Exploring the Immunomodulatory Potential of Pancreatic Cancer-Derived Extracellular Vesicles through Proteomic and Functional Analyses

Pancreatic cancer (PC) has a poor prognosis and displays resistance to immunotherapy. A better understanding of tumor-derived extracellular vesicle (EV) effects on immune responses might contribute to improved immunotherapy. EVs derived from Capan-2 and BxPC-3 PC cells isolated by ultracentrifugation were characterized by atomic force microscopy, Western blot (WB), nanoparticle tracking analysis, and label-free proteomics. Fresh PBMCs from healthy donors were treated with PC- or control-derived heterologous EVs, followed by flow cytometry analysis of CD8+ and CD4+ lymphocytes. The proteomics of lymphocytes sorted from EV-treated or untreated PBMCs was performed, and the IFN-γ concentration was measured by ELISA. Notably, most of the proteins identified in Capan-2 and BxPC-3 EVs by the proteomic analysis were connected in a single functional network (p = 1 × 10-16) and were involved in the "Immune System" (FDR: 1.10 × 10-24 and 3.69 × 10-19, respectively). Interestingly, the treatment of healthy donor-derived PBMCs with Capan-2 EVs but not with BxPC-3 EVs or heterologous control EVs induced early activation of CD8+ and CD4+ lymphocytes. The proteomics of lymphocytes sorted from EV-treated PBMCs was consistent with their activation by Capan-2 EVs, indicating IFN-γ among the major upstream regulators, as confirmed by ELISA. The proteomic and functional analyses indicate that PC-EVs have pleiotropic effects, and some may activate early immune responses, which might be relevant for the development of highly needed immunotherapeutic strategies in this immune-cold tumor.

Human cytomegalovirus infection enhances 5‑lipoxygenase and cycloxygenase‑2 expression in colorectal cancer

Colorectal cancer (CRC) is one of the most common and fatal types of cancer. Inflammation promotes CRC development, however, the underlying etiological factors are unknown. Human cytomegalovirus (HCMV), a virus that induces inflammation and other cancer hallmarks, has been detected in several types of malignancy, including CRC. The present study investigated whether HCMV infection was associated with expression of the pro‑inflammatory enzymes 5‑lipoxygenase (5‑LO) and cyclooxygenase‑2 (COX‑2) and other molecular, genetic and clinicopathological CRC features. The present study assessed 146 individual paraffin‑embedded CRC tissue microarray (TMA) cores already characterized for TP53 and KRAS mutations, microsatellite instability (MSI) status, Ki‑67 index and EGFR by immunohistochemistry (IHC). The cores were further analyzed by IHC for the expression of two HCMV proteins (Immediate Early, IE and pp65) and the inflammatory markers 5‑LO and COX‑2. The CRC cell lines Caco‑2 and LS‑174T were infected with HCMV strain VR1814, treated with antiviral drug ganciclovir (GCV) and/or anti‑inflammatory drug celecoxib (CCX) and analyzed by reverse transcription‑quantitative PCR and immunofluorescence for 5‑LO, COX‑2, IE and pp65 transcripts and proteins. HCMV IE and pp65 proteins were detected in ~90% of the CRC cases tested; this was correlated with COX‑2, 5‑LO and KI‑67 expression, but not with EGFR immunostaining, TP53 and KRAS mutations or MSI status. In vitro, HCMV infection upregulated 5‑LO and COX‑2 transcript and proteins in both Caco‑2 and LS‑174T cells and enhanced cell proliferation as determined by MTT assay. Treatment with GCV and CCX significantly decreased the transcript levels of COX‑2, 5‑LO, HCMV IE and pp65 in infected cells. HCMV was widely expressed in CRC and may promote inflammation and serve as a potential new target for CRC therapy.

Flow Cytometry Detection of Anthracycline-Treated Breast Cancer Cells: An Optimized Protocol

The use of anthracycline derivatives was approved for the treatment of a broad spectrum of human tumors (i.e., breast cancer). The need to test these drugs on cancer models has pushed the basic research to apply many types of in vitro assays, and, among them, the study of anthracycline-induced apoptosis was mainly based on the application of flow cytometry protocols. However, the chemical structure of anthracycline derivatives gives them a strong autofluorescence effect that must be considered when flow cytometry is used. Unfortunately, the guidelines on the analysis of anthracycline effects through flow cytometry are lacking. Therefore, in this study, we optimized the flow cytometry detection of doxorubicin and epirubicin-treated breast cancer cells. Their autofluorescence was assessed both by using conventional and imaging flow cytometry; we found that all the channels excited by the 488 nm laser were affected. Anthracycline-induced apoptosis was then measured via flow cytometry using the optimized setting. Consequently, we established a set of recommendations that enable the development of optimized flow cytometry settings when the in vitro assays of anthracycline effects are analyzed, with the final aim to reveal a new perspective on the use of those in vitro tests for the further implementation of precision medicine strategies in cancer.

High Blood Concentration of Leukocyte-Derived Extracellular Vesicles Is Predictive of Favorable Clinical Outcomes in Patients with Pancreatic Cancer: Results from a Multicenter Prospective Study

Simple Summary

Blood-circulating extracellular vesicles (EVs) are emerging as key players to develop novel liquid biopsy-based approaches in cancer, including pancreatic cancer. In this study, we aimed to explore the prognostic and predictive value of blood-circulating extracellular vesicles released by immune cells in patients with pancreatic cancer. A recently patented flow cytometry protocol was applied for the identification and phenotypical characterization of blood-circulating EVs in a cohort of 56 patients with pancreatic cancer (PC) and in a group of 48 healthy controls. We observed an increased blood concentration of leukocyte-derived EVs (CD45+) and PD-L1+ EVs in patients with PC as compared to healthy controls. Intriguingly, a high blood concentration of leukocyte-derived EVs identified PC patients with a good prognosis and improved clinical outcomes. This study revealed the promising role of EVs released by immune cells as a source of candidate biomarkers in patients with pancreatic cancer.

Abstract

Pancreatic cancer (PC) is one of the leading causes of cancer-related death worldwide. Identification of novel tumor biomarkers is highly advocated in PC to optimize personalized treatment algorithms. Blood-circulating extracellular vesicles hold promise for liquid biopsy application in cancer. We used an optimized flow cytometry protocol to study leukocyte-derived EVs (CD45+) and PD-L1+ EVs in blood from 56 pancreatic cancer patients and 48 healthy controls (HCs). Our results show that PC patients presented higher blood levels of total EVs (p = 0.0003), leukocyte-derived EVs (LEVs) (p = 0.001) and PD-L1+ EVs (p = 0.01), as compared with HCs. Interestingly, a blood concentration of LEVs at baseline was independently associated with improved overall survival in patients with borderline resectable or primary unresectable PC (HR = 0.17; 95% CI 0.04–0.79; p = 0.02). Additionally, increased blood-based LEVs were independently correlated with prolonged progression-free survival (HR = 0.10; 95% CI 0.01–0.82; p = 0.03) and significantly associated with higher disease control rate (p = 0.02) in patients with advanced PC receiving standard chemotherapy. Notably, a strong correlation between a decrease in blood LEVs concentration during chemotherapy and disease control was observed (p = 0.005). These intriguing findings point to the potential of LEVs as novel blood-based EV biomarkers for improved personalized medicine in patients affected by PC.

Repurposing the Veterinary Antibiotic Apramycin for Antibacterial and Antibiofilm Activity Against Pseudomonas aeruginosa From Cystic Fibrosis Patients

Objectives:

To evaluate the in vitro antibacterial, antibiofilm, and antivirulence activities of apramycin, comparatively to tobramycin, against a set of P. aeruginosa from chronically infected cystic fibrosis (CF) patients.

