Cell cycle-independent death of prostate adenocarcinoma is induced by the trk tyrosine kinase inhibitor CEP-751 (KT6587)

Advanced prostate cancer remains largely incurable, primarily because the very low growth fraction present in these tumors makes them generally resistant to treatment with standard chemotherapeutic agents that target cell division. Effective therapies should therefore induce death of prostate cancer cells, independent of their growth rate. trkA, the high-affinity tyrosine kinase-linked receptor for nerve growth factor, has been implicated in prostatic cancer growth and may represent a molecular target for therapeutic agents. At low mg/kg doses, the trk tyrosine kinase inhibitor CEP-751 (KT6587) inhibits prostatic cancer growth in nine different animal models independent of the tumor growth rate, androgen sensitivity, metastatic ability, or state of tumor differentiation. CEP-751 is selective for cancerous versus normal prostate cells and affects the growth of only a limited number of nonprostate tumors. Importantly, CEP-751 induces cell death of prostate cancer cells in a cell cycle-independent fashion and, therefore, represents a novel therapeutic approach to the management of both hormone-dependent and hormone-independent prostate cancer.     

Chronic sparing of delayed alternation performance and choline acetyltransferase activity by CEP-1347/KT-7515 in rats with lesions of nucleus basalis magnocellularis

Peripheral injection of the indolocarbazole CEP-1347/KT-7515 into rats that have sustained ibotenic acid lesions of the nucleus basalis magnocellularis has been shown to prevent the loss of cortically-projecting neurons in that basal forebrain region. The present study tested whether this neuroprotective activity would lead to chronic sparing of a behaviour known to be impaired by that lesion, as well as to chronic maintenance of cholinergic activity in cortical target regions of the nucleus basalis. CEP-1347/KT-7515 was injected into adult rats that had sustained bilateral ibotenic acid lesions of the nucleus basalis magnocellularis; the first injection occurred 18-24 h after lesioning, with subsequent injections of CEP-1347/KT-7515 occurring every other day over 12 days. One day following the last injection the animals were tested for retention of a previously-learned delayed alternation task. Animals that received CEP-1347/KT-7515 committed significantly fewer errors than lesioned animals receiving vehicle. These same animals were tested again eight to 10 weeks later (which was 10-12 weeks post-dosing), without receiving further drug or behaviour training during the test-retest interval. The animals that had received CEP-1347/KT-7515 continued to commit significantly fewer errors than vehicle animals. Furthermore their performance at this time point was indistinguishable from normal controls. Analysis of errors showed that CEP-1347/KT-7515 prevented a lesion-induced increase in perseverative errors, suggesting the drug improved attention in the lesioned animals. Choline acetyltransferase activity in the frontal cortex of the behaviourally tested animals that received CEP-1347/KT-7515 three months previously showed a significant 40% recovery of the lesion-induced loss seen in the vehicle animals. These results demonstrate that treatment with CEP-1347/KT-7515 over 12 days following excitotoxic damage to the nucleus basalis magnocellularis produces long-term sparing of an attention-demanding behaviour.     

In vitro specific binding of Shiga toxin 1 and 2 by TAK-751S (Gb3 analog)

TAK-751S is a synthetic trisaccharide coupled to Chromosorb P using a spacer sequence of 8-methoxycarboyloctyl (MCO). Its chemical structure is similar to a human receptor (Gb3) of Stx produced by enterohemorrhagic Escherichia coli (EHEC). In vitro efficacy of TAK-715S was studied by using ACHN cultured cell assay, which is sensitive and specific for measuring low level of Stx. Under various conditions, TAK-715S was mixed with purified Stx1 and Stx2, and residual free toxins in the solution were measured by using ACHN cells. TAK-715S was demonstrated to bind specifically to Stx1 and Stx2 under the condition similar to a human intestine while Chromsorb P did not bind to any Stx. The binding activity was stable in the presence of various processed foods, fresh vegetables and fruits. Antibiotics such as fosfomycin, kanamycin and norfloxacin did not disturb its binding capability. Minimum inhibitory concentrations of these antibiotics against Staphylococcus aureus FDA209P or E. coli NIHJ JC-2 neither changed after incubating with TAK-751S for 60 min at 37 degrees C. These results suggest that TAK-751S can be given orally with various foods and antibiotics for the elimination of Stx1 and Stx2 in the gut of patients with EHEC infections.     

