PKM2 Modulation in Head and Neck Squamous Cell Carcinoma

The enzyme pyruvate kinase M2 (PKM2) plays a major role in the switch of tumor cells from oxidative phosphorylation to aerobic glycolysis, one of the hallmarks of cancer. Different allosteric inhibitors or activators and several posttranslational modifications regulate its activity. Head and neck squamous cell carcinoma (HNSCC) is a common disease with a high rate of recurrence. To find out more about PKM2 and its modulation in HNSCC, we examined a panel of HNSCC cells using real-time cell metabolic analysis and Western blotting with an emphasis on phosphorylation variant Tyr105 and two reagents known to impair PKM2 activity. Our results show that in HNSCC, PKM2 is commonly phosphorylated at Tyrosine 105. Its levels depended on tyrosine kinase activity, emphasizing the importance of growth factors such as EGF (epidermal growth factor) on HNSCC metabolism. Furthermore, its correlation with the expression of CD44 indicates a role in cancer stemness. Cells generally reacted with higher glycolysis to PKM2 activator DASA-58 and lower glycolysis to PKM2 inhibitor Compound 3k, but some were more susceptible to activation and others to inhibition. Our findings emphasize the need to further investigate the role of PKM2 in HNSCC, as it could aid understanding and treatment of the disease.     

Über Gesetzmäßigkeiten in der π-Elektronenstruktur von heteroanalogen Polyvinylidenverbindungen

On Regularities of the π-Electronic Structure of Heteroanalogous Polyvinylidene Compounds Starting with simple forms of the equations for the eigenvalues and eigencoefficients of the π-system of heteroanalogous polyvinylidene compounds 3 several regularities in the π-electronic structure of these systems are derived and compared with known experimental facts. In this line several predictions are given for the properties of compounds unknown up to now.     

Proteomic Assessment of Extracellular Vesicles from Canine Tissue Explants as a Pipeline to Identify Molecular Targets in Osteosarcoma: PSMD14/Rpn11 as a Proof of Principle

Osteosarcoma (OS) is a highly malignant bone tumour that has seen little improvement in treatment modalities in the past 30 years. Understanding what molecules contribute to OS biology could aid in the discovery of novel therapies. Extracellular vesicles (EVs) serve as a mode of cell-to-cell communication and have the potential to uncover novel protein signatures. In our research, we developed a novel pipeline to isolate, characterize, and profile EVs from normal bone and osteosarcoma tissue explants from canine OS patients. Proteomic analysis of vesicle preparations revealed a protein signature related to protein metabolism. One molecule of interest, PSMD14/Rpn11, was explored further given its prognostic potential in human and canine OS, and its targetability with the drug capzimin. In vitro experiments demonstrated that capzimin induces apoptosis and reduces clonogenic survival, proliferation, and migration in two metastatic canine OS cell lines. Capzimin also reduces the viability of metastatic human OS cells cultured under 3D conditions that mimic the growth of OS cells at secondary sites. This unique pipeline can improve our understanding of OS biology and identify new prognostic markers and molecular targets for both canine and human OS patients.     

How to Differentiate General Toxicity-Related Endocrine Effects from Endocrine Disruption: Systematic Review of Carbon Disulfide Data

This review provides an overview of the assessment of the endocrine disrupting (ED) properties of carbon disulfide (CS₂), following the methodology used at the European level to identify endocrine disruptors. Relevant in vitro, in vivo studies and human data are analyzed. The assessment presented here focuses on one endocrine activity, i.e., thyroid disruption, and two main adverse effects, neurotoxicity and cardiotoxicity. The data available on the different ED or non-ED modes of action (MoA), known to trigger these adverse effects, are described and the strength of evidence of the different MoA is weighted. We conclude that the adverse effects could be due to systemic toxicity rather than endocrine-mediated toxicity. This assessment illustrates the scientific and regulatory challenges in differentiating a specific endocrine disruption from an indirect endocrine effect resulting from a non-ED mediated systemic toxicity. This issue of evaluating the ED properties of highly toxic and reactive substances has been insufficiently developed by European guidance so far and needs to be further addressed. Finally, this example also raises questions about the capacity of the technics available in toxicology to address such a complex issue with certainty.     

