Antitumor effect induced by a hot water extract of Chlorella vulgaris (CE): Resistance to meth-A tumor growth mediated by CE-induced polymorphonuclear leukocytes

Summary When a hot water extract of Chlorella vulgaris (CE) was injected into the peritoneal cavity of BALB/c mice inoculated with syngeneic Meth-A tumor cells, the survival times were strikingly prolonged. Furthermore, peritoneal exudate cells (PEC) rich in polymorphonuclear cells (PMN) obtained from normal mice 24 h after CE injection exhibited an antitumor effect in a Winn-type assay using normal recipients. Such an activity of PEC remained almost intact after T cell or macrophage depletion. However, such PEC did not express an antitumor effect in a Winn-type assay using irradiated recipients. It was suggested that CE-induced PEC, presumably PMN, expressed an antitumor effect in cooperation with a host- or recipient-derived element(s) sensitive to irradiation. The anti-tumor mechanism of CE may be different from that of OK-432, one of the biological response modifiers.     

Application of ES cells for generation of respiration-deficient mice carrying mtDNA with a large-scale deletion

In a previous study, we used mouse zygotes as recipients of mtDNA with a large-scale deletion mutation (DeltamtDNA) and generated respiration-deficient mice (mito-mice) carrying DeltamtDNA. In this study, we used mouse ES cells as recipients of DeltamtDNA, and generated mito-mice with DeltamtDNA only when the ES cells carried 17% DeltamtDNA. No chimera mice or their F(1) progenies were obtained from ES cells carrying more than 61% DeltamtDNA. These observations suggest that respiratory defects of ES cells inhibit their normal differentiation into chimera mice and mito-mice, and that ES cells are more effective than zygotes for generation of mito-mice carrying mtDNAs without significant pathogenic mutations.     

Doppel-induced Purkinje cell death is stoichiometrically abrogated by prion protein

Activin A can induce erythroid differentiation, whereas basic fibroblast growth factor (bFGF) can maintain the undifferentiated status of erythroid progenitors. How these two factors together can affect the regulation of erythroid differentiation in hematopoietic cells has not been elucidated. This study demonstrates that bFGF antagonizes activin A-mediated growth inhibition and hemoglobin (Hb) synthesis in K562 cells. Analyses of mitogen-activated protein kinases revealed that activin A-induced p38 phosphorylation and inhibited ERK1/2 phosphorylation. In contrast, bFGF worked antagonistically to induce ERK1/2 phosphorylation and inhibited p38 phosphorylation in K562 cells. Furthermore, co-treatment of cells with activin A and bFGF decreased p38 phosphorylation and increased ERK1/2 phosphorylation. SB203580 inhibition of p38 activity eliminated activin A-mediated growth inhibition and Hb synthesis, whereas U0126 inhibition of ERK1/2 activity augmented the effects of activin A on K562 cells. These results suggest that bFGF can negatively modulate p38 and positively modulate ERK1/2 to antagonize activin A-mediated growth inhibition and Hb synthesis in K562 cells.     

Restricted expression of tumor necrosis factor-related apoptosis-inducing ligand receptor 4 in human peripheral blood lymphocytes

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in tumor but not normal cells, thus providing therapeutic possibilities for human cancers. However, it is not fully clear how widespread TRAIL receptors are, or how TRAIL signaling is modulated in normal cells. We characterized cell surface expression of TRAIL receptors in normal healthy donor peripheral blood and report that each of the TRAIL receptors are characteristically expressed on restricted cell populations. TRAIL-R1 is distinctively expressed on B-lymphocytes, TRAIL-R2 on monocytes, TRAIL-R3 on neutrophils and most impressively, CD8+ lymphocytes and NKT lymphocytes but not CD4+ lymphocytes express TRAIL-R4.     