Aminolysis and racemization of activated esters with the use of high temperatures (author's transl)

The reactivities in aminolysis of the benzyl, phenyl, p-nitrophenyl and pentachlorophenyl esters of benzyloxycarbonylphenylalanine were ascertained at different temperatures up to 90 degrees C and the occurrence of racemization investigated. It turned out that the protective function of the benzyloxycarbonyl group in relation to the racemization was conserved, even at the high temperatures used in the peptide synthesis.     

Synthesis of N-(2-carboxy-thieno(2,3-b)pyridin-3-yl)-formamidines corresponding alkyl esters with antianaphylactic activity

A lot of N-(2-carboxy-thieno[2,3-b]pyridin-3-yl)formamidines especially in form of their amine salts--were synthesized by reaction of 3-amino-thieno[2,3-b]pyridine-2-carboxylic acids with dimethylformamide/phosphoroxide chloride or by reaction of 4-oxo-4H-pyrido[3',2':4,5]thieno[3,2-d]1,3- oxazines with amines. Carboxylic acid alkylesters of this structure were yielded from 3-amino-thieno[2,3-b]pyridine-2-carbonic acid alkylesters by reaction with dimethylformamide/phosphoroxide chloride or with N-formyl-piperidine or N-formyl-morpholine and phosphoroxide chloride. The compounds showed antianaphylactic activity.     

Mechanism of synergistic extraction of rhenium(VII) by primary amines and neutral phosphorus esters

It has been found in the present study that Re(VII) can be quantitatively separated from Mo(VI) in alkaline solutions by synergistic extraction with primary amine and neutral phosphorus esters. The mechanism of synergistic extraction was studied. Results of extraction with combinations of different donor and acceptor solvents indicated that during extraction hydrogen bonds were formed between perrhenic acid and active hydrogen atoms of primary amines as well as between the acid and active phosphoryl oxygen of neutral phosphorus esters. The composition of the synergistic extraction adduct was studied and its structure was also proposed. This newly found extraction system is important to the extraction and separation of Re(VII) and also to the studies of mechanism of synergistic extraction.     

Transport of LDS-751 from the cytoplasmic leaflet of the plasma membrane by the rhodamine-123-selective site of P-glycoprotein

Hyperfibrinogenemia is a common feature of the nephrotic syndrome, and contributes to increased tendency for thrombosis and atherosclerosis. Its genesis is not certain, but the increase in liver fibrinogen mRNA in nephrotic rats indicates increased synthesis. Data in humans are scarce. We presently compared synthesis rates of fibrinogen and albumin in nephrotic adults (N = 7; plasma albumin 22.3 +/- 0.7 g/liter, proteinuria 12 g/day) and healthy control subjects (N = 8) using a primed/continuous infusion of the stable isotope L-[1-13C]valine for six hours. Absolute synthesis rate (ASR) of fibrinogen was 31 +/- 3 mg/kg/day in nephrotic subjects and 21 +/- 1 mg/kg/day in control subjects (P < 0.05), and positively correlated with plasma fibrinogen (P = 0.0317). The plasma fibrinogen pool was disproportionately increased in the nephrotic patients (271 +/- 30 mg/kg) compared to the controls (126 +/- 8 mg/kg), suggesting decreased fractional catabolic rate as well. The ASR of albumin was increased from 71 +/- 4 mg/kg/day in the controls to 160 +/- 19 mg/kg/day in the patients (P < 0.0001), and strongly correlated with the ASR of fibrinogen (P = 0.0046). Plasma alpha 2-macroglobulin was also elevated and correlated with the albumin synthesis rate, whereas plasma serum amyloid A and C-reactive protein were not elevated. These data suggest that in nephrotic patients the increased albumin synthesis is associated with an increase in synthesis of a specific and coordinated group of proteins, among which is fibrinogen.     

