A Comparative Analysis of NOX4 Protein Expression in Malignant and Non-Malignant Thyroid Tumors.

The comparative analysis of the expression of the reactive oxygen species-generating NADPH oxidase NOX4 from TCGA data shows that the NOX4 transcript is upregulated in papillary thyroid carcinomas (PTC)-BRAFV600E tumors compared to PTC-BRAFwt tumors. However, a comparative analysis of NOX4 at the protein level in malignant and non-malignant tumors is missing. We explored NOX4 protein expression by immunohistochemistry staining in malignant tumors (28 classical forms of PTC (C-PTC), 17 follicular variants of PTC (F-PTC), and three anaplastic thyroid carcinomas (ATCs)) and in non-malignant tumors (six lymphocytic thyroiditis, four Graves' disease, ten goiters, and 20 hyperplasias). We detected the BRAFV600E mutation by Sanger sequencing and digital droplet PCR. The results show that NOX4 was found to be higher (score ≥ 2) in C-PTC (92.9%) compared to F-PTC (52.9%) and ATC (33.3%) concerning malignant tumors. Interestingly, all C-PTC-BRAFV600E expressed a high score for NOX4 at the protein level, strengthening the positive correlation between the BRAFV600E mutation and NOX4 expression. In addition, independent of the mutational status of BRAF, we observed that 90% of C-PTC infiltrating tumors showed high NOX4 expression, suggesting that NOX4 may be considered a complementary biomarker in PTC aggressiveness. Interestingly, NOX4 was highly expressed in non-malignant thyroid diseases with different subcellular localizations.

Caspase Inhibition Modulates Monocyte-Derived Macrophage Polarization in Damaged Tissues.

Circulating monocytes are recruited in damaged tissues to generate macrophages that modulate disease progression. Colony-stimulating factor-1 (CSF-1) promotes the generation of monocyte-derived macrophages, which involves caspase activation. Here, we demonstrate that activated caspase-3 and caspase-7 are located to the vicinity of the mitochondria in CSF1-treated human monocytes. Active caspase-7 cleaves p47PHOX at aspartate 34, which promotes the formation of the NADPH (nicotinamide adenine dinucleotide phosphate) oxidase complex NOX2 and the production of cytosolic superoxide anions. Monocyte response to CSF-1 is altered in patients with a chronic granulomatous disease, which are constitutively defective in NOX2. Both caspase-7 down-regulation and radical oxygen species scavenging decrease the migration of CSF-1-induced macrophages. Inhibition or deletion of caspases prevents the development of lung fibrosis in mice exposed to bleomycin. Altogether, a non-conventional pathway that involves caspases and activates NOX2 is involved in CSF1-driven monocyte differentiation and could be therapeutically targeted to modulate macrophage polarization in damaged tissues.

Redox Homeostasis in Thyroid Cancer: Implications in Na+/I- Symporter (NIS) Regulation.

Radioiodine therapy (RAI) is a standard and effective therapeutic approach for differentiated thyroid cancers (DTCs) based on the unique capacity for iodide uptake and accumulation of the thyroid gland through the Na+/I- symporter (NIS). However, around 5-15% of DTC patients may become refractory to radioiodine, which is associated with a worse prognosis. The loss of RAI avidity due to thyroid cancers is attributed to cell dedifferentiation, resulting in NIS repression by transcriptional and post-transcriptional mechanisms. Targeting the signaling pathways potentially involved in this process to induce de novo iodide uptake in refractory tumors is the rationale of "redifferentiation strategies". Oxidative stress (OS) results from the imbalance between ROS production and depuration that favors a pro-oxidative environment, resulting from increased ROS production, decreased antioxidant defenses, or both. NIS expression and function are regulated by the cellular redox state in cancer and non-cancer contexts. In addition, OS has been implicated in thyroid tumorigenesis and thyroid cancer cell dedifferentiation. Here, we review the main aspects of redox homeostasis in thyrocytes and discuss potential ROS-dependent mechanisms involved in NIS repression in thyroid cancer.

NADPH oxidase DUOX1 sustains TGF-ß1 signalling and promotes lung fibrosis.

