Detection, epitope-mapping and function of anti-Fas autoantibody in patients with silicosis.

Dysregulation of apoptosis through the Fas-Fas ligand pathway is associated with the onset of autoimmune disease. Since autoantibodies directed against unknown antigens are present in the sera of these patients, sera samples were examined for the presence of autoantibodies directed against the Fas molecule. Using Western blotting and a ProteinChip analysis, autoantibodies against Fas were detected in patients with silicosis, systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), and weakly detected in healthy individuals. Using epitope mapping employing 12-amino-acid polypeptides with the SPOTs system, a minimum of four epitopes and a maximum of 10 epitopes were found. Several amino acid residues involved in binding FasL, such as C66, R87, L90, E93 and H126, were presented within the epitopes. Serum containing a large amount of anti-Fas autoantibody from silicosis patients inhibited the growth of a Fas-expressing human cell line, but did not inhibit the growth of a low Fas-expresser nor a Fas-expresser in which the Fas gene had been silenced by small interference RNA. All epitopes in the intracellular region of Fas were located in the death domain. The possible roles of anti-Fas autoantibody detected in healthy volunteers and patients with silicosis or autoimmune diseases are discussed here.

Identification of serum proteins related to adverse effects induced by docetaxel infusion from protein expression profiles of serum using SELDI ProteinChip system.

BACKGROUND: For the development of quick and easy methods for screening and identifying treatment-responsive proteins, we determined the protein expression profile of the serum after docetaxel infusion using a surface-enhanced laser desorption/ionization time-of-flight mass spectroscopy (SELDI TOF-MS) system. MATERIALS AND METHODS: Blood from breast cancer patients was collected before and 4, 8, 24 and 48 hours after docetaxel infusion. The protein expression profile was determined by a SELDI TOF-MS system. The relative expression levels of target proteins were compared during the time-course after docetaxel injection. RESULTS: We identified two representative proteins with molecular weights of 7790 Da and 9285 Da. The 7790 Da protein was high molecular weight kininogen, and the 9285 Da protein was apolipoprotein A-II. These two proteins had similar expression patterns in 5 patients, except one patient who experienced severe, acute, adverse effects. CONCLUSION: These results suggest that protein expression profiles determined by SELDI TOF-MS represent useful data for the identification of treatment-responsive proteins.

Rapid discovery and identification of a tissue-specific tumor biomarker from 39 human cancer cell lines using the SELDI ProteinChip platform.

Useful biomarkers are needed for early detection of cancers. To demonstrate the potential diagnostic usefulness of a new proteomic technology, we performed Expression Difference Mapping analysis on 39 cancer cell lines from 9 different tissues using ProteinChip technology. A protein biomarker candidate of 12kDa was found in colon cancer cells. We then optimized the purification conditions for this biomarker by utilizing Retentate Chromatography mass spectrometry (RC-MS). The optimized purification conditions developed "on-chip" were directly transferred to conventional chromatography to purify the biomarker, which was identified as prothymosin-alpha by ProteinChip time-of-flight mass spectrometry (TOF MS) and ProteinChip-Tandem MS systems. The relative expression level of prothymosin-alpha between colon cancer cells and normal colon mucosal cells was evaluated on the same ProteinChip platform. Prothymosin-alpha expression in colon cancer cells was clearly higher than in normal colon cells. These results indicate that prothymosin-alpha could be a potential biomarker for colon cancer, and that the ProteinChip platform could perform the whole process of biomarker discovery from screening to evaluation of the identified marker.

Reduction of peptide character of HIV protease inhibitors that exhibit nanomolar potency against multidrug resistant HIV-1 strains.

Novel HIV protease inhibitors containing a hydroxyethylamine dipeptide isostere as a transition state-mimic king structure were synthesized by combining substructures of known HIV protease inhibitors. Among them, TYA5 and TYB5 were proven to be not only potent enzyme inhibitors (K(i) = 0.12 nM and 0.10 nM, respectively) but also strong anti-HIV agents (IC(50) = 9.5 nM and 66 nM, respectively), even against viral strains with multidrug resistance. Furthermore, insertion of an (E)-alkene dipeptide isostere at the P(1)-P(2) position of TYB5 led to development of a purely nonpeptidic protease inhibitor, TYB1 (K(i) = 0.38 nM, IC(50) = 160 nM).