Expression of SOX11 transcription factor. Its implication in mantle cell lymphoma

El gen SOX11, perteneciente a la familia de genes SOXC, es un factor de transcripción involucrado en la neurogénesis embrionaria y el remodelado tisular, participando asimismo en el control de la proliferación celular. Su rol en la linfomagénesis es desconocido. Estudios recientes han mostrado expresión proteica nuclear aberrante y sobreexpresión de los niveles de transcripto de SOX11 en pacientes con linfoma de células del manto (LCM). Si bien la mayoría de estos linfomas presentan un curso clínico agresivo, existe un subgrupo de pacientes con enfermedad indolente, sugiriendo una mayor heterogeneidad de esta patología. Actualmente, existen contradicciones respecto de la asociación entre la expresión del gen SOX11 y la evolución clínica del LCM; mientras algunos autores relacionan la ausencia de expresión de SOX11 con buen pronóstico, otros lo encuentran asociado a un curso clínico adverso. Esta diferencia en la expresión estaría relacionada a mecanismos epigenéticos, metilación del ADN y modificaciones a nivel de histonas, que permitirían la expresión aberrante de este gen en algunas neoplasias linfoides, incluyendo LCM. La profundización del conocimiento del gen SOX11 en LCM hará factible, sin duda, lograr una mayor comprensión de los mecanismos involucrados en la patogénesis y/o progresión de este linfoma, así como del rol de SOX11 en estos procesos.SOX11, belonging to the family of genes SOXC, is a transcript factor involved in the embryonic neurogenesis and tissue remodeling, also participating in the control of cell proliferation. Its role in lymphomagenesis still remains unknown. Recent studies have shown aberrant SOX11 nuclear protein expression as well as mRNA levels in patients with mantle cell lymphoma (MCL). Although the majority of these lymphomas have an aggressive clinical course, there is a subgroup of patients with an indolent clinical evolution, suggesting a greater heterogeneity of this disease. Currently, there are contradictions regarding the association of SOX11 gene expression and outcome in MCL, while some authors have related the lack of SOX11 expression with good prognosis, others find it associated with an adverse clinical course. This difference in the gene expression could be associated to epigenetic mechanisms such as modifications at the histone level and DNA methylation that would allow the aberrant expression of this gene in some lymphoid neoplasias, including LCM. More knowledge of gene SOX11 in LCM will lead to a greater understanding of those mechanisms involved in the pathogenesis and progression of this lymphoma, also the involvement of SOX11 in these processes.Fil: Roisman, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Slavutsky, Irma Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; Argentin

Ag-NOR staining and satellite association in bone marrow cells from patients with mycosis fungoides

Silver staining of nucleolus organizing regions (Ag-NORs) of acrocentric chromosomes and the frequency of satellite association (SA) in bone marrow (BM) cells from 7 patients with mycosis fungoides (MF), were studied. BM samples of 7 normal healthy individuals were taken as controls. The mean number of Ag-NORs per metaphase was increased in patients (7.20 +/- 0.25) compared with controls (5.40 +/- 0.16) (p < 0.002), related with the increase of the D group. Moreover, a significant higher percentage of Ag-NOR positive cells in patients (71.7 +/- 3.9) than controls (48.0 +/- 7.8) (p < 0.02), was seen. The analysis of SA revealed a significant increase in the percentage of cells with 1-2 association pairs (ASPs) in patients with respect to their controls (p < 0.05), and a trend to a decrease in the percentage of cells without ASPs. Furthermore, a correlation between the number of Ag-NORs and the mean of ASPs per cell was also found for patients (rk = 0.65; p < 0.05). These results may be associated with a certain degree of immaturity, a high proliferative activity and modifications of the growth rate of BM cells in MF patients.Facultad de Ciencias Exacta

Telomere protein complexes and their role in lymphoid malignancies

Telomeres are highly regulated and dynamic complexes that protect the genomic DNA and prevent the end of linear chromosomes from being misrecognized as a broken DNA. Due to the end replication problem, telomeres of somatic cells shorten with each cell division, inducing cell senescence. Telomerase is a reverse transcriptase capable of compensating telomere attrition by adding telomere repeats to the ends of chromosomes. Human telomeres are associated with the shelterin complex which consists of six telomere-associated proteins that specifically bind to telomeric DNA. Alterations or removal of individual shelterin components would lead to telomere uncapping and telomere dysfunction, resulting in cellular senescence and transformation to a malignant state. Another complex of multifunctional proteins, named non-shelterin complex, is thought to prevent telomere degradation and facilitate telomerase-based telomere elongation. As telomerase is highly expressed in most human tumor cells, it is considered an attractive target for new therapeutic strategies. In this review, we will summarize the characteristics of telomeres and telomerase in lymphoid malignancies and discuss the role of telomere-associated proteins in these entities.Fil: 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: Dos Santos, Patricia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentina. Laboratorio de Genética de Neoplasias Linfoides; ArgentinaFil: Slavutsky, Irma Rosa. Laboratorio de Genética de Neoplasias Linfoides; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentin

Ag-NOR staining and satellite association in bone marrow cells from patients with mycosis fungoides

