Contribution of Genetic Background to the Radiation Risk for Cancer and Non-Cancer Diseases in Ptch1+/- Mice.

Experimental mouse studies are important to gain a comprehensive, quantitative and mechanistic understanding of the biological factors that modify individual risk of radiation-induced health effects, including age at exposure, dose, dose rate, organ/tissue specificity and genetic factors. In this study, neonatal Ptch1+/- mice bred on CD1 and C57Bl/6 background received whole-body irradiation at postnatal day 2. This time point represents a critical phase in the development of the eye lens, cerebellum and dentate gyrus (DG), when they are also particularly susceptible to radiation effects. Irradiation was performed with γ rays (60Co) at doses of 0.5, 1 and 2 Gy, delivered at 0.3 Gy/min or 0.063 Gy/min. Wild-type and mutant mice were monitored for survival, lens opacity, medulloblastoma (MB) and neurogenesis defects. We identified an inverse genetic background-driven relationship between the radiosensitivity to induction of lens opacity and MB and that to neurogenesis deficit in Ptch1+/- mutants. In fact, high incidence of radiation-induced cataract and MB were observed in Ptch1+/-/CD1 mutants that instead showed no consequence of radiation exposure on neurogenesis. On the contrary, no induction of radiogenic cataract and MB was reported in Ptch1+/-/C57Bl/6 mice that were instead susceptible to induction of neurogenesis defects. Compared to Ptch1+/-/CD1, the cerebellum of Ptch1+/-/C57Bl/6 mice showed increased radiosensitivity to apoptosis, suggesting that differences in processing radiation-induced DNA damage may underlie the opposite strain-related radiosensitivity to cancer and non-cancer pathologies. Altogether, our results showed lack of dose-rate-related effects and marked influence of genetic background on the radiosensitivity of Ptch1+/-mice, supporting a major contribution of individual sensitivity to radiation risk in the population.

miRNA-Signature of Irradiated Ptch1+/- Mouse Lens is Dependent on Genetic Background.

One harmful long-term effect of ionizing radiation is cataract development. Recent studies have been focused on elucidating the mechanistic pathways involved in this pathogenesis. Since accumulating evidence has established a role of microRNAs in ocular diseases, including cataract, the goal of this work was to determine the microRNA signature of the mouse lens, at short time periods postirradiation, to understand the mechanisms related to radio-induced cataractogenesis. To evaluate the differences in the microRNA profiles, 10-week-old Patched1 heterozygous (Ptch1+/-) mice, bred onto two different genetic backgrounds (CD1 and C57Bl/6J), received whole-body 2 Gy γ-ray irradiation, and 24 h later lenses were collected. Next-generation sequencing and bioinformatics analysis revealed that genetic background markedly influenced the list of the deregulated microRNAs and the mainly predicted perturbed biological functions of 2 Gy irradiated Ptch1+/- mouse lenses. We identified a subset of microRNAs with a contra-regulated expression between strains, with a key role in regulating Toll-like receptor (TLR)-signaling pathways. Furthermore, a detailed analysis of miRNome data showed a completely different DNA damage response in mouse lenses 24 h postirradiation, mainly mediated by a marked upregulation of p53 signaling in Ptch1+/-/C57Bl/6J lenses that was not detected on a CD1 background. We propose a strict interplay between p53 and TLR signaling in Ptch1+/-/C57Bl/6J lenses shortly after irradiation that could explain both the resistance of this strain to developing lens opacities and the susceptibility of CD1 background to radiation-induced cataractogenesis through activation of epithelial-mesenchymal transition.

FAM49B, a novel regulator of mitochondrial function and integrity that suppresses tumor metastasis.

