Gilbert J. Pommier

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To investigate endoproteolytic processing of the type I insulin-like growth factor receptor (IGF-IR), we have examined its structure and activity in the furin-deficient LoVo-C5 cell line. Immunoprecipitation experiments using the monoclonal anti-IGF-IR antibody (alpha-IR3) showed that LoVo-C5 cells expressed a major high molecular mass receptor (200 kDa)(More)
In the tumor microenvironment, autocrine/paracrine loops of insulin-like growth factors (IGFs) contribute to cancer cell survival. However, we report here that IGF-I can send contradictory signals that interfere with cell death induced by different ligands of the tumor necrosis factor (TNF) superfamily. IGF-I protected human colon carcinoma cells from(More)
It has been reported that insulin-like growth factor (IGF) II is associated with human primary colorectal tumors and colon-carcinoma cell lines. Here, we examine alterations in circulating levels of IGFs and IGF binding proteins (IGFBPs) in patients with colorectal carcinoma, and compare them to age- and nutrition-adjusted references. We report (i) an(More)
HT29-D4 human colon-carcinoma cells have been shown to secrete insulin-like growth factor (IGF)-II and to simultaneously express type-I IGF receptors. However, the sequestration of IGF-II by several molecular forms of IGF-binding proteins (IGFBP) in the culture medium prevents the establishment of an operative IGF-II autocrine loop. IGFBPs secreted by(More)
Resistance of cancer cells against apoptosis induced by death factors contributes to the limited efficiency of immune- and drug-induced destruction of tumors. We report here that insulin and insulin-like growth factor-I (IGF-I) fully protect HT29-D4 colon carcinoma cells from IFN-gamma/tumor necrosis factor-alpha (TNF) induced apoptosis. Survival signaling(More)
Dynamic crosstalk between cell adhesion molecules, extracellular matrix and soluble informative factors is essential for cancer cell migration and invasion. Here, we investigated the mechanisms by which the E-cadherin/catenin complex and alpha v integrin can modulate insulin-like growth factor-I (IGF-I)-induced cell migration. Human colon mucosa, human(More)
Limited proteolysis of insulin-like-growth-factor (IGF)-binding proteins (IGFBPs) represents a key process to modulate IGF bio-availability at the cellular level. In human colon carcinomas, urokinase-type plasminogen activator (u-PA) produced by stroma cells can bind to cancer-cell-associated u-PA receptor (u-PAR), and then catalyze the conversion of(More)
BACKGROUND & AIMS The mechanisms by which epithelial cells migrate during the repair of damaged colonic mucosa are poorly understood. This study investigated the insulin-like growth factor I (IGF-I) signaling pathway leading to HT29-D4 human colonic epithelial cell line migration. METHODS IGF-stimulated cell migration was determined using a wound model in(More)
Endotoxin (LPS), a membrane component of gram-negative bacteria produces multiple endocrine and metabolic effects that mimic those seen in acute sepsis. It induces species-dependent alterations of the growth hormone (GH) axis that may participate in the shift of the metabolism towards catabolic events. Humans and sheep show increased GH secretion in(More)
Coxiella burnetii, the agent of Q fever, is an obligate intracellular microorganism that grows in monocytes/macrophages. The internalization of virulent organisms by monocytes is lower than that of avirulent variants and is associated with actin cytoskeleton reorganization. We studied the activation of protein tyrosine kinases (PTKs) by C. burnetii in THP-1(More)