Unexpected chronic lymphocytic leukemia B cell activation by bisphosphonates.

Chronic lymphocytic leukemia (CLL) is a disease of the elderly, often presenting comorbidities like osteoporosis and requiring, in a relevant proportion of cases, treatment with bisphosphonates (BPs). This class of drugs was shown in preclinical investigations to also possess anticancer properties. We started an in vitro study of the effects of BPs on CLL B cells activated by microenvironment-mimicking stimuli and observed that, depending on drug concentration, hormetic effects were induced on the leukemic cells. Higher doses induced cytotoxicity whereas at lower concentrations, more likely occurring in vivo, the drugs generated a protective effect from spontaneous and chemotherapy-induced apoptosis, and augmented CLL B cell activation/proliferation. This CLL-activation effect promoted by the BPs was associated with markers of poor CLL prognosis and required the presence of bystander stromal cells. Functional experiments suggested that this phenomenon involves the release of soluble factors and is increased by cellular contact between stroma and CLL B cells. Since CLL patients often present comorbidities such as osteoporosis and considering the diverse outcomes in both CLL disease progression and CLL response to treatment among patients, illustrating this phenomenon holds potential significance in driving additional investigations.

A Proteomics Approach Identifies RREB1 as a Crucial Molecular Target of Imidazo-Pyrazole Treatment in SKMEL-28 Melanoma Cells.

Cutaneous melanoma is the most dangerous and deadly form of human skin malignancy. Despite its rarity, it accounts for a staggering 80% of deaths attributed to cutaneous cancers overall. Moreover, its final stages often exhibit resistance to drug treatments, resulting in unfavorable outcomes. Hence, ensuring access to novel and improved chemotherapeutic agents is imperative for patients grappling with this severe ailment. Pyrazole and its fused systems derived thereof are heteroaromatic moieties widely employed in medicinal chemistry to develop effective drugs for various therapeutic areas, including inflammation, pain, oxidation, pathogens, depression, and fever. In a previous study, we described the biochemical properties of a newly synthesized group of imidazo-pyrazole compounds. In this paper, to improve our knowledge of the pharmacological properties of these molecules, we conduct a differential proteomic analysis on a human melanoma cell line treated with one of these imidazo-pyrazole derivatives. Our results detail the changes to the SKMEL-28 cell line proteome induced by 24, 48, and 72 h of 3e imidazo-pyrazole treatment. Notably, we highlight the down-regulation of the Ras-responsive element binding protein 1 (RREB1), a member of the zinc finger transcription factors family involved in the tumorigenesis of melanoma. RREB1 is a downstream element of the MAPK pathway, and its activation is mediated by ERK1/2 through phosphorylation.

Gene's expression underpinning the divergent predictive value of [18F]F-fluorodeoxyglucose and prostate-specific membrane antigen positron emission tomography in primary prostate cancer: a bioinformatic and experimental study.

BACKGROUND: Positron Emission Tomography (PET) imaging with Prostate-Specific Membrane Antigen (PSMA) and Fluorodeoxyglucose (FDG) represent promising biomarkers for risk-stratification of Prostate Cancer (PCa). We verified whether the expression of genes encoding for PSMA and enzymes regulating FDG cellular uptake are independent and additive prognosticators in PCa. METHODS: mRNA expression of genes involved in glucose metabolism and PSMA regulation obtained from primary PCa specimens were retrieved from open-source databases and analyzed using an integrative bioinformatics approach. Machine Learning (ML) techniques were used to create predictive Progression-Free Survival (PFS) models. Cellular models of primary PCa with different aggressiveness were used to compare [18F]F-PSMA-1007 and [18F]F-FDG uptake kinetics in vitro. Confocal microscopy, immunofluorescence staining, and quantification analyses were performed to assess the intracellular and cellular membrane PSMA expression. RESULTS: ML analyses identified a predictive functional network involving four glucose metabolism-related genes: ALDOB, CTH, PARP2, and SLC2A4. By contrast, FOLH1 expression (encoding for PSMA) did not provide any additive predictive value to the model. At a cellular level, the increase in proliferation rate and migratory potential by primary PCa cells was associated with enhanced FDG uptake and decreased PSMA retention (paralleled by the preferential intracellular localization). CONCLUSIONS: The overexpression of a functional network involving four glucose metabolism-related genes identifies a higher risk of disease progression since the earliest phases of PCa, in agreement with the acknowledged prognostic value of FDG PET imaging. By contrast, the prognostic value of PSMA PET imaging is independent of the expression of its encoding gene FOLH1. Instead, it is influenced by the protein docking to the cell membrane, regulating its accessibility to tracer binding.