Methods

The activity of antibiotics against planktonic cells was assessed by performing MIC, MBC, and time-kill assays. The activity against mature biofilms was evaluated, in a microtiter plate, both in terms of dispersion (crystal violet assay) and residual viability (viable cell count). The effect of drug exposure on selected P. aeruginosa virulence genes expression was assessed by real-time Reverse Transcription quantitative PCR (RT-qPCR).

Results

Apramycin MIC₉₀ and MBC₉₀ values were found at least fourfold lower than those for tobramycin. A comparable trend was observed for mucoid strains. Only 4 out of 24 strains (16.6%) showed an apramycin MIC higher than the epidemiological cut-off value of 64 mg/L, whereas a higher resistance rate was observed for tobramycin (62.5%; p < 0.01 vs. apramycin). In time-kill analyses, both aminoglycosides were found bactericidal, although apramycin showed a more rapid effect and did not allow for regrowth. Apramycin generally stimulated biofilm biomass formation, whereas tobramycin showed opposite trends depending on the strain tested. Both drugs caused a highly significant, dose-dependent reduction of biofilm viability, regardless of strain and concentration tested. The exposure to apramycin and tobramycin caused increased expression of mexA and mexC (multidrug efflux pumps), whereas tobramycin specifically increased the expression of aprA (alkaline protease) and toxA (exotoxin A). Neither apramycin nor tobramycin showed cytotoxic potential toward IB3-1 bronchial epithelial CF cells.

Conclusion

Our results warrant future pharmacokinetic and pharmacodynamic studies for supporting the rationale to repurpose apramycin, a veterinary aminoglycoside, for CF lung infections.

Hormonal Regulation of the MHC Class I Gene in Thyroid Cells: Role of the Promoter "Tissue-Specific" Region

In previous studies we have demonstrated that the expression of the Major Histocompatibility Complex (MHC) class I gene in thyrocytes is controlled by several hormones, growth factors, and drugs. These substances mainly act on two regions of the MHC class I promoter a "tissue-specific" region (-800 to -676 bp) and a "hormone/cytokines-sensitive" region (-500 to -68 bp). In a previous study, we have shown that the role of the "tissue-specific" region in the MHC class I gene expression is dominant compared to that of the "hormone/cytokines-sensitive" region. In the present report we further investigate the dominant role of the "tissue-specific" region evaluating the effect of thyroid stimulating hormone (TSH), methimazole (MMI), phenylmethimazole (C10), glucose and thymosin-α1. By performing experiments of electrophoretic mobility shift assays (EMSAs) we show that TSH, MMI and C10, which inhibit MHC class I expression, act on the "tissue-specific" region increasing the formation of a silencer complex. Glucose and thymosin-α1, which stimulate MHC class I expression, act decreasing the formation of this complex. We further show that the silencer complex is formed by two distinct members of the transcription factors families activator protein-1 (AP-1) and nuclear factor-kB (NF-kB), c-jun and p65, respectively. These observations are important in order to understand the regulation of MHC class I gene expression in thyroid cells and its involvement in the development of thyroid autoimmunity.

Evolutionarily-Related Helicobacter pylori Genotypes and Gastric Intraepithelial Neoplasia in a High-Risk Area of Northern Italy

Helicobacter pylori (Hp) is the major recognized risk factor for non-cardia gastric cancer (GC), but only a fraction of infected subjects develop GC, thus GC risk might reflect other genetic/environmental cofactors and/or differences in virulence among infectious Hp strains. Focusing on a high GC risk area of Northern Italy (Cremona, Lombardy) and using archived paraffin-embedded biopsies, we investigated the associations between the Hp vacA and cagA genotype variants and gastric intraepithelial neoplasia (GIN, 33 cases) versus non-neoplastic gastroduodenal lesions (NNGDLs, 37 cases). The glmM gene and the cagA and vacA (s and m) genotypes were determined by polymerase chain reaction (PCR) and sequencing. Hp was confirmed in 37/37 (100%) NNGDLs and detected in 9/33 GINs (27%), consistently with the well-known Hp loss in GC. CagA was detected in 4/9 Hp-positive GINs and in 29/37 NNGDLs. The vacA s1a and m1 subtypes were more common in GINs than in NNGDLs (6/7 vs. 12/34, p=0.014, for s1a; 7/7 vs. 18/34, p=0.020 for m1), with significant vacA s genotype-specific variance. The GIN-associated vacA s1a sequences clustered together, suggesting that aggressive Hp strains from a unique founder contribute to GC in the high-risk area studied.

The Benzimidazole-Based Anthelmintic Parbendazole: A Repurposed Drug Candidate That Synergizes with Gemcitabine in Pancreatic Cancer

Pancreatic cancer (PC) is one of the most lethal, chemoresistant malignancies and it is of paramount importance to find more effective therapeutic agents. Repurposing of non-anticancer drugs may expand the repertoire of effective molecules. Studies on repurposing of benzimidazole-based anthelmintics in PC and on their interaction with agents approved for PC therapy are lacking. We analyzed the effects of four Food and Drug Administration (FDA)-approved benzimidazoles on AsPC-1 and Capan-2 pancreatic cancer cell line viability. Notably, parbendazole was the most potent benzimidazole affecting PC cell viability, with half maximal inhibitory concentration (IC₅₀) values in the nanomolar range. The drug markedly inhibited proliferation, clonogenicity and migration of PC cell lines through mechanisms involving alteration of microtubule organization and formation of irregular mitotic spindles. Moreover, parbendazole interfered with cell cycle progression promoting G2/M arrest, followed by the emergence of enlarged, polyploid cells. These abnormalities, suggesting a mitotic catastrophe, culminated in PC cell apoptosis, are also associated with DNA damage in PC cell lines. Remarkably, combinations of parbendazole with gemcitabine, a drug employed as first-line treatment in PC, synergistically decreased PC cell viability. In conclusion, this is the first study providing evidence that parbendazole as a single agent, or in combination with gemcitabine, is a repurposing candidate in the currently dismal PC therapy.

Novel Phenyldiazenyl Fibrate Analogues as PPAR α/γ/δ Pan-Agonists for the Amelioration of Metabolic Syndrome

The development of PPARα/γ dual or PPARα/γ/δ pan-agonists could represent an efficacious approach for a simultaneous pharmacological intervention on carbohydrate and lipid metabolism. Two series of new phenyldiazenyl fibrate derivatives of GL479, a previously reported PPARα/γ dual agonist, were synthesized and tested. Compound 12a was identified as a PPAR pan-agonist with moderate and balanced activity on the three PPAR isoforms (α, γ, δ). Moreover, docking experiments showed that 12a adopts a different binding mode in PPARγ compared to PPARα or PPARδ, providing a structural basis for further structure-guided design of PPAR pan-agonists. The beneficial effects of 12a were evaluated both in vitro, on the expression of PPAR target key metabolic genes, and ex vivo in two rat tissue inflammatory models. The obtained results allow considering this compound as an interesting lead for the development of a new class of PPAR pan-agonists endowed with an activation profile exploitable for therapy of metabolic syndrome.

