Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The immunogenicity of a multiple antigenic peptide construct consisting of four copies of the synthetic 21-mer peptide DANFDSIRVDAVDNVDADLLQ was measured. The composition of this peptide was derived from a sequence in the N-terminal region of mutans streptococcal glucosyltransferases (GTFs) containing an aspartic acid implicated in catalysis. The peptide (CAT) construct was synthesized as a tetramer on a lysine backbone and subcutaneously injected into Sprague-Dawley rats for polyclonal antibody formation or intraperitoneally injected into BALB/c mice, and then spleen cell fused with Sp2/0Ag14 murine myeloma cells for monoclonal antibody formation. The resulting rat antisera and mouse monoclonal antibodies reacted with CAT and with native GTF isozymes from Streptococcus sobrinus and Streptococcus mutans (in enzyme-linked immunosorbent assay and Western blot [immunoblot] analyses). Functional inhibition of the water-insoluble glucan synthetic activity of S. sobrinus GTF-I was demonstrated with an immunoglobulin M anti-CAT monoclonal antibody (> 80% inhibited) and with rat sera (approximately 17% inhibited). The monoclonal antibody preparation also modestly inhibited the water-soluble glucan synthetic activity of an S. mutans GTF mixture. These results suggest that the CAT peptide contains B-cell epitopes that are similar to those of intact mutans streptococcal GTFs and has the potential to elicit antibody that can inhibit GTF function. Thus, sequences within this peptide construct may have value for inclusion in a synthetic dental caries vaccine.
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PMID:Immunological characteristics of a synthetic peptide associated with a catalytic domain of mutans streptococcal glucosyltransferase. 796 Jan 28

Interleukin-6 (IL-6), a four-helix bundle protein, is a multifunctional cytokine which plays an important role in the regulation of the immune system, hematopoiesis, and inflammatory response, as well as in the pathogenesis of multiple myeloma. We have previously shown that a single-disulfide variant of human IL-6, lacking 22 N-terminal amino acids and the disulfide bond connecting Cys-45 and Cys-51 in the 185-residue chain of the wild-type protein, fully retains the conformational, stability, and functional properties of the full-length human IL-6 [Breton et al. (1995) Eur. J. Biochem. 227, 573-581]. In this study, we have investigated the conformational and stability properties of mutant IL-6 at acidic pH (A-state). Using far- and near-ultraviolet (UV) circular dichroism (CD), fluorescence emission, and second-derivative absorption spectroscopy, we have established that mutant IL-6 at pH 2.0 fully retains the helical secondary structure of the native protein at pH 7.5, while the tertiary interactions are much weaker. At variance from the native species, mutant IL-6 in the A-state binds 1-anilinonaphthalene-8-sulfonic acid (ANS), a property considered most typical of a protein in the molten globule state. The pH-induced conformational change from the native to the A-state, monitored either by near-UV CD or by ANS-binding measurements, shows a transition midpoint at pH approximately 4.5, thus indicating that the partial unfolding of the protein is mediated by the titration of glutamic and/or aspartic acid residues. At pH 2.0, the thermal denaturation of mutant IL-6 occurs as a broad process of low cooperativity with a transition at 50-60 degrees C, whereas at pH 7.5 the thermal unfolding is cooperative and characterized by a transition midpoint at 65 degrees C. Of interest, the unfolding of the A-state is not complete even up to approximately 85 degrees C. The urea-mediated unfolding profile of mutant IL-6, measured by far-UV CD, is essentially identical at both pH 7.5 and 2.0, with a midpoint of the cooperative unfolding transition at 5.5 +/- 0.1 M denaturant. Both thermal and urea denaturations of the A-state are complex and cannot fit to a two-state model for unfolding. The unusual stability of mutant IL-6 in acid is also reflected by the resistance to proteolysis at pH 3.6-4.0 by Staphylococcus aureus V8 protease or cathepsin D, an acid protease released by machrophages upon inflammatory stimulation. It is suggested that the molten globule state of IL-6 at acidic pH can play a role in the biological activity of this cytokine, which can exert its activity also at mildly acidic pH, as in inflammation sites.
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PMID:Acid-induced molten globule state of a fully active mutant of human interleukin-6. 878 6