Mandatory role of endoplasmic reticulum and its pentose phosphate shunt in the myocardial defense mechanisms against the redox stress induced by anthracyclines.

Anthracyclines' cardiotoxicity involves an accelerated generation of reactive oxygen species. This oxidative damage has been found to accelerate the expression of hexose-6P-dehydrogenase (H6PD), that channels glucose-6-phosphate (G6P) through the pentose phosphate pathway (PPP) confined within the endoplasmic/sarcoplasmic reticulum (SR). To verify the role of SR-PPP in the defense mechanisms activated by doxorubicin (DXR) in cardiomyocytes, we tested the effect of this drug in H6PD knockout mice (H6PD-/-). Twenty-eight wildtype (WT) and 32 H6PD-/- mice were divided into four groups to be treated with intraperitoneal administration of saline (untreated) or DXR (8 mg/Kg once a week for 3 weeks). One week thereafter, survivors underwent imaging of 18F-deoxyglucose (FDG) uptake and were sacrificed to evaluate the levels of H6PD, glucose-6P-dehydrogenase (G6PD), G6P transporter (G6PT), and malondialdehyde. The mRNA levels of SR Ca2+-ATPase 2 (Serca2) and ryanodine receptors 2 (RyR2) were evaluated and complemented with Hematoxylin/Eosin staining and transmission electron microscopy. During the treatment period, 1/14 DXR-WT and 12/18 DXR-H6PD-/- died. At microPET, DXR-H6PD-/- survivors displayed an increase in left ventricular size (p < 0.001) coupled with a decreased urinary output, suggesting a severe hemodynamic impairment. At ex vivo analysis, H6PD-/- condition was associated with an oxidative damage independent of treatment type. DXR increased H6PD expression only in WT mice, while G6PT abundance increased in both groups, mismatching a generalized decrease of G6PD levels. Switching-off SR-PPP impaired reticular accumulation of Ca2+ decelerating Serca2 expression and upregulating RyR2 mRNA level. It thus altered mitochondrial ultrastructure eventually resulting in a cardiomyocyte loss. The recognized vulnerability of SR to the anthracycline oxidative damage is counterbalanced by an acceleration of G6P flux through a PPP confined within the reticular lumen. The interplay of SR-PPP with the intracellular Ca2+ exchanges regulators in cardiomyocytes configure the reticular PPP as a potential new target for strategies aimed to decrease anthracycline toxicity.

OLT1177, a ß-sulfonyl nitrile compound, safe in humans, inhibits the NLRP3 inflammasome and reverses the metabolic cost of inflammation.

