Shedding light on the binding mechanism of kinase inhibitors BI-2536, Volasetib and Ro-3280 with their pharmacological target PLK1.

In the present work, the interactions of the novel kinase inhibitors BI-2536, Volasetib (BI-6727) and Ro-3280 with the pharmacological target PLK1 have been studied by fluorescence spectroscopy and molecular dynamics calculations. High Stern-Volmer constants were found in fluorescence experiments suggesting the formation of stable protein-ligand complexes. In addition, it was observed that the binding constant between BI-2536 and PLK1 increases about 100-fold in presence of the phosphopeptide Cdc25C-p that docks to the polo box domain of the protein and releases the kinase domain. All the determined binding constants are higher for the kinase inhibitors than for their competitor for the active center (ATP) being BI-2536 and Volasertib the inhibitors that showed more affinity for PLK1. Calculated binding free energies confirmed the higher affinity of PLK1 for BI-2536 and Volasertib than for ATP. The higher affinity of the inhibitors to PLK1 compared to ATP was mainly attributed to stronger van der Waals interactions. Results may help with the challenge of designing and developing new kinase inhibitors more effective in clinical cancer therapy.

Los receptores acoplados a proteínas G como blanco terapéutico / G protein-coupled receptors as therapeutic target

Resumen Los receptores son proteínas codificadas por el ADN, algunos de los cuales ya han sido cristalizados, lo que permite conocer los detalles de su estructura a nivel atómico y algunos aspectos de su función. Esta revisión se enfoca en los más diversos y abundantes, los receptores acoplados a la proteína G. Esta familia de receptores reconoce y media la acción de varios ligandos endógenos (hormonas, neurotransmisores, factores de crecimiento y hormonas locales) y también interviene en la patogenia de diversas enfermedades, por lo que son el blanco terapéutico de aproximadamente 30 a 40 % de los medicamentos que se emplean en la práctica clínica cotidiana y de diversas drogas ilegales. La cristalografía de rayos X es una de las herramientas clave que ha permitido observar la estructura de estos receptores en los aminoácidos que participan en esta interacción, lo que posibilita conocer el sitio de unión del ligando endógeno y de moléculas sintéticas que actúan sobre ellos para modular su acción. El modelado molecular es también una herramienta bioinformática computacional que apoya la investigación sobre la unión receptor-ligando, que hace posible el diseño y desarrollo de fármacos cada vez más específicos. A estos desarrollos se suman importantes cambios en los conceptos farmacodinámicos fundamentales.

Abstract Receptors are proteins coded by DNA, some of which have already been crystalized, thus allowing the details of their structure at the atomic level and some aspects of their function to be known. This review focuses on the most diverse and abundant family of receptors, G protein-coupled receptors. This family of receptors recognizes and mediates the action of several endogenous ligands (hormones, neurotransmitters, growth factors and local hormones) and also intervenes in the pathogenesis of various diseases, which is why they are targeted by approximately 30 to 40% of medications that are used in daily clinical practice and of various illegal drugs as well. X-ray crystallography is one of the essential tools that has allowed to observe the structure of these receptors in the amino acids that participate in this interaction, which allows to know the binding site of the endogenous ligand and of synthetic molecules that act on them to modulate their action. Molecular modeling or "docking" is also a computational bioinformatics tool that supports research on receptor-ligand binding, which allows the design and development of increasingly specific drugs. These developments have brought along significant changes in fundamental pharmacodynamic concepts.

Binding of the anticancer drug BI-2536 to human serum albumin. A spectroscopic and theoretical study.

BI-2536 is a potent Polo-like kinase inhibitor which induces apoptosis in diverse human cancer cell lines. The binding affinity of BI-2536 for human serum albumin (HSA) protein may define its pharmacokinetic and pharmacodynamic profile. We have studied the binding of BI-2536 to HSA by means of different spectroscopic techniques and docking calculations. We have experimentally observed that the affinity of BI-2536 for HSA is higher than that of other common HSA binding drugs. Therefore, it can be postulated that the drug dose should be increased to achieve a certain concentration of free drug in plasma, although BI-2536 could also reach tumour tissues by uptaking HSA/BI-2536 complex. Only a single binding site on HSA has been observed for BI-2536 which seems to correspond to the subdomain IIA pocket. The formation of the HSA/BI-2536 complex is a spontaneous and entropy-driven process that does not cause a significant change of the secondary structure of the protein. Its endothermic character could be related to proton release. Thermodynamic analysis showed that the main protein-drug interactions are of the van der Waals type although the presence of amide and ether groups in BI-2536 could also allow H-bonding with some residues in the subdomain IIA pocket.