Interstitial lung fibroblast activation coupled with extracellular matrix production is a pathological signature of pulmonary fibrosis, and is governed by transforming growth factor (TGF)-ß1/Smad signalling. TGF-ß1 and oxidative stress cooperate to drive fibrosis. Cells can produce reactive oxygen species through activation and/or induction of NADPH oxidases, such as dual oxidase (DUOX1/2). Since DUOX enzymes, as extracellular hydrogen peroxide (H2O2--)-generating systems, are involved in extracellular matrix formation and in wound healing in different experimental models, we hypothesised that DUOX-based NADPH oxidase plays a role in the pathophysiology of pulmonary fibrosis.Our in vivo data (idiopathic pulmonary fibrosis patients and mouse models of lung fibrosis) showed that the NADPH oxidase DUOX1 is induced in response to lung injury. DUOX1-deficient mice (DUOX1+/- and DUOX1-/-) had an attenuated fibrotic phenotype. In addition to being highly expressed at the epithelial surface of airways, DUOX1 appears to be well expressed in the fibroblastic foci of remodelled lungs. By using primary human and mouse lung fibroblasts, we showed that TGF-ß1 upregulates DUOX1 and its maturation factor DUOXA1 and that DUOX1-derived H2O2 promoted the duration of TGF-ß1-activated Smad3 phosphorylation by preventing phospho-Smad3 degradation. Analysis of the mechanism revealed that DUOX1 inhibited the interaction between phospho-Smad3 and the ubiquitin ligase NEDD4L, preventing NEDD4L-mediated ubiquitination of phospho-Smad3 and its targeting for degradation.These findings highlight a role for DUOX1-derived H2O2 in a positive feedback that amplifies the signalling output of the TGF-ß1 pathway and identify DUOX1 as a new therapeutic target in pulmonary fibrosis.

NADPH oxidase DUOX1 promotes long-term persistence of oxidative stress after an exposure to irradiation.

Ionizing radiation (IR) causes not only acute tissue damage, but also late effects in several cell generations after the initial exposure. The thyroid gland is one of the most sensitive organs to the carcinogenic effects of IR, and we have recently highlighted that an oxidative stress is responsible for the chromosomal rearrangements found in radio-induced papillary thyroid carcinoma. Using both a human thyroid cell line and primary thyrocytes, we investigated the mechanism by which IR induces the generation of reactive oxygen species (ROS) several days after irradiation. We focused on NADPH oxidases, which are specialized ROS-generating enzymes known as NOX/DUOX. Our results show that IR induces delayed NADPH oxidase DUOX1-dependent H2O2 production in a dose-dependent manner, which is sustained for several days. We report that p38 MAPK, activated after IR, increased DUOX1 via IL-13 expression, leading to persistent DNA damage and growth arrest. Pretreatment of cells with catalase, a scavenger of H2O2, or DUOX1 down-regulation by siRNA abrogated IR-induced DNA damage. Analysis of human thyroid tissues showed that DUOX1 is elevated not only in human radio-induced thyroid tumors, but also in sporadic thyroid tumors. Taken together, our data reveal a key role of DUOX1-dependent H2O2 production in long-term persistent radio-induced DNA damage. Our data also show that DUOX1-dependent H2O2 production, which induces DNA double-strand breaks, can cause genomic instability and promote the generation of neoplastic cells through its mutagenic effect.

The extracellular A-loop of dual oxidases affects the specificity of reactive oxygen species release.

