Do neuroendocrine cells in human prostate cancer express androgen receptor?

The presence of androgen receptors (AR) in neuroendocrine cells was investigated in benign tissue of 10 prostatectomy specimens, in 12 prostatic adenocarcinomas with focal neuroendocrine differentiation and in 1 case of a pure neuroendocrine small cell carcinoma of the prostate. Neuroendocrine cells were defined by their reactivity with an antibody to chromogranin A. Monoclonal antibody F39.4 directed against the amino-terminal domain of the AR molecule was used to detect AR. AR and chromogranin A were simultaneously visualized with a double immunofluorescence technique. The results indicate that chromogranin positive cells in both benign and malignant prostatic tissue lack detectable expression of AR. No effect of endocrine therapy was noted. These results are in agreement with the hypothesis that prostatic neuroendocrine tumour cells represent an androgen insensitive cell population, which incidentally may expand to replace the androgen-sensitive tumour cell population during androgen ablation therapy.     

Regulated exocytosis in chromaffin cells and cytotoxic T lymphocytes: How similar are they?

Chromaffin cells from the adrenal medulla secrete catecholamines into the blood stream as part of the fight-or-flight response. Cytotoxic T lymphocytes from the immune system release cytotoxic substances to kill antigen-presenting cells. While at first glance these two cell types do not seem to have much in common, evidence from human diseases indicates that the molecular mechanisms of exocytosis of the respective granules share many similar features. In this review we highlight the similarities and differences of individual aspects of granule maturation and release in both cell types. In addition, we discuss established and putative molecules involved in distinct steps and suggest technical approaches which might facilitate future studies in chromaffin cells and cytotoxic T lymphocytes.     

Do cells treated with human interferon survive virus infection?

Abstract HeLa cells pretreated with human lympho-blastoid interferon (Hu IFN-α (Ly)), at concentrations up to 100 IU / ml and infected with moderate multiplicities of encephalomyocarditis (EMC) virus (10 PFU / cell) died 1 or 2 days after infection. However, if cells were repeatedly treated with high doses of IFN (800 IU / ml) they survived infection by EMC virus for at least a month. Cells survived Semliki Forest virus (SFV) infection when even lower IFN concentrations were used. By contrast infection of IFN-treated HeLa cells with other RNA-containing viruses, such as poliovirus, vesicular stomatitis virus (VSV), Newcastle disease virus (NDV) and reovirus type 3 resulted in cell death. Similarly, infection with a number of DNA-containing viruses such as adenovirus type 5, Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) and vaccinia virus killed cells. The results are discussed in the light of different models for the molecular mechanism of action of interferon.     

Do plant and human pathogens have a common pathogenicity strategy?

Recently, a novel 'two-step' model of pathogenicity has been described that suggests host-cell-derived vasculoproliferative factors play a crucial role in the pathogenesis of bacillary angiomatosis, a disease caused by the human pathogenic bacterium Bartonella henselae. The resulting proliferation of endothelial cells could be interpreted as bacterial pathogens triggering the promotion of their own habitat: the host cell. Similar disease mechanisms are well known in the plant pathogen Agrobacterium tumefaciens, which causes crown gall disease. There are notable similarities between the pathogenicity of A. tumefaciens leading to tumourous disease in plants and to the B. henselae-triggered proliferation of endothelial cells in humans. Here, we hypothesize that this pathogenicity strategy might be common to several bacterial species in different hosts owing to shared pathogenicity factors.     

Do cells in a reproductive state exhibit a fermi-pasta-ulam-fröhlich resonance and emit electromagnetic radiation?