Comparative blood transcriptome analysis in idiopathic and LRRK2 G2019S-associated Parkinson's disease.

Patients with Parkinson's disease (PD) carrying the G2019S mutation of the LRRK2 gene provide an opportunity of studying in a homogeneous setting the molecular pathways involved in the pathogenesis of common idiopathic forms of PD. However, whether common mechanisms are involved in both conditions in not known. Here, we compared genome-wide gene expression (RNA sequencing) in peripheral blood between PD patients carrying the G2019S mutation of the LRRK2 gene and idiopathic PD cases, to deepen in the understanding of this topic. In addition, we compared the blood transcriptome between 2 cohorts of carriers of the G2019S mutation (symptomatic and asymptomatic) and 2 cohorts of noncarriers (symptomatic and asymptomatic) for detecting transcriptomic changes attributable to the presence of the G2019S mutation. We searched for gene enrichment in Reactome or Kyoto Encyclopedia of Genes and Genomes pathways. We found that despite some overlap, peripheral blood transcriptome differs widely between idiopathic and LRRK2 G2019S-associated PD, with only 4 deregulated pathways shared by both conditions (complement and coagulation cascades, cell adhesion molecules, hematopoietic cell lineage, and extracellular matrix organization). Changes in the blood transcriptome observed in asymptomatic carriers of the mutation included 6 genes known to be associated with PD in genome-wide association studies and also pathways related with immunity. Our findings emphasize the notion that PD is likely a pathogenically heterogeneous condition and suggest the existence of specific mechanisms involved in LRRK2-associated PD.

Two novel type 2 diabetes loci revealed through integration of TCF7L2 DNA occupancy and SNP association data.

BACKGROUND: The transcription factor 7-like 2 (TCF7L2) locus is strongly implicated in the pathogenesis of type 2 diabetes (T2D). We previously mapped the genomic regions bound by TCF7L2 using ChIP (chromatin immunoprecipitation)-seq in the colorectal carcinoma cell line, HCT116, revealing an unexpected highly significant over-representation of genome-wide association studies (GWAS) loci associated primarily with endocrine (in particular T2D) and cardiovascular traits. METHODS: In order to further explore if this observed phenomenon occurs in other cell lines, we carried out ChIP-seq in HepG2 cells and leveraged ENCODE data for five additional cell lines. Given that only a minority of the predicted genetic component to most complex traits has been identified to date, plus our GWAS-related observations with respect to TCF7L2 occupancy, we investigated if restricting association analyses to the genes yielded from this approach, in order to reduce the constraints of multiple testing, could reveal novel T2D loci. RESULTS: We found strong evidence for the continued enrichment of endocrine and cardiovascular GWAS categories, with additional support for cancer. When investigating all the known GWAS loci bound by TCF7L2 in the shortest gene list, derived from HCT116, the coronary artery disease-associated variant, rs46522 at the UBE2Z-GIP-ATP5G1-SNF8 locus, yielded significant association with T2D within DIAGRAM. Furthermore, when we analyzed tag-SNPs (single nucleotide polymorphisms) in genes not previously implicated by GWAS but bound by TCF7L2 within 5 kb, we observed a significant association of rs4780476 within CPPED1 in DIAGRAM. CONCLUSIONS: ChIP-seq data generated with this GWAS-implicated transcription factor provided a biologically plausible method to limit multiple testing in the assessment of genome-wide genotyping data to uncover two novel T2D-associated loci.

Nuclear receptor NR5A2 and bone: gene expression and association with bone mineral density.

OBJECTIVE: There is growing evidence for a link between energy and bone metabolism. The nuclear receptor subfamily 5 member A2 (NR5A2) is involved in lipid metabolism and modulates the expression of estrogen-related genes in some tissues. The objective of this study was to explore the influence of NR5A2 on bone cells and to determine whether its allelic variations are associated with bone mineral density (BMD). DESIGN: Analyses of gene expression by quantitative PCR and inhibition of NR5A2 expression by siRNAs were used to explore the effects of NR5A2 in osteoblasts. Femoral neck BMD and 30 single nucleotide polymorphisms (SNPs) were first analyzed in 935 postmenopausal women and the association of NR5A2 genetic variants with BMD was explored in other 1284 women in replication cohorts. RESULTS: NR5A2 was highly expressed in bone. The inhibition of NR5A2 confirmed that it modulates the expression of osteocalcin, osteoprotegerin, and podoplanin in osteoblasts. Two SNPs were associated with BMD in the Spanish discovery cohort (rs6663479, P=0.0014, and rs2816948, P=0.0012). A similar trend was observed in another Spanish cohort, with statistically significant differences across genotypes in the combined analysis (P=0.03). However, the association in a cohort from the United States was rather weak. Electrophoretic mobility assays and studies with luciferase reporter vectors confirmed the existence of differences in the binding of nuclear proteins and the transcriptional activity of rs2816948 alleles. CONCLUSIONS: NR5A2 modulates gene expression in osteoblasts and some allelic variants are associated with bone mass in Spanish postmenopausal women.

