Chemotherapy-Induced Activation of ADAM-17: A Novel Mechanism of Drug Resistance in Colorectal Cancer

Purpose: We have shown previously that exposure to anticancer drugs can trigger the activation of human epidermal receptor survival pathways in colorectal cancer (CRC). In this study, we examined the role of ADAMs (a disintegrin and metalloproteinases) and soluble growth factors in this acute drug resistance mechanism.

Experimental Design: In vitro and in vivo models of CRC were assessed. ADAM-17 activity was measured using a fluorometric assay. Ligand shedding was assessed by ELISA or Western blotting. Apoptosis was assessed by flow cytometry and Western blotting.

Results: Chemotherapy (5-fluorouracil) treatment resulted in acute increases in transforming growth factor-a, amphiregulin, and heregulin ligand shedding in vitro and in vivo that correlated with significantly increased ADAM-17 activity. Small interfering RNA–mediated silencing and pharmacologic inhibition confirmed that ADAM-17 was the principal ADAM involved in this prosurvival response. Furthermore, overexpression of ADAM-17 significantly decreased the effect of chemotherapy on tumor growth and apoptosis. Mechanistically, we found that ADAM-17 not only regulated phosphorylation of human epidermal receptors but also increased the activity of a number of other growth factor receptors, such as insulin-like growth factor-I receptor and vascular endothelial growth factor receptor.

Conclusions: Chemotherapy acutely activates ADAM-17, which results in growth factor shedding, growth factor receptor activation, and drug resistance in CRC tumors. Thus, pharmacologic inhibition of ADAM-17 in conjunction with chemotherapy may have therapeutic potential for the treatment of CRC.

Effect of growth-promoting 17ß estradiol, 19 nortestosterone and dexamethasone on circulating levels of nine potential biomarker candidates in veal calves

The use of screening methods based on the detection of biological effects of growth promoters is a promising approach to assist residue monitoring. To reveal useful effects on protein metabolism, male and female veal calves at 10 weeks of age were treated thrice with a combination of 25 mg 17ß-estradiol 3-benzoate and 150 mg 19-nortestosterone decanoate with 2 weeks intervals and finally once with 4 mg dexamethasone. Hormone-treated calves showed a significant accelerated growth rate over 6 weeks. Plasma samples of treated and control calves were analysed for immunoreactive inhibin (ir-inhibin), osteocalcin, insulin-like growth factor 1 (IGF-1), insulin-like growth factor-binding protein 2 (IGFBP-2), IGFBP-3, luteinzing hormone (LH), follicle-stimulating hormone (FSH) and prolactin using immunoaffinity assays. Hormone treatment did not affect levels of IGF-1, IGFBP-2, IGFBP-3, LH, FSH and prolactin. The concentration of circulating ir-inhibin decreased, however, significantly (P < 0.05) in bull calves upon administration of the sex steroids, whereas it remained unchanged in the female animals. Dexamethasone treatment decreased significantly (P < 0.05) circulating levels of osteocalcin in both female and male animals. Ir-inhibin and osteocalcin were, therefore, considered as candidates for a protein biomarker-based screening assay for detection of abuse of estrogens, androgens and/or glucocorticoids in cattle fattening, which is being developed in the framework of EU research project BioCop

Inhibition of Secretion of Interleukin (IL)-12/IL-23 Family Cytokines by 4-Trifluoromethyl-celecoxib Is Coupled to Degradation via the Endoplasmic Reticulum Stress Protein HERP

Interleukin-12 (IL-12), p80, and IL-23 are structurally related cytokines sharing a p40 subunit. We have recently demonstrated that celecoxib and its COX-2-independent analogue 4-trifluoromethyl-celecoxib (TFM-C) inhibit secretion but not transcription of IL-12 (p35/p40) and p80 (p40/p40). This is associated with a mechanism involving altered cytokine-chaperone interaction in the endoplasmic reticulum (ER). In the present study, we found that celecoxib and TFM-C also block secretion of IL-23 (p40/p19 heterodimers). Given the putative ER-centric mode of these compounds, we performed a comprehensive RTPCR analysis of 23 ER-resident chaperones/foldases and associated co-factors. This revealed that TFM-C induced 1.5-3-fold transcriptional up-regulation of calreticulin, GRP78, GRP94, GRP170, ERp72, ERp57, ERdj4, and ERp29. However, more significantly, a 7-fold up-regulation of homocysteine-inducible ER protein (HERP) was observed. HERP is part of a high molecular mass protein complex involved in ER-associated protein degradation (ERAD). Using co-immunoprecipitation assays, we show that TFM-C induces protein interaction of p80 and IL-23 with HERP. Both HERP siRNA knockdown and HERP overexpression coupled to cycloheximide chase assays revealed that HERP is necessary for degradation of intracellularly retained p80 by TFM-C. Thus, our data suggest that targeting cytokine folding in the ER by small molecule drugs could be therapeutically exploited to alleviate in appropriate inflammation in autoimmune conditions.

Performance, représentation et (il)lisibilité du genre dans la fiction sandienne des années 1830

Dans son premier roman, Indiana (1832), Sand établit un réseau de correspondances entre la langue, la performance et l'identité sexuelle qui n'ont pas encore fait l'objet d'une étude approfondie. Or, ces correspondances sous-tendent d'autres romans des années 1830, notamment Lélia (1833), Le Secrétaire intime (1834) et Gabriel (1839). Deux concepts – la performance et la lisibilité – fondent en fait les réflexions de Sand sur la représentation et le genre. Il s'agit dans cet article d'étudier ce réseau d'associations et d'explorer son évolution dans la fiction sandienne des années 1830. Cette analyse permettra de souligner comment, chez Sand, la performativité du genre met en question et trouble la représentation mimétique.