CEP-1347/KT7515, a JNK pathway inhibitor, supports the in vitro survival of chick embryonic neurons

Developing neurons depend on target-derived trophic factors for survival in vivo and in vitro, which also decrease the activity of c-Jun N-terminal kinase (JNK). We have recently described a survival-promoting effect of inhibitors of cyclin-dependent kinases and JNK on chick peripheral embryonic neurons. Here, we report that the small trophic molecule CEP-1347/KT7515, which has been shown to inhibit the JNK signalling pathway, can promote long term-survival of cultured chick embryonic dorsal root ganglion, sympathetic, ciliary and motor neurons. Because of their pharmacological properties, small trophic molecules such as CEP-1347/KT7515 might be of interest for the treatment of neurodegenerative disorders.     

Poisoning of topoisomerase I by an antitumor indolocarbazole drug: stabilization of topoisomerase I-DNA covalent complexes and specific inhibition of the protein kinase activity

The authors describe an eye with a central retinal vein occlusion that developed chorioretinal anastomoses following transvitreal venipuncture, a vitreoretinal surgical technique.     

Simultaneous induction of an HDL receptor protein (SR-BI) and the selective uptake of HDL-cholesteryl esters in a physiologically relevant steroidogenic cell model

This study addresses the question of whether the level of expression of SR-BI (an HDL receptor) is linked to the expression of selective lipoprotein-cholesteryl ester delivery in a steroidogenic cell model. Rat ovarian granulosa cells are physiologically normal cells which show no selective uptake of HDL-cholesteryl esters and no progestin production until luteinized by trophic hormones or adenylate cyclase stimulators, after which expression of the selective cholesterol pathway and production of steroid hormone is dramatically up-regulated. The current study demonstrates that at every cell stage studied, the protein content and level of expression of SR-BI mRNA are linked to changes that occur in HDL-cholesteryl ester uptake; i.e., SR-BI is not present in basal (non-luteinized) cells, develops slowly (from 6-9 h) after hormone treatment, increases robustly from 9-48 h after stimulation, and remains high after incubation with HDL. In contrast, another structural protein, caveolin, did not follow this pattern; caveolin expression showed an inverse relationship to selective cholesteryl ester uptake, and was most prominent in basal cells and least prominent in luteinized, HDL-incubated cells. Morphologically, SR-BI appears to be associated with cell surface sites showing high levels of cholesteryl ester uptake (after luteinization and/or incubation with HDL labeled with fluorescent cholesteryl esters), and at the electron microscope level, SR-BI is most clearly associated with microvillar regions on the cell surface which also bind HDL-labeled with colloidal gold. Thus, induction of the SR-BI receptor system and induction of the HDL-selective cholesterol uptake pathway in rat granulosa cells appear to be linked morphologically, biochemically, and functionally.     

Cellular determinants of resistance to indolocarbazole analogue 6-N-formylamino-12,13-dihydro-1,11-dihydroxy-13(beta-D-glucopyranosyl)- 5H-indolo[2,3-alpha]pyrrolo[3,4-c]carbazole-5,7(6H)-dione (NB-506), a novel potent topoisomerase I inhibitor, in multidrug-resistant human tumor cells

