RESUMEN

Rhabdomyosarcomas (RMS) are the most frequent soft-tissue sarcoma in children and characteristically show features of developing skeletal muscle. The alveolar subtype is frequently associated with a PAX3-FOXO1 fusion protein that is known to contribute to the undifferentiated myogenic phenotype of RMS cells. Histone methylation of lysine residues controls developmental processes in both normal and malignant cell contexts. Here we show that JARID2, which encodes a protein known to recruit various complexes with histone-methylating activity to their target genes, is significantly overexpressed in RMS with PAX3-FOXO1 compared with the fusion gene-negative RMS (t-test; P < 0.0001). Multivariate analyses showed that higher JARID2 levels are also associated with metastases at diagnosis, independent of fusion gene status and RMS subtype (n = 120; P = 0.039). JARID2 levels were altered by silencing or overexpressing PAX3-FOXO1 in RMS cell lines with and without the fusion gene, respectively. Consistent with this, we demonstrated that JARID2 is a direct transcriptional target of the PAX3-FOXO1 fusion protein. Silencing JARID2 resulted in reduced cell proliferation coupled with myogenic differentiation, including increased expression of Myogenin (MYOG) and Myosin Light Chain (MYL1) in RMS cell lines representative of both the alveolar and embryonal subtypes. Induced myogenic differentiation was associated with a decrease in JARID2 levels and this phenotype could be rescued by overexpressing JARID2. Furthermore, we that showed JARID2 binds to and alters the methylation status of histone H3 lysine 27 in the promoter regions of MYOG and MYL1 and that the interaction of JARID2 at these promoters is dependent on EED, a core component of the polycomb repressive complex 2 (PRC2). Therefore, JARID2 is a downstream effector of PAX3-FOXO1 that maintains an undifferentiated myogenic phenotype that is characteristic of RMS. JARID2 and other components of PRC2 may represent novel therapeutic targets for treating RMS patients.

Asunto(s)

Diferenciación Celular/genética , Desarrollo de Músculos/genética , Proteínas de Fusión Oncogénica/genética , Factores de Transcripción Paired Box/genética , Complejo Represivo Polycomb 2/genética , Rabdomiosarcoma/genética , Línea Celular Tumoral , Proliferación Celular , Proteína Potenciadora del Homólogo Zeste 2 , Regulación Neoplásica de la Expresión Génica/genética , Histona Demetilasas/genética , Histona Demetilasas/metabolismo , Humanos , Miogenina/genética , Miogenina/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas de Fusión Oncogénica/metabolismo , Factores de Transcripción Paired Box/metabolismo , Complejo Represivo Polycomb 2/metabolismo , Regiones Promotoras Genéticas/genética , Proteína de la Leucemia Promielocítica , Rabdomiosarcoma/patología , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Transcripción Genética/genética , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo

RESUMEN

Acquired resistance to selective FLT3 inhibitors is an emerging clinical problem in the treatment of FLT3-ITD(+) acute myeloid leukaemia (AML). The paucity of valid pre-clinical models has restricted investigations to determine the mechanism of acquired therapeutic resistance, thereby limiting the development of effective treatments. We generated selective FLT3 inhibitor-resistant cells by treating the FLT3-ITD(+) human AML cell line MOLM-13 in vitro with the FLT3-selective inhibitor MLN518, and validated the resistant phenotype in vivo and in vitro. The resistant cells, MOLM-13-RES, harboured a new D835Y tyrosine kinase domain (TKD) mutation on the FLT3-ITD(+) allele. Acquired TKD mutations, including D835Y, have recently been identified in FLT3-ITD(+) patients relapsing after treatment with the novel FLT3 inhibitor, AC220. Consistent with this clinical pattern of resistance, MOLM-13-RES cells displayed high relative resistance to AC220 and Sorafenib. Furthermore, treatment of MOLM-13-RES cells with AC220 lead to loss of the FLT3 wild-type allele and the duplication of the FLT3-ITD-D835Y allele. Our FLT3-Aurora kinase inhibitor, CCT137690, successfully inhibited growth of FLT3-ITD-D835Y cells in vitro and in vivo, suggesting that dual FLT3-Aurora inhibition may overcome selective FLT3 inhibitor resistance, in part due to inhibition of Aurora kinase, and may benefit patients with FLT3-mutated AML.

