High-affinity urokinase-derived cyclic peptides inhibiting urokinase/urokinase receptor-interaction: effects on tumor growth and spread

Urokinase-type plasminogen activator (uPA) binds with high affinity to its specific cell surface receptor (uPAR) (CD87) via a well-defined sequence within the N-terminal region of uPA (uPA(19-31)). Since this uPA/uPAR-interaction plays a significant role in tumor cell invasion and metastasis, it has become an attractive therapeutic target. Two small peptidic cyclic competitive antagonists of uPA/uPAR-interaction have been developed, based on the uPAR binding site in uPA: WX-360 (cyclo(21,29)[D-Cys21]-uPA(21-30)[S21C;H29C]) and its norleucine (Nle) derivative WX-360-Nle (cyclo(21,29)[D-Cys21]-uPA(21-30)[S21C;K23Nle;H29C]). These peptides display an only five to 10-fold lower affinity to uPAR as compared to the naturally occurring uPAR-ligand uPA. In this study, WX-360 and WX-360-Nle were tested in nude mice for their potency to inhibit tumor growth and intraperitoneal spread of lacZ-tagged human ovarian cancer cells. Intraperitoneal administration of either cyclic peptide (20 mg peptide/kg; 1x daily for 37 days) into the tumor-bearing nude mice resulted in a significant reduction of tumor weight and spread within the peritoneum as compared to the untreated control group. This is the first report demonstrating effective reduction of tumor growth and spread of human ovarian cancer cells in vivo by small synthetic uPA-derived cyclic peptides competitively interfering with uPA/uPAR-interaction. Thus, both WX-360 and WX-360-Nle are promising novel compounds to reduce dissemination of human ovarian carcinoma.     

A novel PKC-regulated mechanism controls CD44 ezrin association and directional cell motility

The dynamic assembly and disassembly of membrane cytoskeleton junctional complexes is critical in cell migration. Here we describe a novel phosphorylation mechanism that regulates the hyaluronan receptor CD44. In resting cells, CD44 is constitutively phosphorylated at a single serine residue, Ser325. After protein kinase C is activated, a switch in phosphorylation results in CD44 being phosphorylated solely at an alternative residue, Ser291. Using fluorescence resonance energy transfer (FRET) monitored by fluorescence lifetime imaging microscopy (FLIM) and chemotaxis assays we show that phosphorylation of Ser291 modulates the interaction between CD44 and the cytoskeletal linker protein ezrin in vivo, and that this phosphorylation is critical for CD44-dependent directional cell motility.     

Traumatic Brain Injury Increases β-Amyloid Peptide 1-42 in Cerebrospinal Fluid

Abstract: The β-amyloid peptides, Aβ1-42 and Aβ1-40, were quantified in ventricular CSF taken daily for up to 3 weeks from six individuals with severe traumatic brain injury (TBI). There was considerable interindividual variability in the levels of Aβ peptides, but in general Aβ1-42 levels equalled or exceeded those of Aβ1-40. Averaging the daily totals of our trauma cohort revealed that the levels of Aβ1-42 and Aβ1-40 rose after injury, peaking in the first week and then declining toward control levels over the next 2 weeks. Aβ1-42 levels were on average two to three times higher in the trauma cohort than in CSF from nontrauma samples. Compared with nontrauma samples, the Aβ1-40/Aβ1-42 ratio decreased about fivefold in the trauma patients, further indicative of increased Aβ1-42 levels. The ratio remained low at all time points studied. No change was measured in the levels of β-amyloid precursor protein during the same interval. These results suggest that Aβ1-42 becomes elevated in the CSF after severe brain trauma.     

Relative Importance of Rotavirus-Specific Effector and Memory B Cells in Protection against Challenge

