Focus on the use of resveratrol in bladder cancer

Bladder cancer is the most common tumor of the urinary system, with a high incidence in the male population. Surgery and intravesical instillations can eradicate it, although recurrences are very common, with possible progression. For this reason, adjuvant therapy should be considered in all patients. Resveratrol displays a biphasic dose response both in vitro and in vivo (intravesical application) with an antiproliferative effect at high concentrations and antiangiogenic action in vivo (intraperitoneal application) at a low concentration, suggesting a potential role for it in clinical management as an adjuvant to conventional therapy. In this review, we examine the standard therapeutical approach to bladder cancer and the preclinical studies that have investigated resveratrol in xenotransplantation models of bladder cancer. Molecular signals are also discussed, with a particular focus on the STAT3 pathway and angiogenic growth factor modulation

Pfnek-1, a NIMA-related kinase from the human malaria parasite Plasmodium falciparum: Biochemical properties and possible involvement in MAPK regulation

We have cloned Pfnek-1, a gene encoding a novel protein kinase from the human malaria parasite Plasmodium falciparum. This enzyme displays maximal homology to the never-in-mitosis/Aspergillus (NIMA)/NIMA-like kinase (Nek) family of protein kinases, whose members are involved in eukaryotic cell division processes. Similar to other P. falciparum protein kinases and many enzymes of the NIMA/Nek family, Pfnek-1 possesses a large C-terminal extension in addition to the catalytic domain. Bacterially expressed recombinant Pfnek-1 protein is able to autophosphorylate and phosphorylate a panel of protein substrates with a specificity that is similar to that displayed by other members of the NIMA/Nek family. However, the FXXT motif usually found in NIMA/Nek protein kinases is substituted in Pfnek-1 by a SMAHS motif, which is reminiscent of a MAP/ERK kinase (MEK) activation site. Mutational analysis indicates that only one of the serine residues in this motif is essential for Pfnek-1 kinase activity in vitro. We show (a) that recombinant Pfnek-1 is able to specifically phosphorylate Pfmap-2, an atypical P. falciparum MAPK homologue, in vitro, and (b) that coincubation of Pfnek-1 and Pfmap-2 results in a synergistic increase in exogenous substrate labelling. This suggests that Pfnek-1 may be involved in the modulation of MAPK pathway output in malaria parasites. Finally, we demonstrate that recombinant Pfnek-1 can be used in inhibition assays to monitor the effect of kinase inhibitors, which opens the way to the screening of chemical libraries aimed at identifying potential new antimalarials

Chromosome mapping in Cryptosporidium parvum and establishment of a long-range restriction map for chromosome VI

We used contour-clamped homogeneous electric field (CHEF) gel electrophoresis and Southern blot hybridization to analyze the molecular karyotype of Cryptosporidium parvum and establish the chromosomal location of 12 single copy genes. In agreement with previous studies, the molecular karyotype of C. parvum was found to consist of partially co-migrating chromosomes ranging in size from 0.97 to 1.55 Mb and segregating into five distinct electrophoretic bands. Hybridization results allowed the definition of a linkage group comprised of five distinct loci located on chromosome VI. Southern hybridization and restriction analysis of total C. parvum chromosomes or isolated chromosome VI using gene-specific probes and an oligonucleotide specific for C. parvum telomeres allowed the development of a long-range restriction map of chromosome VI

Plasmodium falciparum glycogen synthase kinase-3: molecular model, expression, intracellular localisation and selective inhibitors

Plasmodium falciparum glycogen synthase kinase-3: molecular model, expression, intracellular localisation and selective inhibitors Worldwide increasing resistance of Plasmodium falciparum to common anti-malaria agents calls for the urgent identification of new drugs. Glycogen synthase kinase-3 (GSK-3) represents a potential screening target for the identification of such new compounds. We have cloned PfGSK-3, the R falciparum gene homologue of GSK-3beta. It encodes a 452-amino-acid, 53-kDa protein with an unusual N-terminal extension but a well- conserved catalytic domain. A PfGSK-3 tridimensional homology model was generated on the basis of the recently crystallised human GSK-3beta. It illustrates how the regions involved in the active site, in substrate binding (P + 4 phosphate binding domain) and in activity regulation are highly conserved. Recombinant PfGSK-3 phosphorylates GS-1, a GSK-3-specific peptide substrate, glycogen synthase, recombinant axin and the microtubule-binding protein tau. Neither native nor recombinant PfGSK-3 binds to axin. Expression and intracellular localisation of PfGSK-3 were investigated in the erythrocytic stages. Although PfGSK-3 mRNA is present in similar amounts at all stages, the PfGSK-3 protein is predominantly expressed at the early trophozoite stage. Once synthesized, PfGSK-3 is rapidly transported to the erythrocyte cytoplasm where it associates with vesicle-like structures. The physiological functions of PfGSK-3 for the parasite remain to be elucidated. A series of GSK-3beta inhibitors were tested on both PfGSK-3 and mammalian GSK-3. Remarkably these enzymes show a partially divergent sensitivity to the compounds, suggesting that PfGSK-3 selective compounds might be identified. (C) 2004 Elsevier B.V. All rights reserved

Molecular and morphological evidence of a new sibling species of Calobius (Coleoptera: Hydraenidae) of the C. quadricollis complex from peninsular Italy

A molecular and morphological analysis was performed to clarify the taxonomic status of Italian members of the Calobius quadricollis complex (Coleoptera, Hydraenidae, Ochthebiinae), including species strictly associated with hypersaline marine rock pools along the Mediterranean and Macaronesian coasts. The analysis was mainly focused on the specific distinction and formal description of a new species, Calobius urbanelliae n. sp., from peninsular Italy. This species is of difficult morphological distinction, but, on the basis of the mitochondrial DNA marker cytochrome c oxidase subunit I, it is highly differentiated from C. quadricollis Mulsant, 1844 (NW Mediterranean) and C. steinbuehleri Baudi, 1864 (NE Mediterranean), which are partially sympatric with it along part of the western and eastern coasts of peninsular Italy. One possible palaeogeographical scenario underlying the specific differentiation of the three species is briefly discussed