Activation of the NLRP3 inflammasome induces maturation of IL-1ß and IL-18, both validated targets for treating acute and chronic inflammatory diseases. Here, we demonstrate that OLT1177, an orally active ß-sulfonyl nitrile molecule, inhibits activation of the NLRP3 inflammasome. In vitro, nanomolar concentrations of OLT1177 reduced IL-1ß and IL-18 release following canonical and noncanonical NLRP3 inflammasome activation. The molecule showed no effect on the NLRC4 and AIM2 inflammasomes, suggesting specificity for NLRP3. In LPS-stimulated human blood-derived macrophages, OLT1177 decreased IL-1ß levels by 60% and IL-18 by 70% at concentrations 100-fold lower in vitro than plasma concentrations safely reached in humans. OLT1177 also reduced IL-1ß release and caspase-1 activity in freshly obtained human blood neutrophils. In monocytes isolated from patients with cryopyrin-associated periodic syndrome (CAPS), OLT1177 inhibited LPS-induced IL-1ß release by 84% and 36%. Immunoprecipitation and FRET analysis demonstrated that OLT1177 prevented NLRP3-ASC, as well as NLRP3-caspase-1 interaction, thus inhibiting NLRP3 inflammasome oligomerization. In a cell-free assay, OLT1177 reduced ATPase activity of recombinant NLRP3, suggesting direct targeting of NLRP3. Mechanistically, OLT1177 did not affect potassium efflux, gene expression, or synthesis of the IL-1ß precursor. Steady-state levels of phosphorylated NF-κB and IkB kinase were significantly lowered in spleen cells from OLT1177-treated mice. We observed reduced IL-1ß content in tissue homogenates, limited oxidative stress, and increased muscle oxidative metabolism in OLT1177-treated mice challenged with LPS. Healthy humans receiving 1,000 mg of OLT1177 daily for 8 d exhibited neither adverse effects nor biochemical or hematological changes.

A novel knock-in mouse model of cryopyrin-associated periodic syndromes with development of amyloidosis: Therapeutic efficacy of proton pump inhibitors.

BACKGROUND: Cryopyrin-associated periodic syndromes (CAPS) are a group of autoinflammatory diseases linked to gain-of-function mutations in the NOD-like receptor family, pyrin domain containing 3 (NLRP3) gene, which cause uncontrolled IL-1ß secretion. Proton pump inhibitors (PPIs), which are commonly used as inhibitors of gastric acid production, also have anti-inflammatory properties, protect mice from sepsis, and prevent IL-1ß secretion by monocytes from patients with CAPS. OBJECTIVE: We sought to develop a novel Nlrp3 knock-in (KI) mouse model of CAPS to study amyloidosis, a severe CAPS complication, and test novel therapeutic approaches. METHODS: We generated KI mice by engineering the N475K mutation, which is associated with the CAPS phenotype, into the mouse Nlrp3 gene. KI and wild-type mice received PPIs or PBS intraperitoneally and were analyzed for survival, inflammation, cytokine secretion, and amyloidosis development. RESULTS: Mutant Nlrp3 KI mice displayed features that recapitulate the immunologic and clinical phenotype of CAPS. They showed systemic inflammation with high levels of serum proinflammatory cytokines, inflammatory infiltrates in various organs, and amyloid deposits in the spleen, liver, and kidneys. Toll-like receptor stimulated macrophages from KI mice secreted high levels of IL-1ß, IL-18, and IL-1α but low amounts of IL-1 receptor antagonist. Treatment of KI mice with PPIs had a clear clinical effect, showing a reduction in inflammatory manifestations, regression of amyloid deposits, and normalization of proinflammatory and anti-inflammatory cytokine production by macrophages. CONCLUSION: Nlrp3 KI mice displayed a CAPS phenotype with many characteristics of autoinflammation, including amyloidosis. The therapeutic effectiveness of PPIs associated with a lack of toxicity indicates that these drugs could represent relevant adjuvants to the anti-IL-1 drugs in patients with CAPS and other IL-1-driven diseases.

Oxidation of methionine residues in human apolipoprotein A-I generates a potent pro-inflammatory molecule.