Cells in the reproductive state seem to act like small signal generators and emit radiation which is detectable by small polarizable particles nearby in a medium of suitable osmolarity, but very low conductivity. Evidence for this was seen upon using mouse sarcoma (ascites) cells, and by comparing rapidly dividing mouse "L" fibroblasts with confluent ones. Reproducing cells attracted many more highly polarizable BaTiO₃ particles than they did of the much less polarizable BaSO₄ (dielectric constants 4000 and 11, respectively).This preferential attraction of certain cells for highly polarizable small particles is interpreted as due in large measure to the action of dielectrophoresis on a very small scale.evoked by the presence of nonuniform electric fields of cellular origin acting upon the nearby neutral, polarizable particles.a process called microdielectrophoresis. Consideration of the conductive nature of the surrounding medium forces the conclusion that the cell-generated fields must be oscillatory in nature and have a frequency in the order of a megaherz. These observations recall predictions made earlier by Szent-Györgyi on cellular electronic processes, and by Fröhlich on the possibility of Bose-Einstein condensations to a single quantum state of oscillatory ferroelectric character, due to cooperative long-range interactions among dipolar features of cells. The persistence of oscillatory energy in the lower modes is reminiscent of the Fermi-Pasta-Ulam problem.     

Ratio of 3′ → 5′-exonuclease and DNA polymerase activities in normal and cancer cells of rodents and human

Mutations in genes of DNA polymerases or corrective 3′ → 5′-exonucleases lead to a decrease in the fidelity of DNA biosynthesis throughout the genome, which is accompanied by an increase in the probability of mutagenesis and carcinogenesis. In the present work, activities of 3′ → 5′-exonucleases and DNA polymerases are studied in extracts of rodents and human normal and cancer cells and, for the first time, their integral ratios are measured to elucidate the role of correcting exonucleases in carcinogenesis. Thus, in experiments on cells growing in culture, it has been found that in adult human dermal fibroblasts the value of ratio of activity of 3′ → 5′-exonucleases to the DNA polymerase activity (3′-exo/pol) exceeds this ratio for HeLa cells. A similar situation is also observed in a comparison of normal rat embryo fibroblasts and Syrian hamster A238 transformed fibroblasts. Experiments with extracts of the cells some organs of healthy rats of different ages have shown that in norm the proliferating cells are characterized by higher activities of 3′ → 5′-exonucleases and higher 3′-exo/pol values than in quiescent cells. A comparison of these data allows us to conlude that a disturbance in the functions of corrective 3′ → 5′-exonucleases occurs in pathologically growing cancer cells.     

Is 2,3-butanedione monoxime an effective inhibitor of myosin-based activities in plant cells?

The effectiveness of 2,3-butanedione monoxime (BDM) as an inhibitor of plant myosins has been investigated. Three myosin-dependent motility phenomena in plants, namely cytoplasmic streaming in Chara corallina, light-dependent chloroplast repositioning in Elodea sp., and brefeldin A(BFA)-induced Golgi membrane dynamics in wheat (Triticum aestivum L. cv. Kite) root-tip cells were investigated. All three processes were inhibited by the sulfhydryl-modifying agent N-ethylmalemide (NEM), indicating the probable involvement of myosin as the motor protein in each case. However, none of these myosin-dependent processes were inhibited by BDM at concentrations as high as 20 mM in some instances. These results therefore question the general usefulness of BDM as an inhibitor of myosin-based activities in plant cells.     

Is 2,3-butanedione monoxime an effective inhibitor of myosin-based activities in plant cells?

Summary The effectiveness of 2,3-butanedione monoxime (BDM) as an inhibitor of plant myosins has been investigated. Three myosin-dependent motility phenomena in plants, namely cytoplasmic streaming inChara corallina, light-dependent chloroplast repositioning inElodea sp., and brefeldin A(BFA)-induced Golgi membrane dynamics in wheat (Triticum aestivum L. cv. Kite) roottip cells were investigated. All three processes were inhibited by the sulfhydryl-modifying agent N-ethylmalemide (NEM), indicating the probable involvement of myosin as the motor protein in each case. However, none of these myosin-dependent processes were inhibited by BDM at concentrations as high as 20 mM in some instances. These results therefore question the general usefulness of BDM as an inhibitor of myosin-based activities in plant cells.     

Ecological assessment of running waters: Do macrophytes,macroinvertebrates, diatoms and fish show similar responses to human pressures?

