Inhibition of the spindle assembly checkpoint kinase TTK enhances the efficacy of docetaxel in a triple-negative breast cancer model.

BACKGROUND: Triple-negative breast cancers (TNBC) are considered the most aggressive type of breast cancer, for which no targeted therapy exists at the moment. These tumors are characterized by having a high degree of chromosome instability and often overexpress the spindle assembly checkpoint kinase TTK. To explore the potential of TTK inhibition as a targeted therapy in TNBC, we developed a highly potent and selective small molecule inhibitor of TTK, NTRC 0066-0. RESULTS AND CONCLUSIONS: The compound is characterized by long residence time on the target and inhibits the proliferation of a wide variety of human cancer cell lines with potency in the same range as marketed cytotoxic agents. In cell lines and in mice, NTRC 0066-0 inhibits the phosphorylation of a TTK substrate and induces chromosome missegregation. NTRC 0066-0 inhibits tumor growth in MDA-MB-231 xenografts as a single agent after oral application. To address the effect of the inhibitor in breast cancer, we used a well-defined mouse model that spontaneously develops breast tumors that share key morphologic and molecular features with human TNBC. Our studies show that combination of NTRC 0066-0 with a therapeutic dose of docetaxel resulted in doubling of mouse survival and extended tumor remission, without toxicity. Furthermore, we observed that treatment efficacy is only achieved upon co-administration of the two compounds, which suggests a synergistic in vivo effect. Therefore, we propose TTK inhibition as a novel therapeutic target for neoadjuvant therapy in TNBC.

Comparación de tres métodos de determinación de la actividad colinesterasa plasmática en perro / Comparison of three methods for the determination of plasma cholinesterase activity in dog

La determinación de la actividad colinesterasa es un elemento importante en el diagnóstico y monitorización de las intoxicaciones por plaguicidas anticolinesterásicos (organofosforados y carbamatos). El objetivo de este trabajo es determinar en plasma de perro la influencia que tiene sobre los valores fisiológicos de esta enzima el uso de diferentes metodologías para su determinación. El plasma de 141 perros fue analizado para la actividad butirilcolinesterasa (BChE) para comprobar la influencia del cromóforo usado en la reacción y la diferencia entre el uso de kits comerciales o la preparación de los reactivos en el laboratorio. Los resultados no difirieron mucho entre los métodos y usando DTNB (5,5'-ditio-bis-(2-ácido nitrobenzoico)) como cromóforo los valores fueron de 3276 ± 845 UI/L preparando los reactivos en el laboratorio y 3013 ± 1081 UI/L utilizando un kit comercial. Con hexacianoferrato III como cromóforo el resultado fue de 3330 ± 1184 UI/L. Se comprueba que las concentraciones de tampón, de sustrato, el pH del medio y el cromóforo utilizado no influyen decisivamente en el resultado. Se concluye la conveniencia de obtención de valores de referencia propios en cada laboratorio y la ventaja de la preparación de los reactivos frente a la compra de kits comerciales (AU)

The determination of cholinesterase activity is important in the diagnosis and monitoring of poisoning by anticholinesterase pesticides (organophosphates and carbamates). The aim of this work was to study the influence of different methodologies in the determination of normal activity values of this enzyme in canine plasma. Samples from 141 dogs were analyzed for butyrylcholinesterase (BChE) activity to test the influence of the chromophore in the reaction and the differences in the results by using commercial kits or reagents prepared in the laboratory. The results were similar for the different methods. With DTNB as chromophore mean values were 3276 ± 845 UI/L using reagents prepared in the lab and 3013 ± 1081 UI/L using a commercial kit. With hexacyanoferrate III as chromophore mean value was 3330 ± 1184 UI/L. The buffer concentration, the pH of the medium and the chromophore used did not significantly influenced the final value. In conclusion, for the interpretation of ChE values it is important to get reference values in each laboratory and it is advantageous to prepare the reagents in the laboratory instead of purchasing commercial kits (AU)

Intraflagellar transport complex in Leishmania spp. In silico genome-wide screening and annotation of gene function.

Flagella are constructed and maintained through the highly conserved process of intraflagellar transport (IFT), which is a rapid movement of particles along the axonemal microtubules of cilia/flagella. Particles that are transported by IFT are composed of several protein subunits comprising two complexes (A and B), which are conserved among green algae, nematodes, and vertebrates. To determine whether or not homologues to members of the IFT complex proteins are conserved in Leishmania spp, we scanned genomes, transcriptomes and proteomes of Leishmania species in a search for putative IFT factors, which were then identified in silico, compared, cataloged, and characterized. Since a large proportion of newly identified genes in L. major remain unclassified, with many of these being potentially Leishmania- (or kinetoplastid-) specific, there is a need for detailed analyses of homologs/orthologs that could help us understand the functional assignment of these gene products. We used a combination of integrated bioinformatics tools in a pathogenomics approach to contribute to the annotation of Leishmania genomes, particularly regarding flagellar genes and their roles in pathogenesis. This resulted in the formal in silico identification of eight of these homologs in Leishmania (IFT subunits, 20, 27, 46, 52, 57, 88, 140, and 172), along with others (IFTs 71, 74/72, and 81), as well as sequence comparisons and structural predictions. IFT, an important flagellar pathway in Leishmania, begins to be revealed through screening of trypanosomatid genomes; this information could also be used to better understand fundamental processes in Leishmania, such as motility and pathogenesis.

Intraflagellar transport complex in Leishmania spp. In silico genome-wide screening and annotation of gene function

Flagella are constructed and maintained through the highly conserved process of intraflagellar transport (IFT), which is a rapid movement of particles along the axonemal microtubules of cilia/flagella. Particles that are transported by IFT are composed of several protein subunits comprising two complexes (A and B), which are conserved among green algae, nematodes, and vertebrates. To determine whether or not homologues to members of the IFT complex proteins are conserved in Leishmania spp, we scanned genomes, transcriptomes and proteomes of Leishmania species in a search for putative IFT factors, which were then identified in silico, compared, cataloged, and characterized. Since a large proportion of newly identified genes in L. major remain unclassified, with many of these being potentially Leishmania- (or kinetoplastid-) specific, there is a need for detailed analyses of homologs/orthologs that could help us understand the functional assignment of these gene products. We used a combination of integrated bioinformatics tools in a pathogenomics approach to contribute to the annotation of Leishmania genomes, particularly regarding flagellar genes and their roles in pathogenesis. This resulted in the formal in silico identification of eight of these homologs in Leishmania (IFT subunits, 20, 27, 46, 52, 57, 88, 140, and 172), along with others (IFTs 71, 74/72, and 81), as well as sequence comparisons and structural predictions. IFT, an important flagellar pathway in Leishmania, begins to be revealed through screening of trypanosomatid genomes; this information could also be used to better understand fundamental processes in Leishmania, such as motility and pathogenesis.