Amyloid deposits of apolipoprotein A-I (apoA-I) and inflammation are common in atherosclerotic arteries. In this study, we investigated the interplay between oxidation of apoA-I methionine residues (Met(O)-ApoA-I), a known amyloidogenic modification of apoA-I, and the inflammatory response of immune cells. Soluble pre-fibrillar Met(O)-ApoA-I, but not apoA-I, induced intracellular accumulation of pro-interleukin (IL)-1ß and secretion of the pro-inflammatory cytokines tumor necrosis factor α (TNFα) and IL-6 in mouse bone marrow-derived macrophages (BMDMs) and human primary monocytes. Additionally, secretion of mature IL-1ß was also activated in human monocytes. The pro-inflammatory activity of Met(O)-ApoA-I was Toll-like receptor 4 (TLR4)-dependent and CD36-independent and was solely determined by oxidation of apoA-I methionine residues, in particular Met-86 and Met-148. In contrast, amyloid fibrils or reconstituted high-density lipoproteins (HDLs) generated from Met(O)-ApoA-I did not induce cytokine production in BMDMs. Although lipid-free Met(O)-ApoA-I remained functional in extracting lipids from cells and generating HDL, it gained strong pro-inflammatory properties that may aggravate local inflammation in the arteries and atherosclerosis. Our study indicates that oxidation of apoA-I methionine residues produces a potent danger-associated molecular pattern capable of stimulating pro-inflammatory cytokine secretion at levels similar to those induced by known pathogen-associated molecular patterns, such as lipopolysaccharide.

Cell stress increases ATP release in NLRP3 inflammasome-mediated autoinflammatory diseases, resulting in cytokine imbalance.

Cell stress is implicated in triggering bouts of systemic inflammation in patients with autoinflammatory disorders. Blood monocytes from patients affected by NLRP3-mediated cryopyrin-associated periodic syndromes (CAPS) release greater amounts of IL-1ß than monocytes from unaffected subjects. Here we show that stress lowers the threshold of activation; blood monocytes from CAPS patients maintain the high levels of secreted IL-1ß (fivefold) and IL-18 (10-fold) when stimulated with 1,000-fold less LPS than that required for full IL-1ß secretion in control subjects. Unexpectedly, IL-1α secretion is increased 10-fold, indicating that inflammatory episodes in CAPS may not be entirely a result of IL-1ß but may also involve IL-1α. In CAPS monocytes, LPS induces the externalization of copious amounts of ATP (10-fold), which drive IL-1ß, IL-18, and IL-1α release via activation of the P2X purinoceptor 7. This enhanced ATP release appears to be the link between cell stress and increased cytokine secretion in CAPS. In the later phase after LPS stimulation, CAPS monocytes undergo oxidative stress, which impairs production of the anti-inflammatory IL-1 receptor antagonist (IL-1Ra). Remarkably, IL-1Ra secretion is fully restored by treatment with antioxidants. In two patients with the same NLRP3 mutation, but different disease severity, monocytes from the mildly affected patient exhibited more efficient redox response, lower ATP secretion, and more balanced cytokine production. Thus, the robustness of the individual antioxidant response increases the tolerance to stress and reduces the negative effect of the disease. Pharmacologic block of P2X purinoceptor 7 and improved stress tolerance may represent novel treatment strategies in stress-associated inflammatory diseases.

Disease activity accounts for long-term efficacy of IL-1 blockers in pyogenic sterile arthritis pyoderma gangrenosum and severe acne syndrome.

OBJECTIVE: To provide a rationale for anti-IL-1 treatment in pyogenic sterile arthritis, pyoderma gangrenosum and acne (PAPA) by defining whether IL-1ß secretion is enhanced; requires NLRP3; and correlates with proline-serine-threonine phosphatase-interacting protein 1 mutations, disease activity and/or the clinical picture in PAPA. METHODS: Monocytes were isolated from 13 patients and 35 healthy donors and studied at baseline and following activation. Secretion pattern of IL-1ß, IL-1α, IL-1Ra, IL-6, IL-18 and TNF-α was assessed in supernatants by ELISA. The NLRP3 requirement for IL-1ß secretion was investigated by silencing technique in PAPA and healthy donor monocytes. Long-term follow-up (mean 26 months, range 4-38) was performed in five patients enrolled in an anti-IL-1 regimen. RESULTS: IL-1ß secretion in PAPA is increased, requires NLRP3 and correlates with disease activity. Patients with a history of osteoarticular flares release more IL-1ß, IL-6 and TNF-α compared with those with predominant cutaneous recurrences. Monocytes from patients in anti-IL-1 treatment dramatically reduced IL-1ß secretion after ex vivo activation, and long-term follow-up demonstrated decreased frequency of flares and normalization of acute phase reactants in all the patients. A straightforward correlation between genotype and IL-1ß signalling was not observed suggesting that factors other than mutation itself may play a role in regulating IL-1ß secretion and response to treatment in PAPA. CONCLUSION: PAPA patients with active lesions display increased NLRP3-mediated IL-1ß secretion, and long-term efficacy of IL-1 blockade was demonstrated. Even if other mechanisms related to the complex proline-serine-threonine phosphatase-interacting protein 1 protein networking might play additional roles, this study further supports the potential of IL-1 blockade as an effective therapeutic strategy in PAPA syndrome.