NADPH oxidase (Nox) family proteins produce superoxide (O2 (⨪)) directly by transferring an electron to molecular oxygen. Dual oxidases (Duoxes) also produce an O2 (⨪) intermediate, although the final species secreted by mature Duoxes is H2O2, suggesting that intramolecular O2 (⨪) dismutation or other mechanisms contribute to H2O2 release. We explored the structural determinants affecting reactive oxygen species formation by Duox enzymes. Duox2 showed O2 (⨪) leakage when mismatched with Duox activator 1 (DuoxA1). Duox2 released O2 (⨪) even in correctly matched combinations, including Duox2 + DuoxA2 and Duox2 + N-terminally tagged DuoxA2 regardless of the type or number of tags. Conversely, Duox1 did not release O2 (⨪) in any combination. Chimeric Duox2 possessing the A-loop of Duox1 showed no O2 (⨪) leakage; chimeric Duox1 possessing the A-loop of Duox2 released O2 (⨪). Moreover, Duox2 proteins possessing the A-loops of Nox1 or Nox5 co-expressed with DuoxA2 showed enhanced O2 (⨪) release, and Duox1 proteins possessing the A-loops of Nox1 or Nox5 co-expressed with DuoxA1 acquired O2 (⨪) leakage. Although we identified Duox1 A-loop residues (His(1071), His(1072), and Gly(1074)) important for reducing O2 (⨪) release, mutations of these residues to those of Duox2 failed to convert Duox1 to an O2 (⨪)-releasing enzyme. Using immunoprecipitation and endoglycosidase H sensitivity assays, we found that the A-loop of Duoxes binds to DuoxA N termini, creating more stable, mature Duox-DuoxA complexes. In conclusion, the A-loops of both Duoxes support H2O2 production through interaction with corresponding activators, but complex formation between the Duox1 A-loop and DuoxA1 results in tighter control of H2O2 release by the enzyme complex.

New insights in the molecular regulation of the NADPH oxidase 2 activity: Negative modulation by Poldip2.

Poldip2 was shown to be involved in oxidative signaling to ensure certain biological functions. It was proposed that, in VSMC, by interaction with the Nox4-associated membrane protein p22phox, Poldip2 stimulates the level of reactive oxygen species (ROS) production. In vitro, with fractionated membranes from HEK393 cells over-expressing Nox4, we confirmed the up-regulation of NADPH oxidase 4 activity by the recombinant and purified Poldip2. Besides Nox4, the Nox1, Nox2, or Nox3 isoforms are also established partners of the p22phox protein raising the question of their regulation by Poldip2 and of the effect in cells expressing simultaneously different Nox isoforms. In this study, we have addressed this issue by investigating the potential regulatory role of Poldip2 on NADPH oxidase 2, present in phagocyte cells. Unexpectedly, the effect of Poldip2 on phagocyte NADPH oxidase 2 was opposite to that observed on NADPH oxidase 4. Using membranes from circulating resting neutrophils, the ROS production rate of NADPH oxidase 2 was down-regulated by Poldip2 (2.5-fold). The down-regulation effect could not be correlated to the interaction of Poldip2 with p22phox but rather, to the interaction of Poldip2 with the p47phox protein, one of the regulatory proteins of the phagocyte NADPH oxidase. Our results show that the interaction of Poldip2 with p47phox constitutes a novel regulatory mechanism that can negatively modulate the activity of NADPH oxidase 2 by trapping the so-called "adaptor" subunit of the complex. Poldip2 could act as a tunable switch capable of specifically regulating the activities of NADPH oxidases. This selective regulatory role of Poldip2, positive for Nox4 or negative for Nox2 could orchestrate the level and the type of ROS generated by Nox enzymes in the cells.

The emerging role of ROS-generating NADPH oxidase NOX4 in DNA-damage responses.

The human genome is continuously exposed to such potentially deleterious agents as the highly reactive molecules known as reactive oxygen species (ROS). ROS include superoxide anions (O(2)(-)) and hydrogen peroxide (H(2)O(2)). Over the last decade, the ROS-generating NADPH oxidases (NOXs) have been recognized as one of the main sources of ROS production in numerous human cell types. In addition to regulating normal physiological redox-dependent processes, the NOXs are involved in cellular oxidative stress. In contrast to the other NOXs, the NADPH oxidase NOX4 exists in the immediate environment of the nucleus. There is accumulating evidence for the involvement of NOX4-derived ROS in genomic instability as well as in cancer and other inflammation-related diseases. We recently showed that NOX4 plays a critical role in oncogenic Ras-induced DNA damage. Here we reflect upon the growing awareness of NOX4, review its role in inducing genomic instability, and call attention to its possible role in nuclear redox-sensitive mechanisms underlying DNA-damage signaling and repair.