1. In this study we hypothesized that in individuals with certain genetic makeup, MTBE, benzene or their metabolites act as adducts and may induce programmed cell death. 2. Our study involved a group of 60 male and female subjects who were exposed to MTBE and benzene-contaminated water concentrations up to 76 PPB for MTBE and 14 PPB for benzene, for a period of 5 to 8 years. For comparison, we recruited a control group consisting of 32 healthy males and females with similar age distribution and without a history of exposure to MTBE or benzene. 3. Peripheral blood lymphocytes (PBL) of both groups were tested for the percentage of apoptotic cells and cell cycle progression using flow cytometry. 4. When apoptotic lymphocytes from exposed individuals were compared to apoptotic lymphocytes from the control group, statistically-significant differences between each mean group were detected (26.4 +/- 1.8 and 12.1 +/- 1.3, respectively), indicating an increased rate of apoptosis in 80.5% of exposed individuals (P < 0.0001, Mann-Whitney U-Test). MTBE and benzene-induced apoptosis is attributed to a discrete block within the cell cycle progression. Because cell cycle analysis showed that in PBL from chemically-exposed individuals, between 20-50% of cells were accumulated at the S-G2/M boundaries. 5. One of the signaling molecules which mediates programmed cell death is nuclear factor Kappa-B (NF-kappa B). NF-kappa B was examined as one of the many molecular mechanisms for mediating cell death by MTBE and benzene. Indeed, addition of inhibitors of NF-kappa B activation pyrrolidine dithiocarbamate (PDTC), to the lymphocytes of the chemically-exposed group was capable of inhibiting programmed cell death by 40%. This reversal of apoptosis almost to the control level by inhibitor of NF-kappa B activation may indicate involvement of this signaling molecule in MTBE and benzene induction of programmed cell death.     

New chiral inhibitors of induced platelet aggregation: the enantiomeric specificity of (R)- and (S)-methyl and ethyl esters of 1-(4-[(1-hydroxycarbonyl)-ethoxy]-benzyl)-1H-1,2,3-triazole as a tool for determining their biological target

The synthesis of title enantiomers was accomplished and their biological behaviour as inhibitors of rabbit platelet aggregation process induced by ADP and arachidonic acid was determined. Structure-activity comparison with that of SM-12502 [(2R,5S)-(+) 3,5-dimethyl-2-(3-pyridyl)-thiazolidin-4-one hydrochloride] and Dazoxiben [4-[2-(1H-imidazol-1-yl)-ethoxy]-benzoic acid] allowed us to formulate the possible capability for the synthesized compounds to interact with the biological targets of the model molecules.     

Flavonoid glycosides and hydroxycinnamic acid esters of blackcurrants (Ribes nigrum). Phenolics of fruits 9

The major flavonol glycosides of ripe blackcurrants (Ribes nigrum cv. Silvergieters Schwarze), myricetin 3-beta-D-glucopyranoside, rutin, and isoquercitrin, have been isolated in crystalline form. Analysis by thin-layer chromatography confirmed the occurrence of the 3-rutinosides and 3-glucosides of cyanidin and delphinidin. No free flavonoid aglycones could, however, be detected in the fresh berries. The major constituent fluorescing blue under ultraviolet light on paper and cellulose thin-layer chromatograms, was isolated and characterized as 1-O-caffeyl-beta-D-glucopyranose. Also isolated were 1-O-ferulyl- and 1-O-p-coumaryl-beta-D-glucopyranose. The occurrence fo hydroxycinnamyl-D-glucoses in blackcurrants does not appear to have been recognized previously.     

Fluoroprostaglandins: synthesis and biological evaluation of the methyl esters of (+)-12-fluoro-, (-)-ent-12-fluoro-, (+)-15-epi-fluoro-, and (-)-ent-15 epi-12-fluoroprostaglandin F2 alpha

The synthesis and biological activity of the methyl esters of (+)-12-fluoroPGF2 alpha, (+)-15-epi-12-fluoroPGF2 alpha, (-)-ent-12-flurorPGF2 alpha, and (-)-ent-15-epi-12-fluoroPGF2 alpha are described. Each fluoroprostaglandin has been evaluated from pregnancy interruption in the hamster and smooth-muscle stimulating effects on gerbil colon and hamster uterine strips. All fluoroprostaglandins synthesized were shown to be neither substrates for the 15-hydroxyprostaglandin dehydrogenase nor inhibitors of the enzyme.