A Developmental Perspective on Paragangliar Tumorigenesis

In this review, we propose that paraganglioma is a fundamentally organized, albeit aberrant, tissue composed of neoplastic vascular and neural cell types that share a common origin from a multipotent mesenchymal-like stem/progenitor cell. This view is consistent with the pseudohypoxic footprint implicated in the molecular pathogenesis of the disease, is in harmony with the neural crest origin of the paraganglia, and is strongly supported by the physiological model of carotid body hyperplasia. Our immunomorphological and molecular studies of head and neck paragangliomas demonstrate in all cases relationships between the vascular and the neural tumor compartments, that share mesenchymal and immature vasculo-neural markers, conserved in derived cell cultures. This immature, multipotent phenotype is supported by constitutive amplification of NOTCH signaling genes and by loss of the microRNA-200s and -34s, which control NOTCH1, ZEB1, and PDGFRA in head and neck paraganglioma cells. Importantly, the neuroepithelial component is distinguished by extreme mitochondrial alterations, associated with collapse of the ΔΨm. Finally, our xenograft models of head and neck paraganglioma demonstrate that mesenchymal-like cells first give rise to a vasculo-angiogenic network, and then self-organize into neuroepithelial-like clusters, a process inhibited by treatment with imatinib.

Germline TP53 mutation spectrum in Sudanese premenopausal breast cancer patients: correlations with reproductive factors

Purpose

The role of non-genetic factors as modifiers of TP53-related hereditary breast cancer (BC) risk is debated. In this regard, little is known about the impact of germline TP53 mutations on BC in sub-Saharan Africa, where the disease often presents in non-contraceptive multiparous premenopausal women with extended history of breastfeeding. Herein, we report the germline TP53 mutations found in a series of 92 Sudanese premenopausal BC patients characterized for reproductive history.

Methods

The entire TP53 coding sequence, including intron–exon boundaries and UTRs, was analyzed via DHPLC and direct sequencing, and the association of TP53 genotypes with BC risk and with individual lifetime exposures to reproductive factors was investigated with statistical tools.

Results

The germline TP53 mutation spectrum comprised 20 variants, 15 in the non-coding and 5 in the coding region. The latter included a deleterious missense mutation, c.817C>T (p.Arg273Cys), in a unique patient, and the common and functionally relevant coding polymorphism at amino acid 72 [Pro72Arg (rs1042522)]. The non-coding mutations included c.919+1G>A, a known deleterious splice site mutation, also in a unique patient. Notably, the 2 carriers of deleterious TP53 mutations clustered in the subset of cases with stronger reproductive history relative to childbearing age. When analyzed in comparison to population controls, the codon 72 polymorphism did not reveal associations with BC.

Conclusions

Our study suggests that the codon 72 Arg>Pro polymorphism is not implicated in premenopausal BC susceptibility, whereas multiparity and breastfeeding might be BC risk factors for carriers of deleterious TP53 mutations.

Electronic supplementary material

The online version of this article (10.1007/s10549-019-05168-1) contains supplementary material, which is available to authorized users.

Effects of dichloroacetate as single agent or in combination with GW6471 and metformin in paraganglioma cells

Paragangliomas (PGLs) are infiltrating autonomic nervous system tumors that cause important morbidity. At present, surgery is the only effective therapeutic option for this rare tumor. Thus, new agents for PGL treatment should be identified. Using unique PGL cell models established in our laboratory, we evaluated the effect of dichloroacetate (DCA) as single agent or in a novel combination with other metabolic drugs, including GW6471 and metformin. DCA and metformin had not been tested before in PGL. DCA reduced PGL cell viability and growth through mechanisms involving reactivation of PDH complex leading to promotion of oxidative metabolism, with lowering of lactate and enhanced ROS production. This resulted in cell cycle inhibition and induction of apoptosis in PGL cells, as shown by flow cytometry and immunoblot analyses. Moreover, DCA drastically impaired clonogenic activity and migration of PGL cells. Also metformin reduced PGL cell viability as single agent and the combinations of DCA, GW6471 and metformin had strong effects on cell viability. Furthermore, combined treatments had drastic and synergistic effects on clonogenic ability. In conclusion, DCA, GW6471 and metformin as single agents and in combination appear to have promising antitumor effects in unique cell models of PGL.

Myroides odoratimimus Forms Structurally Complex and Inherently Antibiotic-Resistant Biofilm in a Wound-Like in vitro Model

Myroides odoratimimus is an aerobic, non-fermenting Gram-negative multidrug-resistant bacterium widely distributed in nature that rarely causes infections in immunocompromised patients. We recently described in a diabetic patient a case of recurrent calcaneal ulcer infection caused by a M. odoratimimus strain showing potential for biofilm formation. For the first time, we therefore evaluated the ability of M. odoratimimus to form biofilm under different pH values and glucose concentrations using an in vitro “skin-like” model, and its susceptibility to levofloxacin, meropenem, and tigecycline. The expression of some antibiotic-resistance related genes was also monitored by RT-PCR during planktonic-to-biofilm transition. Our results indicated that M. odoratimimus can produce relevant amounts of biofilm biomass, in a time-dependent manner, especially at acidic pH and regardless of glucose concentration tested. The comparative analysis of MIC and MBC values between planktonic and sessile cells showed that resistance to antibiotics increased during the planktonic-to-biofilm transition. Viable cell count indicated that none of the tested antibiotics were able to completely eradicate preformed biofilms, although meropenem and levofloxacin were the most active causing a significant, dose-independent, reduction of biofilm's viability, as also confirmed by microscopic analysis. RT-PCR showed that antibiotic-resistance related gyrA and acrB genes are over-expressed during the transition from planktonic to sessile (biofilm) lifestyle. Overall, our findings showed that M. odoratimimus can form relevant amounts of inherently antibiotic-resistant biofilm under conditions relevant to wound site, therefore suggesting a role in the pathogenesis of chronic ulcer infections.

Cytotoxic effect of a family of peroxisome proliferator-activated receptor antagonists in colorectal and pancreatic cancer cell lines

Recent studies report an interesting role of peroxisome proliferator-activated receptor (PPAR) antagonists in different tumor models, being these compounds able to perturb metabolism and viability in cancer cells. In this work, the identification of a novel PPAR antagonist, showing inhibitory activity on PPARα and a weaker antagonism on PPARγ, is described. The activity of this compound and of a series of chemical analogues was investigated in selected tumor cell lines, expressing both PPARα and PPARγ. Data obtained show a dose-dependent cytotoxic effect of the novel PPAR antagonist in colorectal and pancreatic cancer models.

Effects of PPARα inhibition in head and neck paraganglioma cells

Head and neck paragangliomas (HNPGLs) are rare tumors that may cause important morbidity, because of their tendency to infiltrate the skull base. At present, surgery is the only therapeutic option, but radical removal may be difficult or impossible. Thus, effective targets and molecules for HNPGL treatment need to be identified. However, the lack of cellular models for this rare tumor hampers this task. PPARα receptor activation was reported in several tumors and this receptor appears to be a promising therapeutic target in different malignancies. Considering that the role of PPARα in HNPGLs was never studied before, we analyzed the potential of modulating PPARα in a unique model of HNPGL cells. We observed an intense immunoreactivity for PPARα in HNPGL tumors, suggesting that this receptor has an important role in HNPGL. A pronounced nuclear expression of PPARα was also confirmed in HNPGL-derived cells. The specific PPARα agonist WY14643 had no effect on HNPGL cell viability, whereas the specific PPARα antagonist GW6471 reduced HNPGL cell viability and growth by inducing cell cycle arrest and caspase-dependent apoptosis. GW6471 treatment was associated with a marked decrease of CDK4, cyclin D3 and cyclin B1 protein expression, along with an increased expression of p21 in HNPGL cells. Moreover, GW6471 drastically impaired clonogenic activity of HNPGL cells, with a less marked effect on cell migration. Notably, the effects of GW6471 on HNPGL cells were associated with the inhibition of the PI3K/GSK3β/β-catenin signaling pathway. In conclusion, the PPARα antagonist GW6471 reduces HNPGL cell viability, interfering with cell cycle and inducing apoptosis. The mechanisms affecting HNPGL cell viability involve repression of the PI3K/GSK3β/β-catenin pathway. Therefore, PPARα could represent a novel therapeutic target for HNPGL.

