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Classical growth factors for colon cancer cells have been extensively described including agonists of tyrosine kinase receptors such as epidermal growth factor and related proteins (1) or insulin-like growth factors (2). More recently, some G protein-coupled receptor (GPCR) 1 agonists such as peptide hormones (3-5), prostaglandins (6), or serine proteases (7, 8) have been shown also to promote colon cancer cell proliferation often through transactivation of the epidermal growth factor receptor (6, 8). These GPCRs are expressed in both normal colonic epithelium and colon tumors (9) or even ectopically expressed by cancer cells such as in the case of the neurotensin receptor NT1 (10) or the thrombin receptor protease-activated receptor 1 (7). Whatever their expression pattern, they probably all contribute to the growth of colon tumors because of the presence of abundant ligands in the neuroendocrine environment of colonic tumors and/or to the production of receptor ligands by the tumor itself (11, 12).Our knowledge of receptor agonist suppressing colon cancer cell growth is much more limited apart from a few observations regarding transforming growth factor-␤ (13) or Fas ligand (14). We reasoned that among the very rich environment of peptide hormones and neuropeptides in the gut, we should be able to find natural agonists behaving as suppressors of colon cancer growth. In order to test this hypothesis, we developed a very simple assay by using human colon adenocarcinoma cells HT29-D4 grown in 10% FCS and screened for various peptides by their ability to inhibit cell growth. We made two dramatic hits with orexin-A and orexin-B, which appear to be robust growth inhibitors as shown here.Orexin-A and orexin-B (15), also named hypocretin-1 and hypocretin-2 (16), were discovered in 1998 by orphan receptor technologies (15) or subtractive cDNA cloning (16). They are encoded by a single gene that drives the synthesis of preproorexin that is subsequently matured into the 33-amino acid orexin-A and the 28-amino acid orexin-B, sharing 46% amino acid identity in humans (reviewed in Ref. 17). Two orexin receptor subtypes OX 1 R and OX 2 R have been cloned (15). They are serpentine GPCRs that bind both orexins with poor selectivity and are coupled to Ca 2ϩ mobilization (15). Orexins were initially characterized as neuropeptides restricted to hypothalamic neurons that project in the brain to nuclei involved in the

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PurposePositron emission tomography (PET) imaging of brain amyloid load has been suggested as a core biomarker for Alzheimer’s disease (AD). The aim of this study was to test the feasibility of using PET imaging with 18F-AV-45 (florbetapir) in a routine clinical environment to differentiate between patients with mild to moderate AD and mild cognitive impairment (MCI) from normal healthy controls (HC).MethodsIn this study, 46 subjects (20 men and 26 women, mean age of 69.0 ± 7.6 years), including 13 with AD, 12 with MCI and 21 HC subjects, were enrolled from three academic memory clinics. PET images were acquired over a 10-min period 50 min after injection of florbetapir (mean ± SD of radioactivity injected, 259 ± 57 MBq). PET images were assessed visually by two individuals blinded to any clinical information and quantitatively via the standard uptake value ratio (SUVr) in the specific regions of interest, which were defined in relation to the cerebellum as the reference region.ResultsThe mean values of SUVr were higher in AD patients (median 1.20, Q1-Q3 1.16-1.30) than in HC subjects (median 1.05, Q1-Q3 1.04-1.08; p = 0.0001) in the overall cortex and all cortical regions (precuneus, anterior and posterior cingulate, and frontal median, temporal, parietal and occipital cortex). The MCI subjects also showed a higher uptake of florbetapir in the posterior cingulate cortex (median 1.06, Q1-Q3 0.97-1.28) compared with HC subjects (median 0.95, Q1-Q3 0.82-1.02; p = 0.03). Qualitative visual assessment of the PET scans showed a sensitivity of 84.6% (95% CI 0.55–0.98) and a specificity of 38.1% (95% CI 0.18–0.62) for discriminating AD patients from HC subjects; however, the quantitative assessment of the global cortex SUVr showed a sensitivity of 92.3% and specificity of 90.5% with a cut-off value of 1.122 (area under the curve 0.894).ConclusionThese preliminary results suggest that PET with florbetapir is a safe and suitable biomarker for AD that can be used routinely in a clinical environment. However, the low specificity of the visual PET scan assessment could be improved by the use of specific training and automatic or semiautomatic quantification tools.