Strategies for Radioiodine Treatment: What's New.

Radioiodine treatment (RAI) represents the most widespread and effective therapy for differentiated thyroid cancer (DTC). RAI goals encompass ablative (destruction of thyroid remnants, to enhance thyroglobulin predictive value), adjuvant (destruction of microscopic disease to reduce recurrences), and therapeutic (in case of macroscopic iodine avid lesions) purposes, but its use has evolved over time. Randomized trial results have enabled the refinement of RAI indications, moving from a standardized practice to a tailored approach. In most cases, low-risk patients may safely avoid RAI, but where necessary, a simplified protocol, based on lower iodine activities and human recombinant TSH preparation, proved to be just as effective, reducing overtreatment or useless impairment of quality of life. In pediatric DTC, RAI treatments may allow tumor healing even at the advanced stages. Finally, new challenges have arisen with the advancement in redifferentiation protocols, through which RAI still represents a leading therapy, even in former iodine refractory cases. RAI therapy is usually well-tolerated at low activities rates, but some concerns exist concerning higher cumulative doses and long-term outcomes. Despite these achievements, several issues still need to be addressed in terms of RAI indications and protocols, heading toward the RAI strategy of the future.

Anaplastic Thyroid Carcinoma: An Update.

Anaplastic thyroid carcinoma (ATC) is a rare and undifferentiated form of thyroid cancer. Its prognosis is poor: the median overall survival (OS) of patients varies from 4 to 10 months after diagnosis. However, a doubling of the OS time may be possible owing to a more systematic use of molecular tests for targeted therapies and integration of fast-track dedicated care pathways for these patients in tertiary centers. The diagnostic confirmation, if needed, requires an urgent biopsy reread by an expert pathologist with additional immunohistochemical and molecular analyses. Therapeutic management, defined in multidisciplinary meetings, respecting the patient's choice, must start within days following diagnosis. For localized disease diagnosed after primary surgical treatment, adjuvant chemo-radiotherapy is recommended. In the event of locally advanced or metastatic disease, the prognosis is very poor. Treatment should then involve chemotherapy or targeted therapy and decompressive cervical radiotherapy. Here we will review current knowledge on ATC and provide perspectives to improve the management of this deadly disease.

Prognostic of recurrence and survival in poorly differentiated thyroid cancer.

The prognosis of poorly differentiated thyroid carcinomas (PDTC) defined by the Turin criteria is variable. The aim of this study on 51 PDTC patients was to determine clinical, histological and molecular prognostic factors associated with recurrence in patients with localized disease at initial treatment and with overall survival in patients with distant metastases. Of 40 patients for whom next-generation sequencing (NGS) by ThyroSeq v3 was able to be performed on historical samples, we identified high-risk molecular signature (TERT, TP53 mutations) in 24 (60%) cases, intermediate risk signature in 9 (22.5%) cases and low-risk signature in 7 (17.5%) cases. Potentially actionable mutations were identified in 10% of cases. After a median follow-up of 57.5 months, recurrence occurred in 11 (39%) of the 28 patients with localized disease. The American Thyroid Association (ATA) high risk of relapse, high mitotic count, high molecular risk signature and CD163 expression were associated with recurrence (P = 0.009, 0.01, 0.049, 0.03 respectively). After a median follow-up of 49.5 months, thyroid cancer-related death occurred in 53% of the patients with distant metastases. There was no significant prognostic factor associated with death in univariate analysis. However, none of the patients with intermediate ATA risk of recurrence and none of the patients with low-risk molecular signature died from the disease. In addition, high molecular-risk signature was associated with the presence of synchronous or metachronous distant metastasis (P = 0.007) and with poor overall survival (P = 0.01). In conclusion, ATA risk of relapse and high mitotic count was associated with higher rate of recurrence in localized PDTC. High molecular-risk signature was associated with the presence of distant metastasis and poor overall survival. Further studies are needed to determine if molecular testing adds to ATA risk stratification or response to therapy in predicting outcomes.