Adult BALB/c mice were orally inoculated with murine (strain EDIM), simian (strain RRV), or bovine (strain WC3) rotavirus. Six or 16 weeks after inoculation, mice were challenged with EDIM. At the time of challenge and in the days immediately following challenge, production of rotavirus-specific immunoglobulin A (IgA), IgG, and IgM by small intestinal lamina propria lymphocytes (LPL) was determined by fragment culture, and quantities of virus-specific antibodies at the intestinal mucosal surface were determined by intestinal lavage. Mice immunized with EDIM were completely protected against EDIM challenge both 6 and 16 weeks after immunization. Protection was associated with production of high levels of IgA by LPL and detection of virus-specific IgA at the intestinal mucosal surface. In addition, animals immunized and later challenged with EDIM did not develop a boost in antibody responses, suggesting that they were also not reinfected. We also found that in mice immunized with nonmurine rotaviruses, (i) quantities of virus-specific IgA generated following challenge were greater 16 weeks than 6 weeks after immunization, (ii) immunization enhanced the magnitude but did not hasten the onset of production of high quantities of virus-specific IgA by LPL after challenge, and (iii) immunization induced partial protection against challenge; however, protection was not associated with either production of virus-specific antibodies by LPL or detection of virus-specific antibodies at the intestinal mucosal surface.     

Planning Biodegradable Waste Management in Stockholm

The environmental impact of the management of biodegradable waste in Stockholm, based mainly on incineration and landfilling, was compared to systems with significant nutrient recycling; large-scale composting, anaerobic digestion, and separate collection and utilization of urine. The systems' emissions, residual products, energy turnover, and resource consumption were evaluated from a life-cycle perspective, using a computerized model, ORWARE (ORganic WAste REsearch model).
Transportation was of relatively low importance to overall environmental impact, even at high rates of nutrient recycling. This is remarkable considering the geographical setting of Stockholm, with high population density and little nearby farmland. Ancillary systems, such as generation of electricity and district heating, were crucial for the overall outcome.
Increased recycling of nutrients in solid biodegradable waste in Stockholm can reduce net environmental impact, whereas separation of human urine to be spread as fertilizer cannot yet be introduced without increased acidification. Increased nutrient recycling from solid biodegradable waste inevitably increases spreading of metals on arable land. Urine is by far the least contaminated residual product. Spreading of all other residuals would be limited by their metal content.     

Effect of maternal serum on viability and function of early human placental explants

Summary Fetal bovine serum (FBS) is frequently used to supplement chemically defined media such as Ham’s F10 when studying placental explant cultures. However in vitro production of hormones is usually declining by the 2nd or 3rd day and is short-lived (7 to 10 days). In this study we explored the use of human maternal serum (HMS) from early gestation as the medium supplement to Ham’s F10. Early placental hormone production was compared using two concentrations of FBS and HMS. On Day 3 of incubation, progesterone production in 10% HMS was 12-fold increased over that in 10% FBS, estradiol production was increased 10-fold, and βhCG production more than 3-fold. When the serum concentrations were increased to 40%, the results in all cases were similar to those at 10%. Preliminary characterization studies revealed that the stimulatory activity of HMS is heat-labile, neither extractable into organic solvent (diethyl ether) nor dialyzable, suggesting that it is protein in nature. In a long-term incubation, compared with FBS (7 days), HMS permitted survival of culture up to 30 days, judged both histologically and biochemically. We conclude that HMS provides substance(s), probably protein in nature, not present in FBS or non-pregnant human serum, which are important for human placental viability and function in vivo.     

Silicon amelioration of aluminium toxicity in teosinte (Zea mays L. ssp. mexicana)

The influence of different Al concentrations, (0, 60 and 120 M Al) on growth and internal concentrations of Al, Si and selected organic acids was analysed in plants of teosinte (Zea mays L. ssp. mexicana), a wild form of maize from acid soils from Mexico. The plants were grown in nutrient solutions (pH 4.0) with or without 4 M silicon. Analysis with the GEOCHEM speciation program did not reveal differences between free activities of Al³⁺ in solutions with and without 4 M Si, but solutions with Si yielded lower concentrations of monomeric Al species, [Al]_mono, when analysed by a modified aluminon method. Plants grown on solutions with similar [Al]_mono, but differing in silicon, showed highly significant differences in growth and tissue concentrations of Al and organic acids. Silicon prevented growth inhibition at [Al]_mono concentrations as high as 35 M, while plants grown without Si suffered severe growth reductions with 33 M [Al]_mono. In solutions with similar [Al]_mono concentrations plants with Si had lower tissue Al concentrations and higher concentrations of malic acid than plants without Si. In view of both the significant influence of Si on the response of plants to Al toxicity and the fact that some soluble Si is always present in soil solutions, the addition of low Si concentrations to nutrient solutions used for Al-tolerance screening is recommended.