Resistance to apoptosis is a recurrent theme in colon cancer. We have shown previously that the 7-transmembrane spanning receptor OX1R for orexins promotes robust apoptosis in the human colon cancer cell line HT29 through an entirely novel mechanism involving phosphorylation of tyrosine-based motifs in OX1R. Here, we investigated the status of OX1R in a large series of human colorectal tumors and hepatic metastases. All primary colorectal tumors regardless of their localization and Duke's stages and all hepatic metastases tested expressed OX1R mRNA and/or protein. In sharp contrast, adjacent normal colonocytes or hepatocytes as well as control normal tissues were negative. Next, we showed that nine human colon cancer cell lines established from primary tumors or metastases expressed OX1R mRNA and underwent important apoptosis on orexin-A challenge. Most interestingly, orexin-A also promoted robust apoptosis in cells that are resistant to the most commonly used drug in colon cancer chemotherapy, 5-fluorouracil. When human colon cancer cells were xenografted in nude mice, orexin-A administered at day 0 strongly slowed the tumor growth and even reversed the development of established tumors when administered 7 days after cell inoculation. Orexin-A also acts by promoting tumor apoptosis in vivo because caspase-3 is activated in tumors on orexin treatment of nude mice. These findings support that OX1R is an Achilles heel of colon cancers, even after metastasis or chemoresistance. They suggest that OX1R agonists might be novel candidates for colon cancer therapy. Cancer Res; 71(9);

1- "Iatrogenic disability" was defined by the task force as the avoidable dependence which often occurs during the course of care. It involves three components that interact and have a cumulative effect: a) the patient's pre-existing frailty, b) the severity of the disorder that led to the patient's admission, and lastly c) the hospital structure and the process of care. 2- The prevention of "iatrogenic disability" involves successive stages. - becoming aware that hospitalization may induce dependence. Epidemiological studies have identified at-risk populations by the use of composite scores (HARP, ISAR, SHERPA, COMPRI, etc). - considering that functional decline is not a fatality. Quality references have already been defined. Interventions to prevent dependence in targeted populations have been set up: simple geriatric consultation teams, single-factor interventions (aimed for example at mobility, delirium, iatrogenic disorders) or multidomain interventions (such as GEM and ACE units, HELP, Fast Track, NICHE). These interventions are essentially centered on the patient's frailty and have limited results, as they take little account of the way the institution functions, which is not aimed at prevention of functional decline. The process of care reveals shortcomings: lack of geriatric knowledge, inadequate evaluation and management of functional status. The group suggests that interventions must not only identify at-risk patients so that they may benefit from specialized management, but they must also target the hospital structure and the process of care. This requires a graded "quality approach" and rethinking of the organization of the hospital around the elderly person.

Orexins acting at the G protein-coupled receptor (GPCR) OX1R have recently been shown to promote dramatic apoptosis in cancer cells. We report here that orexin-induced apoptosis is driven by an immunoreceptor tyrosine-based inhibitory motif (ITIM) (IIY(358)NFL) present in the OX1R. This effect is mediated by SHP-2 phosphatase recruitment via a mechanism that requires Gq protein but is independent of phospholipase C activation. This is based on the following observations: 1) mutation of Y(358) into F abolished orexin-induced tyrosine phosphorylation in ITIM, orexin-induced apoptosis, and uncoupled OX1R from Gq protein in transfected Chinese hamster ovary (CHO) cells; 2) orexin-induced apoptosis in CHO cells expressing recombinant OX1R and in colon cancer cells expressing the native receptor was abolished by treatment with the tyrosine phosphatase inhibitor PAO and by transfection with a dominant-negative mutant of SHP-2; 3) orexins were unable to promote apoptosis in fibroblast cells invalidated for the G alpha q subunit and transfected with OX1R cDNA, whereas they promoted apoptosis in cells equipped with G alpha q and OX1R; and 4) the phospholipase C inhibitor U-73122 blocked orexin-stimulated inositol phosphate formation, whereas it had no effect on orexin-induced apoptosis in CHO cells expressing OX1R. These data unravel a novel mechanism, whereby ITIM-expressing GPCRs may trigger apoptosis.

Orexins, also named hypocretins, were discovered in 1998 by subtractive cDNA cloning or orphan receptor technologies. Prepro-orexin is enzymatically matured into two peptides, orexin-A and orexin-B which are 33- and 28-amino-acid peptides, respectively. Two cloned orexin receptors OX1R and OX2R are serpentine G-protein-coupled receptors, both of which bind orexins and are coupled to Ca2+ mobilization. Orexins are neuropeptides present in hypothalamic neurons that project throughout the central nervous system to nuclei involved in the control of feeding, sleep-wakefulness, neuroendocrine homeostasis and autonomic regulation. The interest of investigators in orexins has focused on narcolepsy, since genetic or experimental alterations of the orexin system are associated with this sleep disorder. However, orexins are not restricted to the hypothalamus and together with their receptors they are expressed in peripheral tissues. This new multifaceted aspect of orexin biology is reviewed here in descriptions of (i) the proform, maturation and structure of orexins, (ii) the structure, signal transduction and pharmacology of orexin receptors and (iii) the expression of orexins and orexin receptors as well as their biological role in the hypothalamus-pituitary-adrenal axis, gastrointestinal tract, endocrine pancreas and other peripheral tissues.