TCTP as a therapeutic target in melanoma treatment.

BACKGROUND: Translationally controlled tumour protein (TCTP) is an antiapoptotic protein highly conserved through phylogeny. Translationally controlled tumour protein overexpression was detected in several tumour types. Silencing TCTP was shown to induce tumour reversion. There is a reciprocal repression between TCTP and P53. Sertraline interacts with TCTP and decreases its cellular levels. METHODS: We evaluate the role of TCTP in melanoma using sertraline and siRNA. Cell viability, migration, and clonogenicity were assessed in human and murine melanoma cells in vitro. Sertraline was evaluated in a murine melanoma model and was compared with dacarbazine, a major chemotherapeutic agent used in melanoma treatment. RESULTS: Inhibition of TCTP levels decreases melanoma cell viability, migration, clonogenicity, and in vivo tumour growth. Human melanoma cells treated with sertraline show diminished migration properties and capacity to form colonies. Sertraline was effective in inhibiting tumour growth in a murine melanoma model; its effect was stronger when compared with dacarbazine. CONCLUSIONS: Altogether, these results indicate that sertraline could be effective against melanoma and TCTP can be a target for melanoma therapy.

Meticillin-resistant Staphylococcus aureus: spread of specific lineages among patients in different wards at a Brazilian teaching hospital.

This study aimed to characterize meticillin-resistant Staphylococcus aureus (MRSA) lineages circulating in a Brazilian teaching hospital. MRSA isolates from nasal swabs were evaluated to assess antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec), Panton-Valentine leucocidin status, pulsed-field gel electrophoresis profile and multi-locus sequence type (MLST) analysis. Eighty-three MRSA isolates were analysed. SCCmec III (43.4%) and IV (49.4%) were predominant. ST1-IV (USA400) was more common in internal medicine (P = 0.002) whereas 'clone M' (SCCmec III) was more common in the medical and surgical intensive care unit (P = 0.004), and all isolates were ST5-IV (USA800) in dermatology (P < 0.001). These data improved the understanding of the MRSA epidemiology inside the hospital and helped to establish effective control measures.

Identification of an important thyrotrophin binding site on the human thyrotrophin receptor using monoclonal antibodies.

A thyrotrophin (TSH) binding site has been identified on the extracellular domain of the human thyrotrophin receptor (hTSHR) using monoclonal antibodies that recognise the native hTSHR. These antibodies were produced by immunising BALB/c mice with denatured recombinant material, selected by their reaction with recombinant hTSHR expressed on heterologous cell lines using flow cytofluorimetric analysis, and characterised by immunoblotting and immunoprecipitation. The epitopes the monoclonal antibodies recognise were determined using multiple overlapping synthetic peptides. All of the antibodies reacted with epitopes within the region 335-390; these epitopes must be accessible on the external surface of the native hTSHR. None of the antibodies stimulated cAMP production of recombinant hTSHR cell lines. The epitopes of two antibodies (residues 337-342 and 355-358) are in the small peptide thought to be removed by proteolytic processing of hTSHR. A further five different antibodies (determined from their variable region sequences) all reacted with residues 381-384 emphasising the immunogenicity of this region. The functional importance of residues 381-384 as a TSH binding site was shown by the fact that some of these monoclonal antibodies caused inhibition of radiolabelled TSH binding of 80-90% at 1 microg/ml and greater than 50% inhibition at 0.1 microg/ml (0.65 nM--i.e. comparable in effectiveness with TSH itself). Residues 381-384 may form part of the target regions recognised by inhibitory autoantibodies found in Graves' disease.

Production of the thyrotrophin receptor extracellular domain as a glycosylphosphatidylinositol-anchored membrane protein and its interaction with thyrotrophin and autoantibodies.

The thyrotrophin (TSH) receptor (TSHR) is synthesized as a single polypeptide with a predicted large extracellular domain (ECD), a seven-transmembrane pass region and a C-terminal intracellular tail. It is a common target for production of autoantibodies. To investigate whether the ECD is solely responsible for ligand interaction, we directed the expression of this domain in isolation on the cell surface by means of a glycosylphosphatidylinositol (GPI) anchor sequence. Immunoblotting detected TSHR material of Mr 70,000 expressed at high levels. In immunoprecipitation studies, the GPI-anchored ECD was recognized by experimental and pathological antibodies. The molecule was detected on the cell surface by flow cytofluorimetry at up to 10-fold higher amounts than the highest expressing full-length receptor clone. Radioligand binding studies confirmed this and showed that the recombinant molecule bound TSH with high affinity similar to full-length receptor; however, studies with human autoimmune sera indicated differences in the degree of inhibition when compared with full-length receptor. The existence of the GPI anchor was confirmed by cleavage with a GPI-specific phospholipase C and biosynthetic labeling with [3H]ethanolamine. TSHR material was also present inside the cell in both soluble and membrane-bound forms. Thus, the recombinant GPI-anchored ECD is the smallest known fragment of the TSHR that retains high-affinity TSH binding and is expressed at high levels on the cell surface as well as internally; this approach may well be useful for other membrane proteins.