Quinazolinedione SIRT6 inhibitors sensitize cancer cells to chemotherapeutics.

The NAD(+)-dependent sirtuin SIRT6 is highly expressed in human breast, prostate, and skin cancer where it mediates resistance to cytotoxic agents and prevents differentiation. Thus, SIRT6 is an attractive target for the development of new anticancer agents to be used alone or in combination with chemo- or radiotherapy. Here we report on the identification of novel quinazolinedione compounds with inhibitory activity on SIRT6. As predicted based on SIRT6's biological functions, the identified new SIRT6 inhibitors increase histone H3 lysine 9 acetylation, reduce TNF-α production and increase glucose uptake in cultured cells. In addition, these compounds exacerbate DNA damage and cell death in response to the PARP inhibitor olaparib in BRCA2-deficient Capan-1 cells and cooperate with gemcitabine to the killing of pancreatic cancer cells. In conclusion, new SIRT6 inhibitors with a quinazolinedione-based structure have been identified which are active in cells and could potentially find applications in cancer treatment.

Synthesis and structure-activity relationship of aminoarylthiazole derivatives as correctors of the chloride transport defect in cystic fibrosis.

The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel present in the membrane of epithelial cells. Mutations affecting the CFTR gene cause cystic fibrosis (CF), a multi-organ severe disease. The most common CF mutation, F508del, impairs the processing and activity (gating) of CFTR protein. Other mutations, like G551D, only cause a gating defect. Processing and gating defects can be targeted by small molecules called generically correctors and potentiators, respectively. Aminoarylthiazoles (AATs) represent an interesting class of compounds that includes molecules with dual activity, as correctors and potentiators. With the aim to improve the activity profile of AATs, we have now designed and synthesized a library of novel compounds in order to establish an initial SAR that may provide indications about the chemical groups that are beneficial or detrimental for rescue activity. The new compounds were tested as correctors and potentiators in CFBE41o-expressing F508del-CFTR using a functional assay. A dual active compound, AAT-4a, characterized by improved efficacy and marked synergy when combined with the corrector VX-809 has been identified. Moreover, by computational methods, a possible binding site for AATs in nucleotide binding domain NBD1 has been detected. These results will direct the synthesis of new analogues with possibly improved activity.

Synthesis, structural characterization and effect on human granulocyte intracellular cAMP levels of abscisic acid analogs.

The phytohormone abscisic acid (ABA), in addition to regulating physiological functions in plants, is also produced and released by several mammalian cell types, including human granulocytes, where it stimulates innate immune functions via an increase of the intracellular cAMP concentration ([cAMP]i). We synthesized several ABA analogs and evaluated the structure-activity relationship, by the systematical modification of selected regions of these analogs. The resulting molecules were tested for their ability to inhibit the ABA-induced increase of [cAMP]i in human granulocytes. The analogs with modified configurations at C-2' and C-3' abrogated the ABA-induced increase of the [cAMP]i and also inhibited several pro-inflammatory effects induced by exogenous ABA on granulocytes and monocytes. Accordingly, these analogs could be suitable as novel putative anti-inflammatory compounds.

Selection and characterization of single stranded DNA aptamers for the hormone abscisic Acid.

The hormone abscisic acid (ABA) is a small molecule involved in pivotal physiological functions in higher plants. Recently, ABA has been also identified as an endogenous hormone in mammals, regulating different cell functions including inflammatory processes, stem cell expansion, insulin release, and glucose uptake. Aptamers are short, single-stranded (ss) oligonucleotidesable to recognize target molecules with high affinity. The small size of the ABA molecule represented a challenge for aptamer development and the aim of this study was to develop specific anti-ABA DNA aptamers. Biotinylated abscisic acid (bio-ABA) was immobilized on streptavidin-coated magnetic beads. DNA aptamers against bio-ABA were selected with 7 iterative rounds of the systematic evolution of ligands by exponential enrichment method (SELEX), each round comprising incubation of the ABA-binding beads with the ssDNA sequences, DNA elution, electrophoresis, and polymerase chain reaction (PCR) amplification. The PCR product was cloned and sequenced. The binding affinity of several clones was determined using bio-ABA immobilized on streptavidin-coated plates. Aptamer 2 and aptamer 9 showed the highest binding affinity, with dissociation constants values of 0.98 ± 0.14 µM and 0.80 ± 0.07 µM, respectively. Aptamers 2 and 9 were also able to bind free, unmodified ABA and to discriminate between different ABA enantiomers and isomers. Our findings indicate that ssDNA aptamers can selectively bind ABA and could be used for the development of ABA quantitation assays.