Trauma no reciente en abdomen cerrado / Non-recent abdominal closed trauma

Entre las urgencias atendidas por traumatismos diversos, en el Centro Diagnóstico Integral Dr Salvador Allende, en Caracas, Venezuela, se destacó el caso que se expone, luego de estar 60 días procurando atención médica en diferentes instituciones hospitalarias, sin recibir credibilidad la joven enferma. Se expone la historia de la paciente, y sus eventualidades con los hallazgos laparotómicos. Se corrobora la necesidad laparotómica con la presunción inicial por juicio clínico y se logra el consentimiento informado familiar. Como refuerzo de la praxis se efectuó el procedimiento omentun mayus, que combate la sepsis futura y garantiza la integridad subfrénica. Este caso trauma visceral circunscrito al lóbulo derecho del hígado favorece, por su carácter y modo, la enseñanza a educandos y especialistas, en caso de afrontar traumas no recientes(AU)

Among all the emergencies seen due to different traumata in the Dr Salvador Allende Integral Diagnosis Center in Caracas Venezuela is emphasized the present case, after 60 days seeking medical in different hospital institutions without to receive medical care. Her history is exposed and its eventualities with the laparotomy findings. Laparotomy need is corroborated according an early clinical criterion and the achievement of the family informed consent. As a praxis effort, the omentum mayus procedure was carried out preventing the future sepsis and to guarantee the subfrenic integrity. Present case —visceral trauma restricted to liver right lobule, due to its character and mode, favors the teaching to students and specialists when they to face non-recent traumata(AU)

Uso de malla de polipropileno en la hernioplastia por técnica de Lichtenstein / Use of polypropylene mesh in hernioplasty by Lichtenstein's technique

INTRODUCCIÓN. El objetivo del estudio fue evaluar el beneficio del uso de prótesis (malla de polipropileno) en la hernioplastia por la técnica de Lichtenstein, en el Hospital Clinicoquirúrgico Joaquín Albarrán. MÉTODOS. Se estudiaron de forma prospectiva (14 meses de por medio) 140 intervenciones quirúrgicas realizadas, mediante la técnica de Lichtenstein, a pacientes con hernia inguinal. Se excluyeron 110 por haber sido practicadas de forma ambulatoria. Se estudiaron los datos siguientes: tipo de hernia encontrada en el examen físico, edad, sexo, raza, ocupación laboral, fecha de la intervención, técnica utilizada y complicaciones durante el posoperatorio inmediato. Se consideró además la reproducción de la hernia luego de la operación, las complicaciones quirúrgicas y la tolerancia a la malla de polipropileno. RESULTADOS. Hubo un marcado predominio del sexo masculino y se constató una influencia directa entre las ocupaciones laborales que requieren esfuerzo físico elevado y la aparición de hernias inguinales (63,3 por ciento). Se registraron únicamente 3 complicaciones: un hematoma y dos seromas. No se documentaron recidivas. No se presentó ningún caso de infección, ni sistémica ni local. El uso de antibióticos profilácticos mostró una relación costo-beneficio adecuada. CONCLUSIONES. La edad avanzada, el sexo masculino y el esfuerzo físico mantenido tienen una relación directamente proporcional con la aparición de hernias inguinales. La factibilidad de la hernioplastia de Lichtenstein, la incidencia nula de recidivas herniarias y la escasa aparición de complicaciones, como el rechazo al material protésico, hablan de manera favorable sobre el uso de polipropileno en esta plastia. Recomendamos utilizar antibioticoterapia profiláctica perioperatoria para evitar la infección de la herida y por tanto asegurar el resultado de la intervención quirúrgica y su perduración(AU)

