGHV (immunoglobulin heavy chain variable region) mutational status, telomere length (TL) and clinico pathological characteristics of patients. Our results showed significant decreased expression of GAR1, NOP10, DKC1 and hTR, as well as increased mRNA levels of hTERT in patients compared to controls (p=0.04). A positive correlation between the expression of GAR1-NHP2, GAR1-NOP10, and NOP10-NHP2 (p=0.0001), were observed. The analysis taking into account prognostic factors showed a significant increased expression of hTERT gene in unmutated-IGHV cases compared to mutated-CLL patients (p = 0.0185). The comparisons among FISH groups exhibited increased expression of DKC1 in cases with two or more alterations with respect to no abnormalities, trisomy 12 and del13q14, and of NHP2 and NOP10 compared to those with del13q14 (p = 0.03). The analysis according to TL showed a significant increased expression of hTERT (p = 0.0074) and DKC1 (p = 0.0036) in patients with short telomeres compared to those with long TL. No association between gene expression and clinical parameters was found. Our results suggest a role for these telomere associated genes in genomic instability and telomere dysfunction in CLL.Fil: Dos Santos, Patricia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Panero, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Stanganelli, Carmen Graciela. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas "Mariano R. Castex"; ArgentinaFil: Palau Nagore, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Stella, Flavia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Bezares, Raimundo F.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Dr. Teodoro Álvarez"; ArgentinaFil: Slavutsky, Irma Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

SEPT10 expression in chronic lymphocytic leukemia. Correlation with clinical and biological prognostic factors

Chronic lymphocytic leukemia (CLL) is characterized by a highly variable clinical course. Microarray studies allowed highlight genes differentially expressed in this pathology. In this study, we have evaluated the prognostic significance of SEPT10 expression in CLL patients. Results were correlated with immunoglobulin heavy-chain variable (IGHV) genes mutational status, genomic rearrangements and clinical parameters. SEPT10 mRNA levels were determined by quantitative real-time PCR in 70 newly diagnosed CLL patients consecutively referred to our Institution. A wide heterogeneity for SEPT10 expression was found. Gene upregulation was observed in 18.5% of cases. The univariate analysis showed a positive association between gen expression and platelet count (p < 0.0001) and a negative correlation with hemoglobin levels (p = 0.0094). Although no significant differences were observed, mean treatment free survival was shorter in patients with high expression (31 months) with respect to those with low mRNA levels (72 months). Cases with abnormal karyotypes had increased expression compared to those with normal karyotypes and no association between gene expression and FISH (fluorescence in situ hybridization) risk groups and IGHV mutational status was found. Cases using IGHV3-23 gene rearrangement had low SEPT10 expression. Our results showed an association between SEPT10 expression and features of adverse outcome but without independent prognostic value. The study of SEPT10 expression may be important for a better understanding of disease heterogeneity, adding further information to those provided by established prognostic factors.Fil: Travella, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Panero, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Stanganelli, Carmen Graciela. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas "Mariano R. Castex"; ArgentinaFil: Bezares, Raimundo F.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Dr. Teodoro Álvarez"; ArgentinaFil: Slavutsky, Irma Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; Argentin

Ibrutinib impairs the phagocytosis of rituximab-coated leukemic cells from chronic lymphocytic leukemia patients by human macrophages