Mitochondrial dysregulation plays a central role in cancers and drives reactive oxygen species (ROS)-dependent tumor progression. We investigated the pro-tumoral roles of mitochondrial dynamics and altered intracellular ROS levels in pancreatic ductal adenocarcinoma (PDAC). We identified 'family with sequence similarity 49 member B' (FAM49B) as a mitochondria-localized protein that regulates mitochondrial fission and cancer progression. Silencing FAM49B in PDAC cells resulted in increased fission and mitochondrial ROS generation, which enhanced PDAC cell proliferation and invasion. Notably, FAM49B expression levels in PDAC cells were downregulated by the tumor microenvironment. Overall, the results of this study show that FAM49B acts as a suppressor of cancer cell proliferation and invasion in PDAC by regulating tumor mitochondrial redox reactions and metabolism.

Allele-specific silencing of EEC p63 mutant R304W restores p63 transcriptional activity.

EEC (ectrodactily-ectodermal dysplasia and cleft lip/palate) syndrome is a rare genetic disease, autosomal dominant inherited. It is part of the ectodermal dysplasia disorders caused by heterozygous mutations in TP63 gene. EEC patients present limb malformations, orofacial clefting, skin and skin's appendages defects, ocular abnormalities. The transcription factor p63, encoded by TP63, is a master gene for the commitment of ectodermal-derived tissues, being expressed in the apical ectodermal ridge is critical for vertebrate limb formation and, at a later stage, for skin and skin's appendages development. The ΔNp63α isoform is predominantly expressed in epithelial cells and it is indispensable for preserving the self-renewal capacity of adult stem cells and to engage specific epithelial differentiation programs. Small interfering RNA (siRNA) offers a potential therapy approach for EEC patients by selectively silencing the mutant allele. Here, using a systemic screening based on a dual-luciferase reported gene assay, we have successfully identified specific siRNAs for repressing the EEC-causing p63 mutant, R304W. Upon siRNA treatment, we were able to restore ΔNp63-WT allele transcriptional function in induced pluripotent stem cells that were derived from EEC patient biopsy. This study demonstrates that siRNAs approach is promising and, may pave the way for curing/delaying major symptoms, such as cornea degeneration and skin erosions in young EEC patients.

Differences in the efficacy and safety among inhaled corticosteroids (ICS)/long-acting beta2-agonists (LABA) combinations in the treatment of chronic obstructive pulmonary disease (COPD): Role of ICS.

Inhaled corticosteroids (ICS) are frequently recommended for the treatment of asthma and COPD, often in combination with long-acting beta2-agonists (LABA), depending on the severity of the disease and/or on the specific phenotype. Several ICS/LABA combinations are currently available that differ in their pharmacokinetic characteristics and dose of both components. Thus, this review assesses differences in the efficacy and the safety profiles of the ICS components in the two more frequently used ICS/LABA combinations (budesonide/formoterol and fluticasone/salmeterol) for the management of COPD. Whereas the basic mechanism of action is similar for all ICS (binding with the intracellular glucocorticoid receptor, which mediates both genomic and non genomic effects), the pharmacokinetic and characteristics of ICS are quite different in terms of receptor affinity, bioavailability, lipophilicity and drug persistence in the airways. Fluticasone persists longer in airway mucus and requires more time to dissolve in the lining fluid and then enter the airway wall, whereas budesonide is cleared more quickly from the airways. Comparative efficacy of the two major ICS/LABA combinations recommended for the treatment of COPD show similar efficacy in terms of reduction of exacerbations, improvement in forced expiratory volume in the first second (FEV1) and quality of life. One retrospective cohort study suggested a greater efficacy for the budesonide/formoterol combination on hospital or emergency department admissions, oral corticosteroid courses, and addition of tiotropium, and an observational real-life study reported a greater reduction of COPD exacerbations with budesonide/formoterol than with fluticasom/salmeterol combination. Among the potential side effects of chronic ICS treatment in patients with COPD, recently the use of fluticasone or fluticasone/salmeterol combination has been associated with a higher prevalence of pneumonia in the major long-term studies. On the other hand, no similar increased risk of pneumonia has been reported in patients with COPD treated with the budesonide/formoterol combination. A recent population-based cohort study from the Quebec database showed that the adjusted odds ratio for having severe pneumonia was higher for fluticasone (2.1) than for budesonide (1.17) or other ICS (1.41). Of the ICS studied, only fluticasone demonstrated a dose-related increase in risk of pneumonia in patients with COPD. This difference between fluticasone and budesonide may be explained by the longer retention of fluticasone in the airways, with potentially greater inhibition of type-1 innate immunity. Therefore, the risk:benefit ratio should be evaluated thoroughly when choosing an ICS/LABA combination for patients with COPD.