INTRODUCTION. The aim of present study was to assess the benefit using the prosthesis (polypropylene mesh) in the hernioplasty using the Lichtenstein's technique in the "Joaquín Albarrán" Clinical Surgical Hospital. METHODS. A prospective study (with an interval of 14 months) was conducted in 140 surgical interventions carried out using the Lichtenstein's technique in patients presenting with inguinal hernia. One hundred and ten patients were excluded due to interventions were of ambulatory method. The following data were studied: type of hernia found in the physical examination, age, sex, and race, type of job, intervention's date, and technique used as well as the complications during the immediate postoperative time. Also, the hernia's relapse after operation, surgical complications and tolerance to polypropylene mesh were taking into account. RESULTS. There was predominance of male sex confirming a direct influence among types of jobs requiring a strong physical effort and the appearance of inguinal hernias (63,3 percent). There were only three complications: a hematoma and two seromas. There were not relapses and any case of infection, both local and systemic. The use of prophylactic antibiotics showed an appropriate cost-benefit relationship. CONCLUSIONS. The old age, the male sex and a sustained physical effort have a directly proportional relation to appearance of inguinal hernias. The feasibility of Lichtenstein's hernioplasty, the null incidence of hernia relapses and no appearance of complications including the rejection to prosthetic material, favoured the use of polypropylene in this plasty. Authors recommended the use of perioperative prophylactic antibiotic therapy to avoid wound's infection and thus to secure the result of surgical intervention and its durability(AU)

Biología molecular y cáncer de tiroides / Molecular biology and thyroid cancer

Se realiza una revisión actualizada sobre aspectos de biología molecular que servirán de base al cirujano actuante para un mejor conocimiento del cáncer tiroideo. El objetivo radica en alertar a los cirujanos sobre las nuevas evaluaciones a las que podrán someterse los tumores de la tiroides, que implicarán cambios en toda la gama de conductas actuales en estos casos. Se señalan aspectos que sin duda cambiarán los conceptos que se manejan hoy día(AU)

A updating review is carry out on the features of molecular biology as a basis for acting surgeon to a better knowledge of thyroid cancer. The objective is to alert surgeons on the new assessments for this type of cancer, implicating changes in all the range of current behaviors in these cases. The features that will change the nowadays concepts in this respect(AU)

A common variant associated with prostate cancer in European and African populations.

With the increasing incidence of prostate cancer, identifying common genetic variants that confer risk of the disease is important. Here we report such a variant on chromosome 8q24, a region initially identified through a study of Icelandic families. Allele -8 of the microsatellite DG8S737 was associated with prostate cancer in three case-control series of European ancestry from Iceland, Sweden and the US. The estimated odds ratio (OR) of the allele is 1.62 (P = 2.7 x 10(-11)). About 19% of affected men and 13% of the general population carry at least one copy, yielding a population attributable risk (PAR) of approximately 8%. The association was also replicated in an African American case-control group with a similar OR, in which 41% of affected individuals and 30% of the population are carriers. This leads to a greater estimated PAR (16%) that may contribute to higher incidence of prostate cancer in African American men than in men of European ancestry.

Neuregulin 1 and susceptibility to schizophrenia.

The cause of schizophrenia is unknown, but it has a significant genetic component. Pharmacologic studies, studies of gene expression in man, and studies of mouse mutants suggest involvement of glutamate and dopamine neurotransmitter systems. However, so far, strong association has not been found between schizophrenia and variants of the genes encoding components of these systems. Here, we report the results of a genomewide scan of schizophrenia families in Iceland; these results support previous work, done in five populations, showing that schizophrenia maps to chromosome 8p. Extensive fine-mapping of the 8p locus and haplotype-association analysis, supplemented by a transmission/disequilibrium test, identifies neuregulin 1 (NRG1) as a candidate gene for schizophrenia. NRG1 is expressed at central nervous system synapses and has a clear role in the expression and activation of neurotransmitter receptors, including glutamate receptors. Mutant mice heterozygous for either NRG1 or its receptor, ErbB4, show a behavioral phenotype that overlaps with mouse models for schizophrenia. Furthermore, NRG1 hypomorphs have fewer functional NMDA receptors than wild-type mice. We also demonstrate that the behavioral phenotypes of the NRG1 hypomorphs are partially reversible with clozapine, an atypical antipsychotic drug used to treat schizophrenia.

Localization of a gene for peripheral arterial occlusive disease to chromosome 1p31.

Peripheral arterial occlusive disease (PAOD) results from atherosclerosis of large and medium peripheral arteries, as well as the aorta, and has many risk factors, including smoking, diabetes, hypertension, and hyperlipidemia. PAOD often coexists with coronary artery disease and cerebrovascular disease. Cross-matching a population-based list of Icelandic patients with PAOD who had undergone angiography and/or revascularization procedures with a genealogy database of the entire Icelandic nation defined 116 extended families containing 272 patients. A genomewide scan with microsatellite markers revealed significant linkage to chromosome 1p31 with an allele-sharing LOD score of 3.93 (P=1.04 x 10(-5)). We designate this locus as "PAOD1." Subtracting 35 patients with a history of stroke increased the LOD score to 4.93. This suggests that, although PAOD and other vascular diseases share risk factors, genetic factors specific to subtypes of vascular disease may exist.