In vitro activity of levofloxacin against planktonic and biofilm Stenotrophomonas maltophilia lifestyles under conditions relevant to pulmonary infection in cystic fibrosis, and relationship with SmeDEF multidrug efflux pump expression

The activity of levofloxacin against planktonic and biofilm Stenotrophomonas maltophilia cells and the role played by the multidrug efflux pump SmeDEF were evaluated under conditions relevant to the cystic fibrosis (CF) lung. MIC, MBC and MBEC of levofloxacin were assessed, against five CF strains, under 'standard' (CLSI-recommended) and 'CF-like' (pH 6.8, 5% CO2, in a synthetic CF sputum) conditions. Levofloxacin was tested against biofilms at concentrations (10, 50 and 100 μg mL(-1)) corresponding to achievable serum levels and sputum levels by aerosolisation. smeD expression was evaluated, under both conditions, in planktonic and biofilm cells by RT-PCR. The bactericidal effect of levofloxacin was decreased, in three out of five strains tested, under 'CF-like' conditions (MBC: 2-4 vs 8-16 μg mL(-1), under 'standard' and 'CF-like' conditions, respectively). Biofilm was intrinsically resistant to levofloxacin, regardless of conditions tested (MBECs ≥ 100 μg mL(-1) for all strains). Only under 'CF-like' conditions, smeD expression increased during planktonic-to-biofilm transition, and in biofilm cells compared to stationary planktonic cells. Our findings confirmed that S. maltophilia biofilm is intrinsically resistant to therapeutic concentrations of levofloxacin. Under conditions relevant to CF, smeD overexpression could contribute to levofloxacin resistance. Further studies are warranted to define the clinical relevance of our findings.

Low AMY1 Gene Copy Number Is Associated with Increased Body Mass Index in Prepubertal Boys

Background

Genome-wide association studies have identified more than 60 single nucleotide polymorphisms associated with Body Mass Index (BMI). Additional genetic variants, such as copy number variations (CNV), have also been investigated in relation to BMI. Recently, the highly polymorphic CNV in the salivary amylase (AMY1) gene, encoding an enzyme implicated in the first step of starch digestion, has been associated with obesity in adults and children. We assessed the potential association between AMY1 copy number and a wide range of BMI in a population of Italian school-children.

Methods

744 children (354 boys, 390 girls, mean age (±SD): 8.4±1.4years) underwent anthropometric assessments (height, weight) and collection of saliva samples for DNA extraction. AMY1 copies were evaluated by quantitative PCR.

Results

A significant increase of BMI z-score by decreasing AMY1 copy number was observed in boys (β: -0.117, p = 0.033), but not in girls. Similarly, waist circumference (β: -0.155, p = 0.003, adjusted for age) was negatively influenced by AMY1 copy number in boys. Boys with 8 or more AMY1 copy numbers presented a significant lower BMI z-score (p = 0.04) and waist circumference (p = 0.01) when compared to boys with less than 8 copy numbers.

Conclusions

In this pediatric-only, population-based study, a lower AMY1 copy number emerged to be associated with increased BMI in boys. These data confirm previous findings from adult studies and support a potential role of a higher copy number of the salivary AMY1 gene in protecting from excess weight gain.

Synthesis, in vitro evaluation, and molecular modeling investigation of benzenesulfonimide peroxisome proliferator-activated receptors α antagonists

Recent evidences suggest a moderate activation of Peroxisome Proliferator-Activated Receptors (PPARs) could be favorable in metabolic diseases, reducing side effects given from full agonists. PPAR partial agonists and antagonists represent, to date, interesting tools to better elucidate biological processes modulated by these receptors. In this work are reported new benzenesulfonimide compounds able to block PPARα, synthesized and tested by transactivation assays and gene expression analysis. Some of these compounds showed a dose-dependent antagonistic behavior on PPARα, submicromolar potency, different profiles of selectivity versus PPARγ, and a repressive effect on CPT1A expression. Dockings and molecular dynamics on properly selected benzenesulfonimide derivatives furnished fresh insights into the molecular determinant most likely responsible for PPARα antagonism.

Cooperative pathogenicity in cystic fibrosis: Stenotrophomonas maltophilia modulates Pseudomonas aeruginosa virulence in mixed biofilm

The present study was undertaken in order to understand more about the interaction occurring between S. maltophilia and P. aeruginosa, which are frequently co-isolated from CF airways. For this purpose, S. maltophilia RR7 and P. aeruginosa RR8 strains, co-isolated from the lung of a chronically infected CF patient during a pulmonary exacerbation episode, were evaluated for reciprocal effect during planktonic growth, adhesion and biofilm formation onto both polystyrene and CF bronchial cell monolayer, motility, as well as for gene expression in mixed biofilms. P. aeruginosa significantly affected S. maltophilia growth in both planktonic and biofilm cultures, due to an inhibitory activity probably requiring direct contact. Conversely, no effect was observed on P. aeruginosa by S. maltophilia. Compared with monocultures, the adhesiveness of P. aeruginosa on CFBE41o- cells was significantly reduced by S. maltophilia, which probably acts by reducing P. aeruginosa's swimming motility. An opposite trend was observed for biofilm formation, confirming the findings obtained using polystyrene. When grown in mixed biofilm with S. maltophilia, P. aeruginosa significantly over-expressed aprA, and algD-codifying for protease and alginate, respectively-while the quorum sensing related rhlR and lasI genes were down-regulated. The induced alginate expression by P. aeruginosa might be responsible for the protection of S. maltophilia against tobramycin activity we observed in mixed biofilms. Taken together, our results suggest that the existence of reciprocal interference of S. maltophilia and P. aeruginosa in CF lung is plausible. In particular, S. maltophilia might confer some selective "fitness advantage" to P. aeruginosa under the specific conditions of chronic infection or, alternatively, increase the virulence of P. aeruginosa thus leading to pulmonary exacerbation.

Allele-specific loss and transcription of the miR-15a/16-1 cluster in chronic lymphocytic leukemia

Deregulation of the miR-15a/16-1 cluster has a key role in the pathogenesis of chronic lymphocytic leukemia (CLL), a clinically heterogeneous disease with indolent and aggressive forms. The miR-15a/16-1 locus is located at 13q14, the most frequently deleted region in CLL. Starting from functional investigations of a rare SNP upstream the miR cluster, we identified a novel allele-specific mechanism that exploits a cryptic activator region to recruit the RNA polymerase III for miR-15a/16-1 transcription. This regulation of the miR-15a/16- locus is independent of the DLEU2 host gene, which is often transcribed monoallellically by RPII. We found that normally one allele of miR-15a/16-1 is transcribed by RNAPII, the other one by RNAPIII. In our subset of CLL patients harboring 13q14 deletions, exclusive RNA polymerase III (RPIII)-driven transcription of the miR-15a/16-1 was the consequence of loss of the RPII-regulated allele and correlated with high expression of the poor prognostic marker ZAP70 (P=0.019). Thus, our findings point to a novel biological process, characterized by double allele-specific transcriptional regulation of the miR-15a/16-1 locus by alternative mechanisms. Differential usage of these mechanisms may distinguish at onset aggressive from indolent forms of CLL. This provides a basis for the clinical heterogeneity of the CLL patients carrying 13q14 deletions.

