Involvement of PI3K Pathway in Glioma Cell Resistance to Temozolomide Treatment

The aim of the study was to investigate the anticancer potential of LY294002 (PI3K inhibitor) and temozolomide using glioblastoma multiforme (T98G) and anaplastic astrocytoma (MOGGCCM) cells. Apoptosis, autophagy, necrosis, and granules in the cytoplasm were identified microscopically (fluorescence and electron microscopes). The mitochondrial membrane potential was studied by flow cytometry. The activity of caspases 3, 8, and 9 and Akt was evaluated fluorometrically, while the expression of Beclin 1, PI3K, Akt, mTOR, caspase 12, and Hsp27 was determined by immunoblotting. SiRNA was used to block Hsp27 and PI3K expression. Cell migration and localization of Hsp27 were tested with the wound healing assay and immunocytochemistry, respectively. LY294002 effectively diminished the migratory potential and increased programmed death of T98G and MOGGCCM. Autophagy was dominant in MOGGCCM, while apoptosis was dominant in T98G. LY294002 with temozolomide did not potentiate cell death but redirected autophagy toward apoptosis, which was correlated with ER stress. A similar effect was observed after blocking PI3K expression with siRNA. Transfection with Hsp27 siRNA significantly increased apoptosis related to ER stress. Our results indicate that inhibition of the PI3K/Akt/mTOR pathway sensitizes glioma cells to apoptosis upon temozolomide treatment, which was correlated with ER stress. Hsp27 increases the resistance of glioma cells to cell death upon temozolomide treatment.     

New Succinimides with Potent Anticancer Activity: Synthesis,Activation of Stress Signaling Pathways and Characterization of Apoptosis in Leukemia and Cervical Cancer Cells

Based on previously identified dicarboximides with significant anticancer and immunomodulatory activities, a series of 26 new derivatives were designed and synthesized by the Diels–Alder reaction between appropriate diene and maleimide or hydroxymaleimide moieties. The resulting imides were functionalized with alkanolamine or alkylamine side chains and subsequently converted to their hydrochlorides. The structures of the obtained compounds were confirmed by 1H and 13C NMR and by ESI MS spectral analysis. Their cytotoxicity was evaluated in human leukemia (K562, MOLT4), cervical cancer (HeLa), and normal endothelial cells (HUVEC). The majority of derivatives exhibited high to moderate cytotoxicity and induced apoptosis in K562 cells. Microarray gene profiling demonstrated upregulation of proapoptotic genes involved in receptor-mediated and mitochondrial cell death pathways as well as antiapoptotic genes involved in NF-kB signaling. Selected dicarboximides activated JNK and p38 kinases in leukemia cells, suggesting that MAPKs may be involved in the regulation of apoptosis. The tested dicarboximides bind to DNA as assessed by a plasmid DNA cleavage protection assay. The selected dicarboximides offer new scaffolds for further development as anticancer drugs.     

Epigallocatechin Gallate for Management of Heavy Metal-Induced Oxidative Stress: Mechanisms of Action,Efficacy, and Concerns

In this review, we highlight the effects of epigallocatechin gallate (EGCG) against toxicities induced by heavy metals (HMs). This most active green tea polyphenol was demonstrated to reduce HM toxicity in such cells and tissues as testis, liver, kidney, and neural cells. Several protective mechanisms that seem to play a pivotal role in EGCG-induced effects, including reactive oxygen species scavenging, HM chelation, activation of nuclear factor erythroid 2-related factor 2 (Nrf2), anti-inflammatory effects, and protection of mitochondria, are described. However, some studies, especially in vitro experiments, reported potentiation of harmful HM actions in the presence of EGCG. The adverse impact of EGCG on HM toxicity may be explained by such events as autooxidation of EGCG, EGCG-mediated iron (Fe³⁺) reduction, depletion of intracellular glutathione (GSH) levels, and disruption of mitochondrial functions. Furthermore, challenges hampering the potential EGCG application related to its low bioavailability and proper dosing are also discussed. Overall, in this review, we point out insights into mechanisms that might account for both the beneficial and adverse effects of EGCG in HM poisoning, which may have a bearing on the design of new therapeutics for HM intoxication therapy.     

