Preservation of NADH ubiquinone-oxidoreductase activity by Src kinase-mediated phosphorylation of NDUFB10

The tyrosine kinase Src is upregulated in several cancer cells. In such cells, there is a metabolic reprogramming elevating aerobic glycolysis that seems partly dependent on Src activation. Src kinase was recently shown to be targeted to mitochondria where it modulates mitochondrial bioenergetics in non-proliferative tissues and cells. The main goal of our study was to determine if increased Src kinase activity could also influence mitochondrial metabolism in cancer cells (143B and DU145 cells). We have shown that 143B and DU145 cells produce most of the ATP through glycolysis but also that the inhibition of OXPHOS led to a significant decrease in proliferation which was not due to a decrease in the total ATP levels. These results indicate that a more important role for mitochondria in cancer cells could be ensuring mitochondrial functions other than ATP production. This study is the first to show a putative influence of intramitochondrial Src kinase on oxidative phosphorylation in cancer cells. Indeed, we have shown that Src kinase inhibition led to a decrease in mitochondrial respiration via a specific decrease in complex I activities (NADH-ubiquinone oxidoreductase). This decrease is associated with a lower phosphorylation of the complex I subunit NDUFB10. These results suggest that the preservation of complex I function by mitochondrial Src kinase could be important in the development of the overall phenotype of cancer.     

Modelling the nitrification in a full-scale tertiary biological aerated filter unit

A wastewater biofiltration model is used to assess its capacity to reproduce the treatment behaviour of a plant-sized tertiary nitrifying biofilter unit. It is calibrated on two different types of datasets collected at the Seine-Aval biofiltration plant (Achères, France): grab samples at several heights inside the media bed and a long-term daily plant monitoring over a 1-year period. The model parameters are first calibrated to fit the dynamics observed in the media bed, after which the model is compared to the second dataset. Further parameter changes are then made if necessary and the model is once again compared to both datasets to ensure its ability to predict the treatment behaviour on both size scales. The calibrated model provides correct predictions for most observed nutrient variables for both datasets. An overestimation of the oxygen transfer under a summer, low ammonia load period however leads to a slight underestimation of the nitrifying efficiency of the biofilters. Statistical score computation corroborates the model accuracy as the mean error scores usually remain low. They also point to a certain weakness of the model regarding the suspended solids filtration. Both datasets are overall correctly modelled using a single parameter set. Most of this parameter set is close to or contained in value ranges found in the literature. The parameters related to aeration, however, seem to be slightly higher than what is reported elsewhere.     

Validation of Genotyping-By-Sequencing Analysis in Populations of Tetraploid Alfalfa by 454 Sequencing

Genotyping-by-sequencing (GBS) is a relatively low-cost high throughput genotyping technology based on next generation sequencing and is applicable to orphan species with no reference genome. A combination of genome complexity reduction and multiplexing with DNA barcoding provides a simple and affordable way to resolve allelic variation between plant samples or populations. GBS was performed on ApeKI libraries using DNA from 48 genotypes each of two heterogeneous populations of tetraploid alfalfa (Medicago sativa spp. sativa): the synthetic cultivar Apica (ATF0) and a derived population (ATF5) obtained after five cycles of recurrent selection for superior tolerance to freezing (TF). Nearly 400 million reads were obtained from two lanes of an Illumina HiSeq 2000 sequencer and analyzed with the Universal Network-Enabled Analysis Kit (UNEAK) pipeline designed for species with no reference genome. Following the application of whole dataset-level filters, 11,694 single nucleotide polymorphism (SNP) loci were obtained. About 60% had a significant match on the Medicago truncatula syntenic genome. The accuracy of allelic ratios and genotype calls based on GBS data was directly assessed using 454 sequencing on a subset of SNP loci scored in eight plant samples. Sequencing depth in this study was not sufficient for accurate tetraploid allelic dosage, but reliable genotype calls based on diploid allelic dosage were obtained when using additional quality filtering. Principal Component Analysis of SNP loci in plant samples revealed that a small proportion (<5%) of the genetic variability assessed by GBS is able to differentiate ATF0 and ATF5. Our results confirm that analysis of GBS data using UNEAK is a reliable approach for genome-wide discovery of SNP loci in outcrossed polyploids.     

A novel series of metabotropic glutamate receptor 5 negative allosteric modulators based on a 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine core

A series of potent non-acetylinic negative allosteric modulators of the metabotropic glutamate receptor 5 (mGlu5 NAMs) was developed starting from HTS screening hit 1. Potency was improved via iterative SAR, and physicochemical properties were optimized to deliver orally bioavailable compounds acceptable for in vivo testing. A lead molecule from the series demonstrated dose-dependent activity in the second phase of the rat formalin test from 30 mg/kg, and a preliminary PK/PD relationship was established.     