TLR costimulation causes oxidative stress with unbalance of proinflammatory and anti-inflammatory cytokine production.

IL-1ß acts in concert with anti-inflammatory cytokines, in particular, IL-1R antagonist (IL-1Ra), to ensure the correct development and outcome of the inflammation: imbalance in the IL-1ß/IL-1Ra ratio is implicated in many human diseases and may lead to dramatic consequences. In this article, we show that single TLR engagement induces IL-1ß and, with a little delay, IL-1Ra. Differently, costimulation of TLR2, TLR4, and TLR7/8 enhances IL-1ß secretion but severely inhibits IL-1Ra production. The IL-1ß/IL-1Ra unbalance after activation of multiple TLRs depends on the insurgence of oxidative stress, because of enhanced production of reactive oxygen species and failure of the antioxidant systems. Increased reactive oxygen species levels increase ATP externalization by monocytes, resulting in enhanced inflammasome activation and IL-1ß secretion. Oxidative stress then induces cell responses to stress, including inhibition of protein synthesis, which, in turn, is responsible for the impaired production of IL-1Ra. IL-1Ra secretion is restored by exogenous antioxidants that oppose oxidative stress. Similar effects are evident also on other cytokines: TNF-α is induced, whereas IL-6 is inhibited by costimulation. Our findings provide a molecular basis to the imbalance between proinflammatory and regulatory cytokine circuits that occur in various pathologic conditions, and suggest new strategies for controlling inflammation.

Increased NLRP3-dependent interleukin 1ß secretion in patients with familial Mediterranean fever: correlation with MEFV genotype.

OBJECTIVES: To define in patients affected by familial Mediterranean fever (FMF) whether or not interleukin (IL)-1ß secretion (1) is enhanced, (2) correlates with the type of MEFV mutation and (3) is mediated by NLRP3. METHODS: Freshly isolated monocytes from 21 patients with FMF (12 homozygous and 9 heterozygous), 14 MEFV healthy carriers and 30 healthy donors (HDs), unstimulated or after lipopolysaccharide (LPS)-induced activation, were analysed for redox state (production of reactive oxygen species (ROS) and antioxidant responses) and IL-1ß and IL-1 receptor antagonist (IL-1Ra) secretion. NLRP3 down-modulation was induced by in vitro silencing of the NLRP3 gene. RESULTS: LPS-stimulated monocytes from patients with FMF displayed enhanced IL-1ß secretion, which correlated with number and penetrance of MEFV mutations. Silencing of NLRP3 consistently inhibited IL-1ß secretion. As in other autoinflammatory diseases, FMF monocytes produced more ROS than genetically negative cells from HDs. Unlike in cryopyrin-associated periodic fever syndromes (CAPS), however, they were characterised by a conserved and sustained antioxidant response. Consistent with this finding, activated MEFV-mutated monocytes did not exhibit the functional indicators of oxidative stress observed in CAPS, including accelerated IL-1ß secretion and deficient production of IL-1Ra. CONCLUSIONS: MEFV-mutated monocytes display enhanced IL-1ß secretion, which correlates with number of high-penetrance mutations and level of endogenous ROS. Unlike NLRP3-mutated cells, monocytes carrying MEFV mutations withstand oxidative stress and preserve IL-1Ra production, thereby limiting inflammation. Finally, in contrast with that found in the animal model, the increased secretion of IL-1ß by LPS-stimulated FMF monocytes is NLRP3-dependent.