Effects of IL-13 on Mucociliary Differentiation of Pediatric Asthmatic Bronchial Epithelial Cells

Goblet cell hyperplasia (GCH) and decreased ciliated cells are characteristic of asthma. We examined the effects of IL-13 (2 and 20 ng/mL) on in vitro mucociliary differentiation in pediatric bronchial epithelial cells (PBECs) of normal PBEC [PBEC(N)] and asthmatic PBEC [PBEC(A)] children. Markers of differentiation, real-time PCR for MUC5AC, MUC5AC ELISA, and transepithelial electrical resistance (TEER) were assessed. Stimulation with 20 ng/mL IL-13 in PBEC(N) resulted in GCH [20 ng/mL IL-13: mean, 33.8% (SD, 7.2) versus unstimulated: mean, 18.9% (SD, 5.0); p < 0.0001] and decreased ciliated cell number [20 ng/mL IL-13: mean, 8% (SD, 5.6) versus unstimulated: mean, 22.7% (SD,7.6); p < 0.01]. PBEC(N) stimulated with 20 ng/mL IL-13 resulted in >5-fold (SD, 3.2) increase in MUC5AC mRNA expression, p < 0.001, compared with unstimulated PBEC(N). In PBEC(A), GCH was also seen [20 ng/mL IL-13: mean, 44.7% (SD, 16.4) versus unstimulated: mean, 30.4% (SD, 13.9); p < 0.05] with a decreased ciliated cell number [20 ng/mL IL-13: mean, 8.8% (SD, 7.5) versus unstimulated: mean, 16.3% (SD, 4.2); p < 0.001]. We also observed an increase in MUC5AC mRNA expression with 20 ng/mL IL-13 in PBEC(A), p < 0.05. IL-13 drives PBEC(N) toward an asthmatic phenotype and worsens the phenotype in PBEC(A) with reduced ciliated cell numbers and increased goblet cells.

A phase I study of the Heat Shock Protein 90 inhibitor alvespimycin (17-DMAG) given intravenously to patients with advanced, solid tumours.

PURPOSE: A phase I study to define toxicity and recommend a phase II dose of the HSP90 inhibitor alvespimycin (17-DMAG; 17-dimethylaminoethylamino-17-demethoxygeldanamycin). Secondary endpoints included evaluation of pharmacokinetic profile, tumor response, and definition of a biologically effective dose (BED). PATIENTS AND METHODS: Patients with advanced solid cancers were treated with weekly, intravenous (i.v.) 17-DMAG. An accelerated titration dose escalation design was used. The maximum tolerated dose (MTD) was the highest dose at which = 1/6 patients experienced dose limiting toxicity (DLT). Dose de-escalation from the MTD was planned with mandatory, sequential tumor biopsies to determine a BED. Pharmacokinetic and pharmacodynamic assays were validated prior to patient accrual. RESULTS: Twenty-five patients received 17-DMAG (range 2.5-106 mg/m(2)). At 106 mg/m(2) of 17-DMAG 2/4 patients experienced DLT, including one treatment-related death. No DLT occurred at 80 mg/m(2). Common adverse events were gastrointestinal, liver function changes, and ocular. Area under the curve and mean peak concentration increased proportionally with 17-DMAG doses 80 mg/m(2) or less. In peripheral blood mononuclear cells significant (P

The Deubiquitinating Enzyme USP17 is Essential for GTPase Subcellular localization and Cell Motility

Deubiquitinating enzymes are now emerging as potential therapeutic targets that control many cellular processes, but few have been demonstrated to control cell motility. Here, we show that ubiquitin-specific protease 17 (USP17) is rapidly and transiently induced in response to chemokines SDF-1/CXCL12 and IL-8/CXCL8 in both primary cells and cell lines, and that its depletion completely blocks chemokine-induced cell migration and cytoskeletal rearrangements. Using live cell imaging, we demonstrate that USP17 is required for both elongated and amoeboid motility, in addition to chemotaxis. USP17 has previously been reported to disrupt Ras localization and we now find that USP17 depletion blocks chemokine-induced subcellular relocalization of GTPases Cdc42, Rac and RhoA, which are GTPases essential for cell motility. Collectively, these results demonstrate that USP17 has a critical role in cell migration and may be a useful drug target for both inflammatory and metastatic disease.

A novel small-molecule inhibitor of IL-6 signalling.

A small library of pyrrolidinesulphonylaryl molecules has been synthesized via an efficient 4-step route, and members evaluated for their ability to inhibit IL-6 signalling. One molecule (6a) was found to have promising activity against IL-6/STAT3 signalling at the low micromolar level, and to selectively inhibit phosphorylation of STAT3 (but not STAT1) in IL-6 stimulated MDA-MB-231 breast cancer and HeLa cell lines. It was also selectively cytostatic in MDA-MB-231 (STAT3-dependent) versus A4 (STAT3-null) cells suggesting STAT3-specific inhibitory properties.

D'une langue a l'autre. De l'Allemagne

This article deals with the translation of Patrick Beurard-Valdoye's texts and the inter-cultural dimension (German-French) of his work.