Determinants of the prognosis of idiopathic pulmonary fibrosis.

OBJECTIVE: Fibrotic idiopathic interstitial pneumonias are chronic and progressive lung diseases with different prognosis, with idiopathic pulmonary fibrosis (IPF) having the worst prognosis. Many patients need a surgical lung biopsy for the definite diagnosis of IPF but age and the clinical context often contraindicate this procedure. The aim of this study is to identify predictors of survival, apart from lung biopsy, in patients with definite and possible IPF. PATIENTS AND METHODS: We studied 42 patients with HRCT pattern of definite or possible IPF, by assessing the mortality in relationship with baseline HRCT and functional findings. HRCT was assessed both as prevalent pattern (definite vs possible UIP) and as score of the different abnormalities (in particular, honeycombing (HC) and total fibrotic score). Pulmonary function was assessed as baseline FVC, TLC and DLCO values, as well as change over 6 months of follow-up. Both univariate and multivariate analyses were performed in order to detect predictors of mortality. RESULTS: During follow-up, 10 out of 42 patients died. Mortality rate was not different according to the qualitative pattern of fibrosis at HRCT. Among the different HRCT scores, a cut-off of 15% in the HC score differentiated patients with higher mortality rate. A lower baseline FVC, and a greater decrease in pulmonary function after 6 months, were both associated with higher mortality. In a logistic analysis taking in consideration clinical, radiological and functional findings, only baseline FVC and FVC change after 6 months resulted significant predictors of mortality. CONCLUSIONS: Functional evaluation at the baseline and during follow-up is more relevant than HC score for the prognosis of patients with definite and possible IPF.

Are sputum eosinophil cationic protein and eosinophils differently associated with clinical and functional findings of asthma?

BACKGROUND: Sputum eosinophil counts and eosinophil cationic protein (ECP) levels are usually increased in asthmatic patients. The correlation between sputum eosinophils or ECP and clinical findings of asthma has been previously investigated but many of these studies have been performed on small samples of asthmatic patients, considering only few clinical indices and often including patients on oral or inhaled corticosteroids, which might be confounding when interpreting the relationship between disease activity and airway inflammation. OBJECTIVE: To assess whether sputum eosinophils and ECP were differently related to functional and clinical parameters of asthma in a large number of steroid-naïve asthmatic patients, taking into account several potential determinants of activity and chronicity of asthma. METHODS: One hundred and twenty-nine patients with mild-moderate asthma were studied. Sputum was induced by hypertonic saline inhalation and processed using the whole sample method. RESULTS: Sputum eosinophils and ECP significantly correlated with each other (r = 0.41, P < 0.001). When patients were grouped on the basis of high/low sputum eosinophils and high/low sputum ECP levels, significant differences were observed among groups, with patients with high sputum eosinophils and ECP showing the greatest asthma severity. In the overall sample, disease duration inversely correlated with sputum eosinophils, whereas FEV1 and peak expiratory flow (PEF) inversely correlated with sputum ECP. Rescue ß2 -agonist use and total symptom score positively correlated with both eosinophil counts and sputum ECP. Stepwise regression analysis showed that symptom score and disease duration accounted for 17.6% of sputum eosinophil variance, whereas symptom score and FEV1 accounted for 14.7% of sputum ECP variance. CONCLUSIONS AND CLINICAL RELEVANCE: Both sputum eosinophils and ECP are weakly related to clinical markers of asthma severity. However, ECP was more closely related to lung function parameters than eosinophil counts.

Effects of PARP-1 deficiency on Th1 and Th2 cell differentiation.