Altered redox state of monocytes from cryopyrin-associated periodic syndromes causes accelerated IL-1beta secretion.

In healthy monocytes, Toll-like receptor (TLR) engagement induces production of reactive oxygen species (ROS), followed by an antioxidant response involved in IL-1beta processing and secretion. Markers of the antioxidant response include intracellular thioredoxin and extracellular release of reduced cysteine. Cryopyrin-associated periodic syndromes (CAPS) are autoinflammatory diseases in which Nod-like receptor family pyrin domain-containing 3 (NLRP3) gene mutations lead to increased IL-1beta secretion. We show in a large cohort of patients that IL-1beta secretion by CAPS monocytes is much faster than that by healthy monocytes. This accelerated kinetics is caused by alterations in the basal redox state, as well as in the redox response to TLR triggering displayed by CAPS monocytes. Indeed, unstimulated CAPS monocytes are under a mild oxidative stress, with elevated levels of both ROS and antioxidants. The redox response to LPS is quickened, with early generation of the reducing conditions favoring IL-1beta processing and secretion, and then rapidly exhausted. Therefore, secretion of IL-1beta is accelerated, but reaches a plateau much earlier than in healthy controls. Pharmacologic inhibition of the redox response hinders IL-1beta release, confirming the functional link between redox impairment and altered kinetics of secretion. Monocytes from patients with juvenile idiopathic arthritis display normal kinetics of redox response and IL-1beta secretion, excluding a role of chronic inflammation in the alterations observed in CAPS. We conclude that preexisting redox alterations distinct from CAPS monocytes anticipate the pathogen-associated molecular pattern molecule-induced generation of the reducing environment favorable to inflammasome activation and IL-1beta secretion.

Methods to Study NLR in Human Blood Cells.

Autoinflammatory diseases are a group of inherited and multifactorial disorders characterized by an over-activation of innate immune response. In most cases, the clinical manifestations are due to increased activity of the NLRP3 inflammasome resulting in increased IL-1ß secretion. Investigating inflammatory cells from subjects affected by autoinflammatory diseases presents a number of technical difficulties related to the rarity of the diseases, to the young age of most patients, to the difficult modulation of gene expression in primary cells. However, since cell stress is involved in the pathophysiology of these diseases, the study of freshly drawn blood monocytes from patients affected by IL-1-mediated diseases strongly increases the chances that the observed phenomena is indeed pertinent to the pathogenesis of the disease and not influenced by the long-term cell culture conditions (e.g., the high O2 tension) or gene transfection in continuous cell lines that may lead to artifacts.

Divergent Oxidative Stress in Normal Tissues and Inflammatory Cells in Hodgkin and Non-Hodgkin Lymphoma.

BACKGROUND: Previous studies reported mitochondrial and endoplasmic reticulum redox stress in peripheral blood mononucleated cells (PBMCs) of treatment-naïve Hodgkin lymphoma (HL) patients. Here, we assessed whether this response also applies to non-HL (NHL) patients, and whether the oxidative damage is a selective feature of PBMCs or, rather, also affects tissues not directly involved in the inflammatory response. METHODS: Isolated PBMCs of 28 HL, 9 diffuse large B cell lymphoma, 8 less aggressive-NHL, and 45 controls underwent flow cytometry to evaluate redox stress and uptake of the glucose analogue 2-NBDG. This analysis was complemented with the assay of malondialdehyde (MDA) levels and enzymatic activity of glucose-6P-dehydrogenase and hexose-6P-dehydrogenase (H6PD). In all lymphoma patients, 18F-fluoro-deoxyglucose uptake was estimated in the myocardium and skeletal muscles. RESULTS: Mitochondrial reactive oxygen species generation and MDA levels were increased only in HL patients as well as H6PD activity and 2-NBDG uptake. Similarly, myocardial FDG retention was higher in HL than in other groups as opposed to a similar tracer uptake in the skeletal muscle. CONCLUSIONS: Redox stress of PBMCs is more pronounced in HL with respect to both NHL groups. This phenomenon is coherent with an increased activity of H6PD that also extends to the myocardium.