Dependence of immunoglobulin class switch recombination in B cells on vesicular release of ATP and CD73 ectonucleotidase activity.

Immunoglobulin (Ig) isotype diversification by class switch recombination (CSR) is an essential process for mounting a protective humoral immune response. Ig CSR deficiencies in humans can result from an intrinsic B cell defect; however, most of these deficiencies are still molecularly undefined and diagnosed as common variable immunodeficiency (CVID). Here, we show that extracellular adenosine critically contributes to CSR in human naive and IgM memory B cells. In these cells, coordinate stimulation of B cell receptor and toll-like receptors results in the release of ATP stored in Ca(2+)-sensitive secretory vesicles. Plasma membrane ectonucleoside triphosphate diphosphohydrolase 1 CD39 and ecto-5'-nucleotidase CD73 hydrolyze ATP to adenosine, which induces CSR in B cells in an autonomous fashion. Notably, CVID patients with impaired class-switched antibody responses are selectively deficient in CD73 expression in B cells, suggesting that CD73-dependent adenosine generation contributes to the pathogenesis of this disease.

Functional characterization of a synthetic abscisic acid analog with anti-inflammatory activity on human granulocytes and monocytes.

The phytohormone abscisic acid (ABA), in addition to regulating several important physiological functions in plants, is also produced and released by human granulocytes and monocytes where it stimulates cell activities involved in the innate immune response. Here we describe the properties of an ABA synthetic analog that competes with the hormone for binding to human granulocyte membranes and to purified recombinant LANCL2 (the human ABA receptor) and inhibits several ABA-triggered inflammatory functions of granulocytes and monocytes in vitro: chemotaxis, phagocytosis, reactive oxygen species production and release of prostaglandin E(2) (PGE(2)) by human granulocytes, release of PGE(2) and of monocyte chemoattractant protein-1 by human monocytes. This observation provides a proof of principle that ABA antagonists may represent a new class of anti-inflammatory agents.

PHOX2B-mediated regulation of ALK expression: in vitro identification of a functional relationship between two genes involved in neuroblastoma.

BACKGROUND: Neuroblastoma (NB) is a severe pediatric tumor originating from neural crest derivatives and accounting for 15% of childhood cancer mortality. The heterogeneous and complex genetic etiology has been confirmed with the identification of mutations in two genes, encoding for the receptor tyrosine kinase Anaplastic Lymphoma Kinase (ALK) and the transcription factor Paired-like Homeobox 2B (PHOX2B), in a limited proportion of NB patients. Interestingly, these two genes are overexpressed in the great majority of primary NB samples and cell lines. These observations led us to test the hypothesis of a regulatory or functional relationship between ALK and PHOX2B underlying NB pathogenesis. METHODOLOGY/PRINCIPAL FINDINGS: Following this possibility, we first confirmed a striking correlation between the transcription levels of ALK, PHOX2B and its direct target PHOX2A in a panel of NB cell lines. Then, we manipulated their expression in NB cell lines by siRNA-mediated knock-down and forced over-expression of each gene under analysis. Surprisingly, PHOX2B- and PHOX2A-directed siRNAs efficiently downregulated each other as well as ALK gene and, consistently, the enhanced expression of PHOX2B in NB cells yielded an increment of ALK protein. We finally demonstrated that PHOX2B drives ALK gene transcription by directly binding its promoter, which therefore represents a novel PHOX2B target. CONCLUSIONS/SIGNIFICANCE: These findings provide a compelling explanation of the concurrent involvement of these two genes in NB pathogenesis and are going to foster a better understanding of molecular interactions at the base of the disease. Moreover, this work opens new perspectives for NBs refractory to conventional therapies that may benefit from the design of novel therapeutic RNAi-based approaches for multiple gene targets.

Juvenile rheumatoid arthritis and bronchiolitis obliterans organized pneumonia.