Asunto(s)

Resistencia a Antineoplásicos/genética , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Mutación/genética , Inhibidores de Proteínas Quinasas/farmacología , Secuencias Repetidas en Tándem/genética , Tirosina Quinasa 3 Similar a fms/genética , Animales , Apoptosis/efectos de los fármacos , Aurora Quinasas , Bencenosulfonatos/farmacología , Benzotiazoles/farmacología , Western Blotting , Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Femenino , Humanos , Imidazoles/farmacología , Ratones , Ratones Desnudos , Niacinamida/análogos & derivados , Compuestos de Fenilurea/farmacología , Piperazinas/farmacología , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Piridinas/farmacología , Quinazolinas/farmacología , Sorafenib , Células Tumorales Cultivadas , Tirosina Quinasa 3 Similar a fms/antagonistas & inhibidores , Tirosina Quinasa 3 Similar a fms/metabolismo

RESUMEN

Aurora kinases are a family of protein kinases that have a key role in multiple stages of mitosis. Over-expression of Aurora kinases, particularly Aurora A, has been demonstrated in a number of solid tumors and hematological malignancies. Not surprisingly, these serine/threonine kinases have become attractive small molecule targets for cancer therapeutics, with several inhibitors currently in early-phase clinical trials. A small number of compounds developed to date are highly selective for either Aurora A or Aurora B, while the majority inhibit both Aurora A and Aurora B; many of these compounds exhibit 'off-target' inhibition of kinases such as ABL, JAK2 and FLT3. It is currently unclear whether the therapeutic activity of these compounds in leukemia is primarily due to selective Aurora or multi-kinase inhibition. The most promising application for Aurora kinase inhibitors to date appears to be in FLT3-mutated acute myeloid leukemia (AML) and imatinib-resistant chronic myeloid leukemia/Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia, particularly when caused by the T315I mutation. Here we review the growing body of evidence supporting the use of Aurora kinase inhibitors as effective agents for AML and Ph+ leukemias.

Asunto(s)

Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mieloide Aguda/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Aurora Quinasa B , Aurora Quinasas , Humanos , Leucemia Mielógena Crónica BCR-ABL Positiva/enzimología , Leucemia Mieloide Aguda/enzimología

RESUMEN

In this report we describe the molecular defect underlying partial and severe quantitative von Willebrand factor (VWF) deficiencies in 3 families previously diagnosed with types 1 and 3 Von Willebrand-disease. Analysis of the VWF gene in affected family members revealed a novel C to T transition at nucleotide 1067 of the VWF complemetary DNA (cDNA), predicting substitution of arginine by tryptophan at amino acid position 273 (R273W) of pre-pro-VWF. Two patients, homozygous for the R273W mutation, had a partial VWF deficiency (VWF:Ag levels of 0.06 IU/mL and 0.09 IU/mL) and lacked high-molecular weight VWF multimers in plasma. A third patient, also homozygous for the R273W mutation, had a severe VWF deficiency (VWF:Ag level of less than 0.01 IU/mL) and undetectable VWF multimers in plasma. Recombinant VWF having the R273W mutation was expressed in COS-7 cells. Pulse-chase experiments showed that secretion of rVWFR273W was severely impaired compared with wild-type rVWF. However, the mutation did not affect the ability of VWF to form dimers in the endoplasmic reticulum (ER). Multimer analysis showed that rVWFR273W failed to form high-molecular-weight multimers present in wild-type rVWF. We concluded that the R273W mutation is responsible for the quantitative VWF deficiencies and aberrant multimer patterns observed in the affected family members. To identify factors that may function in the intracellular retention of rVWFR273W, we investigated the interactions of VWF expressed in COS-7 cells with molecular chaperones of the ER. The R273W mutation did not affect the ability of VWF to bind to BiP, Grp94, ERp72, calnexin, and calreticulin in COS-7 cells. (Blood. 2000;96:560-568)

Asunto(s)

Mutación , Precursores de Proteínas/genética , Enfermedades de von Willebrand/genética , Factor de von Willebrand/genética , Secuencia de Aminoácidos , Animales , Proteínas de Unión al Calcio/metabolismo , Calnexina , Calreticulina , Consanguinidad , Dimerización , Femenino , Homocigoto , Humanos , Masculino , Ratones , Datos de Secuencia Molecular , Ratas , Proteínas Recombinantes , Ribonucleoproteínas/metabolismo , Turquía , Factor de von Willebrand/química , Factor de von Willebrand/metabolismo