Germline mutations of LKB1/Peutz-Jeghers syndrome gene predispose carriers to hamartomatous polyposis of the gastrointestinal tract as well as to cancer of different organ systems. Although Peutz-Jeghers syndrome patients frequently present with neoplasms of the colon, stomach, small intestine, pancreas, breast, ovaries, and cervix, somatic mutations appear to be rare in the sporadic tumor types thus far studied (colorectal, gastric, testicular, and breast cancers). To evaluate whether somatic mutations of LKB1 contribute to the tumorigenesis of yet unstudied tumor types, we screened 14 cell lines and 129 tumor specimens from different cancers for a genetic defect in LKB1. Six melanoma and eight myeloma cell lines were scrutinized for LKB1 somatic mutations by genomic sequencing. No changes were found in the coding LKB1 sequence and exon/intron boundaries. Next, we analyzed 12 pancreatic, 8 gastric, 12 ovarian granulosa cell, 26 cervical, 28 lung, 24 soft tissue, and 19 renal tumors by single-strand conformational polymorphism analysis. Three changes in LKB1 coding nucleotide sequence were identified. One base pair deletion at A957 and G958 substitution by T occurred in a cervical adenocarcinoma sample, resulting in a frameshift and premature stop codon at position 335. Substitution of A581 by T occurred in a lung adenocarcinoma sample, resulting in the change of aspartic acid at position 194 to valine. A loss of another allele was detected in this sample. One silent change, C1257T, was found in a pancreatic carcinoma sample. The changes were not present in the matched normal tissue DNA samples. Our results suggest that mutational inactivation of LKB1 is a rare event in most sporadic tumor types.
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PMID:LKB1 somatic mutations in sporadic tumors. 1007 45

Sapphyrins are pentapyrrolic, metal-free, expanded porphyrins. In the present study, the activity of sapphyrins as anticancer agents in hematopoietic-derived tumor cells was explored. It was found that a dihydroxylated water-soluble sapphyrin derivative (PCI-2000) is a potent inducer of apoptosis in a wide variety of tumor cell lines including lymphoma (Ramos, DHL-4, and HF-1), leukemia (Jurkat and HL-60), and myeloma (8226/S, 1-310, C2E3, and 1-414). PCI-2000 triggers an apoptotic pathway in these tumor cells as shown by release of cytochrome c from mitochondria; activation of caspases 9, 8, and 3; cleavage of the caspase substrate poly(ADP-ribose) polymerase; and Annexin V binding. Apoptosis can be partially inhibited by overexpression of the antiapoptotic protein Bcl-2 or treatment with benzyloxycarbonyl-valine-alanine-aspartic acid-fluoromethylketone, a cell-permeable caspase inhibitor. Both PCI-2000 and PCI-2010, a tetrahydroxy bis-carbamate derivative of PCI-2000, result in increased levels of phosphorylated p38 mitogen-activated protein kinase. Inhibition of p38 mitogen-activated protein kinase phosphorylation resulted in a synergistic increase of PCI-2000 cytotoxicity. PCI-2010 showed less toxicity in mice than PCI-2000 and was active in slowing the growth of Ramos and HL-60 tumor xenografts in nude mice. These results provide preclinical rationale for the further study of sapphyrins for potential use in the treatment of hematopoietic-derived tumors.
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PMID:Sapphyrins induce apoptosis in hematopoietic tumor-derived cell lines and show in vivo antitumor activity. 1595 54

Zymography of concentrated conditioned medium (CM) from protein-free NS0 myeloma cell cultures showed that this cell line produced and released/secreted several proteases. Two caseinolytic activities at 45-50 and 90 kDa were identified as aspartic acid proteases, and at least two cathepsins of the papain-like cysteine protease family with molecular masses of 30-35 kDa were found by gelatin zymography. One of these cathepsins was identified as cathepsin L by using an enzyme assay exploiting the substrate Z-Phe-Arg-AMC and the inhibitor Z-Phe-Tyr-t(Bu)-DMK. The aspartic acid and cysteine proteases were active only at acidic pH and are therefore not a potential risk for degrading the product or affecting cell growth during culture. Secreted proforms of cathepsins may, however, possess mitogenic functions, but addition of anti-procathepsin L antibodies to NS0 cultures did not influence proliferation. The recombinant antibody product was not degraded in cell-free CM incubated at pH 7, but when the pH was decreased to 3.5-4, the aspartic acid proteases degraded the product. Gelatin zymography also revealed the presence of several serine proteases in NS0 CM, one at 85 kDa and two at 50 kDa, with pH optima close to culture pH. Addition of the serine protease inhibitor aprotinin significantly increased the specific proliferation rate as compared to the control. In addition to these data, N-terminal amino acid sequencing identified two proteins in NS0 CM as the protease inhibitors secretory leukocyte protease inhibitor and cystatin C.
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PMID:Protease activity in protein-free NS0 myeloma cell cultures. 1644 22