We have read with great interest the recent article of Kohrt, H.E. et al1 showing that Ibrutinib prevented NK cell mediated cytotoxicity of antibody-coated CLL cells in vitro. They also found that the concurrent treatment with Ibrutinib and rituximab or trastuzumab reduces the therapeutic efficacy of both anti-CD20 antibodies in a mouse model, while the sequential treatment with Ibrutinib and rituximab restored its anti-lymphoma activity. Since macrophages are the most important effector cells in CD20-directed cytotoxicity in murine models2,3 and they probably play a key role in human anti-CD20 therapy4,5, we determined whether Ibrutinib interferes the capacity of human macrophages to mediate phagocytosis of rituximab-coated CLL cells. To address this issue, macrophages differentiated from healthy peripheral blood monocytes were treated with or without Ibrutinib for 30 minutes and then cultured for 1, 2 or 3 hours with CFSE-labeled CLL cells or rituximab-coated CFSE-labeled CLL cells. Then, cells were tripsinized and the proportion of macrophages that have taken up CFSE-labeled CLL cells (CFSE+ macrophages) were scored by flow cytometry and verified using confocal microscopy, as previously described6. As expected, we found that the cultures with rituximab-coated CLL cells showed the highest percentage of CFSE+ macrophages, which increase in a time dependent manner (open circles in Figure 1A). Ibrutinib was able to reduce these values in all the times evaluated (solid circles in Figure 1A). Low percentages of CFSE+ macrophages were obtained in cultures with uncoated CLL cells, which were not modified by Ibrutinib (open and solid squares in Figure 1A). In addition, we found that Ibrutinib diminishes the percentage of CFSE+ macrophages in the cultures with rituximab-coated cells in a dose dependent manner (Figure 1B), which was not associated to a decreased viability of the macrophages (not shown). Moreover, the inhibitory effect of Ibrutinib was not limited to rituximab since comparable results were obtained when campath-coated CFSE-labeled CLL cells were employed (Figure 1C). Similar results were found when macrophages from CLL patients were used: mean±SE of the % of CFSE+ macrophages: 26.8 ± 2.1 vs, 17.3 ± 2.7 vs 10.8 ± 0.7 for rituximab-coated CFSE-labeled CLL cells alone, with 0.5μM or 5μM of Ibrutinib (n= 6). Representative dot plots are shown in Figure 1D. The results obtained by flow cytometry analysis were validated by confocal microscopy quantifying the number of macrophages that engulfed at least one tumor target cell (Figure 1E). A representative experiment is shown in Figure 1F. In addition, by performing a binding assay at 4oC, we confirmed that Ibrutinib did not reduce the binding of rituximab-coated CFSE-labeled CLL cells to macrophages (Figure 1G). Interestingly, while the presence of Ibrutinib during the assay impairs the phagocytosis of rituximab-coated CLL cells, when Ibrutinib was washed out, macrophages recovered their phagocytic capacity in a time-dependent manner (Figure 1H). In conclusion we found that the presence of Ibrutinib impairs the phagocytosis of rituximab-opsonized CLL cells by human macrophages, which was restored when the inhibitor was removed from the cultures. Our results, and those obtained by Kohrt et al1 suggest that the sequential administration of Ibrutinib followed by rituximab, and not the concurrent treatment of the patients with these agents, might enhance their anti-tumor activity in vivo.Fil: Borge, Mercedes. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Almejún, María Belén. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Cátedra de Microbiología, Parasitología e Inmunología; ArgentinaFil: Podaza, Enrique Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Colado, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Fernández Grecco, Horacio. Sanatorio Municipal Dr. Julio Méndez; ArgentinaFil: Cabrejo, María. Sanatorio Municipal Dr. Julio Méndez; ArgentinaFil: Bezares, Raimundo F.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos ; ArgentinaFil: Giordano, Mirta Nilda. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Gamberale, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentin

Anomalías cromosómicas estructurales nuevas en leucemia linfocítica crónica. Su valor pronóstico

El análisis citogenético permite la detección de anomalías estructurales (AE) que pasan desapercibidas con la técnica de FISH (fluorescence in situ hybridization). En este trabajo se analizaron 34 pacientes con leucemia linfocítica crónica (LLC) portadores de anomalías estructurales (AE) clonales y un grupo control de 78 pacientes sin alteraciones. Se realizó estudio cromosómico por bandeo G complementado con FISH, y análisis molecular del estado mutacional de IGVH y de la expresión de los genes LPL y ADAM-29. Se detectaron 16 casos (47%) con AE nuevas. El cromosoma 8 fue el más implicado con 7 alteraciones, seguido por los pares 13 (6), 12 (5) y 15 (4). Se observó una similar distribución de AE entre los pacientes con IGVH mutado y no mutado. Los casos con AE mostraron una tendencia a mayor expresión de LPL y menor de ADAM-29. Se encontraron diferencias significativas en el recuento de blancos (p=0,019), plaquetas (p=0,002), LDH (p=0,029) y sobrevida libre de tratamiento (13 meses) en los pacientes con AE nuevas respecto de controles (69 meses) (p=0,087). Los resultados obtenidos confirman el pronóstico adverso de las AE en pacientes con LLC reforzando la importancia del análisis citogenético en esta patología.Fil: Travella, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Bezares, Raimundo F.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Dr. Teodoro Álvarez"; ArgentinaFil: Rodriguez, Andrea. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Slavutsky, Irma Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

Anomalías cromosómicas estructurales nuevas en leucemia linfocítica crónica. Su valor pronóstico

El análisis citogenético permite la detección de anomalías estructurales (AE) que pasan desapercibidas con la técnica de FISH (fluorescence in situ hybridization). En este trabajo se analizaron 34 pacientes con leucemia linfocítica crónica (LLC) portadores de anomalías estructurales (AE) clonales y un grupo control de 78 pacientes sin alteraciones. Se realizó estudio cromosómico por bandeo G complementado con FISH, y análisis molecular del estado mutacional de IGVH y de la expresión de los genes LPL y ADAM-29. Se detectaron 16 casos (47%) con AE nuevas. El cromosoma 8 fue el más implicado con 7 alteraciones, seguido por los pares 13 (6), 12 (5) y 15 (4). Se observó una similar distribución de AE entre los pacientes con IGVH mutado y no mutado. Los casos con AE mostraron una tendencia a mayor expresión de LPL y menor de ADAM-29. Se encontraron diferencias significativas en el recuento de blancos (p=0,019), plaquetas (p=0,002), LDH (p=0,029) y sobrevida libre de tratamiento (13 meses) en los pacientes con AE nuevas respecto de controles (69 meses) (p=0,087). Los resultados obtenidos confirman el pronóstico adverso de las AE en pacientes con LLC reforzando la importancia del análisis citogenético en esta patología.Fil: Travella, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Bezares, Raimundo F.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Dr. Teodoro Álvarez"; ArgentinaFil: Rodriguez, Andrea. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Slavutsky, Irma Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