AgNOR technique could be useful for differential diagnosis of squamous carcinomatous cells and atypical cells related to human papillomavirus in cervical smears

The human papillomavirus (HPV)-associated effect can mimic invasive squamous cell carcinoma. Measurements of the argyrophilic nucleolar organizer region (AgNOR) area of cells from smears with HPV infection of the cervix with marked atypia were carried out to differentiate this pathology from keratinizing carcinomas. After destaining, the smears were incubated in the dark for 25 min with a mixture of silver nitrate and gelatin in formic acid. After washing with deionized water and sodium thiosulfate, the slides were dehydrated and mounted with Canada balsam. The average AgNOR area was determined by image cytometry using the immersion oil objective and selecting 100 cells in each smear. Twenty-three patients with a mean AgNOR area of 1.32 µm² among their samples showed normal colposcopies and cervical smears after 18 months. In four patients, whose samples were diagnosed as atypical squamous cells of undetermined significance with viral atypia, the average AgNOR area was 7.70 µm²; biopsies showed keratinizing squamous carcinomas in three of these cases and moderately differentiated squamous carcinoma in one of them. We propose a cutoff of 2.2 µm² for the AgNOR area of cells from smears with HPV infection of the cervix with marked atypia to differentiate this group from keratinizing carcinomas.     

Usefulness of AgNOR technique and CEA expression in atypical metaplastic cells from cervical smears

OBJECTIVE: To evaluate the proliferating capacity of atypical metaplastic cells in cervical smears by AgNOR technique and image analysis and investigate the probable relation with squamous intraepithelial lesions (SIL) using immunocytochemical assay for carcinoembryonic antigen (CEA). STUDY DESIGN: Eight cervical smears were stained with Papanicolaou stain for diagnosis of atypical metaplastic cells. After removal of the stain the smears were processed with a silver colloidal solution and the AgNOR area determined by image cytometry. Differences in the mean AgNOR protein area between reactive metaplastic cells and controls were tested by Student's t test. The CEA was investigated by immunocytochemical staining in smears with atypical metaplastic cells and smears from high-grade squamous intraepithelial lesions (HSIL). RESULTS: The mean AgNOR areas from atypical metaplastic cells (4.55, 6.66, 4.68, 5.30, 4.97, 6.20, 6.28, and 7.35) were significantly greater those that of intermediate metaplastic cells and cells from low-grade squamous intraepithelial lesions (LSIL) (0.77, 0.99, and 0.82, respectively). The atypical metaplastic cells showed values of mean AgNOR area intermediate between that of basal cells (3.28) and HSIL cells (7.73) or neoplastic cells (16.12). The CEA was strongly expressed by the atypical metaplastic cells. CONCLUSION: The expression of CEA in the atypical metaplastic cells underlies the probable relation to SIL. Although the organizer region areas raised high values, it would be necessary to use a greater number of cases to define whether the AgNOR area is indicative of the proliferative activity of the atypical metaplastic cells.     

A comparative proteomic study identified LRPPRC and MCM7 as putative actors in imatinib mesylate cross-resistance in Lucena cell line

Background

Although chronic myeloid leukemia (CML) treatment has improved since the introduction of imatinib mesylate (IM), cases of resistance have been reported. This resistance has been associated with the emergence of multidrug resistance (MDR) phenotype, as a BCR-ABL independent mechanism. The classic pathway studied in MDR promotion is ATP-binding cassette (ABC) family transporters expression, but other mechanisms that drive drug resistance are largely unknown. To better understand IM therapy relapse due to the rise of MDR, we compared the proteomic profiles of K562 and Lucena (K562/VCR) cells.

Results

The use of 2-DE coupled with a MS approach resulted in the identification of 36 differentially expressed proteins. Differential mRNA levels of leucine-rich PPR motif-containing (LRPPRC) protein, minichromosome maintenance complex component 7 (MCM7) and ATP-binding cassette sub-family B (MDR/TAP) member 1 (ABCB1) were capable of defining samples from CML patients as responsive or resistant to therapy.

Conclusions

Through the data presented in this work, we show the relevance of MDR to IM therapy. In addition, our proteomic approach identified candidate actors involved in resistance, which could lead to additional information on BCR-ABL-independent molecular mechanisms.     

B56-containing PP2A dephosphorylate ERK and their activity is controlled by the early gene IEX-1 and ERK

The protein phosphatase 2A (PP2A) acts on several kinases in the extracellular signal-regulated kinase (ERK) signaling pathway but whether a specific holoenzyme dephosphorylates ERK and whether this activity is controlled during mitogenic stimulation is unknown. By using both RNA interference and overexpression of PP2A B regulatory subunits, we show that B56, but not B, family members of PP2A increase ERK dephosphorylation, without affecting its activation by MEK. Induction of the early gene product and ERK substrate IEX-1 (ier3) by growth factors leads to opposite effects and reverses B56-PP2A-mediated ERK dephosphorylation. IEX-1 binds to B56 subunits and pERK independently, enhances B56 phosphorylation by ERK at a conserved Ser/Pro site in this complex and triggers dissociation from the catalytic subunit. This is the first demonstration of the involvement of B56-containing PP2A in ERK dephosphorylation and of a B56-specific cellular protein inhibitor regulating its activity in an ERK-dependent fashion. In addition, our results raise a new paradigm in ERK signaling in which ERK associated to a substrate can transphosphorylate nearby proteins.