Redifferentiation-facilitated radioiodine therapy in thyroid cancer.

Based on experimental data, the inhibition of the MAPkinase pathway in patients with radioiodine-refractory thyroid cancer was capable of inducing a redifferentiation. Preliminary data obtained in a small series of patients were encouraging and this strategy might become an alternative treatment in those patients with a druggable mutation that induces a stimulation of the MAP kinase pathway. This is an active field of research to answer many still unresolved questions.

Exercise-Stimulated ROS Sensitive Signaling Pathways in Skeletal Muscle.

Physical exercise represents a major challenge to whole-body homeostasis, provoking acute and adaptative responses at the cellular and systemic levels. Different sources of reactive oxygen species (ROS) have been described in skeletal muscle (e.g., NADPH oxidases, xanthine oxidase, and mitochondria) and are closely related to the physiological changes induced by physical exercise through the modulation of several signaling pathways. Many signaling pathways that are regulated by exercise-induced ROS generation, such as adenosine monophosphate-activated protein kinase (AMPK), mitogen activated protein kinase (MAPK), nuclear respiratory factor2 (NRF2), and PGC-1α are involved in skeletal muscle responses to physical exercise, such as increased glucose uptake, mitochondriogenesis, and hypertrophy, among others. Most of these adaptations are blunted by antioxidants, revealing the crucial role played by ROS during and after physical exercise. When ROS generation is either insufficient or exacerbated, ROS-mediated signaling is disrupted, as well as physical exercise adaptations. Thus, an understanding the limit between "ROS that can promote beneficial effects" and "ROS that can promote harmful effects" is a challenging question in exercise biology. The identification of new mediators that cause reductive stress and thereby disrupt exercise-stimulated ROS signaling is a trending on this topic and are covered in this current review.

The Pseudomonas toxin pyocyanin inhibits the dual oxidase-based antimicrobial system as it imposes oxidative stress on airway epithelial cells.

The dual oxidase-thiocyanate-lactoperoxidase (Duox/SCN(-)/LPO) system generates the microbicidal oxidant hypothiocyanite in the airway surface liquid by using LPO, thiocyanate, and Duox-derived hydrogen peroxide released from the apical surface of the airway epithelium. This system is effective against several microorganisms that infect airways of cystic fibrosis and other immunocompromised patients. We show herein that exposure of airway epithelial cells to Pseudomonas aeruginosa obtained from long-term cultures inhibits Duox1-dependent hydrogen peroxide release, suggesting that some microbial factor suppresses Duox activity. These inhibitory effects are not seen with the pyocyanin-deficient P. aeruginosa strain PA14 Phz1/2. We show that purified pyocyanin, a redox-active virulence factor produced by P. aeruginosa, inhibits human airway cell Duox activity by depleting intracellular stores of NADPH, as it generates intracellular superoxide. Long-term exposure of human airway (primary normal human bronchial and NCI-H292) cells to pyocyanin also blocks induction of Duox1 by Th2 cytokines (IL-4, IL-13), which was prevented by the antioxidants glutathione and N-acetylcysteine. Furthermore, we showed that low concentrations of pyocyanin blocked killing of wild-type P. aeruginosa by the Duox/SCN(-)/LPO system on primary normal human bronchial epithelial cells. Thus, pyocyanin can subvert Pseudomonas killing by the Duox-based system as it imposes oxidative stress on the host. We also show that lactoperoxidase can oxidize pyocyanin, thereby diminishing its cytotoxicity. These data establish a novel role for pyocyanin in the survival of P. aeruginosa in human airways through competitive redox-based reactions between the pathogen and host.

Redox Signaling in Widespread Health Benefits of Exercise.

