PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 10397497

A substrate combinatorial array for caspases.

D Lee·J L Adams·M Brandt·W E DeWolf·P M Keller·M A Levy
View original source ↗Export metadata ↓

Abstract

An efficient strategy for the synthesis of a tetrapeptidyl substrate combinatorial array directed toward the caspases is described. Testing of this array with caspases 1 and 4 gave substrate hydrolytic profiles characteristic of each caspase, and permitted the identification of efficiently processed substrates. A comparison of this approach to that using a positional scanning library is presented.

Explore related subjects

Caspase 1CaspasesCaspases, InitiatorCatalysisKineticsOligopeptidesSubstrate SpecificityJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D Lee, J L Adams, M Brandt, W E DeWolf, P M Keller, M A Levy. 1999-06-21. A substrate combinatorial array for caspases.. https://doi.org/10.1016/s0960-894x(99)00260-7

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1999

Bioactive IL-18 expression is up-regulated in Crohn's disease.

An imbalance of immunoregulatory factors is believed to contribute to uncontrolled mucosal Th1 cell activation in Crohn's disease (CD). IL-18, a macrophage-like cell-derived cytokine, is involved in Th1 clone development, and IFN-gamma production. Therefore, IL-18 expression was investigated in CD. Whole mucosal intestinal tissue and lamina propria mononuclear cells (LPMC) of 12 CD and 9 ulcerative colitis (UC) patients and 15 non-inflammatory bowel disease (IBD) controls were tested for IL-18 by semiquantitative RT-PCR and Western blot analysis. Transcripts for IL-18 were found in all samples tested. However, increased IL-18 mRNA accumulation was detected in both mucosal and LPMC samples from CD in comparison to UC and controls. In CD, transcripts for IL-18 were more abundant in the mucosal samples taken from involved areas. An 18-kDa band consistent with mature IL-18 was predominantly found in CD mucosal samples. In mucosal samples from non-IBD controls, IL-18 was present as a 24-kDa polypeptide. Consistently, active IL-1beta-converting enzyme (ICE) subunit (p20) was expressed in samples from either CD or UC, whereas, in colonic mucosa from non-IBD controls, ICE was synthesized as precursor (p45) only. To confirm that IL-18 produced in CD tissue was functionally active, CD LPMC were treated with a specific IL-18 antisense oligonucleotide. In these cultures, IL-18 down-regulation was accompanied by a decrease in IFN-gamma expression. In aggregate, our data indicate that IL-18 up-regulation is a feature of CD and suggest that IL-18 may contribute to the local immunoinflammatory response in CD.

Caspase 1↗
PubMed1999

Modulation of interleukin-18 expression in human colon carcinoma: consequences for tumor immune surveillance.

The production in colon cancer of interferon-gamma (IFN-gamma), a type-1 T-helper (TH1) cytokine, is considered as a marker of good prognosis. We asked whether interleukin-18 (IL-18), which strongly induces IFN-gamma and regulates Fas ligand (Fas-L)-dependent cytotoxicity, may play a role in colon homeostasis, and if its expression was modulated in colon adenocarcinomas. We analyzed 14 specimens of colon adenocarcinomas, 6 of normal colon mucosa of the series, and 6 colon-tumor cell lines. The expression of IL-18, of ICE protease, involved in the processing of this cytokine, and of the downstream effectors of IL-18, IFN-gamma and Fas-L was analyzed by RT-PCR. We further performed IL-18 immunostaining of normal and tumor specimens. The results were correlated with tumor dissemination and clinical outcome. We report the synthesis of IL-18 in human normal colon, mainly by epithelial cells of the mucosa. Out of the 6 tumor cell lines, 4 expressed IL-18 transcripts, but neither ICE mRNA nor secreted forms of IL-18 were detected. We observed decreased or abolished synthesis of IL-18 in colon adenocarcinomas, as compared with normal mucosa. Thus, half of the colon-cancer tissues (7/14 cases) expressed neither IFN-gamma nor Fas-L. This feature was correlated with the existence of distant metastases (Fischer's exact test, p = 0.02) and an unfavorable outcome. These findings suggest that production of IL-18 in human colon may play a role in homeostasis and in tumor immune surveillance, by enhancing IFN-gamma production and Fas-L-dependent cytotoxicity of immune cells.

Caspase 1↗