Diverse pleuropulmonary manifestations, including pleural effusion, rheumatoid nodulosis, fibrosis, obliterans brochiolitis, bronchiectasias, vasculitis, drug-induced lung disease, and obliterans bronchiolitis with organized pneumonia, have been described in patients with rheumatoid arthritis (RA). Bronchiolitis obliterans organized pneumonia (BOOP) is an uncommon condition described in patients with RA but not in juvenile RA (JRA). We described a patient with JRA who developed a BOOP.

Adenocarcinoma apocrino, a propósito de un caso: revisión de la literatura / Apocrine adenocarcinoma: a case report and a review of the literature

Se presenta el caso de una mujer de 31 años de edad, que consulta por un nódulo de 2 cm de diámetro localizado en axila derecha, de dos años de evolución. La histopatología con técnicas de rutina y especiales revela un adenocarcinoma apocrino. Se realiza una revisión del tema, con los 48 casos publicados hasta la fecha

Adenocarcinoma apocrino, a propósito de un caso: revisión de la literatura / Apocrine adenocarcinoma: a case report and a review of the literature

Se presenta el caso de una mujer de 31 años de edad, que consulta por un nódulo de 2 cm de diámetro localizado en axila derecha, de dos años de evolución. La histopatología con técnicas de rutina y especiales revela un adenocarcinoma apocrino. Se realiza una revisión del tema, con los 48 casos publicados hasta la fecha (AU)

Adelantos en el manejo clínico-quirúrgico del feocromocitoma / Advances in clinical-surgical management of pheochromocytoma

Fue revisado el manejo y evolución de 25 pacientes operados por feocromocitoma entre 1977 y 1994. Tres de ellos fueron tratados inicialmente en otros centros y se presentaron con metástasis regionales y/o a distancia. Los restantes 22 recibieron tratamiento primario en nuestra institución. La edad promedio fue de 35 años, y quince (60 por ciento) fueron mujeres. La hipertensión asociada con ataques paroxísticos estuvo presente en 17 casos (68 por ciento), e hipertensión sostenida en 8 (32 por ciento). En todos los enfermos menos uno se encontraron niveles altos de ácido vainillilmandélico y de catecolaminas en orina de 24 horas. Todos los tumores pudieron ser localizados correctamente en el preoperatorio. Los métodos más comunmente usados fueron la tomografía computada, el centellograma con MIBG I 131 y la ecografía. Se consiguió un adecuado bloqueo alfa adrenérgico preoperatorio con dibencilina o con prazosin. Los feocromocitomas fueron resecados a través de una vía anterior transperitoneal en 20 casos ((80 por ciento) y de una vía posterolateral extraperitoneal en 5 (4 por ciento). El índice de malignidad de la serie fue del 23 por ciento. Todos los tumores malignos habían sido diagnosticados inicialmente como benignos. La bilateralidad ocurrió en el 16 por ciento, y existió asociación con carcinoma medular de tiroides en 13 por ciento. Los criterios morfológicos usados para predecir el comportamiento de estos tumores fueron de poca utilidad. Se confirmó la sensibilidad de los marcadores neuroendocrinos y la falta de valor pronóstico de la proteína S-100 y de la mutación de la proteína p53. Valores de proliferación superiores al 10 por ciento con PCNA serían un indicador útil de pronóstico adverso. El análisis de ADN reveló valores aneuploides en el 85 por ciento de los casos. Los tumores diploides o near-diploides mostraron un comportamiento clínico benigno

Adelantos en el manejo clínico-quirúrgico del feocromocitoma / Advances in clinical-surgical management of pheochromocytoma