The Polycomb group (PcG) protein EZH2 supports the survival of PAX3-FOXO1 alveolar rhabdomyosarcoma by repressing FBXO32 (Atrogin1/MAFbx)

The Polycomb group (PcG) proteins regulate stem cell differentiation via the repression of gene transcription, and their deregulation has been widely implicated in cancer development. The PcG protein Enhancer of Zeste Homolog 2 (EZH2) works as a catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) by methylating lysine 27 on histone H3 (H3K27me3), a hallmark of PRC2-mediated gene repression. In skeletal muscle progenitors, EZH2 prevents an unscheduled differentiation by repressing muscle-specific gene expression and is downregulated during the course of differentiation. In rhabdomyosarcoma (RMS), a pediatric soft-tissue sarcoma thought to arise from myogenic precursors, EZH2 is abnormally expressed and its downregulation in vitro leads to muscle-like differentiation of RMS cells of the embryonal variant. However, the role of EZH2 in the clinically aggressive subgroup of alveolar RMS, characterized by the expression of PAX3-FOXO1 oncoprotein, remains unknown. We show here that EZH2 depletion in these cells leads to programmed cell death. Transcriptional derepression of F-box protein 32 (FBXO32) (Atrogin1/MAFbx), a gene associated with muscle homeostasis, was evidenced in PAX3-FOXO1 RMS cells silenced for EZH2. This phenomenon was associated with reduced EZH2 occupancy and H3K27me3 levels at the FBXO32 promoter. Simultaneous knockdown of FBXO32 and EZH2 in PAX3-FOXO1 RMS cells impaired the pro-apoptotic response, whereas the overexpression of FBXO32 facilitated programmed cell death in EZH2-depleted cells. Pharmacological inhibition of EZH2 by either 3-Deazaneplanocin A or a catalytic EZH2 inhibitor mirrored the phenotypic and molecular effects of EZH2 knockdown in vitro and prevented tumor growth in vivo. Collectively, these results indicate that EZH2 is a key factor in the proliferation and survival of PAX3-FOXO1 alveolar RMS cells working, at least in part, by repressing FBXO32. They also suggest that the reducing activity of EZH2 could represent a novel adjuvant strategy to eradicate high-risk PAX3-FOXO1 alveolar RMS.

Integrative genetic, epigenetic and pathological analysis of paraganglioma reveals complex dysregulation of NOTCH signaling

Head and neck paragangliomas, rare neoplasms of the paraganglia composed of nests of neurosecretory and glial cells embedded in vascular stroma, provide a remarkable example of organoid tumor architecture. To identify genes and pathways commonly deregulated in head and neck paraganglioma, we integrated high-density genome-wide copy number variation (CNV) analysis with microRNA and immunomorphological studies. Gene-centric CNV analysis of 24 cases identified a list of 104 genes most significantly targeted by tumor-associated alterations. The "NOTCH signaling pathway" was the most significantly enriched term in the list (P = 0.002 after Bonferroni or Benjamini correction). Expression of the relevant NOTCH pathway proteins in sustentacular (glial), chief (neuroendocrine) and endothelial cells was confirmed by immunohistochemistry in 47 head and neck paraganglioma cases. There were no relationships between level and pattern of NOTCH1/JAG2 protein expression and germline mutation status in the SDH genes, implicated in paraganglioma predisposition, or the presence/absence of immunostaining for SDHB, a surrogate marker of SDH mutations. Interestingly, NOTCH upregulation was observed also in cases with no evidence of CNVs at NOTCH signaling genes, suggesting altered epigenetic modulation of this pathway. To address this issue we performed microarray-based microRNA expression analyses. Notably 5 microRNAs (miR-200a,b,c and miR-34b,c), including those most downregulated in the tumors, correlated to NOTCH signaling and directly targeted NOTCH1 in in vitro experiments using SH-SY5Y neuroblastoma cells. Furthermore, lentiviral transduction of miR-200s and miR-34s in patient-derived primary tympano-jugular paraganglioma cell cultures was associated with NOTCH1 downregulation and increased levels of markers of cell toxicity and cell death. Taken together, our results provide an integrated view of common molecular alterations associated with head and neck paraganglioma and reveal an essential role of NOTCH pathway deregulation in this tumor type.

Novel insulin receptor substrate 1 and 2 variants in breast and colorectal cancer

The insulin/insulin-like growth factor pathway is involved in breast and colorectal cancer (CRC) development. In the present study, we analyzed the coding region and short intron-exon borders of the insulin receptor substrate 1 and 2 (IRS-1 and IRS-2) genes in 12 cell lines derived from breast cancer (BC), 14 cell lines derived from CRC and 33 primary CRCs. The nucleotide variants identified in BC were 3 in IRS-1, 1 of which (p.Arg267Cys) was novel and with a pathogenic potential as predicted by in silico analysis and 6 in IRS-2. Twenty-one variants in IRS-1 and 18 in IRS-2 were identified in the CRC samples. These included 11 novel IRS-1 variants detected exclusively in CRCs, which included 5 missense (p.Pro559Leu, p.Gln655His, p.Asp1014Gly, p.Asp1181His and pPro1203Ser) with a pathogenic potential as predicted by in silico analysis, 2 frameshifts predicted to generate a truncated protein, 1 splice-site mutation and 3 silent variants. In the CRC samples we also identified 7 novel IRS-2 variants, including 4 missense variants, which included 2 (p.Asp782Asn and p.Gly1230Ser) with a pathogenic potential as predicted by in silico analysis, 2 frame insertion mutations and 1 silent variant. Most of the novel IRS-1 and IRS-2 variants may be involved in the modulation of IRS-1 or IRS-2 functions and could be relevant to breast and colorectal tumorigenesis.

Distinctive gene expression profiles in Balb/3T3 cells exposed to low dose cobalt nanoparticles, microparticles and ions: potential nanotoxicological relevance

Size-dependent characteristics of novel engineered nanomaterials might result in unforeseen biological responses and toxicity. To address this issue, we used cDNA microarray analysis (13443 genes) coupled with bioinformatics and functional gene annotation studies to investigate the transcriptional profiles of Balb/3T3 cells exposed to a low dose (1 &#956;M) of cobalt nanoparticles (CoNP), microparticles (CoMP) and ions (Co2+). CoNP, CoMP and Co2+ affected 124, 91 and 80 genes, respectively. Hierarchical clustering revealed two main gene clusters, one up-regulated, mainly after Co2+, the other down-regulated, mainly after CoNP and CoMP. The significant Gene Ontology (GO) terms included oxygen binding and transport and hemoglobin binding for Co2+, while the GOs of CoMP and CoNP were related to nucleus and intracellular components. Pathway analysis highlighted: i) mitochondrial dysfunction for Co2+, ii) signaling, activation of innate immunity, and apoptosis for CoNP, and iii) cell metabolism, G1/S cell cycle checkpoint regulation and signaling for CoMP. Unlike ions, particles affected toxicologically-relevant pathways implicated in carcinogenesis and inflammation.

Killing of Kras-mutant colon cancer cells via Rac-independent actin remodeling by the βGBP cytokine, a physiological PI3K inhibitor therapeutically effective in vivo

Activating mutations in Kras are the most frequent mutations in human cancer. They define a subset of patients who do not respond to current therapies and for whom prognosis is poor. Oncogenic Kras has been shown to deregulate numerous signaling pathways of which the most intensively studied are the Ras/extracellular signal-regulated kinase cascade and the phosphoinositide 3-kinase (PI3K)/Akt cascade. However, to date, there are no effective targeted therapies in the clinic against Kras-mutant cancers. Here, we report that the β-galactoside-binding protein (βGBP) cytokine, a physiologic inhibitor of class I PI3Ks, is a potent activator of apoptosis in Kras-mutant colorectal cancer cells, even when coharboring mutant-activated PIK3CA. Our study unveils an elective route to intrinsic and extrinsic apoptosis, which involves the cytoskeleton. Early events are inhibition of PI3K activity and Rac-independent actin rearrangement assignable to phosphoinositide changes at the plasma membrane. Cyclin E deregulation, arrest of DNA synthesis, and checkpoint kinase 2 activation underscore events critical to the activation of an intrinsic apoptotic program. Clustering of CD95/Fas death receptors underscore events critical to the activation of extrinsic apoptosis. In nude mice, we present the first evidence that xenograft tumor development is strongly inhibited by Hu-r-βGBP. Taken together, our results open a new therapeutic opportunity to a subset of patients refractive to current treatments. This first demonstration of therapeutic efficacy against Kras-mutant colon cancer suggests that Hu-r-βGBP may also be therapeutically effective against other cancers harboring activating Ras mutations as well as PIK3CA mutations.