This study aimed to compare the intensity and the sensitivity of the responses of four river biological quality elements (BQEs) – macrophytes, fish, diatoms and macroinvertebrates – to human pressures excluding natural variations in stream ecosystem functioning. Biological, water quality and hydro-morphological data were compiled for 290 French river sites.Out of the 93 metrics tested, 51 covering the four BQEs responded significantly to global degradation. The responses to specific pressures were consistent with the BQEs’ ecological and biological characteristics. For the four BQEs, metrics responded strongly to water quality degradations. Like fish, macroinvertebrate metrics were very sensitive to morphological degradations such as the presence of an impoundment, while diatom and macrophyte metrics did not show strong responses to these changes. Among the four BQEs’ metrics, fish metrics responded the strongest to hydrological perturbations. Although a high proportion of the metrics responded only to high levels of human-induced degradations, trait-based metrics seemed the most sensitive and responded to lower levels of pressure. Global and water quality degradations of the river appear to be better detected by BQE metrics than channel morphological and hydrological degradations. Our results highlight the different impacts of human-induced pressures on the four BQE metrics and the challenging task of assessing the effect of single pressures when most of sites are multi-impacted.     

Enhancement of cytotoxic T-lymphocyte responses in patients with gastrointestinal malignancies following vaccination with CEA peptide–pulsed dendritic cells

Carcinoembryonic antigen (CEA) is strongly expressed in a vast majority of gastrointestinal carcinomas. Recently, epitope peptides of CEA were identified. We have demonstrated HLA-A24–restricted peptide, CEA652[9] (TYACFVSNL), was capable of eliciting specific cytotoxic T lymphocytes (CTLs) which could lyse tumor cells expressing HLA-A24 and CEA. HLA-A24 is the most applicable MHC class I allele in the Japanese population. In this pilot study, we have used the peptide-pulsed dendritic cells (DCs) generated from peripheral blood mononuclear cells (PBMCs) supplemented with GM-CSF and IL-4 as the source of the vaccine. Eight patients with advanced CEA-expressing gastrointestinal malignancies received subcutaneous injections every 2 or 3 weeks. Immunomonitoring was performed by ELISpot (enzyme-linked immunosorbent spot) assay to measure the precursor frequency of CTLs and their capacity to elicit antitumor CTLs in vitro. Four of seven patients have developed their CTL response after vaccinations. DTH reaction was observed in one of eight patients at the DC-injected site. Skin biopsy at the injected site showed the infiltration of the lymphocytes. Furthermore, A24/CEA peptide tetramer assay revealed an increase in peptide-specific T-cell precursor frequency in vaccinated patients. No significant toxic adverse effects were observed, except for mild diarrhea in one case after three vaccinations. Three patients have shown stabilization of the disease after vaccinations. In conclusion, our results clearly demonstrated that our vaccination protocol was safe and might develop a CEA-specific CTL response in cancer patients.     

Do plant families with contrasting functional traits show similar patterns of endemism? A case study with Central African Orchidaceae and Rubiaceae

The influence of functional traits on floristic patterns remains poorly understood in tropical rain forests. This contribution explores whether patterns of endemism of plant species are influenced by their life form and mode of dispersal. We used a comprehensive dataset of 3650 georeferenced plant specimens collected in Cameroon belonging to 115 taxa of Orchidaceae and 207 Rubiaceae endemic to Atlantic Central Africa. Species diversity of each family was compared using raw species richness (SR) and an index of species diversity (S _k ) using subsampling procedure to correct for sampling bias. Measures were compared at three scales (square grids of one half-degree and one-degree per side and ecoregions) and according to elevation and continentality gradients. Species similarity between grid cells was measured using the sample-size corrected NNESS index. For both families, SR and S _k decreased along the continentality gradient. In forest habitats below 1500 m altitude, both Orchidaceae and Rubiaceae show similar endemism patterns, but they differ in intensity. At higher altitudes, S _k is higher for orchids due to the presence of endemic terrestrial taxa in grasslands, where the endemic Rubiaceae flora is rather poor. Substantial endemism observed at the ecoregion level and turnover analysis supported the role of the Sanaga River as a phytogeographical boundary. Similar endemism patterns were observed in lowland forests for Orchidaceae and Rubiaceae, even though Orchidaceae are assumed to have better long distance dispersal capabilities. The dispersal ability of Orchidaceae could be limited by the need of specific mycorhizal fungi for seed germination or host specificity for epiphytic orchids.     