Proapoptotic drugs are a mainstay of cancer drug treatment. These drugs stress cells and ultimately trigger the activation of caspases, cysteine-class proteases that cleave after aspartic acid and deconstruct the cell. It is well known that cells respond differently to proapoptotic cancer drug treatments. Here, using a global and unbiased quantitative N-terminomics technology, we show that ~500 products of caspase cleavage and their kinetics vary dramatically between cell type and cytotoxic drug treatment. It is likely that variations arise from differences in baseline proteome composition of the cell type and the alterations induced by drug treatments to yield a unique cohort of proteins that caspases finally target. Many targets are specific to both drug treatment and cell type, providing candidate-specific biomarkers for apoptosis. For example, in multiple myeloma cells treated with the proteasome inhibitor bortezomib, levels of activating transcription factor-4 increase dramatically early in drug treatment and then decrease upon cleavage by activated caspases. Thus, caspase-derived cleavage products are a sensitive reflection of cell-type and drug-induced stress, and provide useful fingerprints for mechanisms of drug action and response.
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PMID:Quantitative profiling of caspase-cleaved substrates reveals different drug-induced and cell-type patterns in apoptosis. 2280 52

A strategy is presented for enhancing the middle-down analysis of higher mass peptides recovered from complex protein mixtures. Following a 30-min digestion of multiple myeloma cell lysate by an acid cleavage reaction that is selective for aspartic acid, a 3000 Da membrane filter is used to bifurcate the peptide product mixture, and the heavier fraction is subjected to collisional activation with precursor selection that excludes charge states below +4. Filtration and charge state selection are shown to provide significant increases in the number of peptides identified in the mass range above 3000 Da and in information about protein sequences.
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PMID:Mass-biased partitioning to enhance middle down proteomics analysis. 2349 89

Rpn13 is a proteasome ubiquitin receptor that has emerged as a therapeutic target for human cancers. Its ubiquitin-binding activity is confined to an N-terminal Pru (pleckstrin-like receptor for ubiquitin) domain that also docks it into the proteasome, while its C-terminal DEUBAD (DEUBiquitinase ADaptor) domain recruits deubiquitinating enzyme Uch37 to the proteasome. Bis-benzylidine piperidone derivatives that were found to bind covalently to Rpn13 C88 caused the accumulation of polyubiquitinated proteins as well as ER stress-related apoptosis in various cancer cell lines, including bortezomib-resistant multiple myeloma lines. We find that a 38-amino acid peptide derived from the C-terminus of proteasome PC repeat protein hRpn2/PSMD1 binds to hRpn13 Pru domain with 12 nM affinity. By using NMR, we identify the hRpn13-interacting amino acids in this hRpn2 fragment, some of which are conserved among eukaryotes. Importantly, we find the hRpn2-derived peptide to immunoprecipitate endogenous Rpn13 from 293T cells, and to displace it from the proteasome. These findings indicate that this region of hRpn2 is the primary binding site for hRpn13 in the proteasome. Moreover, the hRpn2-derived peptide was no longer able to interact with endogenous hRpn13 when a strictly conserved phenylalanine (F948 in humans) was replaced with arginine or a stop codon, or when Y950 and I951 were substituted with aspartic acid. Finally, over-expression of the hRpn2-derived peptide leads to an increased presence of ubiquitinated proteins in 293T cells. We propose that this hRpn2-derived peptide could be used to develop peptide-based strategies that specifically target hRpn13 function in the proteasome.
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PMID:A High Affinity hRpn2-Derived Peptide That Displaces Human Rpn13 from Proteasome in 293T Cells. 2646 95


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