Helicobacter pylori biofilm: a protective environment for bacterial recombination

AIMS

The aim of this work was to investigate the interaction between two Helicobacter pylori strains in promoting genetic transfer, when grown in the biofilm mode.

METHODS AND RESULTS

Biofilms produced by H. pylori 9/10 (A), H. pylori 15/4 (B) and their mixture (C) were studied for biomass production and cell viability. The genetic heterogeneity of 45 clones, coming from mature biofilm of co-cultured H. pylori strains was studied by both RAPD and cagA (EPIYA motifs)/vacA virulence genes analysis. Helicobacter pylori A, B and C developed a well-structured biofilm without significant differences in viability. No significant differences were recorded between A and B biomass measurement, whereas C biofilm expressed a significant (P < 0.001) higher adhesive capability when compared with A and B biofilms. C-clones DNA-fingerprintings showed an high genetic heterogeneity (mean similarity value = 0.528). The 60% of C-clones displayed vacA allelic combination s1i1m1m2 associated with cagA EPIYA motif pattern P1P2P3P3P3.

CONCLUSIONS

Biofilms developed by multiple H. pylori strains are more complex than those associated with single strains. Such condition might promote the genetic exchange favouring the generation of more virulent strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

The 'biofilm niche' represents a successful strategy and a suitable environment for promoting bacterial population persistence by recombination events.

Inhibition of Notch3 signalling induces rhabdomyosarcoma cell differentiation promoting p38 phosphorylation and p21(Cip1) expression and hampers tumour cell growth in vitro and in vivo

Rhabdomyosarcoma (RMS) is a paediatric soft-tissue sarcoma arising from skeletal muscle precursors coexpressing markers of proliferation and differentiation. Inducers of myogenic differentiation suppress RMS tumourigenic phenotype. The Notch target gene HES1 is upregulated in RMS and prevents tumour cell differentiation in a Notch-dependent manner. However, Notch receptors regulating this phenomenon are unknown. In agreement with data in RMS primary tumours, we show here that the Notch3 receptor is overexpressed in RMS cell lines versus normal myoblasts. Notch3-targeted downregulation in RMS cells induces hyper-phosphorylation of p38 and Akt essential for myogenesis, resulting in the differentiation of tumour cells into multinucleated myotubes expressing Myosin Heavy Chain. These phenomena are associated to a marked decrease in HES1 expression, an increase in p21^Cip1 level and the accumulation of RMS cells in the G1 phase. HES1-forced overexpression in RMS cells reverses, at least in part, the pro-differentiative effects of Notch3 downregulation. Notch3 depletion also reduces the tumourigenic potential of RMS cells both in vitro and in vivo. These results indicate that downregulation of Notch3 is sufficient to force RMS cells into completing a correct full myogenic program providing evidence that it contributes, partially through HES1 sustained expression, to their malignant phenotype. Moreover, they suggest Notch3 as a novel potential target in human RMS.

Phenotypic and genotypic characterization of Stenotrophomonas maltophilia isolates from patients with cystic fibrosis: genome diversity, biofilm formation, and virulence

Background

Stenotrophomonas maltophilia is emerging as one of the most frequently found bacteria in cystic fibrosis (CF) patients. In the present study, phenotypic and genotypic traits of a set of 98 isolates of S. maltophilia obtained from clinical (CF and non-CF patients) and environmental sources were comparatively evaluated.

Results

S. maltophilia exhibited a high level of genomic diversity in both CF and non-CF group, thus possibly allowing this bacterium to expand its pathogenic potentials. Strains sharing the same pulsotype infected different patients, thus likely indicating the occurrence of clonal spread or acquisition by a common source. CF isolates differed greatly in some phenotypic traits among each other and also when compared with non-CF isolates, demonstrating increased mean generation time and susceptibility to oxidative stress, but reduced ability in forming biofilm. Furthermore, in CF isolates flagella- and type IV pili-based motilities were critical for biofilm development, although not required for its initiation. Sequential isogenic strains isolated from the same CF patient displayed heterogeneity in biofilm and other phenotypic traits during the course of chronic infection. CF and non-CF isolates showed comparable virulence in a mouse model of lung infection.

Conclusions

Overall, the phenotypic differences observed between CF and non-CF isolates may imply different selective conditions and persistence (adaptation) mechanisms in a hostile and heterogeneous environment such as CF lung. Molecular elucidation of these mechanisms will be essential to better understand the selective adaptation in CF airways in order to design improved strategies useful to counteract and eradicate S. maltophilia infection.

Transitions at CpG dinucleotides, geographic clustering of TP53 mutations and food availability patterns in colorectal cancer

BACKGROUND

Colorectal cancer is mainly attributed to diet, but the role exerted by foods remains unclear because involved factors are extremely complex. Geography substantially impacts on foods. Correlations between international variation in colorectal cancer-associated mutation patterns and food availabilities could highlight the influence of foods on colorectal mutagenesis.

METHODOLOGY

To test such hypothesis, we applied techniques based on hierarchical clustering, feature extraction and selection, and statistical pattern recognition to the analysis of 2,572 colorectal cancer-associated TP53 mutations from 12 countries/geographic areas. For food availabilities, we relied on data extracted from the Food Balance Sheets of the Food and Agriculture Organization of the United Nations. Dendrograms for mutation sites, mutation types and food patterns were constructed through Ward's hierarchical clustering algorithm and their stability was assessed evaluating silhouette values. Feature selection used entropy-based measures for similarity between clusterings, combined with principal component analysis by exhaustive and heuristic approaches.

CONCLUSION/SIGNIFICANCE

Mutations clustered in two major geographic groups, one including only Western countries, the other Asia and parts of Europe. This was determined by variation in the frequency of transitions at CpGs, the most common mutation type. Higher frequencies of transitions at CpGs in the cluster that included only Western countries mainly reflected higher frequencies of mutations at CpG codons 175, 248 and 273, the three major TP53 hotspots. Pearson's correlation scores, computed between the principal components of the datamatrices for mutation types, food availability and mutation sites, demonstrated statistically significant correlations between transitions at CpGs and both mutation sites and availabilities of meat, milk, sweeteners and animal fats, the energy-dense foods at the basis of "Western" diets. This is best explainable by differential exposure to nitrosative DNA damage due to foods that promote metabolic stress and chronic inflammation.

J1-M267 Y lineage marks climate-driven pre-historical human displacements

The present day distribution of Y chromosomes bearing the haplogroup J1 M267(*)G variant has been associated with different episodes of human demographic history, the main one being the diffusion of Islam since the Early Middle Ages. To better understand the modes and timing of J1 dispersals, we reconstructed the genealogical relationships among 282 M267(*)G chromosomes from 29 populations typed at 20 YSTRs and 6 SNPs. Phylogenetic analyses depicted a new genetic background consistent with climate-driven demographic dynamics occurring during two key phases of human pre-history: (1) the spatial expansion of hunter gatherers in response to the end of the late Pleistocene cooling phases and (2) the displacement of groups of foragers/herders following the mid-Holocene rainfall retreats across the Sahara and Arabia. Furthermore, J1 STR motifs previously used to trace Arab or Jewish ancestries were shown unsuitable as diagnostic markers for ethnicity.