Localization of adenylate cyclase and 5′-nucleotidase activities in human thyroid follicular cells

Summary The localization of adenylate cyclase and 5-nucleotidase activities in the follicular cells of adenomatous goiter and normal thyroid was studied by light and electron microscopy. Simultanous biochemical measurement for both activities was carried out to confirm the histochemical findings. Adenylyl-imidodiphosphate (AMP-PNP) was used as an effective substrate for adenylate cyclase. The specificity of the adenylate cyclase reaction was also examined by adding oxalacetic acid or PCMB as an adenylate cyclase inhibitor, and by adding sodium fluoride or TSH as an adenylate cyclase stimulator to the reaction mixture. In the case of tissue from adenomatous goiter, a large amount of the reaction product of the adenylate cyclase activity was found uniformly in the apical and lateral plasma membrane and not in the basal plasma membrane. In the cases of normal thyroid, a small amount of the reaction product of adenylate cyclase activity was demonstrated, and only in the lateral plasma membrane of the follicular cells. On the other hand, the histochemical localization of 5-nucleotidase activity was the same in adenomatous goiter and normal thyroid. The reaction product of 5-nucleotidase activity was found predominantly in the apical plasma membrane of the follicular cells. The biochemical findings indicated that the activity of adenylate cyclase per gram tissue was approximately 2 times higher in the case of adenomatous goiter than that in the case of normal thyroid, while the 5-nucleotidase activity in adenomatous goiter was in slightly higher level than in normal thyroid. Thus the histochemically demonstrable amount of adenylate cyclase and 5-nucleotidase reflected the activity levels measured biochemically. The lack of demonstrable adenylate cyclase activity in the basal plasma membrane suggests the possibility that this structure may not play any important role in TSH reception.     

Do neuroendocrine cells come up large in small cell lung cancer?

Comment on: Park K, et al. Cell Cycle 2011; 10:2140-50.     

Investigation of carvedilol-evoked Ca²+ movement and death in human oral cancer cells

The effect of carvedilol on cytosolic free Ca2? concentrations ([Ca2?](i)) in OC2 human oral cancer cells is unknown. This study examined if carvedilol altered basal [Ca2?](i) levels in suspended OC2 cells by using fura-2 as a Ca2?-sensitive fluorescent probe. Carvedilol at concentrations between 10 and 40 μM increased [Ca2?](i) in a concentration-dependent fashion. The Ca2? signal was decreased by 50% by removing extracellular Ca2?. Carvedilol-induced Ca2? entry was not affected by the store-operated Ca2? channel blockers nifedipine, econazole, and SK&F96365, but was enhanced by activation or inhibition of protein kinase C. In Ca2?-free medium, incubation with the endoplasmic reticulum Ca2? pump inhibitor thapsigargin did not change carvedilol-induced [Ca2?](i) rise; conversely, incubation with carvedilol did not reduce thapsigargin-induced Ca2? release. Pretreatment with the mitochondrial uncoupler carbonylcyanide m-chlorophenylhydrazone (CCCP) inhibited carvedilol-induced [Ca2?](i) release. Inhibition of phospholipase C with U73122 did not alter carvedilol-induced [Ca2?](i) rise. Carvedilol at 5-50 μM induced cell death in a concentration-dependent manner. The death was not reversed when cytosolic Ca2? was chelated with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA/AM). Annexin V/propidium iodide staining assay suggests that apoptosis played a role in the death. Collectively, in OC2 cells, carvedilol induced [Ca2?](i) rise by causing phospholipase C-independent Ca2? release from mitochondria and non-endoplasmic reticulum stores, and Ca2? influx via protein kinase C-regulated channels. Carvedilol (up to 50 μM) induced cell death in a Ca2?-independent manner that involved apoptosis.     