Chronic lymphocytic leukemia cells increase neutrophils survival and promote their differentiation into CD16 high CD62L dim immunosuppressive subset

Reprogramming of neutrophils by malignant cells is well-described for many types of solid tumors, but data remain scarce for hematological diseases. Chronic lymphocytic leukemia (CLL) is characterized for a deep immune dysregulation mediated by leukemic cells that compromises patient´s outcome. Murine models of CLL highlight the relevance of myeloid cells as tumor-driven reprogramming targets. In our study, we evaluated neutrophil reprogramming by CLL cells. We first show that the proportion of the CD16high CD62Ldim neutrophil subset in peripheral blood of CLL patients is increased compared to age-matched healthy donors (HD). In vitro, neutrophils from HD cultured in the presence of CLL cells or conditioned media (CM) from CLL cells exhibited a longer lifespan. Depletion of G-CSF and GM-CSF from CM partially reversed the protective effect. In addition, the proportion of viable neutrophils that displayed a CD16high CD62Ldim phenotype was increased in the presence of CM from CLL cells, being TGF-β/IL-10 responsible for this effect. Altogether, our results describe a novel mechanism through which CLL cells can manipulate neutrophils.Fil: Podaza, Enrique Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Risnik, Denise Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Colado, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Elías, Esteban Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Almejún, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Fernandez Grecco, Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Bezares, Raimundo Fernando. Sanatorio Municipal "Dr. Julio Mendez"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Dr. Teodoro Álvarez"; ArgentinaFil: Borge, Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Gamberale, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Giordano, Mirta Nilda. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

Autologous t-cell activation fosters ABT-199 resistance in chronic lymphocytic leukemia: Rationale for a combined therapy with SYK inhibitors and anti-CD20 monoclonal antibodies

Fil: Elías, Esteban Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Almejún, María Belén. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Colado, Ana. Academia Nacional de Medicina de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Cordini, Gregorio. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Vergara Rubio, Maricef. Academia Nacional de Medicina de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Podaza, Enrique Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Risnik, Denise Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Cabrejo, María. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Fernández Grecco, Horacio. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Bezares, Raimundo Fernando. Universidad de Buenos Aires; ArgentinaFil: Custidiano, María Del Rosario. Sanatorio Municipal Dr. Julio Méndez; ArgentinaFil: Sánchez Ávalos, Julio César Américo. Sanatorio Municipal Dr. Julio Méndez; ArgentinaFil: Vicente, Ángeles. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Dr. Teodoro Álvarez"; ArgentinaFil: Garate, Gonzalo Martín. Instituto Alexander Fleming; ArgentinaFil: Borge, Mercedes. Instituto Alexander Fleming; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Giordano, Mirta Nilda. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Hospital Alemán; ArgentinaFil: Gamberale, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Hospital Aleman; Argentin

Neutrophils from chronic lymphocytic leukemia patients exhibit an increased capacity to release extracellular traps (NETs)

Chronic lymphocytic leukemia (CLL) is characterized by immune defects that contribute to a high rate of infections and autoimmune cytopenias. Neutrophils are the first line of innate immunity and respond to pathogens through multiple mechanisms, including the release of neutrophil extracellular traps (NETs). These web-like structures composed of DNA, histones, and granular proteins are also produced under sterile conditions and play important roles in thrombosis and autoimmune disorders. Here we show that neutrophils from CLL patients are more prone to release NETs compared to those from age-matched healthy donors (HD). Increased generation of NETs was not due to higher levels of elastase, myeloperoxidase, or reactive oxygen species production. Instead, we found that plasma from CLL patients was able to prime neutrophils from HD to generate higher amounts of NETs upon activation. Plasmatic IL-8 was involved in the priming effect since its depletion reduced plasma capacity to enhance NETs release. Finally, we found that culture with NETs delayed spontaneous apoptosis and increased the expression of activation markers on leukemic B cells. Our study provides new insights into the immune dysregulation in CLL and suggests that the chronic inflammatory environment typical of CLL probably underlies this inappropriate neutrophil priming.Fil: Podaza, Enrique Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Sabbione, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Risnik, Denise Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Borge, Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Almejún, María Belén. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Fisiología, Biología Molecular y Celular; ArgentinaFil: Colado, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Fernández Grecco, Horacio. Servicio de Hematología, Sanatorio Municipal Dr. Julio Méndez; ArgentinaFil: Cabrejo, María del Rosario. Servicio de Hematología, Sanatorio Municipal Dr. Julio Méndez; ArgentinaFil: Bezares, Raimundo F.. Servicio de Hematología, Hospital Municipal Dr. Teodoro Alvarez; ArgentinaFil: Trevani, Analía Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina; ArgentinaFil: Gamberale, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Giordano, Mirta Nilda. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