Fue revisado el manejo y evolución de 25 pacientes operados por feocromocitoma entre 1977 y 1994. Tres de ellos fueron tratados inicialmente en otros centros y se presentaron con metástasis regionales y/o a distancia. Los restantes 22 recibieron tratamiento primario en nuestra institución. La edad promedio fue de 35 años, y quince (60 por ciento) fueron mujeres. La hipertensión asociada con ataques paroxísticos estuvo presente en 17 casos (68 por ciento), e hipertensión sostenida en 8 (32 por ciento). En todos los enfermos menos uno se encontraron niveles altos de ácido vainillilmandélico y de catecolaminas en orina de 24 horas. Todos los tumores pudieron ser localizados correctamente en el preoperatorio. Los métodos más comunmente usados fueron la tomografía computada, el centellograma con MIBG I 131 y la ecografía. Se consiguió un adecuado bloqueo alfa adrenérgico preoperatorio con dibencilina o con prazosin. Los feocromocitomas fueron resecados a través de una vía anterior transperitoneal en 20 casos ((80 por ciento) y de una vía posterolateral extraperitoneal en 5 (4 por ciento). El índice de malignidad de la serie fue del 23 por ciento. Todos los tumores malignos habían sido diagnosticados inicialmente como benignos. La bilateralidad ocurrió en el 16 por ciento, y existió asociación con carcinoma medular de tiroides en 13 por ciento. Los criterios morfológicos usados para predecir el comportamiento de estos tumores fueron de poca utilidad. Se confirmó la sensibilidad de los marcadores neuroendocrinos y la falta de valor pronóstico de la proteína S-100 y de la mutación de la proteína p53. Valores de proliferación superiores al 10 por ciento con PCNA serían un indicador útil de pronóstico adverso. El análisis de ADN reveló valores aneuploides en el 85 por ciento de los casos. Los tumores diploides o near-diploides mostraron un comportamiento clínico benigno (AU)

Estesioneuroblastomas: estudio clínico-patológico, inmunohistoquímico y de ploidía nuclear / Esthesioneuroblastomas: clinico-pathological, immunohistochemical and nuclear ploidy study

Se presentaron 9 casos de estesioneuroblastomas (ENB), 5 varones y 4 mujeres cuyas edades promedio fueron 39 y 55 años respectivamente. Todos presentaban masas polipoides, friables, ubicadas a nivel de nariz y/o senos paranasales. El tratamiento consistió en 8 resecciones quirúrgicas locales, considerándose irresecable uno de los casos. Histológicamente los tumores se hallaban constituidos por células redondas, pequeñas y uniformes dispuestas en planchas y nidos con una matriz fibrilar de fondo, identificándose en un caso pseudorosetas de Homer-Wright. Los estudios inmunohistoquímicos fueron positivos para: enolasa neuronoespecífica (9); proteína S-100 (8); sinaptofisina (7); cromogranina (6); neurofilamentos (6); anticuerpo 013 (4); citoqueratina (1); proteína gliofibrilar ácida (1) y negativos para desmina y CD 45. La determinación del antígeno nuclear de proliferación celular mostró una actividad proliferativa baja en 6 casos (0 a 20 por ciento), y alta en los restantes 3(30 a 50 por ciento). El análisis de ADN reveló 3 tumores diploides y 6 aneuroploides. Un paciente falleció (tumor irresecable y diploide), y los restantes 8 se hallan vivos con seguimientos de 6 meses a 22 años. Se demostró la utilidad de un panel de anticuerpos en el diagnóstico de ENB y el posible valor pronóstico adverso de los histogramas diploides

Estesioneuroblastomas: estudio clínico-patológico, inmunohistoquímico y de ploidía nuclear / Esthesioneuroblastomas: clinico-pathological, immunohistochemical and nuclear ploidy study

Se presentaron 9 casos de estesioneuroblastomas (ENB), 5 varones y 4 mujeres cuyas edades promedio fueron 39 y 55 años respectivamente. Todos presentaban masas polipoides, friables, ubicadas a nivel de nariz y/o senos paranasales. El tratamiento consistió en 8 resecciones quirúrgicas locales, considerándose irresecable uno de los casos. Histológicamente los tumores se hallaban constituidos por células redondas, pequeñas y uniformes dispuestas en planchas y nidos con una matriz fibrilar de fondo, identificándose en un caso pseudorosetas de Homer-Wright. Los estudios inmunohistoquímicos fueron positivos para: enolasa neuronoespecífica (9); proteína S-100 (8); sinaptofisina (7); cromogranina (6); neurofilamentos (6); anticuerpo 013 (4); citoqueratina (1); proteína gliofibrilar ácida (1) y negativos para desmina y CD 45. La determinación del antígeno nuclear de proliferación celular mostró una actividad proliferativa baja en 6 casos (0 a 20 por ciento), y alta en los restantes 3(30 a 50 por ciento). El análisis de ADN reveló 3 tumores diploides y 6 aneuroploides. Un paciente falleció (tumor irresecable y diploide), y los restantes 8 se hallan vivos con seguimientos de 6 meses a 22 años. Se demostró la utilidad de un panel de anticuerpos en el diagnóstico de ENB y el posible valor pronóstico adverso de los histogramas diploides (AU)