Essential roles of Meltrin beta (ADAM19) in heart development

Morphogenesis of the heart requires development of the endocardial cushion tissue that gives rise to the membranous septa and valves. Here we show that Meltrin beta/ADAM19, a novel metalloprotease-disintegrin, participates in the development of the endocardial cushion. Mice lacking Meltrin beta exhibit ventricular septal defect (VSD) and immature valves, and most of the animals die soon after birth. During development of the endocardial cushion, epithelial-mesenchymal transformation (EMT) of endocardial epithelial cells generates most of the cushion mesenchymes that constitute the main components of the septa and valves. Meltrin beta is expressed in both the epithelia and the mesenchymes of the endocardial cushion. In the absence of Meltrin beta, the cushion is small or thin in the septum-forming region and show poor remodeling of cardiac jelly components; both of these characteristics suggest impaired growth and differentiation of the endocardial cushion. When embryonic fibroblasts are cultured sparsely, Meltrin beta-lacking cells exhibit aberrant ectodomain shedding of type I Neuregulin, one of the ErbB ligands expressed in endocardial cells. These results suggest the necessity of proteolytic regulation of ErbB ligands by Meltrin beta for proper heart development.     

Discovery of hydroxamic acid analogs as dual inhibitors of phosphodiesterase-1 and -5

HTS and the following synthesis of a series of the compounds led us to the discovery of hydroxamic acid analogs as potent dual inhibitors of phosphodiesterase (PDE)-1 and 5. These compounds have highly related structure and deviation of the structure usually resulted in reduced potency. This result can be used to design other molecules that may be utilized for the therapy of cardiovascular symptoms that relates to cGMP level.     

Symbioimine and neosymbioimine, amphoteric iminium metabolites from the symbiotic marine dinoflagellate Symbiodinium sp

Two amphoteric iminium metabolites, symbioimine (1) and neosymbioimine (2), were isolated from a cultivated symbiotic marine dinoflagellate Symbiodinium sp. Compounds 1 and 2 have a characteristic 6,6,6-tricyclic iminium ring structure and an aryl sulfate moiety. The plausible biogenetic pathway of 1 and 2 can be explained by an intramolecular Diels-Alder reaction followed by imine cyclization. Symbioimine (1) inhibited the differentiation of RAW264 cells into osteoclasts (EC50 = 44 microM), and significantly inhibited cyclooxygenase-2 activity at 10 microM. Thus, symbioimine is a potent anti-resorptive and anti-inflammatory drug.     

Bridge-linked bis-quaternary ammonium anti-microbial agents: relationship between cytotoxicity and anti-bacterial activity of 5,5'-[2,2'-(tetramethylenedicarbonyldioxy)-diethyl]bis(3-alkyl-4-methylthiazonium iodide)s

We examined the correlation between the anti-bacterial activity against Escherichia coli and the cytotoxicity of five synthesized bridge types of bis-quaternary ammonium compounds (bis-QACs) as follows: thioether type, 4,4'-(p-xylydithio)bis(1-octylpyridinium iodide) (4DTBP-X,8); amide type, N,N'-tetramethylenebis(1-dodecyl-4-carbamoylpyridinium iodide) (4BCAP-4,12), N,N'-(phenylene)bis(1-octyl-4-carbamoylpyridinium iodide) (4BCAP-P,8); anti-amide type, 4,4'-(tetramethylenedicarbonyldiamino)bis(1-octylpyridinium iodide) (4DCABP-4,8), 4,4'-(phenylenedicarbonyldiamino)bis(1-octylpyridinium iodide) (4DCABP-P,8); ester type, 4,4'-(1,6-hexamethylenedioxydicarbonyl)bis(1-dodecylpyridinium iodide) (4DOCBP-6,12); and an anti-ester type, 5,5'-[2,2'-(tetramethylenedicarbonyldioxy)diethyl]bis(3-alkyl-4-methylthiazolium iodide) (5DEBT-4,n, The letter n indicates the carbon number of the alkyl group). 5DEBT-4,8 showed low cytotoxicity (LD(50)) to human erythrocytes (97+/-6microM) and the NB1RGB cell line (111+/-20microM) and remarkable anti-bacterial activity (MIC) toward E. coli K12 W3110 (7.9microM). Moreover, 5DEBT-4,8 indicated 1144 conformers by global minimum analysis and had two minimum dGW (solvation free energy) points as well as 4DTBP-6,8, which had been previously examined and concluded to be a significant useful anti-bacterial compound.