P53 mutations in colorectal cancer from northern Iran: Relationships with site of tumor origin, microsatellite instability and K-ras mutations

CRC-associated P53 mutations have not been studied extensively in non-Western countries at relatively low CRC risk. We examined, for the first time, 196 paraffin-embedded CRC cases from Northern Iran for mutations in P53 exons 5-8 using PCR-direct sequencing. P53 status and mutation site/type were correlated with nuclear protein accumulation, clinicopathologic variables and data on K-ras mutations and high-level microsatellite instability (MSI-H). We detected 96 P53 mutations in 87 (44.4%) cases and protein accumulation in 84 cases (42.8%). P53 mutations correlated directly with stage and inversely with MSI-H. Distal CRCs were more frequently mutated at major CpG hotspot codons [248 (8/66, 12.1%), 175 (7/66, 10.6%), and 245 (7/66, 10.6%)], while in proximal tumors codon 213, emerged as most frequently mutated (5/28, 17.9% vs. 3/66, 4.5%, P = 0.048). Transitions at CpGs, the most common mutation type, were more frequent in non-mucinous (25% vs. 10.4% in mucinous, P = 0.032), and distal CRC (27% vs. 12.5% in proximal, P = 0.02), and correlated with K-ras transversions. Transitions at non-CpGs, second most common P53 mutation, were more frequent in proximal tumors (15.6% vs. 4.7% in distal, P = 0.01), and correlated with K-ras transitions and MSI-H. Overall frequency and types of mutations and correlations with P53 accumulation, stage and MSI-H were as reported for non-Iranian patients. However P53 mutation site/type and correlations between P53 and K-ras mutation types differed between proximal and distal CRC. The codon 213 P53 mutation that recurred in proximal CRC was previously reported as frequent in esophageal cancer from Northern Iran.

Histological heterogeneity and somatic mtDNA mutations in gastric intraepithelial neoplasia

Somatic mutations of mitochondrial DNA (mtDNA) are associated with various types of human cancer. To elucidate their role in gastric carcinogenesis, we analyzed mutations in the displacement loop region of mtDNA in 24 paraffin-embedded gastric intraepithelial neoplasias (formerly dysplasia) from a high gastric cancer risk area in northern Italy. Helicobacter pylori infection was assessed by histological examination (Giemsa staining). Gastritis was classified according to the guidelines of the Updated Sydney System. The mtDNA displacement loop region was amplified and sequenced from gastric intraepithelial neoplasia samples and adjacent non-neoplastic gastric mucosa. The gastric intraepithelial neoplasias were divided into two groups by their association with H. pylori gastritis. Group A with lesions arising on a background of H. pylori-positive gastritis contained 7 patients, and group B with lesions associated with H. pylori-negative gastritis contained 17 patients. Group A had a larger proportion of high-grade lesions than group B and showed a foveolar phenotype (type II dysplasia). Group B had a larger proportion of cases with mtDNA displacement loop region mutations than group A (P=0.004, Fisher's exact test) and exhibited an intestinal phenotype. No evidence of heteroplasmic variants in the mtDNA displacement loop, suggestive of mutations, was detected in gastric biopsies from 25 H. pylori-negative subjects and 60 cancer-unaffected H. pylori-positive patients. These results provide further evidence for the morphologic and mtDNA biomolecular differences of gastric intraepithelial neoplasias, and suggest the existence of two distinct pathways to gastric cancer--corpus-dominant H. pylori gastritis and the atrophy-metaplasia pathway.

Gastric adenomas: relationship between clinicopathological findings, Helicobacter pylori infection, APC mutations and COX-2 expression

Gastric adenomas are rare neoplastic growths characterized by localized polypoid proliferations of dysplastic epithelium that tend to progress to infiltrating adenocarcinoma. Therefore, the identification of molecular markers that could reliably recognize adenomas at risk of progression is advocated in the clinical management. In this study we investigated, in a series of gastric adenoma specimens from an area at high risk of gastric cancer, the relationship between clinicopathological characteristics of adenoma and Helicobacter pylori infection, APC mutational status, and COX-2 and the down-stream enzyme mPGES1 expression. Helicobacter pylori infection, detected in 24%, and 33% by histology and PCR analyses, respectively, did not show any relationship with growth pattern, localization, size, dysplasia grade and presence of synchronous cancer. Pathogenetic mutations of MCR region (codons 1269-1589) of the APC gene were detected only in one case corresponding to a single, small size, low grade, H. pylori-negative adenoma. The expression of COX-2 largely matched that of mPGES(1). Both were overexpressed in 79% of cases showing a relationship with high-grade dysplasia, size >10 mm and presence of a synchronous carcinoma. In conclusion, COX-2 may play a key role in the development and progression of gastric adenoma and could be an attractive target in the management of gastric adenoma at major risk of cancer development.

Patterns of K-ras mutation in colorectal carcinomas from Iran and Italy (a Gruppo Oncologico dell'Italia Meridionale study): influence of microsatellite instability status and country of origin

BACKGROUND

K-ras mutations are a key step in colorectal cancer progression. Such mutations have been widely studied in case series from Western countries but there are few data on the rate and spectrum of mutations in tumors from countries where the epidemiological features of the disease are different.

PATIENTS AND METHODS

Tumor samples from 182 Iranian colorectal cancer patients (170 sporadic cases and 12 HNPCC cases) were screened for K-ras mutations at codons 12, 13 and 61 by sequencing analysis. The cases were also characterized for microsatellite instability at mononucleotide repeats by PCR and fragment analysis, and classified according to microsatellite instability status. The frequency and the spectrum of K-ras mutations were compared with those observed in a series of colorectal cancer patients from Italy.

RESULTS

K-ras mutations were observed in 68/182 (37.4%) cases. Mutation frequencies were similar in HNPCC-associated, sporadic MSI-H and sporadic microsatellite-stable (MSS) tumors. However, the G13D substitution was more frequent in HNPCC (3/4, 75%) and sporadic MSI-H (7/11, 63.6%) tumors compared to sporadic MSS tumors (11/53, 20.4%) (P <0.01). Comparison of mutations in the two series from Iran and Italy showed a significantly higher frequency of G13D among Italian patients.

CONCLUSIONS

While the frequency of K-ras mutations could be similar, the mutational spectrum could be differentially influenced by genetic and environmental factors.

BRCA1 and BRCA2 status in a Central Sudanese series of breast cancer patients: interactions with genetic, ethnic and reproductive factors

The etiology of breast cancer in Africa is scarcely investigated. Breast cancer was responsible for 456/2,233 cancer patients (20.4%) ascertained between 1999 and 2004 at Gezira University, Central Sudan. Male breast cancer accounted for 16/456 patients (3.5%), 275/440 female patients (62.5%) were premenopausal and 150/440 cases (34%) occurred in women with > or =5 childbirths. We characterized for germline BRCA1/2 mutations a one-year series of patients (34 females, 1 male) selected by diagnosis within age 40 years or male gender. Overall 33/35 patients were found to carry 60 BRCA1/2 variants, of which 17 (28%) were novel, 22 (37%) reported in populations from various geographic areas and 21 (35%) reported worldwide. Detected variants included 5 truncating mutations, one of which (in BRCA2) was in the male patient. The 55 non-truncating variants included 3 unclassified variants predicted to affect protein product and not co-occurring with a truncating mutation in the same gene. Patients were from different tribes but AMOVA showed that most BRCA1/2 variation was within individuals (86.41%) and patients clustered independently of tribe in a phylogenetic tree. Cluster analysis based on age at cancer diagnosis and reproductive variables split female patients in two clusters that, by factor analysis, were explained by low versus high scores of the total period occupied by pregnancies and lactation. The cluster with low scores comprised all 4 patients with truncating mutations and 3 of the 4 carriers of unclassified variants predicted to affect protein product. Our findings suggest that in Central Sudan BRCA1/2 represent an important etiological factor of breast cancer in males and young women less exposed to pregnancy and lactation. Factors other than BRCA1/2 may contribute to breast cancer in young highly multiparous women who breast-fed for prolonged periods.