Silver staining of nucleolus organizing regions (Ag-NORs) of acrocentric chromosomes and the frequency of satellite association (SA) in bone marrow (BM) cells from 7 patients with mycosis fungoides (MF), were studied. BM samples of 7 normal healthy individuals were taken as controls. The mean number of Ag-NORs per metaphase was increased in patients (7.20 +/- 0.25) compared with controls (5.40 +/- 0.16) (p < 0.002), related with the increase of the D group. Moreover, a significant higher percentage of Ag-NOR positive cells in patients (71.7 +/- 3.9) than controls (48.0 +/- 7.8) (p < 0.02), was seen. The analysis of SA revealed a significant increase in the percentage of cells with 1-2 association pairs (ASPs) in patients with respect to their controls (p < 0.05), and a trend to a decrease in the percentage of cells without ASPs. Furthermore, a correlation between the number of Ag-NORs and the mean of ASPs per cell was also found for patients (rk = 0.65; p < 0.05). These results may be associated with a certain degree of immaturity, a high proliferative activity and modifications of the growth rate of BM cells in MF patients.Facultad de Ciencias Exacta

Age related decrease of NOR activity in bone marrow metaphase chromosomes from healthy individuals

Aims—To present data obtained from human bone marrow preparations from healthy individuals showing that the proportion of metaphases with silver stained nucleolar organiser region (AgNOR) chromosomes is associated with the age of the donor. Methods—Bone marrow preparations from eight Russian and 10 Argentinian healthy individuals donating bone marrow for heterologous transplantation were studied by silver staining. The Russian bone marrow preparations were used directly, while the bone marrow specimens from Argentinian donors were incubated for 24 hours at 37°C in F-10 medium with 15% fetal bovine serum. The slides were silver stained by the one step method of Howell and Black with slight modifications. Thirty metaphases with clearly defined D and G group chromosomes were scored for the numbers of AgNORs. All metaphases that were adjacent to silver stained interphase nuclei were analysed to assess the percentage of AgNOR positive mitoses. The Kruskal Wallis test and Kendall’s rank correlation coeYcient (rK) were used to assess the relation between age and the percentage of AgNOR positive cells. Results—The mean numbers (SE) of AgNORs per metaphase were 5.06 (0.17) and 5.56 (0.23) for the Russian and Argentinian groups, respectively, with no significant diVerences between the two groups. The common percentage of AgNOR positive cells decreased significantly as a function of age, with an rK = −0.57 (p &lt; 0.0012). Conclusions—The percentages of AgNOR negative metaphases in bone marrow from healthy individuals is strongly associated with age and this may be related to age related telomere loss.Facultad de Ciencias Exacta

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

IGHV gene rearrangements and mutational status in chronic lymphocytic leukemia and mantle cell lymphoma patients

El estatus mutacional del gen IGHV (immunoglobulin heavy chain vaiable region) es considerado un importante factor pronóstico en leucemia linfocítica crónica (LLC), en tanto que en linfoma de células del manto (LCM) su utilidad desde el punto de vista clínico requiere una evaluación más extensa. El análisis de la literatura muestra un repertorio sesgado en ambas patologías, con mayor participación de las familias VH3, VH4 y VH1, así como una expresión diferencial de genes IGHV. En este estudio se efectuó el análisis comparativo del estatus mutacional, los rearreglos de IGHV y la presencia de receptores estereotipados de una cohorte argentina de 174 pacientes con LLC y de 31 casos con LCM de Brasil. En LLC se observó mayor diversidad de genes, siendo los más frecuentes IGHV1-69, IGHV3-23, IGHV4-34, IGHV3-21 e IGHV3-48 (34,1% del total), en tanto que en LCM se encontró un repertorio muy reducido que incluye: IGHV3-21, IGHV4-34, IGHV3-23 e IGHV4-39 (66,7% del total), y una menor carga mutacional respecto de LLC. En LCM sólo 3,2% de los casos presentaron receptores estereotipados, mientras que en LLC el 14,2% de los rearreglos fueron estereotipados, siendo los clusters más representados #2, #7 y #9. Nuestros datos y los previamente reportados en la literatura sustentan la presencia de estímulos antigénicos en el desarrollo y la patogénesis de ambas entidades, con características específicas en cada una de ellas. En LLC, la incorporación del análisis de los receptores estereotipados podría refinar el pronóstico del estatus mutacional de IGHV.The mutational status of IGHV (immunoglobulin heavy chain variable region) gene is considered an important prognostic factor in chronic lymphocytic leukemia (CLL), nevertheless its clinical usefulness in mantle cell lymphoma (MCL) requires a more extensive evaluation. In both pathologies, the analysis of the literature showed bias repertoire, with higher representation of VH3, VH4 and VH1 families, as well as a differential usage of IGHV genes. In this study, we have performed the analysis of IGHV mutational status and gene rearrangements as well as the evaluation of the presence of stereotyped receptors, in an Argentinean cohort of 174 CLL patients and 31 cases of Brazilian patients with MCL. In CLL, a greater diversity of genes was observed, being the most frequent: IGHV1-69, IGHV3-23, IGHV4-34, IGHV3-21 and IGHV3-48 (34.1% of the total), while in MCL a very small repertoire including: IGHV3-21, IGHV4-34, IGHV3- 23 and IGHV4-39 (66.7% of total), was found. In addition, MCL had a lower mutational load compared to CLL. In MCL only 3.2% of the cases presented stereotyped receptors, whereas in CLL this value reached 14.2%, being the most represented clusters #2, #7 and #9. Our data and previous reports in the literature support the presence of antigenic stimuli in the development and pathogenesis of both entities with specific characteristics in each of them. In CLL, the analysis of stereotypic receptors could refine the clinical outcome on beyond immunoglobulin mutational status.Fil: Stanganelli, Carmen Graciela. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas ; ArgentinaFil: Dos Santos, Patricia. 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: Santana, B. A.. Faculdade de Medicina de Ribeirão Preto; BrasilFil: Calado, Rodrigo. Faculdade de Medicina de Ribeirão Preto; BrasilFil: 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

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