RESUMEN

Two novel mutations, a T-to-C transition at nucleotide 2612 and a T-to-G transversion at nucleotide 3923 of the von Willebrand factor (vWF) complementary DNA, were detected by analysis of the vWF gene in DNA from members of 2 families with atypical von Willebrand disease. The T2612C transition predicts substitution of cysteine by arginine at amino acid position 788 (C788R), and the T3923G transversion predicts substitution of cysteine by glycine at position 1225 (C1225G) of pre-pro-vWF. The patients homozygous for the C788R and C1225G mutations both had a partial vWF deficiency (0. 18 IU/mL and 0.07 IU/mL vWF antigen, respectively); vWF in plasma from patients homozygous for either the C788R or the C1225G mutation failed to bind factor VIII and lacked high molecular weight multimers. Recombinant (r) vWF molecules having the C788R or C1225G mutation were expressed in COS-7 cells. Both rvWF C788R and rvWF C1225G exhibited significantly impaired secretion and failed to bind factor VIII. Recombinant vWF C788R in COS-7 culture medium showed a severe reduction in high molecular weight multimers, whereas rvWF C1225G showed a very mild reduction in high molecular weight multimers when compared with wild-type rvWF. (Blood. 2000;95:2000-2007)

Asunto(s)

Factor VIII/metabolismo , Enfermedades de von Willebrand/genética , Factor de von Willebrand/metabolismo , Animales , Células COS , Niño , Preescolar , Relación Dosis-Respuesta a Droga , Factor VIII/genética , Femenino , Humanos , Masculino , Mutación , Linaje , Fenotipo , Plásmidos/metabolismo , Mutación Puntual , Pruebas de Precipitina , Unión Proteica , Proteínas Recombinantes/metabolismo , Transfección , Factor de von Willebrand/genética

Asunto(s)

Alelos , Enfermedades de von Willebrand/genética , Factor de von Willebrand/genética , Frecuencia de los Genes , Humanos , Prevalencia , Reino Unido

Asunto(s)

Inhibidores de 5-alfa-Reductasa , Antagonistas Adrenérgicos alfa/uso terapéutico , Endotelinas/antagonistas & inhibidores , Inhibidores Enzimáticos/uso terapéutico , Próstata/efectos de los fármacos , Hiperplasia Prostática/tratamiento farmacológico , Receptores Adrenérgicos alfa/metabolismo , Antagonistas Adrenérgicos alfa/química , Antagonistas Adrenérgicos alfa/metabolismo , Antagonistas Adrenérgicos alfa/farmacología , Animales , Unión Competitiva , Ensayos Clínicos Controlados como Asunto , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Humanos , Masculino , Próstata/metabolismo , Hiperplasia Prostática/metabolismo , Relación Estructura-Actividad

RESUMEN

Although the letter of recommendation is the most commonly requested information relating to the personal qualities of applicants to dietetics internship programs, little research has focused on its value in selection decisions. The purpose of this study was to review how 318 letters of recommendation submitted on a standardized form related to the source of the reference and to the admission status of the applicants. The form contained 40 attributes that raters assigned to one of six categories. Nine of the 40 attributes were not rated by more than 75% of the raters, and 3 of the attributes were rated as outstanding by more than 60% of the raters. We concluded that these attributes did little to distinguish among applicants. The attribute maturity correlated 0.70 with 5 attributes and 0.99 with 2 attributes, so duplication of information existed. Raters were categorized as follows: adviser, major professor, other professor, employer, and other. The highest mean ratings were given by advisers; major professors rated students lowest. Analysis of variance supported a significant difference in rating by type of rater. Our findings suggest that fewer items should be used on a standardized form and that the type of rater should be specified if references are to distinguish among applicants.

Asunto(s)

Dietética/educación , Internado no Médico , Criterios de Admisión Escolar , Análisis de Varianza , Humanos , Estudios Retrospectivos

RESUMEN

The continuing decline in the number of applicants to allied health educational programs combined with the need to ensure that graduates are competent has made essential the development of reliable predictors that more fully assess the potential of all individuals in the restricted applicant pool. The letter of recommendation is the most commonly requested information that relates to personal qualities in college applicants, but little research has been conducted on the value of this predictor. The purpose of this study was to retroactively review how attribute ratings in letters of recommendation submitted on standardized forms (N = 500) related to the source of the reference and the admission status of students applying to allied health educational programs. Results indicated that some attribute ratings distinguish between students and some do not, that standardized forms can be refined by elimination of items that failed to distinguish students, that ratings vary significantly by type of rater, and that the relationship between rating scores and admission status supports the efficacy of the standardized recommendation forms.

