Structure–activity relationship (SAR) of parthenin analogues with pro-apoptotic activity: Development of novel anti-cancer leads

Analogues of parthenin were synthesized by substitutions at different reaction centres to establish a structure–activity relationship (SAR). Some of the molecules have displayed significant cytotoxicity in human cervical carcinoma (HeLa) and human myeloid leukemia (HL-60) cells. A few of the compounds also induced apoptosis in HL-60 cells measured in terms of sub-Go/G1 DNA fraction. Also one of the lead molecules has been shown to be the inhibitor of both telomerase and topoisomerase-II.     

An improved method for the hydrolysis of hardwood carbohydrates to monomers

The range of xylan content reported for sugar maple (Acer saccharum) is wider than for most hardwoods. Credible values have been reported that range from less than 16 wt% to more than 19 wt% based on extractive-free wood. Carbohydrate composition of biomass is normally determined by a two stage H₂SO₄ hydrolysis followed by quantification of the sugar monomers. Acetic and uronic acids are also quantified for xylan-rich materials. In this research, the H₂SO₄ hydrolysis conditions were modified and an average xylan content of 18.7% was obtained for sugar maple with a standard deviation (SD) of 0.41% for eight analyses. Minor refinements were made and an average of 18.6% (SD = 0.29%) was obtained for another eight analyses. On this occasion the acetyl to xylose mole ratio was 0.71 with a standard deviation of only 0.008. Proton NMR was utilized in quantifying sugar monomers and acetic acid. The modified hydrolysis procedure gave all the expected results for Betula papyrifera, a species without much controversy regarding its carbohydrate composition. A high percentage of glucan plus xylan was also obtained for an experimentally grown poplar with a low lignin content of 17.7%. The summative analyses varied from 99.7% to 101.5% for the three species.     

Vitamin E isoform-specific inhibition of the exercise-induced heat shock protein 72 expression in humans.

Increased levels of reactive oxygen and nitrogen species, as seen in response to exercise, challenge the cellular integrity. Important protective adaptive changes include induction of heat shock proteins (HSPs). We hypothesized that supplementation with antioxidant vitamins C (ascorbic acid) and E (tocopherol) would attenuate the exercise-induced increase of HSP72 in the skeletal muscle and in the circulation. Using randomization, we allocated 21 young men into three groups receiving one of the following oral supplementations: RRR-alpha-tocopherol 400 IU/day + ascorbic acid (AA) 500 mg/day (CEalpha), RRR-alpha-tocopherol 290 IU/day + RRR-gamma-tocopherol 130 IU/day + AA 500 mg/day (CEalphagamma), or placebo (Control). After 28 days of supplementation, the subjects performed 3 h of knee extensor exercise at 50% of the maximal power output. HSP72 mRNA and protein content was determined in muscle biopsies obtained from vastus lateralis at rest (0 h), postexercise (3 h), and after a 3-h recovery (6 h). In addition, blood was sampled for measurements of HSP72, alpha-tocopherol, gamma-tocopherol, AA, and 8-iso-prostaglandin-F2alpha (8-PGF2alpha). Postsupplementation, the groups differed with respect to plasma vitamin levels. The marker of lipid peroxidation, 8-iso-PGF2alpha, increased from 0 h to 3 h in all groups, however, markedly less (P < 0.05) in CEalpha. In Control, skeletal muscle HSP72 mRNA content increased 2.5-fold (P < 0.05) and serum HSP72 protein increased 4-fold (P < 0.05) in response to exercise, whereas a significant increase of skeletal muscle HSP72 protein content was not observed (P = 0.07). In CEalpha, skeletal muscle HSP72 mRNA, HSP72 protein, and serum HSP72 were not different from Control in response to exercise. In contrast, the effect of exercise on skeletal muscle HSP72 mRNA and protein, as well as circulating HSP72, was completely blunted in CEalphagamma. The results indicate that gamma-tocopherol comprises a potent inhibitor of the exercise-induced increase of HSP72 in skeletal muscle as well as in the circulation.     

Oxidized LDL immune complexes induce release of sphingosine kinase in human U937 monocytic cells

