Antonello D'Arrigo

Metastatic transcriptional pattern revealed by gene expression profiling in primary colorectal carcinoma

Metastatic spread to the liver is the major contributor to mortality in patients with colorectal carcinoma (CRC). In order to seek for gene expression patterns associated with metastatic potential in primary CRC, we compared the transcriptional profiles of 10 radically resected primary CRCs from patients who did not develop distant metastases within a 5‐year follow‐up period with those of 10 primary/metastatic tumor pairs from patients with synchronous liver metastases. To focus selectively on neoplastic cells, the study was conducted on laser‐microdissected bioptic tissues. Arrays of 7,864 human cDNAs were utilized. While a striking transcriptional similarity was observed between the primary tumors and their distant metastases, the nonmetastasizing primary tumors were clearly distinct from the primary/metastatic tumor pairs. Of 37 gene expression differences found between the 2 groups of primary tumors, 29 also distinguished nonmetastasizing tumors from metastases. The gene encoding for mannosyl (α‐1,3‐)‐glycoprotein β‐1,4‐N‐acetyl‐glucosaminyl‐transferase (GnT‐IV) became significantly upregulated in primary/metastatic tumor pairs (p < 0.001). GnT‐IV upregulation was confirmed by RT‐PCR. These data support the existence of a specific transcriptional signature distinguishing primary colon adenocarcinomas with different metastatic potential, the further pursuit of which may lead to relevant clinical and therapeutic applications.

1-(3′,4′-Dichloro-2-fluoro[1,1′-biphenyl]-4-yl)-cyclopropanecarboxylic Acid (CHF5074), a Novel γ-Secretase Modulator, Reduces Brain β-Amyloid Pathology in a Transgenic Mouse Model of Alzheimer's Disease without Causing Peripheral Toxicity

Some nonsteroidal anti-inflammatory drugs has been shown to allosterically modulate the activity of γ-secretase, the enzymatic complex responsible for the formation of β-amyloid (Aβ). 1-(3′,4′-Dichloro-2-fluoro[1,1′-biphenyl]-4-yl)-cyclopropanecarboxylic acid (CHF5074) is a new γ-secretase modulator, devoid of anticyclooxygenase (COX) and Notch-interfering activities in vitro. We evaluated the effects of chronic CHF5074 treatment on brain Aβ pathology in Tg2576 transgenic mice. Twenty-eight animals of 9.5 to 10.5 months of age received CHF5074-medicated diet (375 ppm) or standard diet for 17 weeks. Compared with controls, CHF5074 treatment significantly reduced the area occupied by plaques and the number of plaques in cortex (–52.2 ± 5.6%, p = 0.0003 and –48.9 ± 6.6%, p = 0.0004, respectively) and hippocampus (–76.7 ± 6.4%, p = 0.004 and –66.2 ± 10.3%, p = 0.037, respectively). Biochemical analysis confirmed the histopathological measures, with CHF5074-treated animals showing reduced total brain Aβ40 (–49.2 ± 9.2%, p = 0.017) and Aβ42 (–43.5 ± 9.7%, p = 0.027) levels. In a human neuroglioma cell line expressing Swedish mutated form of amyloid precursor protein (H4swe), CHF5074 reduced Aβ42 and Aβ40 secretion, with an IC50 of 3.6 and 18.4 μM, respectively, values consistent with those measured in the brain of the CHF5074-treated Tg2576 mice (6.4 ± 0.4 μM). At 5 μM, no effects were observed on Notch intracellular cleavage in human embryonic kidney 293swe cells. CHF5074 was well tolerated by Tg2576 mice. No abnormal findings were observed upon histopathological examination of the gastrointestinal tract, indicating the absence of COX-related toxicity. Semiquantitative histochemical evaluation of goblet cells in the ileum of vehicle- and CHF5074-treated animals yielded similar results, suggesting no effects on Notch pathway. CHF5074 is therefore a promising therapeutic agent for Alzheimers disease.