Antibiotic resistance and hypermutability of Escherichia coli O157 from feedlot cattle treated with growth-promoting agents

In a longitudinal study (165 days), we investigated the effect of growth-promoting agents (monensin and trenbolone acetate-estradiol) and an antibiotic (oxytetracycline) on the incidence in feedlot steers of Escherichia coli O157, including antibiotic-resistant and hypermutable isolates. Eighty steers in 16 pens were treated with eight combinations of promoters, and each treatment was duplicated. Fecal samples were collected at nine different sampling times for detection of E. coli O157. Overall, 50 E. coli O157 isolates were detected in treated animals, and none were found in untreated animals. Compared with untreated controls, there was a significant association between the utilization of growth-promoting agents or antibiotics and the shedding of E. coli O157 at day 137 (P = 0.03), when a prevalence peak was observed and 50% of the isolates were detected. Multiplex PCR assays were conducted for some virulence genes. PCR results indicated that all except one isolate possessed at least the Shiga toxin gene stx2. MICs for 12 antibiotics were determined, and eight oxytetracycline-resistant E. coli O157 strains were identified. Antibiotic-resistant strains were considered a distinct subpopulation of E. coli O157 by pulsed-field gel electrophoresis typing. Seven of these antibiotic-resistant strains were isolated early in the study (on or before day 25), and among them two were also hypermutable as determined by rifampin mutation frequencies. The proportion of hypermutable strains among E. coli O157 isolates remained relatively constant throughout the study period. These results indicate that the use of growth-promoting agents and antibiotics in beef production may increase the risk of environmental contamination by E. coli O157.     

Determination of celiac disease-specific peptidase activity of germinated cereals

A method to determine the celiac disease-specific peptidase activity of different germinated cereals was developed. Kernels of common wheat, spelt, emmer, einkorn, rye, and barley were germinated, lyophilized, and milled into flour and bran. The latter was extracted at pH 4.0 to obtain a solution enriched with peptidases. The synthetic α-gliadin peptide with the amino acid sequence PQPQLPYPQPQLPY (peptide IV), which has been shown to be toxic for celiac disease patients, was selected as substrate for bran peptidases. It was quantified by reversed-phase high-performance liquid chromatography on C₁₈ silica gel. For kinetic studies, rye bran extract was incubated with peptide IV at 50 °C and pH 6.5. The peptide was degraded continuously, and only 30.2% of the original peptide was detected after 90 min. Accordingly, the bran extracts of all cereals were investigated. The incubation time was set to 60 min at 50 °C, and the degradation of peptide IV was performed at pH 4.0 and 6.5, respectively. Except for rye, peptide degradation was faster at pH 4.0 than at pH 6.5. At pH 4.0, emmer extract was most active, followed by spelt, common wheat, and einkorn extracts. The activity of rye and barley extracts was significantly lower. In conclusion, the method is easy to perform, quick, and provides reproducible results. It can be applied to other peptidase sources such as bacterial or fungal cultures to optimize peptidase preparations suitable for detoxifying gluten-containing food or for drugs to treat celiac disease.     

Polymerisation von Vinylverbindungen in Gegenwart von Titan(III)-chlorid

Polymerization of Vinyl Compounds in the Presence of Titanium(III)Chloride The polymerization of styrene, acrylonitrile and some methacrylates initiated by a titanium(III) chloride dichloroacetic acid redox system was studied. The monomer selectivity of the polymerization in the presence of titanium(III) chloride was found to be affected by a reductive termination reaction. Titanium(III) chloride acts as a retarder in the polymerization of styrene initiated by azobisisobutyronitrile (AIBN). The polymerization of polar monomers like acrylonitrile, methyl, ethyl and propyl methacrylate by AIBN is inhibited by titanium(III) chloride.