Cobalt nano-particles modulate cytokine in vitro release by human mononuclear cells mimicking autoimmune disease

The use of particles from micro to nanoscale provides benefits to diverse scientific fields, but because a large percentage of their atoms lie on the surface, nanomaterials could be highly reactive and pose potential risks to humans. Due to their wide range of application, Cobalt nano-particles are of great interest both in industry and in life-science. To date, there are few studies on Co nano-particle toxicology. In this respect, this study aims at evaluating in vitro the potential interference of Co nano-particles on the production of several cytokines (IL-2, IL-4, IL-6, IL-10, IFNgamma and TNFalpha) by PBMCs, comparing their effects to those of Co micro-particles and Co solution (CoCl2). Cells were cultured in Opticell flasks with escalating concentrations (10-5, 10-6 and 10-7 M), of Co nano and micro-particles and CoCl2 or without metal. Cytokines were quantified in the supernatants using a human Th1/Th2 cytokine cytometric bead array. Co micro-particles showed a greater inhibitory effect compared to other Co forms. Its inhibitory activity was detected at all concentrations and towards all cytokines, whereas Co solutions selectively inhibited IL-2, IL-10 and TNF-alpha at maximal concentration. Co nano-particles induced an increase of TNF-alpha and IFN-gamma release and an inhibition of IL-10 and IL-2: a cytokine pattern similar to that detected in the experimental and clinical autoimmunity. On the basis of the obtained data, immune endpoints should be sought in the next series of studies both in vitro and in vivo in subjects exposed to cobalt nano-particles.

[The origins of dogs: archaeozoology, genetics, and ancient DNA]

The domestication of the dog from the wolf was a key step in the pathway that led to the Neolithic revolution. The earliest fossil dogs, dated to the end of the last glacial period (17,000 to 12,000 years ago), have been found in Russia, Germany and the Middle East. No dogs are represented in the naturalistic art of the European Upper Palaeolithic, suggesting that dogs were introduced at a later date. Genetic studies of extant dog and wolf mitochondrial DNA sequences were interpreted in favour of multiple dog founding events as early as 135-76,000 years ago, or of a single origin in East Asia, 40,000 or 15,000 years ago. Our study included mitochondrial DNA sequences from Italian fossil bones attributed to three Late Pleistocene-Early Holocene wolves (dated from a15,000 to a10,000 14C years ago) and two dogs, dated to a4000 and a3000 14C years ago respectively. Taking paleogeography into account, our phylogenetic data point to a contribution of European wolves to the three major dog clades, in agreement with archaeozoological data. Our phylogeographic studies also suggest genetic differentiation of dogs and wolves related to isolation by geographic distance, supporting multicentric origins of dogs from wolves throughout their vast range of sympatry.

Brief communication: mtDNA variation in North Cameroon: lack of Asian lineages and implications for back migration from Asia to sub-Saharan Africa

The hypervariable region-1 and four nucleotide positions (10400, 10873, 12308, and 12705) of the coding region of mitochondrial DNA (mtDNA) were analyzed in 441 individuals belonging to eight populations (Daba, Fali, Fulbe, Mandara, Uldeme, Podokwo, Tali, and Tupuri) from North Cameroon and four populations (Bakaka, Bassa, Bamileke, and Ewondo) from South Cameroon. All mtDNAs were assigned to five haplogroups: three sub-Saharan (L1, L2, and L3), one northern African (U6), and one European (U5). Our results contrast with the observed high frequencies of a Y-chromosome haplogroup of probable Asian origin (R1*-M173) in North Cameroon. As a first step toward a better understanding of the evident discrepancy between mtDNA and Y-chromosome data, we propose two contrasting scenarios. The first one, here termed "migration and asymmetric admixture," implies a back migration from Asia to North Cameroon of a population group carrying the haplotype R1*-M173 at high frequency, and an admixture process restricted to migrant males. The second scenario, on the other hand, temed "divergent drift," implies that modern populations of North Cameroon originated from a small population group which migrated from Asia to Africa and in which, through genetic drift, Y-chromosome haplotype R1*-M173 became predominant, whereas the Asian mtDNA haplogroups were lost.

Mutations in the p53 and Ki-ras genes, microsatellite instability and site of tumor origin in colorectal cancer

Using PCR-SSCP screening and direct sequencing we analyzed a series of 28 colorectal carcinomas for mutations in p53 (exons 5-8) and Ki-ras (codons 12, 13 and 61), and for micro-satellite instability (MSI) at BAT25 and BAT26, supplementing data with the analysis of the IARC colorectal cancer p53 mutation database. Mutations were correlated with the site of tumor origin (proximal or distal to the splenic flexure). We identified 19 mutations in p53, 9 in Ki-ras, and 4 MSI-positive cases in a total of 20 tumors. Only 6/20 cases (30%) carried mutations in both p53 and Ki-ras. Mutations in p53 were detected at similar frequencies in proximal and distal tumors, while IARC data pointed to a strong association of p53 mutations with distal cancers. Ki-ras mutations were more frequent in proximal tumors, and MSI occurred at similar frequencies in proximal and distal tumors and was associated with mutations in p53 or Ki-ras. The p53 mutations detected in the series analyzed, as well as those retrieved from the IARC database, were predominantly transitions, with no preferential sequence localization or nucleotide position. Ki-ras mutations were predominantly transversions in position 2 at codon 12. MSI-H occurred at similar frequencies in proximal and distal tumors and was associated with either p53 or Ki-ras mutations. Overall these data suggest that distinct mutagenic factors target p53 and Ki-ras in colorectal epithelium irrespective of MSI-H status.

Mitochondrial DNA from prehistoric canids highlights relationships between dogs and South-East European wolves

The question of the origins of the dog has been much debated. The dog is descended from the wolf that at the end of the last glaciation (the archaeologically hypothesized period of dog domestication) was one of the most widespread among Holarctic mammals. Scenarios provided by genetic studies range from multiple dog-founding events to a single origin in East Asia. The earliest fossil dogs, dated approximately 17-12,000 radiocarbon ((14)C) years ago (YA), were found in Europe and in the Middle East. Ancient DNA (a-DNA) evidence could contribute to the identification of dog-founder wolf populations. To gain insight into the relationships between ancient European wolves and dogs we analyzed a 262-bp mitochondrial DNA control region fragment retrieved from five prehistoric Italian canids ranging in age from approximately 15,000 to approximately 3,000 (14)C YA. These canids were compared to a worldwide sample of 547 purebred dogs and 341 wolves. The ancient sequences were highly diverse and joined the three major clades of extant dog sequences. Phylogenetic investigations highlighted relationships between the ancient sequences and geographically widespread extant dog matrilines and between the ancient sequences and extant wolf matrilines of mainly East European origin. The results provide a-DNA support for the involvement of European wolves in the origins of the three major dog clades. Genetic data also suggest multiple independent domestication events. East European wolves may still reflect the genetic variation of ancient dog-founder populations.