Amniotic fluid stem cells improve survival and enhance repair of damaged intestine in necrotising enterocolitis via a COX-2 dependent mechanism

Objective Necrotising enterocolitis (NEC) remains one of the primary causes of morbidity and mortality in neonates and alternative strategies are needed. Stem cells have become a therapeutic option for other intestinal diseases, which share some features with NEC. We tested the hypothesis that amniotic fluid stem (AFS) cells exerted a beneficial effect in a neonatal rat model of NEC. Design Rats intraperitoneally injected with AFS cells and their controls (bone marrow mesenchymal stem cells, myoblast) were analysed for survival, behaviour, bowel imaging (MRI scan), histology, bowel absorption and motility, immunofluorescence for AFS cell detection, degree of gut inflammation (myeloperoxidase and malondialdehyde), and enterocyte apoptosis and proliferation. Results AFS cells integrated in the bowel wall and improved rat survival and clinical conditions, decreased NEC incidence and macroscopic gut damage, improved intestinal function, decreased bowel inflammation, increased enterocyte proliferation and reduced apoptosis. The beneficial effect was achieved via modulation of stromal cells expressing cyclooxygenase 2 in the lamina propria, as shown by survival studies using selective and non-selective cyclooxygenase 2 inhibitors. Interestingly, AFS cells differentially expressed genes of the Wnt/β-catenin pathway, which regulate intestinal epithelial stem cell function and cell migration and growth factors known to maintain gut epithelial integrity and reduce mucosal injury. Conclusions We demonstrated here for the first time that AFS cells injected in an established model of NEC improve survival, clinical status, gut structure and function. Understanding the mechanism of this effect may help us to develop new cellular or pharmacological therapies for infants with NEC.

CHF5074, a Novel γ-Secretase Modulator, Restores Hippocampal Neurogenesis Potential and Reverses Contextual Memory Deficit in a Transgenic Mouse Model of Alzheimer's Disease

The effects of compounds interfering with gamma-secretase, the enzymatic complex responsible of the formation of the amyloid-beta (Abeta) peptide from amyloid-beta protein precursor (AbetaPP), on plaque deposition in transgenic mouse models of Alzheimers disease are known but scanty data are available on the effects of these drugs on brain plasticity. We evaluated the effects of long-term treatment with CHF5074, a new gamma-secretase modulator, on hippocampal neurogenesis, cortical synaptophysin levels, and contextual memory in transgenic mice carrying the double Swedish mutation of AbetaPP (Tg2576). Six-month old Tg2576 mice were treated with CHF5074 (375 ppm in the diet) up to 15 months of age. Age-matched control transgenic and wild-type mice received standard diet. Compared to wild-type animals, transgenic controls showed a significant decrease in the number of doublecortin-positive neuroblasts in dentate gyrus, synaptophysin intensity in the cortex, freezing to context in the contextual fear conditioning test. Compared to transgenic controls, CHF5074 treatment of Tg2576 mice resulted in a significant attenuation of the neurogenesis impairment in hippocampus (p=0.036), normalization of synaptophysin levels in cortex (p< 0.001), attenuation of plaque burden in the cortex (p=0.033), increases astroglial reaction around plaques (p=0.001), and attenuation of activated microglia (p=0.040). These effects were associated to a complete reversal of contextual memory deficit (p=0.006). Contextual memory significantly correlated with synaptophysin immunoreactivity in the cortex (r=0.548, p=0.0038).

Gene Expression Profile of Primary Gastric Cancer: Towards the Prediction of Lymph Node Status

BackgroundThe identification of gastric tumors associated with a higher risk of lymph node metastasis could help surgeons select patients who may benefit from extended lymph node dissection. The aim of this study was to screen the genome in the search of primary gastric cancer gene expression profiles that might predict lymph node status.MethodsThe gene expression profile was evaluated in frozen tumor samples obtained from 32 patients with primary gastric adenocarcinomas. The array consisted of a duplicated spot panel of 5,541 human genes. To classify node-positive (N+) and node-negative (N−) cases, a logistic regression model was fitted optimizing the Akaike Information Criteria after a stepwise gene selection. The accuracy was evaluated by means of leave-one-out cross validation.ResultsAll patients underwent radical gastrectomy and extended lymphadenectomy. Of all the cases, 21 were N+ and 11 demonstrated no lymph node involvement (N−). After quality filtering, the analysis of variance selected a set of 136 genes potentially correlated with nodal involvement (P value <.05). Of these 136 genes, 5 were differentially expressed (adjusted P value <.05). After a stepwise gene selection, only three genes (Bik, aurora kinase B, eIF5A2) were retained in the logistic model, which could correctly predict lymph node status in 30 of 32 cases.ConclusionsIf our findings were confirmed, the identified gene pattern might be used to tailor the extent of lymph node dissection on a single patient basis.

Pathogenesis of Migraine: Role of Neuromodulators

The pathogenesis of migraine is still, today, a hotly debated issue. Recent biochemical studies report the occurrence in migraine of metabolic abnormalities in the synthesis of neurotransmitters and neuromodulators. These include a metabolic shift directing tyrosine metabolism toward the decarboxylation pathway, therein resulting in an unphysiological production of noradrenaline and dopamine along with increased synthesis of traces amines such as tyramine, octopamine, and synephrine. This biochemical alteration is possibly favored by impaired mitochondrial function and high levels of glutamate in the central nervous system (CNS) of migraine patients. The unbalanced levels of the neurotransmitters (dopamine and noradrenaline) and neuromodulators (eg, tyramine, octopamine, and synephrine) in the synaptic dopaminergic and noradrenergic clefts of the pain matrix pathways may activate, downstream, the trigeminal system that releases calcitonin gene‐related peptide. This induces the formation of an inflammatory soup, the sensitization of first trigeminal neuron, and the migraine attack. In view of this, we propose that migraine attacks derive from a top‐down dysfunctional process that initiates in the frontal lobe in a hyperexcitable and hypoenergetic brain, thereafter progressing downstream resulting in abnormally activated nuclei of the pain matrix.

CHF5074, a new g-secretase modulator, stimulates neurotrophin expression in primary neurons

Background: CHF5074 is a new g-secretase modulator that preferentially inhibits b-amyloid1-42 (Ab42) secretion at low micromolar concentrations. Long-term administration of CHF5074 to transgenic mice carrying the Swedish mutation of human amyloid precursor protein (APPswe) has been shown to robustly reduce brain plaque area fraction in both cortex and hippocampus (JPET 2007; 323: 822-30). The present study was carried out to assess the effects of CHF5074 on primary neuronal cultures, obtained from brain of APPswe transgenic mice and to identify the potential mechanisms involved. Methods: Neuronal cortical-hippocampal cultures were obtained employing embryos of APPswe transgenic mice. Briefly, hippocampi and frontal cortices were dissected from embryonic-day 16-18 (E16-18) mice obtained by breeding female B6SJLF1 mice with hemizygous male transgenic mice. The tissue was mechanically dissociated by pipetting in DMEM (Dulbecco’s modified Eagle’s medium) containing 2 mM L-glutamine and 10% fetal calf serum. Cells were plated overnight on poly-(l-lysine)-coated 24 well plates and maintained at 37 C in humidified 95% air and 5% CO2. After 24 hours, culture medium was substituted with DMEM containing B27 and 2 mM L-glutamine. Experiments with CHF5074 were performed at day 8 in vitro in DMEM supplemented with N-2 (GIBCO). Ab released in the medium was determined by peptide-specific ELISA (Genetics Co.). Total RNA was extracted with Trizol and neurotrophin expression evaluated by semi-quantitative RT-PCR. Results: We found that CHF5074, selectively and dose-dependently decreases Ab42 levels in culture media of primary cortical neurons. The IC50 for inhibition of Ab42 and Ab40 was 5.3 and 54 mM, respectively. Treatment did not result in any significant effect on cell viability. The Ab42-lowering action of CHF5074 was accompanied by a 2-fold up-regulation of nerve growth factor transcription after 48 hour treatments. Conclusions: These findings suggest that increased neurotrophic support might, in addition to gÓsecretase modulation, represent an underlying mechanism contributing to the beneficial effects of CHF-5074 seen in AD animal models.