eIF2 kinases mediate β-lapachone toxicity in yeast and human cancer cells

β-lapachone (β-lap) is a novel anticancer agent that selectively induces cell death in human cancer cells, by activation of the NQO1 NAD(P)H dehydrogenase and radical oxygen species (ROS) generation. We characterized the gene expression profile of budding yeast cells treated with β-lap using cDNA microarrays. Genes involved in tolerance to oxidative stress were differentially expressed in β-lap treated cells. β-lap treatment generated reactive oxygen species (ROS), which were efficiently blocked by dicoumarol, an inhibitor of NADH dehydrogenases. A yeast mutant in the mitocondrial NADH dehydrogenase Nde2p was found to be resistant to β-lap treatment, despite inducing ROS production in a WT manner. Most interestingly, DNA damage responses triggered by β-lap were abolished in the nde2Δ mutant. Amino acid biosynthesis genes were also induced in β-lap treated cells, suggesting that β-lap exposure somehow triggered the General Control of Nutrients (GCN) pathway. Accordingly, β-lap treatment increased phosphorylation of eIF2α subunit in a manner dependent on the Gcn2p kinase. eIF2α phosphorylation required Gcn1p, Gcn20p and Nde2p. Gcn2p was also required for cell survival upon exposure to β-lap and to elicit checkpoint responses. Remarkably, β-lap treatment increased phosphorylation of eIF2α in breast tumor cells, in a manner dependent on the Nde2p ortholog AIF, and the eIF2 kinase PERK. These findings uncover a new target pathway of β-lap in yeast and human cells and highlight a previously unknown functional connection between Nde2p, Gcn2p and DNA damage responses.     

Do variables that affect similar bistable apparent-movement displays result in similar changes in perception?

Two bistable apparent-movement displays (i.e. ones that generate two qualitatively different kinds of movement percepts under different conditions) were compared. They were designed to be as similar as possible spatially, and were studied with identical stimulus manipulations to see whether changes in balance between their bistable percepts would be similar. Results show that the two displays had different response characteristics to the same stimulus manipulations. Two models of motion perception that have previously predicted at least one kind of bistable apparent motion were considered in terms of how well they address the current data. As yet, neither model has been shown to predict the motion states and bistable behavior of the two displays studied here. It is concluded that results of the type described here (specifically, differences in the psychophysical functions yielded by two structurally similar but qualitatively different bistable displays) present a challenge for theories of motion perception.     

Why does iron abrogate the cytotoxic effect of S-nitrosothiols on human and animal cultured cells?

It was found that dinitrosyl iron complexes (DNIC) with thiol-containing ligands (cysteine or glutathione) of concentrations up to 1 mM produce no cytotoxic effect on cultured cells from human milk gland carcinoma (MCF-7). The cytotoxic action on MCF-7 cells was produced by S-nitrosocysteine: at a concentration of 1 mM, it induced the death of 50% cells. A more stable S-nitrosothiol, S-nitrosoglutathione, did not produce any cytotoxic effect at the same concentration. It is assumed that the negative action of nitrosocysteine is due to its rapid degradation, which results in the accumulation of large amounts of free NO molecules followed by their oxidation by superoxide ions to peroxynitrite, an efficient inhibitor of metabolic processes. These processes seem to be not characteristic of the more stable S-nitrosoglutathione. The cytotoxic effect of nitrosocysteine was completlly abrogated by the addition of 0.2 mM ferrous citrate complex to the medium. When S-nitrosoglutathione NO (0.5 mM) or S-nitrosoglutathione (0.5 mM) + Fe(2+)-citrate (0.2 mM) were added to the medium, protein-bound dinitrosyl iron complexes formed with the involvement of endogenous or exogenous iron were detected in cells. The amount of the complexes in the presence of exogenous iron increased four times, reaching the value of 1.6 nmole/5 x 10(6) cells. Therefore, it was proposed that the blockade of the cytotoxic action of S-nitrosoglutathione by iron complexes is due to Cys-NO transformation of S-nitrosocysteine into dinitrosyl iron complexes. The high stability of these complexes ensures only a gradual accumulation of nitric oxide in cells.