In Vitro Sensitivity to Venetoclax and Microenvironment Protection in Hairy Cell Leukemia

Current standard treatment of patients with hairy cell leukemia (HCL), a chronic B-cell neoplasia of low incidence that affects the elderly, is based on the administration of purine analogs such as cladribine. This chemotherapy approach shows satisfactory responses, but the disease relapses, often repeatedly. Venetoclax (ABT-199) is a Bcl-2 inhibitor currently approved for the treatment of chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML) in adult patients ineligible for intensive chemotherapy. Given that HCL cells express Bcl-2, our aim was to evaluate venetoclax as a potential therapy for HCL. We found that clinically relevant concentrations of venetoclax (0.1 and 1 µM) induced primary HCL cell apoptosis in vitro as measured by flow cytometry using Annexin V staining. As microenvironment induces resistance to venetoclax in CLL, we also evaluated its effect in HCL by testing the following stimuli: activated T lymphocytes, stromal cells, TLR-9 agonist CpG, and TLR-2 agonist PAM3. We found decreased levels of venetoclax-induced cytotoxicity in HCL cells exposed for 48 h to any of these stimuli, suggesting that leukemic B cells from HCL patients are sensitive to venetoclax, but this sensitivity can be overcome by signals from the microenvironment. We propose that the combination of venetoclax with drugs that target the microenvironment might improve its efficacy in HCL.Fil: Vereertbrugghen, Alexia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Colado, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Gargiulo, Ernesto. Luxembourg Institute Of Health; LuxemburgoFil: Bezares, Raimundo Fernando. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Dr. Teodoro Álvarez"; ArgentinaFil: Fernández Grecco, Horacio. Sanatorio Municipal Dr. Julio Méndez; ArgentinaFil: Cordini, Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Custidiano, Maria del Rosario. Instituto Alexander Fleming; ArgentinaFil: François, Jean Hugues. Centre Hospitalier de Luxembourg; LuxemburgoFil: Berchem, Guy. Centre Hospitalier de Luxembourg; Luxemburgo. Luxembourg Institute of Health; LuxemburgoFil: Borge, Mercedes. Centre Hospitalier de Luxembourg; Luxemburgo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Paggetti, Jerome. Luxembourg Institute of Health; LuxemburgoFil: Moussay, Etienne. Luxembourg Institute of Health; LuxemburgoFil: Gamberale, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; ArgentinaFil: Giordano, Mirta Nilda. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; ArgentinaFil: Morande, Pablo Elías. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Luxembourg Institute of Health; Luxemburg

Expression and function of cathelicidin hCAP18/LL-37 in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of clonal Bcellsin peripheral blood and lymphoid tissues 1. Circulating CLL cells are non-dividing Blymphocytes, but a significant fraction of the clone proliferates in lymphoid tissues wherethey receive a plethora of signals from the microenvironment that promote their survivaland expansion 2. Cathelicidins are a family of proteins with antibacterial functions mainlyexpressed by neutrophils, macrophages and epithelial cells 3. In humans, the only memberof this family, hCAP18, is encoded by the gene CAMP. The cleavage of hCAP18 generatesthe antimicrobial peptide LL-37, which has been recently implicated in the promotion oftumor growth, through direct stimulation of malignant cells, initiation of angiogenesis andrecruitment of immune cells 4. In this study, we investigated the role of hCAP18/LL-37 inCLL.Fil: Podaza, Enrique Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Palacios, Florencia. The Feinstein Institute for Medical Research. Karches Center for Oncology Research; Estados UnidosFil: Croci Russo, Diego Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Risnik, Denise Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Yan, Xiao J.. The Feinstein Institute for Medical Research. Karches Center for Oncology Research; Estados UnidosFil: Almejún, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Colado, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Elías, Esteban Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Borge, Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Morande, Pablo Elías. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Bezares, Raimundo F.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Dr. Teodoro Álvarez"; ArgentinaFil: Fernández Grecco, Horacio. Sanatorio Municipal Dr. Julio Méndez. Servicio de Hematología; ArgentinaFil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Gamberale, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Chiorazzi, Nicholas. The Feinstein Institute for Medical Research. Karches Center for Oncology Research; Estados UnidosFil: Giordano, Mirta Nilda. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin