Search tips
Search criteria

Results 1-25 (26)

Clipboard (0)

Select a Filter Below

Year of Publication
more »
author:("onnisi, A")
1.  Antagonism of the Prokineticin System Prevents and Reverses Allodynia and Inflammation in a Mouse Model of Diabetes 
PLoS ONE  2016;11(1):e0146259.
Neuropathic pain is a severe diabetes complication and its treatment is not satisfactory. It is associated with neuroinflammation-related events that participate in pain generation and chronicization. Prokineticins are a new family of chemokines that has emerged as critical players in immune system, inflammation and pain. We investigated the role of prokineticins and their receptors as modulators of neuropathic pain and inflammatory responses in experimental diabetes. In streptozotocin-induced-diabetes in mice, the time course expression of prokineticin and its receptors was evaluated in spinal cord and sciatic nerves, and correlated with mechanical allodynia. Spinal cord and sciatic nerve pro- and anti-inflammatory cytokines were measured as protein and mRNA, and spinal cord GluR subunits expression studied. The effect of preventive and therapeutic treatment with the prokineticin receptor antagonist PC1 on behavioural and biochemical parameters was evaluated. Peripheral immune activation was assessed measuring macrophage and T-helper cytokine production. An up-regulation of the Prokineticin system was present in spinal cord and nerves of diabetic mice, and correlated with allodynia. Therapeutic PC1 reversed allodynia while preventive treatment blocked its development. PC1 normalized prokineticin levels and prevented the up-regulation of GluN2B subunits in the spinal cord. The antagonist restored the pro-/anti-inflammatory cytokine balance altered in spinal cord and nerves and also reduced peripheral immune system activation in diabetic mice, decreasing macrophage proinflammatory cytokines and the T-helper 1 phenotype. The prokineticin system contributes to altered sensitivity in diabetic neuropathy and its inhibition blocked both allodynia and inflammatory events underlying disease.
PMCID: PMC4701417  PMID: 26730729
2.  Vesicular Trafficking to the Immune Synapse: How to Assemble Receptor-Tailored Pathways from a Basic Building Set 
The signals that orchestrate T-cell activation are coordinated within a highly organized interface with the antigen-presenting cell (APC), known as the immune synapse (IS). IS assembly depends on T-cell antigen receptor engagement by a specific peptide antigen-major histocompatibility complex ligand. This primary event leads to polarized trafficking of receptors and signaling mediators associated with recycling endosomes to the cellular interface, which contributes to IS assembly as well as signal termination and favors information transfer from T cells to APCs. Here, we will review recent advances on the vesicular pathways implicated in IS assembly and maintenance, focusing on the spatiotemporal regulation of the traffic of specific receptors by Rab GTPases. Based on accumulating evidence that the IS is a functional homolog of the primary cilium, which coordinates several central signaling pathways in ciliated cells, we will also discuss the similarities in the mechanisms regulating vesicular trafficking to these specialized membrane domains.
PMCID: PMC4753310  PMID: 26913036
immune synapse; receptor trafficking; Rab GTPases; IFT; primary cilium
3.  EGFR kinase-dependent and kinase-independent roles in clear cell renal cell carcinoma 
Epidermal growth factor receptor (EGFR) is associated with progression of many epithelial malignancies and represents a significant therapeutic target. Although clear cell renal cell carcinoma (CCRCC) has been widely investigated for EGFR molecular alterations, genetic evidences of EGFR gene activating mutations and/or gene amplification have been rarely confirmed in the literature. Therefore, until now EGFR-targeted therapies in clinical trials have been demonstrated unsuccessful. New evidence has been given about the interactions between EGFR and the sodium glucose co-transporter-1 (SGLT1) in maintaining the glucose basal intracellular level to favour cancer cell growth and survival; thus a new functional role may be attributed to EGFR, regardless of its kinase activity. To define the role of EGFR in CCRCC an extensive investigation of genetic changes and functional kinase activities was performed in a series of tumors by analyzing the EGFR mutational status and expression profile, together with the protein expression of downstream signaling pathways members. Furthermore, we investigated the co-expression of EGFR and SGLT1 proteins and their relationships with clinic-pathological features in CCRCC. EGFR protein expression was identified in 98.4% of CCRCC. Furthermore, it was described for the first time that SGLT1 is overexpressed in CCRCC (80.9%), and that co-expression with EGFR is appreciable in 79.4% of the tumours. Moreover, the activation of downstream EGFR pathways was found in about 79.4% of SGLT1-positive CCRCCs. The mutational status analysis of EGFR failed to demonstrate mutations on exons 18 to 24 and the presence of EGFR-variantIII (EGFRvIII) in all CCRCCs analyzed. FISH analysis revealed absence of EGFR amplification, and high polysomy of chromosome 7. Finally, the EGFR gene expression profile showed gene overexpression in 38.2% of CCRCCs. Our study contributes to define the complexity of EGFR role in CCRCC, identifying its bivalent kinase-dependent and kinase-independent functions, both potentially involved in CCRCC progression. These results might have important implications on therapeutic approaches to CCRCC, since the disruption of the interaction between EGFR/SGLT1, mediated by anti-EGFR antibodies and/or SGLT1 inhibitors, might constitute a novel therapeutic target for CCRCC treatment, and new clinical trials should be evaluated on the basis of this therapeutic proposal.
PMCID: PMC4759398  PMID: 27073724
Clear cell renal cell carcinoma; EGFR; SGLT1; kinase-dependent EGFR function; kinase-independent EGFR function; pAKT; p-p44/42 MAPK; p-STAT3; EGFR-variantIII; FISH analysis
4.  Synthetic Flavonoids, Aminoisoflavones: Interaction and Reactivity with Metal-Free and Metal-Associated Amyloid-β Species 
Metal ion homeostasis in conjunction with amyloid-β (Aβ) aggregation in the brain has been implicated in Alzheimer’s disease (AD) pathogenesis. To uncover the interplay between metal ions and Aβ peptides, synthetic, multifunctional small molecules have been employed to modulate Aβ aggregation in vitro. Naturally occurring flavonoids have emerged as a valuable class of compounds for this purpose due to their ability to modulate both metal-free and metal-induced Aβ aggregation. Although, flavonoids have shown anti-amyloidogenic effects, the structural moieties of flavonoids responsible for such reactivity have not been fully identified. In order to understand the structure-interaction-reactivity relationship within the flavonoid family for metal-free and metal-associated Aβ, we designed, synthesized, and characterized a set of isoflavone derivatives, aminoisoflavones (1-4), that displayed reactivity (i.e., modulation of Aβ aggregation) in vitro. NMR studies revealed a potential binding site for aminoisoflavones between the N-terminal loop and central helix on prefibrillar Aβ different from the non-specific binding observed for other flavonoids. The absence or presence of the catechol group differentiated the binding affinities and enthalpy/entropy balance between aminoisoflavones and Aβ. Furthermore, having a catechol group influenced the binding mode with fibrillar Aβ. Inclusion of additional substituents moderately tuned the impact of aminoisoflavones on Aβ aggregation. Overall, through these studies, we obtained valuable insights on the requirements for parity among metal chelation, intermolecular interactions, and substituent variation for Aβ interaction.
PMCID: PMC4217218  PMID: 25383163
5.  Interaction of the N-(3-Methylpyridin-2-yl)amide Derivatives of Flurbiprofen and Ibuprofen with FAAH: Enantiomeric Selectivity and Binding Mode 
PLoS ONE  2015;10(11):e0142711.
Combined fatty acid amide hydrolase (FAAH) and cyclooxygenase (COX) inhibition is a promising approach for pain-relief. The Flu-AM1 and Ibu-AM5 derivatives of flurbiprofen and ibuprofen retain similar COX-inhibitory properties and are more potent inhibitors of FAAH than the parent compounds. However, little is known as to the nature of their interaction with FAAH, or to the importance of their chirality. This has been explored here.
Methodology/Principal Findings
FAAH inhibitory activity was measured in rat brain homogenates and in lysates expressing either wild-type or FAAHT488A-mutated enzyme. Molecular modelling was undertaken using both docking and molecular dynamics. The (R)- and (S)-enantiomers of Flu-AM1 inhibited rat FAAH with similar potencies (IC50 values of 0.74 and 0.99 μM, respectively), whereas the (S)-enantiomer of Ibu-AM5 (IC50 0.59 μM) was more potent than the (R)-enantiomer (IC50 5.7 μM). Multiple inhibition experiments indicated that both (R)-Flu-AM1 and (S)-Ibu-AM5 inhibited FAAH in a manner mutually exclusive to carprofen. Computational studies indicated that the binding site for the Flu-AM1 and Ibu-AM5 enantiomers was located between the acyl chain binding channel and the membrane access channel, in a site overlapping the carprofen binding site, and showed a binding mode in line with that proposed for carprofen and other non-covalent ligands. The potency of (R)-Flu-AM1 was lower towards lysates expressing FAAH mutated at the proposed carprofen binding area than in lysates expressing wild-type FAAH.
The study provides kinetic and structural evidence that the enantiomers of Flu-AM1 and Ibu-AM5 bind in the substrate channel of FAAH. This information will be useful in aiding the design of novel dual-action FAAH: COX inhibitors.
PMCID: PMC4643906  PMID: 26565710
6.  Characterisation of (R)-2-(2-Fluorobiphenyl-4-yl)-N-(3-Methylpyridin-2-yl)Propanamide as a Dual Fatty Acid Amide Hydrolase: Cyclooxygenase Inhibitor 
PLoS ONE  2015;10(9):e0139212.
Increased endocannabinoid tonus by dual-action fatty acid amide hydrolase (FAAH) and substrate selective cyclooxygenase (COX-2) inhibitors is a promising approach for pain-relief. One such compound with this profile is 2-(2-fluorobiphenyl-4-yl)-N-(3-methylpyridin-2-yl)propanamide (Flu-AM1). These activities are shown by Flu-AM1 racemate, but it is not known whether its two single enantiomers behave differently, as is the case towards COX-2 for the parent flurbiprofen enantiomers. Further, the effects of the compound upon COX-2-derived lipids in intact cells are not known.
Methodology/Principal Findings
COX inhibition was determined using an oxygraphic method with arachidonic acid and 2-arachidonoylglycerol (2-AG) as substrates. FAAH was assayed in mouse brain homogenates using anandamide (AEA) as substrate. Lipidomic analysis was conducted in unstimulated and lipopolysaccharide + interferon γ- stimulated RAW 264.7 macrophage cells. Both enantiomers inhibited COX-2 in a substrate-selective and time-dependent manner, with IC50 values in the absence of a preincubation phase of: (R)-Flu-AM1, COX-1 (arachidonic acid) 6 μM; COX-2 (arachidonic acid) 20 μM; COX-2 (2-AG) 1 μM; (S)-Flu-AM1, COX-1 (arachidonic acid) 3 μM; COX-2 (arachidonic acid) 10 μM; COX-2 (2-AG) 0.7 μM. The compounds showed no enantiomeric selectivity in their FAAH inhibitory properties. (R)-Flu-AM1 (10 μM) greatly inhibited the production of prostaglandin D2 and E2 in both unstimulated and lipopolysaccharide + interferon γ- stimulated RAW 264.7 macrophage cells. Levels of 2-AG were not affected either by (R)-Flu-AM1 or by 10 μM flurbiprofen, either alone or in combination with the FAAH inhibitor URB597 (1 μM).
Both enantiomers of Flu-AM1 are more potent inhibitors of 2-AG compared to arachidonic acid oxygenation by COX-2. Inhibition of COX in lipopolysaccharide + interferon γ- stimulated RAW 264.7 cells is insufficient to affect 2-AG levels despite the large induction of COX-2 produced by this treatment.
PMCID: PMC4583449  PMID: 26406890
7.  Long-Term Clinical Outcome after Treatment for High-Grade Cervical Lesions: A Retrospective Monoinstitutional Cohort Study 
BioMed Research International  2015;2015:984528.
Background. The aim of this retrospective observational study of women treated for cervical intraepithelial neoplasia grade 2 or worse (CIN2+) was to assess the long-term risk of residual/recurrent high-grade CIN. Materials and Methods. We evaluated 760 women treated by loop electrosurgical excision procedure (684) or conization (76) between 2000 and 2009, and followed up to June 30, 2014 (median follow-up 6.7 years, range 4–14). Visits every 6 months for the first year after treatment and yearly for up to the following 10 years included cytology, colposcopy when indicated, and HPV testing (search and typing). Results. CIN2+ or vaginal intraepithelial neoplasia grade 2 or worse (VAIN2+) was detected in 67 cases (8.8%), 39 at first follow-up and 28 after one/more negative visits. The risk of CIN2+ was higher in case of positive margins (odds ratio (OR) 8.04, 95% CI 4.31–15.0), type 3 transformation zone (OR for CIN3 27.7, 95% CI 2.07–36.9), CIN3+ excision (OR 6.02, 95% CI 1.73–20.9), and positive high-risk HPV test at first follow-up (OR for HPV16: 20.6, 95% CI 6.8–62.6; OR for other hrHPV types: 18.3, 95% CI 5.9–57.0). Conclusion. Residual/recurrent high-grade CIN occurred in <9% cases, and the risk was associated with transformation zone type, lesion grade, margins status, and hrHPV test result at 6–12 months of follow-up.
PMCID: PMC4477134  PMID: 26180819
8.  Critical role for prokineticin 2 in CNS autoimmunity 
To investigate the potential role of prokineticin 2 (PK2), a bioactive peptide involved in multiple biological functions including immune modulation, in CNS autoimmune demyelinating disease.
We investigated the expression of PK2 in mice with experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis (MS), and in patients with relapsing-remitting MS. We evaluated the biological effects of PK2 on expression of EAE and on development of T-cell response against myelin by blocking PK2 in vivo with PK2 receptor antagonists. We treated with PK2 immune cells activated against myelin antigen to explore the immune-modulating effects of this peptide in vitro.
Pk2 messenger RNA was upregulated in spinal cord and lymph node cells (LNCs) of mice with EAE. PK2 protein was expressed in EAE inflammatory infiltrates and was increased in sera during EAE. In patients with relapsing-remitting MS, transcripts for PK2 were significantly increased in peripheral blood mononuclear cells compared with healthy controls, and PK2 serum concentrations were significantly higher. A PK2 receptor antagonist prevented or attenuated established EAE in chronic and relapsing-remitting models, reduced CNS inflammation and demyelination, and decreased the production of interferon (IFN)-γ and interleukin (IL)-17A cytokines in LNCs while increasing IL-10. PK2 in vitro increased IFN-γ and IL-17A and reduced IL-10 in splenocytes activated against myelin antigen.
These data suggest that PK2 is a critical immune regulator in CNS autoimmune demyelination and may represent a new target for therapy.
PMCID: PMC4396530  PMID: 25884014
9.  HIV-1 Tat induces DNMT over-expression through microRNA dysregulation in HIV-related non Hodgkin lymphomas 
A close association between HIV infection and the development of cancer exists. Although the advent of highly active antiretroviral therapy has changed the epidemiology of AIDS-associated malignancies, a better understanding on how HIV can induce malignant transformation will help the development of novel therapeutic agents.
HIV has been reported to induce the expression of DNMT1 in vitro, but still no information is available about the mechanisms regulating DNMT expression in HIV-related B-cell lymphomas.
In this paper, we investigated the expression of DNMT family members (DNMT1, DNMT3a/b) in primary cases of aggressive B-cell lymphomas of HIV-positive subjects.
Our results confirmed the activation of DNMT1 by HIV in vivo, and reported for the first time a marked up-regulation of DNMT3a and DNMT3b in HIV-positive aggressive B-cell lymphomas. DNMT up-regulation in HIV-positive tumors correlated with down-regulation of specific microRNAs, as the miR29 family, the miR148-152 cluster, known to regulate their expression. Literature reports the activation of DNMTs by the human polyomavirus BKV large T-antigen and adenovirus E1a, through the pRb/E2F pathway. We have previously demonstrated that the HIV Tat protein is able to bind to the pocket proteins and to inactivate their oncosuppressive properties, resulting in uncontrolled cell proliferation. Therefore, we focused on the role of Tat, due to its capability to be released from infected cells and to dysregulate uninfected ones, using an in vitro model in which Tat was ectopically expressed in B-cells.
Our findings demonstrated that the ectopic expression of Tat was per se sufficient to determine DNMT up-regulation, based on microRNA down-regulation, and that this results in aberrant hypermethylation of target genes and microRNAs.
These results point at a direct role for Tat in participating in uninfected B-cell lymphomagenesis, through dysregulation of the epigenetical control of gene expression.
PMCID: PMC4334912  PMID: 25705251
HIV; Aggressive B-cell lymphomas; microRNAs; DNMTs; Tat
10.  The Epstein Barr-encoded BART-6-3p microRNA affects regulation of cell growth and immuno response in Burkitt lymphoma 
Burkitt lymphoma is an aggressive B-cell lymphoma presenting in three clinical forms: endemic, sporadic and immunodeficiency-associated. More than 90% of endemic Burkitt lymphoma carry latent Epstein-Barr virus, whereas only 20% of sporadic Burkitt lymphoma are associated with Epstein-Barr infection. Although the Epstein-Barr virus is highly related with the endemic form, how and whether the virus participates in its pathogenesis remains to be fully elucidated. In particular, the virus may impair cellular gene expression by its own encoded microRNAs.
Using microRNA profiling we compared Epstein-Barr-positive and Epstein-Barr-negative Burkitt lymphoma cases for both cellular and viral microRNAs. The array results were validated by qRT-PCR, and potential targets of viral microRNAs were then searched by bioinformatic predictions, and classified in functional categories, according to the Gene Ontology. Our findings were validated by in vitro functional studies and by immunohistochemistry on a larger series of cases.
We showed that a few cellular microRNAs are differentially expressed between Epstein-Barr-positive and Epstein-Barr-negative Burkitt lymphoma cases, and identified a subset of viral microRNAs expressed in Epstein-Barr-positive Burkitt lymphomas. Of these, we characterized the effects of viral BART6-3p on regulation of cellular genes. In particular, we analyzed the IL-6 receptor genes (IL-6Rα and IL-6ST), PTEN and WT1 expression for their possible relevance to Burkitt lymphoma. By means of immunohistochemistry, we observed a down-regulation of the IL-6 receptor and PTEN specifically in Epstein-Barr-positive Burkitt lymphoma cases, which may result in the impairment of key cellular pathways and may contribute to malignant transformation. On the contrary, no differences were observed between Epstein-Barr-positive and Epstein-Barr-negative Burkitt lymphoma cases for WT1 expression.
Our preliminary results point at an active role for the Epstein-Barr virus in Burkitt lymphomagenesis and suggest new possible mechanisms used by the virus in determining dysregulation of the host cell physiology.
PMCID: PMC4005456  PMID: 24731550
EBV; Burkitt lymphoma; MicroRNAs
11.  Language experience changes subsequent learning 
Cognition  2012;126(2):268-284.
What are the effects of experience on subsequent learning? We explored the effects of language-specific word order knowledge on the acquisition of sequential conditional information. Korean and English adults were engaged in a sequence learning task involving three different sets of stimuli: auditory linguistic (nonsense syllables), visual non-linguistic (nonsense shapes), and auditory non-linguistic (pure tones). The forward and backward probabilities between adjacent elements generated two equally probable and orthogonal perceptual parses of the elements, such that any significant preference at test must be due to either general cognitive biases, or prior language-induced biases. We found that language modulated parsing preferences with the linguistic stimuli only. Intriguingly, these preferences are congruent with the dominant word order patterns of each language, as corroborated by corpus analyses, and are driven by probabilistic preferences. Furthermore, although the Korean individuals had received extensive formal explicit training in English and lived in an English-speaking environment, they exhibited statistical learning biases congruent with their native language. Our findings suggest that mechanisms of statistical sequential learning are implicated in language across the lifespan, and experience with language may affect cognitive processes and later learning.
PMCID: PMC3800190  PMID: 23200510
Corpus analyses; Experience-dependent learning; Implicit learning; Linguistic typology; Prediction; Retrodiction; Second language acquisition; Sequential learning; Statistical learning; Transitional probabilities; Word order
12.  Inhibitory properties of ibuprofen and its amide analogues towards the hydrolysis and cyclooxygenation of the endocannabinoid anandamide 
A dual-action cyclooxygenase (COX) - fatty acid amide hydrolase (FAAH) inhibitor may have therapeutic usefulness as an analgesic, but a key issue is finding the right balance of inhibitory effects. This can be done by the design of compounds exhibiting different FAAH/COX inhibitory potencies. In the present study, eight ibuprofen analogues were investigated. Ibuprofen (1), 2-(4-Isobutylphenyl)-N-(2-(3-methylpyridin-2-ylamino)-2-oxoethyl)propanamide (9) and N-(3-methylpyridin-2-yl)-2-(4′-isobutylphenyl)propionamide (2) inhibited FAAH with IC50 values of 134, 3.6 and 0.52 μM respectively. The corresponding values for COX-1 were ~29, ~50 and ~60 μM, respectively. Using arachidonic acid as substrate, the compounds were weak inhibitors of COX-2. However, when anandamide was used as COX-2 substrate, potency increased, with approximate IC50 values of ~6, ~10 and ~19 μM, respectively. 2 was confirmed to be active in vivo in a murine model of visceral nociception, but the effects of the compound were not blocked by CB receptor antagonists.
PMCID: PMC3606911  PMID: 22225576
fatty acid amide hydrolase; cyclooxygenase; ibuprofen; analgesia; cannabinoid
13.  Novel 2-amino-isoflavones exhibit aryl hydrocarbon receptor agonist or antagonist activity in a species/cell-specific context 
Toxicology  2012;297(1-3):26-33.
The Aryl hydrocarbon receptor (AhR) mediates the induction of a variety of xenobiotic metabolism genes. Activation of the AhR occurs through binding to a group of structurally diverse compounds, most notably dioxins, which are exogenous ligands. Isoflavones are part of a family which include some well characterised endogenous AhR ligands. This paper analysed a novel family of these compounds, based on the structure of 2-amino-isoflavone. Initially two luciferase-based cell models, mouse H1L6.1c2 and human HG2L6.1c3, were used to identify whether the compounds had AhR agonistic and/or antagonistic properties. This analysis showed that some of the compounds were weak agonists in mouse and antagonists in human. Further analysis of two of the compounds, Chr-13 and Chr-19, was conducted using quantitative real-time PCR in rat H4IIE and human MCF-7 cells. The results indicated that Chr-13 was an agonist in rat but an antagonist in human cells. Chr-19 was shown to be an agonist in rat but more interestingly, a partial agonist in human. Luciferase induction results not only revealed that subtle differences in the structure of the compound could produce species-specific differences in response but also dictated the ability of the compound to be an AhR agonist or antagonist. Substituted 2-amino-isoflavones represent a novel group of AhR ligands that must differentially interact with the AhR ligand binding domain to produce their species-specific agonist or antagonist activity and future ligand binding analysis and docking studies with these compounds may provide insights into the differential mechanisms of action of structurally similar compounds.
PMCID: PMC3515069  PMID: 22507882
Aryl hydrocarbon receptor; AhR; dioxin; isoflavone; species-specific
14.  Similar Neural Correlates for Language and Sequential Learning: Evidence from Event-Related Brain Potentials 
Language and cognitive processes  2011;27(2):231-256.
We used event-related potentials (ERPs) to investigate the time course and distribution of brain activity while adults performed (a) a sequential learning task involving complex structured sequences, and (b) a language processing task. The same positive ERP deflection, the P600 effect, typically linked to difficult or ungrammatical syntactic processing, was found for structural incongruencies in both sequential learning as well as natural language, and with similar topographical distributions. Additionally, a left anterior negativity (LAN) was observed for language but not for sequential learning. These results are interpreted as an indication that the P600 provides an index of violations and the cost of integration of expectations for upcoming material when processing complex sequential structure. We conclude that the same neural mechanisms may be recruited for both syntactic processing of linguistic stimuli and sequential learning of structured sequence patterns more generally.
PMCID: PMC3652480  PMID: 23678205
Event-Related Potentials (ERP); Sequential Learning; Implicit Learning; Language Processing; Prediction; P600; LAN
15.  Prokineticin Receptor 1 Antagonist PC-10 as a Biomarker for Imaging Inflammatory Pain 
Prokineticin receptor 1 (PKR1) and its ligand Bv8 were shown to be expressed in inflammation-induced pain and by tumor-supporting fibroblasts. Blocking this receptor might prove useful for reducing pain and for cancer therapy. However, there is no method to quantify the levels of these receptors in vivo.
A nonpeptidic PKR1 antagonist, N-{2-[5-(4-fluoro-benzyl)-1-(4-methoxy-benzyl)-4,6-dioxo-1,4,5,6-tetrahydro-[1,3,5] triazin-2-ylamino]-ethyl}-guanidine, which contains a free guanidine group, was labeled with 18F by reacting the guanidine function with N-succinimidyl-4-18F-fluorobenzoate to give the guanidinyl amide N-(4-18F-fluoro-benzoyl)-N′-{2-[5-(4-fluoro-benzyl)-1-(4-methoxy-benzyl)-4,6-dioxo-1,4,5,6-tetrahydro-[1,3,5] triazin-2-ylamino]-ethyl}-guanidine (18F-PC-10). Inflammation was induced in C57BL/6 mice by subcutaneous injection of complete Freund adjuvant in the paw. The mice were imaged with 18F-PC-10, 18F-FDG, and 64Cu-pyruvaldehyde bis(4-methyl-3-thiosemicarbazone) (64Cu-PTSM) at 24 h after complete Freund adjuvant injection using a small-animal PET device.
18F-PC-10 was synthesized with a radiochemical yield of 16% ± 3% (decay-corrected). 18F-PC-10 accumulated specifically in the inflamed paw 4- to 5-fold more than in the control paw. Compared with 18F-PC-10, 18F-FDG and 64Cu-PTSM displayed higher accumulation in the inflamed paw but also had higher accumulation in the control paw, demonstrating a reduced signal-to-background ratio. 18F-PC-10 also accumulated in PKR1-expressing organs, such as the salivary gland and gastrointestinal tract.
18F-PC-10 can be used to image PKR1, a biomarker of the inflammation process. However, the high uptake of 18F-PC-10 in the gastrointestinal tract, due to specific uptake and the metabolic processing of this highly lipophilic molecule, would restrict its utility.
PMCID: PMC3629974  PMID: 21421710
prokineticin receptor; inflammation; positron emission tomography (PET); 18F
16.  Autocrine production of IL-11 mediates tumorigenicity in hypoxic cancer cells 
The Journal of Clinical Investigation  2013;123(4):1615-1629.
IL-11 and its receptor, IL-11Ra, are expressed in human cancers; however, the functional role of IL-11 in tumor progression is not known. We found that IL11 is a hypoxia-inducible, VHL-regulated gene in human cancer cells and that expression of IL11 mRNA was dependent, at least in part, on HIF-1. A cooperative interaction between HIF-1 and AP-1 mediated transcriptional activation of the IL11 promoter. Additionally, we found that human cancer cells expressed a functional IL-11Ra subunit, which triggered signal transduction either by exogenous recombinant human IL-11 or by autocrine production of IL-11 in cells cultured under hypoxic conditions. Silencing of IL11 dramatically abrogated the ability of hypoxia to increase anchorage-independent growth and significantly reduced tumor growth in xenograft models. Notably, these results were phenocopied by partial knockdown of STAT1 in a human prostate cancer cell line (PC3), suggesting that this pathway may play an important role in mediating the effects of IL-11 under hypoxic conditions. In conclusion, these results identify IL11 as an oxygen- and VHL-regulated gene and provide evidence of a pathway “hijacked” by hypoxic cancer cells that may contribute to tumor progression.
PMCID: PMC3613900  PMID: 23549086
17.  Epstein-Barr nuclear antigen 1 induces expression of the cellular microRNA hsa-miR-127 and impairing B-cell differentiation in EBV-infected memory B cells. New insights into the pathogenesis of Burkitt lymphoma 
Blood Cancer Journal  2012;2(8):e84-.
Epstein-Barr Virus (EBV) is a γ-herpesvirus that infects >90% of the human population. Although EBV persists in its latent form in healthy carriers, the virus is also associated with several human cancers. EBV is strongly associated with Burkitt lymphoma (BL), even though there is still no satisfactory explanation of how EBV participates in BL pathogenesis. However, new insights into the interplay between viruses and microRNAs (miRNAs) have recently been proposed. In particular, it has been shown that B-cell differentiation in EBV-positive BL is impaired at the post-transcriptional level by altered expression of hsa-miR-127. Here, we show that the overexpression of hsa-miR-127 is due to the presence of the EBV-encoded nuclear antigen 1 (EBNA1) and give evidence of a novel mechanism of direct regulation of the human miRNA by this viral product. Finally, we show that the combinatorial expression of EBNA1 and hsa-miR-127 affects the expression of master B-cell regulators in human memory B cells, confirming the scenario previously observed in EBV-positive BL primary tumors and cell lines. A good understanding of these mechanisms will help to clarify the complex regulatory networks between host and pathogen, and favor the design of more specific treatments for EBV-associated malignancies.
PMCID: PMC3432484  PMID: 22941339
Epstein-Barr virus; microRNAs; Burkitt lymphoma
18.  Learn Locally, Act Globally: Learning Language from Variation Set Cues 
Cognition  2008;109(3):423-430.
Variation set structure — partial overlap of successive utterances in child-directed speech — has been shown to correlate with progress in children’s acquisition of syntax. We demonstrate the benefits of variation set structure directly: in miniature artificial languages, arranging a certain proportion of utterances in a training corpus in variation sets facilitated word and phrase constituent learning in adults. Our findings have implications for understanding the mechanisms of L1 acquisition by children, and for the development of more efficient algorithms for automatic language acquisition, as well as better methods for L2 instruction.
PMCID: PMC3164301  PMID: 19019350
19.  Alteration of MicroRNAs Regulated by c-Myc in Burkitt Lymphoma 
PLoS ONE  2010;5(9):e12960.
Burkitt lymphoma (BL) is an aggressive B-cell lymphoma, with a characteristic clinical presentation, morphology and immunophenotype. Over the past years, the typical translocation t(8;14) and its variants have been considered the molecular hallmark of this tumor. However, BL cases with no detectable MYC rearrangement have been identified. Intriguingly, these cases express MYC at levels comparable with cases carrying the translocation. In normal cells c-Myc expression is tightly regulated through a complex feedback loop mechanism. In cancer, MYC is often dysregulated, commonly due to genomic abnormalities. It has recently emerged that this phenomenon may rely on an alteration of post-transcriptional regulation mediated by microRNAs (miRNAs), whose functional alterations are associated with neoplastic transformation. It is also emerging that c-Myc modulates miRNA expression, revealing an intriguing crosstalk between c-Myc and miRNAs.
Principal Findings
Here, we investigated the expression of miRNAs possibly regulated by c-Myc in BL cases positive or negative for the translocation. A common trend of miRNA expression, with the exception of hsa-miR-9*, was observed in all of the cases. Intriguingly, down-regulation of this miRNA seems to specifically identify a particular subset of BL cases, lacking MYC translocation. Here, we provided evidence that hsa-miR-9-1 gene is heavily methylated in those cases. Finally, we showed that hsa-miR-9* is able to modulate E2F1 and c-Myc expression.
Particularly, this study identifies hsa-miR-9* as potentially relevant for malignant transformation in BL cases with no detectable MYC translocation. Deregulation of hsa-miR-9* may therefore be useful as a diagnostic tool, suggesting it as a promising novel candidate for tumor cell marker.
PMCID: PMC2945769  PMID: 20930934
21.  The Secret Is in the Sound 
Developmental science  2009;12(3):388-395.
When learning language young children are faced with many seemingly formidable challenges, including discovering words embedded in a continuous stream of sounds and determining what role these words play in syntactic constructions. We suggest that knowledge of phoneme distributions may play a crucial part in helping children segment words and determine their lexical category, and propose an integrated model of how children might go from unsegmented speech to lexical categories. We corroborated this theoretical model using a two-stage computational analysis of a large corpus of English child-directed speech. First, we used transition probabilities between phonemes to find words in unsegmented speech. Second, we used distributional information about word edges—the beginning and ending phonemes of words—to predict whether the segmented words from the first stage were nouns, verbs, or something else. The results indicate that discovering lexical units and their associated syntactic category in child-directed speech is possible by attending to the statistics of single phoneme transitions and word-initial and final phonemes. Thus, we suggest that a core computational principle in language acquisition is that the same source of information is used to learn about different aspects of linguistic structure.
PMCID: PMC2743257  PMID: 19371361
22.  Development of HIF-1 Inhibitors for Cancer Therapy 
Intratumor hypoxia has long been considered a driving force of tumor progression and a negative prognostic factor in human cancers. The discovery of hypoxia inducible factors (HIFs), which mediate transcriptional responses to changes in oxygen levels, has renewed enthusiasm for the discovery and development of targeted therapies exploiting the hypoxic tumor microenvironment. In spite of an ever increasing number of putative small molecule inhibitors of HIF, only few are progressing through preclinical and early clinical development. In this review, we will focus primarily on: 1) HIF inhibitors that have been more recently described and 2) small molecules targeting HIF that are being tested in early clinical trials or that are already approved for use in patients. A rigorous “validation” of HIF targeted therapies in relevant preclinical models and eventually in pharmacodynamic-based early clinical trials is essential for “credentialing” HIF-1 as a legitimate target that can be pharmacologically modulated in cancer patients.
PMCID: PMC2832082  PMID: 19674190
HIF-1; hypoxia; cancer therapy
23.  The case for the development of novel analgesic agents targeting both fatty acid amide hydrolase and either cyclooxygenase or TRPV1 
British Journal of Pharmacology  2009;156(3):412-419.
Although the dominant approach to drug development is the design of compounds selective for a given target, compounds targeting more than one biological process may have superior efficacy, or alternatively a better safety profile than standard selective compounds. Here, this possibility has been explored with respect to the endocannabinoid system and pain. Compounds inhibiting the enzyme fatty acid amide hydrolase (FAAH), by increasing local endocannabinoid tone, produce potentially useful effects in models of inflammatory and possibly neuropathic pain. Local increases in levels of the endocannabinoid anandamide potentiate the actions of cyclooxygenase inhibitors, raising the possibility that compounds inhibiting both FAAH and cyclooxygenase can be as effective as non-steroidal anti-inflammatory drugs but with a reduced cyclooxygenase inhibitory ‘load’. An ibuprofen analogue active in models of visceral pain and with FAAH and cyclooxygenase inhibitory properties has been identified. Another approach, built in to the experimental analgesic compound N-arachidonoylserotonin, is the combination of FAAH inhibitory and transient receptor potential vanilloid type 1 antagonist properties. Although finding the right balance of actions upon the two targets is a key to success, it is hoped that dual-action compounds of the types illustrated in this review will prove to be useful analgesic drugs.
PMCID: PMC2697682  PMID: 19226258
endocannabinoid; anandamide; fatty acid amide hydrolase; cyclooxygenase; non-steroidal anti-inflammatory drugs; transient receptor potential vanilloid type 1; inflammatory pain
24.  Development of HIF-1 inhibitors for cancer therapy 
Intratumour hypoxia has long been considered a driving force of tumour progression and a negative prognostic factor in human cancers. The discovery of hypoxia inducible factors (HIFs), which mediate transcriptional responses to changes in oxygen levels, has renewed enthusiasm for the discovery and development of targeted therapies exploiting the hypoxic tumour microenvironment. In spite of an ever increasing number of putative small molecule inhibitors of HIF, only few progress through pre-clinical and early clinical development. In this review, we will focus primarily on: (1) HIF inhibitors that have been more recently described and (2) small molecules targeting HIF that are being tested in early clinical trials or that are already approved for use in patients. A rigorous ‘validation’ of HIF targeted therapies in relevant pre-clinical models and eventually in pharmacodynamic-based early clinical trials is essential for ‘credentialing’ HIF-1 as a legitimate target that can be pharmacologically modulated in cancer patients.
PMCID: PMC2832082  PMID: 19674190
HIF-1; hypoxia; cancer therapy
25.  Effect of Lysine at C-Terminus of the Dmt-Tic Opioid Pharmacophore 
Journal of medicinal chemistry  2006;49(18):5610-5617.
Substitution of Gly with side-chain protected or unprotected Lys in lead compounds containing the opioid pharmacophore Dmt-Tic [H-Dmt-Tic-Gly-NH-CH2-Ph, μ agonist / δ antagonist; H-Dmt-Tic-Gly-NH-Ph, μ agonist / δ agonist and H-Dmt-Tic-NH-CH2-Bid, δ agonist (Bid = 1H-benzimidazole-2-yl)] yielded a new series of compounds endowed with distinct pharmacological activities. Compounds (1-10) included high δ- (Kiδ = 0.068-0.64 nM) and μ-opioid affinities (Kiδ = 0.13-5.50 nM) with a bioactivity that ranged from μ-opioid agonism {10, H-Dmt-Tic-NH-CH[(CH2)4-NH2]-Bid (IC50 GPI = 39.7 nM)} to a selective μ-opioid antagonist [3, H-Dmt-Tic-Lys-NH-CH2-Ph (pA2μ = 7.96)] and a selective δ-opioid antagonist [5, H-Dmt-Tic-Lys(Ac)-NH-Ph (pA2δ = 12.0)]. The presence of a Lys linker provides new lead compounds in the formation of opioid peptidomimetics containing the Dmt-Tic pharmacophore with distinct agonist and / or antagonist properties.
PMCID: PMC2533050  PMID: 16942034

Results 1-25 (26)