High dose esomeprazole as an anti-inflammatory agent in sepsis: Protocol for a randomized controlled trial.

BACKGROUND: Sepsis is caused by dysregulated immune responses due to infection and still presents high mortality rate and limited efficacious therapies, apart from antibiotics. Recent evidence suggests that very high dose proton pump inhibitors might regulate major sepsis mediators' secretion by monocytes, which might attenuate excessive host reactions and improve clinical outcomes. This effect is obtained with doses which are approximately 50 times higher than prophylactic esomeprazole single daily administration and 17 times higher than the cumulative dose of a three day prophylaxis. We aim to perform a randomized trial to investigate if high dose esomeprazole reduces organ dysfunction in patients with sepsis or septic shock. METHODS: This study, called PPI-SEPSIS, is a multicenter, randomized, double blind, placebo-controlled clinical trial on critically ill septic patients admitted to the emergency department or intensive care unit. A total of 300 patients will be randomized to receive high dose esomeprazole (80 mg bolus followed by 12 mg/h for 72 h and a second 80 mg bolus 12 h after the first one) or equivolume placebo (sodium chloride 0.9%), with 1:1 allocation. The primary endpoint of the study will be mean daily Sequential Organ Failure Assessment (SOFA) score over 10 days. Secondary outcomes will include antibiotic-free days, single organ failure severity, intensive care unit-free days at day 28, and mortality. DISCUSSION: This trial aims to test the efficacy of high dose esomeprazole to reduce acute organ dysfunction in patients with septic shock. TRIAL REGISTRATION: This trial was registered on ClinicalTrials.gov with the trial identification NCT03452865 in March 2018.

The rate of interleukin-1beta secretion in different myeloid cells varies with the extent of redox response to Toll-like receptor triggering.

Human myeloid cells activate the NLRP3 inflammasome and secrete interleukin (IL)-1ß in response to various Toll-like receptor (TLR) ligands, but the rate of secretion is much higher in primary human monocytes than in cultured macrophages or THP-1 cells. The different myeloid cells also display different redox status under resting conditions and redox response to TLR activation. Resting monocytes display a balanced redox state, with low production of reactive oxygen species (ROS) and antioxidants. TLR engagement induces an effective redox response with increased ROS generation followed by a sustained antioxidant response, parallelled by efficient IL-1ß secretion. Drugs blocking ROS production or the antioxidant response prevent the secretion of mature IL-1ß but not the biosynthesis of pro-IL-1ß, indicating that redox remodeling is responsible for IL-1ß processing and release. Unlike monocytes, THP-1 cells and cultured macrophages have up-regulated antioxidant systems that buffer the oxidative hit provided by TLR triggering and suppress the consequent redox response. This aborted redox remodeling is paralleled by low efficiency IL-1ß processing and secretion. High doses (5 mM) of H(2)O(2) overcome the high antioxidant capacity of THP-1 cells, restore an efficient redox response, and increase the rate of IL-1ß secretion. Together these data indicate that a tightly controlled redox homeostasis in resting cells is a prerequisite for a robust redox response to TLR ligands, in turn necessary for the efficient inflammasome activation. Inflammasome activation by bacterial DNA is not modulated by redox responses, suggesting that redox-dependent regulation of IL-1ß secretion is restricted to some inflammasomes including NLRP3 but excluding AIM-2.

Deficient production of IL-1 receptor antagonist and IL-6 coupled to oxidative stress in cryopyrin-associated periodic syndrome monocytes.