The transformation of macrophages into foam cells is a critical event in the development of atherosclerosis. The most studied aspect of this process is the uptake of modified LDL through the scavenger receptors. Another salient aspect is the effect of modified LDL immune complexes on macrophages activation and foam cell formation. Macrophages internalize oxidized LDL immune complexes (oxLDL-IC) via the Fc-gamma receptor and transform into activated foam cells. In this study we examined the effect of oxLDL-IC on sphingosine kinase 1 (SK1), an enzyme implicated in mediating pro-survival and inflammatory responses through the generation of the signaling molecule sphingosine-1-phosphate (S1P). Intriguingly, oxLDL-IC, but not oxLDL alone, induced an immediate translocation and release of SK1 into the conditioned medium as evidenced by fluorescence confocal microscopy. Immunoblot analysis of cell lysates and conditioned medium revealed a decrease in intracellular SK1 protein levels accompanied by a concomitant increase in extracellular SK1 levels. Furthermore, measurement of S1P formation showed that the activity of cell-associated SK decreased in response to oxLDL-IC compared to oxLDL alone, whereas the activity of SK increased extracellularly. Blocking oxLDL-IC binding to Fc-gamma receptors resulted in decreased levels of extracellular S1P. The data also show that cell survival of human U937 cells exposed to oxLDL-IC increased compared to oxLDL alone. Exogenously added S1P further increased cell survival induced by oxLDL-IC. Taken together, these findings indicate that S1P may be generated extracellularly in response to modified LDL immune complexes and may therefore promote cell survival and prolong cytokine release by activated macrophages.     

Simple micro-method for the isolation of gangliosides by reversed-phase chromatography

A simple and convenient technique has been developed for the isolation of gangliosides from small amounts of tissues or cells. A ganglioside fraction obtained by chromatography of the total lipid extract of DEAE-Sephadex was subjected to alkaline hydrolysis and salts and other non-lipid contaminants were removed by reversed-phase chromatography on a C₁₈ Sep-Pak cartridge. The purified gangliosides were then obtained by chromatography on a small Iatrobeads or Unisil column. This procedure yields a quantitative recovery of gangliosides that are free of contaminants which interfere with thin-layer chromatographic analysis. The procedure was used for the quantitative isolation of gangliosides from human brain white matter and human erythrocytes.     

Serum selenium predicts levels of F2-isoprostanes and prostaglandin F2alpha in a 27 year follow-up study of Swedish men

Low concentrations of selenium (Se) predict mortality and cardiovascular diseases in some populations. The effect of Se on in vivo indicators of oxidative stress and inflammation, two important features of atherosclerosis, in human populations is largely unexplored. This study investigated the longitudinal association between serum selenium (s-Se) and a golden standard indicator of oxidative stress in vivo (8-iso-prostaglandin F2alpha, a major F2-isoprostane), an indicator of cyclooxygenase (COX)-mediated inflammation (prostaglandin F2alpha), high sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6) and serum amyloid A protein (SAA) in a follow-up study of 27 years. The s-Se was measured in 615 Swedish men at 50 years of age in a health investigation. The status of oxidative stress and inflammation was evaluated in a re-investigation 27 years later by quantification of urinary 8-iso-PGF2alpha and 15-keto-dihydro-PGF2alpha (a major metabolite of PGF2alpha) and serum hsCRP, SAA and IL-6. Men in the highest quartile of s-Se at age 50 had decreased levels of 8-iso-PGF2alpha compared to all lower quartiles and decreased levels of PGF2alpha compared to all lower quartiles at follow-up. These associations were independent of BMI, diabetes, hyperlipidemia, hypertension, smoking, alpha-tocopherol and beta-carotene at baseline. The s-Se was not associated with hsCRP, SAA or IL-6 at follow-up. In conclusion, high concentrations of s-Se predict reduced levels of oxidative stress and subclinical COX-mediated (but not cytokine-mediated) inflammation in a male population. The associations between Se, oxidative stress and inflammation, respectively, might be related to the proposed cardiovascular protective property of Se.     

Nestin-expressing neural stem cells identified in the scar following myocardial infarction

Nerve fiber innervation of the scar following myocardial damage may have occurred either via the growth of pre-existing fibers and/or the mobilization of neural stem cells. The present study examined whether neural stem cells were recruited to the infarct region of the rat heart following coronary artery ligation. The neural stem cell marker nestin was detected in the infarct region of 1-week post-myocardial infarct (MI) male rats and cultured scar-derived neural-like cells. By contrast, nestin staining was undetected in either scar myofibroblasts or cardiac myocytes residing in the non-infarcted left ventricle. Reactive astrocytes were isolated from the infarct region and characterized by the co-expression of nestin, glial fibrillary acidic protein, and vimentin. Specific staining of oligodendrocytes and neurons was also detected in the infarct region and cultured scar-derived neural-like cells. Furthermore, neurofilament-M positive fibers were identified in the scar and tyrosine hydroxylase immunoreactivity was observed in peripherin-positive neurons. Neurite formation was induced in PC12 cells treated with the conditioned-media of primary passage scar-derived cells, highlighting the synthesis and secretion of neurotrophic factors. Nerve growth factor (NGF) and brain-derived neurotrophic factor were detected in myofibroblasts and neural cells, and both cell types expressed the NGF receptors trkA and p75. These data highlight the novel observation that neural stem cells were recruited to the infarct region of the damaged rat heart and may contribute in part to nerve fiber growth and subsequent innervation of the scar.