Changes in the Physicochemical Properties of Blood and Skin Cell Membranes as a Result of Psoriasis Vulgaris and Psoriatic Arthritis Development

Psoriasis is accompanied by disturbed redox homeostasis, with systemic and local oxidative stress promoting the modification of basic components of cellular membranes. Therefore, the aim of the study was to investigate the effect of development of psoriasis vulgaris and psoriatic arthritis on the composition and physicochemical properties of skin cell membranes (keratinocytes and fibroblasts) and blood cells (lymphocytes, granulocytes and erythrocytes). Both forms of psoriasis are characterized by decreased levels and changes in the localization of membrane phospholipids, and an increased level of sialic acid as well as the lipid peroxidation product (malondialdehyde), which resulted in an increase in the zeta potential of skin cells and blood cells, with granulocytes and lymphocytes affected more than erythrocytes. Using theoretical equations and the dependence of the cell membrane surface charge density as a function of pH, it was shown that patients with psoriatic arthritis have a greater increase in the concentration of negatively charged groups on the membrane surface and reduced the value of the association constant with H⁺ compared to patients with psoriasis vulgaris. Therefore, it can be suggested that the physicochemical parameters of membranes, skin and blood cells, especially lymphocytes, can be used to assess the severity of the disease.     

Physicochemical and Biological Characterisation of Diclofenac Oligomeric Poly(3-hydroxyoctanoate) Hybrids as β-TCP Ceramics Modifiers for Bone Tissue Regeneration

Nowadays, regenerative medicine faces a major challenge in providing new, functional materials that will meet the characteristics desired to replenish and grow new tissue. Therefore, this study presents new ceramic-polymer composites in which the matrix consists of tricalcium phosphates covered with blends containing a chemically bounded diclofenac with the biocompatible polymer—poly(3-hydroxyoctanoate), P(3HO). Modification of P(3HO) oligomers was confirmed by NMR, IR and XPS. Moreover, obtained oligomers and their blends were subjected to an in-depth characterisation using GPC, TGA, DSC and AFM. Furthermore, we demonstrate that the hydrophobicity and surface free energy values of blends decreased with the amount of diclofenac modified oligomers. Subsequently, the designed composites were used as a substrate for growth of the pre-osteoblast cell line (MC3T3-E1). An in vitro biocompatibility study showed that the composite with the lowest concentration of the proposed drug is within the range assumed to be non-toxic (viability above 70%). Cell proliferation was visualised using the SEM method, whereas the observation of cell penetration into the scaffold was carried out by confocal microscopy. Thus, it can be an ideal new functional bone tissue substitute, allowing not only the regeneration and restoration of the defect but also inhibiting the development of chronic inflammation.     

Inference of COVID-19 epidemiological distributions from Brazilian hospital data

Knowing COVID-19 epidemiological distributions, such as the time from patient admission to death, is directly relevant to effective primary and secondary care planning, and moreover, the mathematical modelling of the pandemic generally. We determine epidemiological distributions for patients hospitalized with COVID-19 using a large dataset (N = 21 000 − 157 000) from the Brazilian Sistema de Informação de Vigilância Epidemiológica da Gripe database. A joint Bayesian subnational model with partial pooling is used to simultaneously describe the 26 states and one federal district of Brazil, and shows significant variation in the mean of the symptom-onset-to-death time, with ranges between 11.2 and 17.8 days across the different states, and a mean of 15.2 days for Brazil. We find strong evidence in favour of specific probability density function choices: for example, the gamma distribution gives the best fit for onset-to-death and the generalized lognormal for onset-to-hospital-admission. Our results show that epidemiological distributions have considerable geographical variation, and provide the first estimates of these distributions in a low and middle-income setting. At the subnational level, variation in COVID-19 outcome timings are found to be correlated with poverty, deprivation and segregation levels, and weaker correlation is observed for mean age, wealth and urbanicity.     

