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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)
The serum-free medium conditioned by the human colon cancer cell line HT-29 contains insulin-like growth factors (IGF) that are entirely complexed to binding proteins (IGF-BP). Gel filtration in acid conditions of the cell-conditioned medium permits separation of IGF-BP from two molecular forms of IGF of 15,000 and 7,500 Mr. As determined by ligand(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)
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)
Paclitaxel and docetaxel are potent anti-microtubule and antimitotic agents that induce apoptosis in bone marrow-derived cells and epithelial cells. This study examined apoptosis induced by anti-microtubule agents in the neuroblastoma SK-N-SH cell line with a special focus on tau protein which is one of the main Microtubule-Associated- Proteins (MAPs) in(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)
The limited proteolysis of insulin-like growth factor (IGF)-binding protein (IGFBP)-3 is a key event in the regulation of endocrine bioavailability of IGFs. Here, we investigated IGFBP-3 and IGFBP-3 proteolysis in serum from patients with colorectal cancer both before and at different times following surgery. In vivo IGFBP-3 proteolysis, estimated by(More)
In this study, we have used enterocyte-like differentiated HT29-D4 human colonic carcinoma cells cultured in a glucose-free medium (HT29-D4-GAL cells) on semi-permeable supports in order to investigate the polarity of the insulin-like growth factor (IGF) system. We report that these cells secrete endogenous IGF-II predominantly (66%) from the basolateral(More)
We have identified one class of IGF-I-binding sites and two classes of IGF-II-binding sites at the surface of the melanoma cell line IGR39. By means of affinity labeling with 125I-IGF-I, 290-300 kDa form was characterized. Using 125I-IGF-II, a 270 kDa polypeptide was labeled, corresponding to the type II IGF receptor. In the two serials of experiments, the(More)
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)