OBJECTIVE: To determine whether dysregulated production of cytokines downstream of interleukin (IL)-1 participates in the pathophysiology of cryopyrin-associated periodic syndromes (CAPS). METHODS: Primary monocytes from patients with CAPS, unstimulated or after stimulation with lipopolysaccharide (LPS) and other Toll-like receptor (TLR) agonists, were examined for signs of stress and production of IL-1ß, IL-1 receptor antagonist (IL-1Ra) and IL-6 in comparison with monocytes from patients with autoimmune diseases and from healthy donors. RESULTS: Unstimulated CAPS monocytes showed mild signs of stress including elevated levels of reactive oxygen species and fragmented mitochondria. Stress signs were worsened by TLR stimulation and eventually led to protein synthesis inhibition with strong impairment of production of cytokines downstream of IL-1, such as IL-1Ra and IL-6. These defects were not detected in monocytes from autoimmune patients and healthy donors. CONCLUSIONS: The stress state of LPS-stimulated CAPS monocytes and the consequent inhibition of translation are likely to be responsible for the impaired production of IL-1Ra and IL-6. The deficient secretion of these cytokines coupled with increased IL-1ß release explains the severity of the IL-1-related clinical manifestations and the predominant implication of innate immunity in CAPS.

Therapeutic efficacy of proton transport inhibitors alone or in combination with cisplatin in triple negative and hormone sensitive breast cancer models.

Triple negative breast cancers (TNBCs) are very aggressive and have a poor prognosis due to lack of efficacious therapies. The only effective treatment is chemotherapy that however is frequently hindered by the occurrence of drug resistance. We approached this problem in vitro and in vivo on a triple negative and a hormone sensitive breast cancer cell lines: 4T1 and TS/A. A main defense mechanism of tumors is the extrusion of intracellular protons derived from the metabolic shift to glycolysis, and necessary to maintain an intracellular pH compatible with life. The resulting acidic extracellular milieu bursts the malignant behavior of tumors and impairs chemotherapy. Therefore, we investigated the efficacy of combined therapies that associate cisplatin (Cis) with proton exchanger inhibitors, such as esomeprazole (ESO) and 5-(N-ethyl-N-isopropyl)amiloride (EIPA). Our results demonstrate that in the 4T1 triple negative model the combined therapy Cis plus EIPA is significantly more effective than the other treatments. Instead, in the TS/A tumor the best therapeutic result is obtained with ESO alone. Remarkably, in both 4T1 and TS/A tumors these treatments correlate with increase of CD8+  T lymphocytes and dendritic cells, and a dramatic reduction of M2 macrophages and other suppressor myeloid cells (MDSC) in the tumor infiltrates.

Fundamental Role of Pentose Phosphate Pathway within the Endoplasmic Reticulum in Glutamine Addiction of Triple-Negative Breast Cancer Cells.

Cancer utilization of large glutamine equivalents contributes to diverging glucose-6-P flux toward the pentose phosphate shunt (PPP) to feed the building blocks and the antioxidant responses of rapidly proliferating cells. In addition to the well-acknowledged cytosolic pathway, cancer cells also run a largely independent PPP, triggered by hexose-6P-dehydrogenase within the endoplasmic reticulum (ER), whose activity is mandatory for the integrity of ER-mitochondria networking. To verify whether this reticular metabolism is dependent on glutamine levels, we complemented the metabolomic characterization of intermediates of the glucose metabolism and tricarboxylic acid cycle with the estimation of proliferating activity, energy metabolism, redox damage, and mitochondrial function in two breast cancer cell lines. ER-PPP activity and its determinants were estimated by the ER accumulation of glucose analogs. Glutamine shortage decreased the proliferation rate despite increased ATP and NADH levels. It depleted NADPH reductive power and increased malondialdehyde content despite a marked increase in glucose-6P-dehydrogenase. This paradox was explained by the deceleration of ER-PPP favored by the decrease in hexose-6P-dehydrogenase expression coupled with the opposite response of its competitor enzyme glucose-6P-phosphatase. The decreased ER-PPP activity eventually hampered mitochondrial function and calcium exchanges. These data configure the ER-PPP as a powerful, unrecognized regulator of cancer cell metabolism and proliferation.