Subtype-Selective Peptide and Protein Neurotoxic Inhibitors of Nicotinic Acetylcholine Receptors Enhance Proliferation of Patient-Derived Glioblastoma Cell Lines.

Glioblastoma multiforme (GBM) is the most aggressive type of brain cancer, with a poor prognosis. GBM cells, which develop in the environment of neural tissue, often exploit neurotransmitters and their receptors to promote their own growth and invasion. Nicotinic acetylcholine receptors (nAChRs), which play a crucial role in central nervous system signal transmission, are widely represented in the brain, and GBM cells express several subtypes of nAChRs that are suggested to transmit signals from neurons, promoting tumor invasion and growth. Analysis of published GBM transcriptomes revealed spatial heterogeneity in nAChR subtype expression, and functional nAChRs of α1*, α7, and α9 subtypes are demonstrated in our work on several patient-derived GBM microsphere cultures and on the U87MG GBM cell line using subtype-selective neurotoxins and fluorescent calcium mobilization assay. The U87MG cell line shows reactions to nicotinic agonists similar to those of GBM patient-derived culture. Selective α1*, α7, and α9 nAChR neurotoxins stimulated cell growth in the presence of nicotinic agonists. Several cultivating conditions with varying growth factor content have been proposed and tested. The use of selective neurotoxins confirmed that cell cultures obtained from patients are representative GBM models, but the use of media containing fetal bovine serum can lead to alterations in nAChR expression and functioning.

Dependence of Biocatalysis on D/H Ratio: Possible Fundamental Differences for High-Level Biological Taxons.

The kinetics of biological reactions depends on the deuterium/protium (D/H) ratio in water. In this work, we describe the kinetic model of biocatalytic reactions in living organisms depending on the D/H ratio. We show that a change in the lifetime or other characteristics of the vital activity of some organisms in response to a decrease or increase in the content of deuterium in the environment can be a sign of a difference in taxons. For animals-this is a curve with saturation according to the Gauss's principle, for plants-it is the Poisson dependence, for bacteria a weakly saturated curve with a slight reaction to the deuterium/protium ratio toward increasing deuterium. The biological activity of the aquatic environment with reduced, elevated, and natural concentrations of deuterium is considered. The results of the study are presented in different vital indicators of some taxons: the bacteria kingdom-the colony forming units (CFU) index (Escherichia coli); animals-the activation energy of the death of ciliates (Spirostomum ambiguum), embryogenesis of fish (Brachydanio rerio); plants-germination and accumulation of trace elements Callisia fragrans L., sprouting of gametophores and peptidomics of moss Physcomitrella patens. It was found that many organisms change their metabolism and activity, responding to both high and low concentrations of deuterium in water.

Comparison of two lipid/DNA complexes of equal composition and different morphology.

Two types of complexes were prepared from a cationic cholesterol derivative, dioleoylphos-phatidylcholine and DNA. Depending on the preparation procedure complexes were either dense snarls of lipid covered DNA (type A) or multilayer liposomes with DNA between layers (type B). The transfection efficiency of the snarl-shaped complexes was low but positive. The transfection efficiency of the liposome-shaped complexes was zero, while DNA release upon their interaction with anionic liposomes was 1.7 times higher. The differences in transfection efficacy and DNA release could not be ascribed to the difference in resistance of complexes to decomposition upon interaction with anionic liposomes or intracellular environment since the lipid composition of complexes is the same. Instead the complexes in which lipoplex phase is more continuous (type A) should require more anionic lipids or more time within a cell for complete decomposition. Prolonged life time should lead to the higher probability of DNA expression.