T cell differentiation to effector Th cells such as Th1 and Th2 requires the integration of multiple synergic and antagonist signals. Poly(ADP-ribosy)lation is a posttranslational modification of proteins catalyzed by Poly(ADP-ribose) polymerases (PARPs). Recently, many reports showed that PARP-1, the prototypical member of the PARP family, plays a role in immune/inflammatory responses. Consistently, its enzymatic inhibition confers protection in several models of immune-mediated diseases, mainly through an inhibitory effect on NF-κB (and NFAT) activation. PARP-1 regulates cell functions in many types of immune cells, including dendritic cells, macrophages, and T and B lymphocytes. Our results show that PARP-1KO cells displayed a reduced ability to differentiate in Th2 cells. Under both nonskewing and Th2-polarizing conditions, naïve CD4 cells from PARP-1KO mice generated a reduced frequency of IL-4(+) cells, produced less IL-5, and expressed GATA-3 at lower levels compared with cells from wild type mice. Conversely, PARP-1 deficiency did not substantially affect differentiation to Th1 cells. Indeed, the frequency of IFN-γ (+) cells as well as IFN-γ production, in nonskewing and Th1-polarizing conditions, was not affected by PARP-1 gene ablation. These findings demonstrate that PARP-1 plays a relevant role in Th2 cell differentiation and it might be a target to be exploited for the modulation of Th2-dependent immune-mediated diseases.

Early expression of the fractalkine receptor CX3CR1 in pancreatic carcinogenesis.

BACKGROUND: In pancreatic ductal adenocarcinoma (PDAC), fractalkine receptor CX3CR1 contributes to perineural invasion (PNI). We investigated whether CX3CR1 expression occurs early in PDAC and correlates with tumour features other than PNI. METHODS: We studied CX3CR1 and CX3CL1 expression by immunohistochemistry in 104 human PDAC and coexisting Pancreatic Intraepithelial Neoplasia (PanIN), and in PdxCre/LSL-Kras(G12D) mouse model of PDAC. CX3CR1 expression in vitro was studied by a spheroid model, and in vivo by syngenic mouse graft of tumour cells. RESULTS: In total, 56 (53.9%) PDAC expressed CX3CR1, 70 (67.3%) CX3CL1, and 45 (43.3%) both. CX3CR1 expression was independently associated with tumour glandular differentiation (P=0.005) and PNI (P=0.01). Pancreatic Intraepithelial Neoplasias were more frequently CX3CR1+ (80.3%, P<0.001) and CX3CL1+ (86.8%, P=0.002) than matched cancers. The survival of PDAC patients was better in those with CX3CR1+ tumour (P=0.05). Mouse PanINs were also CX3CR1(+) and -CL1(+). In vitro, cytokines significantly increased CX3CL1 but not CX3CR1 expression. Differently, CX3CR1 was upregulated in tumour spheroids, and in vivo only in well-differentiated tumours. CONCLUSION: Tumour differentiation, rather than inflammatory signalling, modulates CX3CR1 expression in PanINs and PDAC. CX3CR1 expression pattern suggests its early involvement in PDAC progression, outlining a potential target for interfering with the PanIN transition to invasive cancer.

Speed limit of the insulator-metal transition in magnetite.

As the oldest known magnetic material, magnetite (Fe3O4) has fascinated mankind for millennia. As the first oxide in which a relationship between electrical conductivity and fluctuating/localized electronic order was shown, magnetite represents a model system for understanding correlated oxides in general. Nevertheless, the exact mechanism of the insulator-metal, or Verwey, transition has long remained inaccessible. Recently, three-Fe-site lattice distortions called trimerons were identified as the characteristic building blocks of the low-temperature insulating electronically ordered phase. Here we investigate the Verwey transition with pump-probe X-ray diffraction and optical reflectivity techniques, and show how trimerons become mobile across the insulator-metal transition. We find this to be a two-step process. After an initial 300 fs destruction of individual trimerons, phase separation occurs on a 1.5±0.2 ps timescale to yield residual insulating and metallic regions. This work establishes the speed limit for switching in future oxide electronics.

Mild improvement in symptoms and pulmonary function in a long-term follow-up of patients with toluene diisocyanate-induced asthma.

BACKGROUND: Long-term follow-up of diisocyanate-induced occupational asthma has been occasionally reported. METHODS: We studied the outcome of toluene diisocyanate (TDI)-induced asthma in 46 patients at diagnosis and after a follow-up of 11 ± 3.6 years. Symptoms, anti-asthma therapy, forced expiratory volume in 1 s (FEV1) and bronchial hyperresponsiveness to methacholine were assessed. RESULTS: A significant improvement in FEV1 (% predicted) and PD20FEV1 methacholine was observed at follow-up in comparison with diagnosis. Anti-asthma treatment was performed by 42% of patients at diagnosis and by 70% at follow-up. At the time of follow-up, 32 subjects had been removed from exposure for 6.0 ± 6.9 years, whereas 14 subjects continued to work with reduced exposure to TDI. There was a significant reduction in the prevalence of attacks of shortness of breath and dyspnoea at follow-up, but only in unexposed patients. PD20FEV1 was significantly improved only in patients with a lower FEV1 at diagnosis and in those who have ceased work. Logistic regression analysis, using different models with some independent variables, showed that there were no significant determinants of improvement in FEV1 at follow-up, while a shorter duration of symptoms before diagnosis was a significant predictor of improvement in PD20FEV1 at follow-up. CONCLUSIONS: Asthma-like symptoms, bronchial hyperresponsiveness and airway obstruction improved, but did not normalize, after a long-term follow-up with cessation or reduction in TDI exposure, mainly in subjects with an early diagnosis of occupational asthma and in patients with a lower baseline FEV1 no longer exposed to TDI.

Tiotropium: a new therapeutic option in asthma.

Although bronchial hyperresponsiveness to cholinergic agents is a main feature of asthma, the role of anticholinergic drugs in chronic asthma management has been largely underestimated. Several single-dose studies comparing acute bronchodilation induced by ipratropium bromide with salbutamol have shown that salbutamol is more effective than ipratropium in treating asthma. Recently, tiotropium has been studied in asthma, when added to low-medium dose inhaled corticosteroids (ICS) in unselected moderate asthmatics or in patients with uncontrolled asthma, or with COPD and history of asthma. Later, studies on patients with Arg/Arg beta2-receptor polymorphism demonstrated a similar efficacy of tiotropium in comparison with salmeterol, when both were added to ICS. More recently, pivotal long-term studies have been performed on severe asthmatics uncontrolled under ICS/LABA combination, showing the efficacy of tiotropium in improving lung function and in increasing the time until the first severe asthma exacerbation. These data support the use of tiotropium on top of ICS/LABA combination in moderate-severe asthmatic patients. New studies are going to be published on the use of tiotropium in mild and moderate asthmatics, when added to low or medium dose ICS, in comparison with ICS alone or with ICS/LABA combination. These data might extend the indication for using tiotropium in asthma. Therefore, tiotropium represents now a valid therapeutic option, in addition to the current therapy available for severe asthmatics, and in alternative to LABA in selected asthma populations. The specific asthma phenotype which may be appropriate for tiotropium treatment should still be defined.

May the reduction of exposure to specific sensitizers be an alternative to work cessation in occupational asthma? Results from a follow-up study.

BACKGROUND: Few data are reported on the effects of a reduction of exposure to specific sensitizers in occupational asthma (OA). The objective of this study was to evaluate the clinical outcome of subjects with OA, comparing the effect of a reduction with that of the persistence or cessation of occupational exposure to the specific sensitizer. SUBJECTS AND METHODS: Forty-one subjects with OA due to different sensitizers were diagnosed via a specific inhalation challenge. After a follow-up interval of 3.5 years, subjects were reexamined by clinical assessment, bronchial hyperresponsiveness (BH) and induced sputum. RESULTS: At follow-up, subjects who had reduced occupational exposure (n = 22) showed a significant improvement in BH and a nonsignificant improvement in sputum eosinophilia (from 5.3 to 1.1%, n.s.), while subjects still exposed (n = 10) showed a significant decrease in FEV(1). Subjects who ceased work (n = 9) showed a trend of improvement in BH and sputum eosinophilia. Logistic analysis showed that the major determinant of improvement in BH at follow-up was the severity of BH at diagnosis, with a minimal contribution from the duration of exposure and treatment with inhaled corticosteroids during follow-up; reduction of work exposure did not enter into any model. CONCLUSION: The reduction of occupational exposure could not be considered to be as effective as work cessation, which remained the best treatment for OA. However, it was not associated with a deterioration of FEV(1) as observed in subjects with persistent exposure.

Are Italian pulmonologists aware of the guidelines for asthma management and do they know how to apply them?

BACKGROUND: Since 1995 GINA (Global Initiative on Asthma) guidelines for asthma management have been updated annually and published in order to promote better management of asthma in real life situations. The aim of our study was to assess the level of implementation of GINA Guidelines among Italian Pulmonary Specialists (PSs). METHODS: A detailed questionnaire was sent to 296 Respiratory Units (RUs) in Italy in order to collect information about personnel involved in the management of asthma patients, availability and use of diagnostic tools, recommended treatment according to the degree of asthma severity, educational activity. Data were analysed by using the SPSS programme. RESULTS: 74 (25%) questionnaires were returned and analysed. Most RUs (70%) do not have a dedicated asthma clinic; however, spirometry is available in more than 90% of RUs, although it is performed in no more than 50% of patients in most RUs. Asthma treatment concurs with GINA recommendations in most RUs. Educational activity is performed by almost all RUs, usually in informal manner, during clinical visits, whereas only few RUs arrange individual educational sessions or "asthma school". CONCLUSIONS: GINA guidelines for asthma management are applied by most Italian RUs included in this study in regard to educational activity and, to a lesser extent, to treatment. Surprisingly, many RUs perform spirometry in a relatively small number of patients despite its availability.

Comparison between Airway Responses to High versus Low Molecular Weight Compounds in Occupational Asthma.

Occupational asthma (OA) is a heterogeneous disease, and the characteristics of the sensitizer responsible for OA may induce different clinical, functional, and biological manifestations. We examined the characteristics of 74 patients with OA induced by low molecular weight compounds (LMWC) or by high molecular weight compounds (HMWC) and diagnosed by specific inhalation challenge (SIC). Patients with OA induced by LMWC had a longer occupational exposure before the beginning of symptoms, a lower sputum eosinophilia, and a higher prevalence of late airway response (LAR), in comparison with patients with OA induced by HMWC. Pulmonary function tended to be poorer and atopy tended to be less frequent in LMWC-induced OA than in HMWC-induced OA. These data confirm and extend previous observations showing that the characteristics of the specific sensitizer inducing OA may determine different clinical, functional, and biological features, probably related to the difference pathogenetic mechanisms underlying these different types of OA.

Malondialdehyde in exhaled breath condensate as a marker of oxidative stress in different pulmonary diseases.

BACKGROUND: Oxidative stress plays a role in the pathogenesis of many chronic inflammatory lung diseases. Exhaled breath condensate (EBC) collection is a noninvasive method to investigate pulmonary oxidative stress biomarkers such as malondialdehyde (MDA). SUBJECTS AND METHODS: We measured MDA levels in EBC in a large number of patients (N = 194) with respiratory diseases: asthma (N = 64), bronchiectasis (BE, N = 19), chronic obstructive pulmonary disease (COPD, N = 73), idiopathic pulmonary fibrosis (IPF, N = 38). Fourteen healthy nonsmoking subjects were included as controls. RESULTS: Excluding IPF subjects, MDA levels were significantly higher in all disease groups than in control group. MDA was significantly higher in COPD than asthmatic and BE subjects. Among asthmatics, corticosteroids-treated subjects had lower MDA levels than untreated subjects. COPD subjects showed an inverse correlation between MDA concentrations and FEV(1)% (rho: -0.24, P < .05). CONCLUSIONS: EBC-MDA is increased in subjects with chronic airway disorders, particularly in COPD, and it is related to FEV(1) reduction.

Quinolizidinyl derivatives of bi- and tricyclic systems as potent inhibitors of acetyl- and butyrylcholinesterase with potential in Alzheimer's disease.

On the pattern of the potent and selective butyrylcholinesterase (BChE) inhibitors ethopropazine and Astra1397, sets of quinolizidinyl derivatives of bi- and tricyclic (hetero)aromatic systems were studied as dual, or BChE-selective inhibitors. All compounds exhibited activity against both cholinesterases, but inhibition of BChE was generally stronger, with submicromolar IC50 values for most of them (e.g. 15: IC50 versus BChE=0.15 µM; SI=47). However, in a subset of quinolizidinyl derivatives of 6-hydroxycoumarin an inverted selectivity for acetylcholinesterase (AChE) was observed (e.g. 46: IC50 versus AChE=0.35 µM; SI=0.06). Docking studies furnished a sound interpretation of the observed different enzyme activity. Several of the studied compounds have shown, in the past, additional pharmacological properties (as antagonism on presynaptic muscarinic autoreceptor; inhibition of enkephaline aminopeptidase and antipsychotic activity) of some relevance in Alzheimer's disease, and may, therefore, represent hits for the development of interesting single-entity multi-target drugs.

IL-6, but not IFN-gamma, triggers apoptosis and inhibits in vivo growth of human malignant T cells on STAT3 silencing.

STAT1 and STAT3 are the main mediators of the signaling of interferons (IFNs) and of gp130 cytokines, respectively. Neoplastic T lymphocytes frequently become resistant to the IFN-gamma/STAT1 apoptotic pathway, often because of the downregulation of the IFN-gammaR2 receptor chain. Many studies suggest that cross-regulation between different STATs, in particular between STAT1 and STAT3, may profoundly affect cytokine/growth factor signaling. Here, the function of STAT3 in the negative regulation of STAT1 apoptotic pathway was investigated by RNA interference-mediated STAT3 silencing in human malignant T lymphocytes. In STAT3-depleted cells, interleukin (IL)-6 acquired the capacity to induce apoptosis, correlating with prolonged STAT1 activation and the induction of major histocompatibility complex (MHC) class I expression. In contrast, in the absence of STAT3, IFN-gamma could slightly enhance apoptosis but its ability to induce MHC class I expression was unchanged. Accordingly, IL-6, but not IFN-gamma, could significantly impair the in vivo growth of STAT3-depleted human neoplastic T lymphocytes transplanted into severe combined immunodeficient mice. Therefore, treatment with IL-6 and simultaneous STAT3 silencing may represent a potential therapeutic approach to control the expansion of IFN-gamma-unresponsive neoplastic T cells.

CCL16 enhances the CD8+ and CD4+ T cell reactivity to human HER-2 elicited by dendritic cells loaded with rat ortholog HER-2.

T cells from HLA-A2+ healthy donors were co-cultured with autologous dendritic cells (DC) loaded with apoptotic tumor cells expressing rat neu, and were induced to mature by tumor necrosis factor (TNF)alpha and interleukin (IL)-1beta (mDC(neu)) or by the CCL16 chemokine (CCL16/mDC(neu)). Priming by CCL16/mDC(neu) induces a larger population of T cells that express cytoplasmatic interferon (IFN)gamma, TNFalpha, perforin and granzyme B compared to those primed by mDC(neu). T cells primed by CCL16/mDC(neu) release IFNgamma in response to human HER-2+ cells and kill human HER-2+ target cells more efficiently than those primed by mDC(neu). Our results show that both the loading of DC with xenogeneic rat neu and their maturation by CCL16 are two issues of critical importance for the elicitation of an effective response to human HER-2 in T cells from normal donors.