Asunto(s)

Evaluación Educacional , Criterios de Admisión Escolar , Escuelas para Profesionales de Salud , Técnicos Medios en Salud/educación , Dietética/educación , Humanos , Ciencia del Laboratorio Clínico/educación , Estudios Retrospectivos , Estudiantes del Área de la Salud , Tecnología Radiológica/educación

RESUMEN

This study was designed to establish a descriptive profile of the personality characteristics of radiologic technology educators in order to draw inferences to the roles the characteristics play in radiologic technology education. The results of the study indicate that R.T. educators tend to be field-dependent, high in integrative complexity, low in dogmatism, and Concrete Sequential in learning style. These results suggest that the educators approach their roles in a structured, open-minded, sequential manner and exercise a high level of interpersonal skills.

Asunto(s)

Determinación de la Personalidad , Enseñanza , Tecnología Radiológica/educación , Humanos , Pruebas de Personalidad/métodos

RESUMEN

The purposes of this study were to determine 1) the nature and magnitude of allied health professionals' continuing education (CE) activities, and 2) the utility of selected demographic and situational characteristics of these personnel as predictors of such activities. A cross-sectional survey design gathered demographic, situational and CE activity data from individuals representing three major allied health occupational clusters. Regarding participation in CE, analysis of the data indicates that those sampled tend to be active learners, that their efforts are more often self-directed than other-directed, and that the pattern of these activities is generally consistent with that observed among other health professional groups. In terms of predicting CE activity, the findings indicate that the situational attributes of these personnel account for more variation in reported levels of both self and other-directed learning efforts than do their demographic characteristics. A knowledge of these relationships has both practical importance for providers of CE and theoretical meaning for those who study this complex phenomenon.

Asunto(s)

Técnicos Medios en Salud/educación , Educación Continua/tendencias , Estados Unidos

RESUMEN

The continuing decline in the number of applicants to radiologic technology educational programs is beginning to stress the traditional standards of excellence in admissions. To maintain standards, it is imperative that reliable predictors are developed to assess the full potential for success of all individuals in the restricted applicant pool. This article reviews the research done with noncognitive measures, identifies those that increase predictive efficiency, and proposes directions for future research in this area.

Asunto(s)

Evaluación Educacional , Criterios de Admisión Escolar , Tecnología Radiológica/educación , Humanos , Estados Unidos

RESUMEN

The inclusion of noncognitive variables in the admissions decision process has been suggested as a reliable means of more fully assessing the potential abilities of individuals within the applicant pool. An increase in predictive efficiency is particularly important now that allied health educational programs are faced with a continuing decline in the number of applicants. This study was designed to determine whether cognitive-style and learning-style variables are predictive of success in a graduate allied health education program. Three cognitive-style measures were used to assess integrative complexity, dogmatism, and field-independence-dependence. Learning-style preferences were measured by Canfield's Learning Styles Inventory. Academic success was measured by scores on the Master's Comprehensive Examination (MCE). The results indicated that there was no significant relationship between academic success and the cognitive-style variables. However, a stepwise multiple regression indicated that 20.44% of the variance on the multiple-choice section of the MCE and 41.36% of the variance on the essay portion of the MCE were explained by learning-style variables.

Asunto(s)

Logro , Cognición , Aprendizaje , Estudiantes del Área de la Salud/psicología , Técnicos Medios en Salud/educación , Área de Dependencia-Independencia , Humanos , Criterios de Admisión Escolar

RESUMEN

Institutions of higher education appear to be using inappropriate measures to select students who aspire to become allied health education administrators. Therefore, new selection predictors need to be developed and validated. This article reports the results of a survey investigation conducted to determine the feasibility of using two cognitive styles, dogmatism and integrative complexity, as selection predictors for allied health graduate leadership programs. The findings indicate that current allied health education administrators are similar in cognitive style, low in dogmatism and high in integrative complexity. The findings support the premise that cognitive styles are related to both occupational choice and performance and, thus, provide a potentially powerful basis for selecting appropriate individuals for allied health graduate leadership programs.

Asunto(s)

Personal Administrativo/educación , Técnicos Medios en Salud/educación , Cognición , Evaluación Educacional , Criterios de Admisión Escolar , Arkansas , Humanos , Probabilidad , Pruebas Psicológicas

RESUMEN

This study was designed to investigate the feasibility of utilizing selected personality inventories and demographic variables as predictors of academic success in radiography programs. The findings of the investigation indicate that the personality and demographic variables are not related to student performance in academic courses, but that the personality variables have potential for utilization as predictors of clinical performance.

Asunto(s)

Logro , Evaluación Educacional/métodos , Personalidad , Radiografía/educación , Factores de Edad , Escolaridad , Predicción , Humanos , Estados Unidos

Asunto(s)

Terapia por Acupuntura , Gingivectomía/métodos , Analgesia/métodos , Femenino , Enfermedades de las Encías , Humanos , Persona de Mediana Edad