Preparation of ω-hydroxynonanoic acid and its ester derivatives

Methyl ricinoleate was ozonized in methanol or in acetic acid and the intermediate hydroperoxides were reduced electrochemically on Pb-cathode to give 9-hydroxynonanoic acid 1 in high yields. The acid 1 was also prepared by direct castor oil ozonolysis in methanol followed by sodium borohydride reduction of the intermediate hydroperoxides. The cost of the electricity for the electroreduction was at least 30 times lower as compared with sodium borohydride consumption. 9-Hydroxynonanoic acid was then transformed to alkyl 9-acetoxynonanoates 3a–3d, for which ¹H nuclear magnetic reasonance, mass, and infrared spectra are given. Esterification of the hydroxy acid 1 with boric acid and pyrolysis of the resultant orthoborates produced 8-nonenoic acid 4 in a 45% yield. Reaction of 4 with lower aliphatic alcohols in presence of Amberlyst 15 produced alkyl 8-noneates 5a–5d along with some amounts of a cis/trans mixture of alkyl 7-noneates.     

Hydrogen entry into iron after potential jumps from cathodic to anodic polarization in 0.1 M NaOH without and with EDTA or sodium molybdate

Hydrogen can enter into iron or steel during anodic polarization when bare metal is exposed, e.g. during stress corrosion cracking, erosion or friction. The hydrogen permeation rate (HPR) through a 35-μm thick iron membrane was studied with the electrochemical technique in 0.1 M NaOH without and with EDTA or Na₂MoO₄ during cathodic and anodic polarization at 25 °C. Anodic polarization of the bare metal was performed by applying fast jumps of anodic potentials to the cathodically treated surface. The jumps resulted in transients of enhanced HPR which continued to rise despite the starting decay of anodic current. The enhanced HPR can be ascribed to acidification associated with anodic oxidation of iron. It is proposed that the continued rise of HPR during anodic current decay can be explained by the formation of low-protective layers which hinder diffusion of hydrated protons out of the metal surface and thereby increase their concentration at the surface. The enhancement of HPR was strongly decreased by EDTA, but increased by Na₂MoO₄ at noble potentials. It is suggested that these effects can be explained in terms of the thickness and type of low-protective layers.     

The rs2516839 Polymorphism of the USF1 Gene May Modulate Serum Triglyceride Levels in Response to Cigarette Smoking

Single nucleotide polymorphisms (SNPs) of the USF1 gene (upstream stimulatory factor 1) influence plasma lipid levels. This study aims to determine whether USF1 SNPs interact with traditional risk factors of atherosclerosis to increase coronary artery disease (CAD) risk. In the present study serum lipid levels and USF1 gene polymorphisms (rs2516839 and rs3737787) were determined in 470 subjects: 235 patients with premature CAD and 235 controls. A trend of increasing triglycerides (TG) levels in relation to the C allele dose of rs2516839 SNP was observed. The synergistic effect of cigarette smoking and C allele carrier state on CAD risk was also found (SIM = 2.69, p = 0.015). TG levels differentiated significantly particular genotypes in smokers (1.53 mmol/L for TT, 1.80 mmol/L for CT and 2.27 mmol/L for CC subjects). In contrast, these differences were not observed in the non-smokers subgroup (1.57 mmol/L for TT, 1.46 mmol/L for CT and 1.49 mmol/L for CC subjects). In conclusion, the rs2516839 polymorphism may modulate serum triglyceride levels in response to cigarette smoking. Carriers of the C allele seem to be particularly at risk of CAD, when exposed to cigarette smoking.