Significance: Exercise-induced reactive oxygen species (ROS) production activates multiple intracellular signaling pathways through genomic and nongenomic mechanisms that are responsible for the beneficial effects of exercise in muscle. Beyond the positive effect of exercise on skeletal muscle cells, other tissues such as white and brown adipose, liver, central nervous system, endothelial, heart, and endocrine organ tissues are also responsive to exercise. Recent Advances: Crosstalk between different cells is essential to achieve homeostasis and to promote the benefits of exercise through paracrine or endocrine signaling. This crosstalk can be mediated by different effectors that include the secretion of metabolites of muscle contraction, myokines, and exosomes. During the past 20 years, it has been demonstrated that contracting muscle cells produce and secrete different classes of myokines, which functionally link muscle with nearly all other cell types. Critical Issues: The redox signaling behind this exercise-induced crosstalk is now being decoded. Many of these widespread beneficial effects of exercise require not only a complex ROS-dependent intramuscular signaling cascade but simultaneously, an integrated network with many remote tissues. Future Directions: Strong evidence suggests that the powerful beneficial effect of regular physical activity for preventing (or treating) a large range of disorders might also rely on ROS-mediated signaling. Within a contracting muscle, ROS signaling may control exosomes and myokines secretion. In remote tissues, exercise generates regular and synchronized ROS waves, creating a transient pro-oxidative environment in many cells. These new concepts integrate exercise, ROS-mediated signaling, and the widespread health benefits of exercise.

Redifferentiation of radioiodine-refractory thyroid cancers.

The management of radioiodine refractory thyroid cancers (RAIR TC) is challenging for the clinician. Tyrosine kinase inhibitors classically prescribed in this setting can fail due to primary or acquired resistance or the necessity of drug withdrawal because of serious or moderate but chronic and deleterious adverse effects. Thus, the concept of redifferentiation strategy, which involves treating patients with one or more drugs capable of restoring radioiodine sensitivity for RAIR TC, has emerged. The area of redifferentiation strategy leads to the creation of new definitions of RAIR TC including persistent non radioiodine-avid patients and 'true' RAIR TC patients. The latter group presents a restored or increased radioiodine uptake in metastatic lesions but with no radiological response on conventional imaging, that is, progression of a metastatic disease, thus proving that they are 'truly' resistant to the radiation delivered by radioiodine. Unlike these patients, metastatic TC patients with restored radioiodine uptake offer the hope of prolonged remission or even cure of the disease as for radioiodine-avid metastatic TC. Here, we review the different redifferentiation strategies based on the underlying molecular mechanism leading to the sodium iodide symporter (NIS) and radioiodine uptake reinduction, that is, by modulating signaling pathways, NIS transcription, NIS trafficking to the plasma membrane, NIS post-transcriptional regulation, by gene therapy and other potential strategies. We discuss clinical trials and promising preclinical data of potential future targets.

BRAFV600E hot spot mutation in thyroid carcinomas: first Moroccan experience from a single-institution retrospective study.

BACKGROUND: The incidence of thyroid cancer is increasing worldwide at an alarming rate. BRAFV600E mutation is described to be associated with a worse prognostic of thyroid carcinomas, as well as extrathyroidal invasion and increased mortality. OBJECTIVE: To our knowledge, there are no reported studies neither from Morocco nor from other Maghreb countries regarding the prevalence of BRAFV600E mutation in thyroid carcinomas. Here we aim to evaluate the frequency of BRAFV600E oncogene in Moroccan thyroid carcinomas. METHODS: In this Single-Institution retrospective study realized in the Anatomic Pathology and Histology Service in the Military Hospital of Instruction Mohammed V 'HMIMV' in Rabat, we report, using direct genomic sequencing, the assessment of BRAFV600E in 37 thyroid tumors. RESULTS: We detected BRAFV600E mutation exclusively in Papillary Thyroid Carcinomas 'PTC' with a prevalence of 28% (8 PTC out 29 PTC). Like international trends, Papillary Thyroid Carcinomas 'PTC' is more frequent than Follicular Thyroid Carcinomas 'FTC' and Anaplastic Thyroid Carcinomas 'ATC' (29 PTC, 7 FTC and 1 ATC). CONCLUSION: Our finding gives to the international community the first estimated incidence of this oncogene in Morocco showing that this prevalence falls within the range of international trends (30% to 90%) reported in distinct worldwide geographic regions.

Dual oxidase 1 limits the IFNγ-associated antitumor effect of macrophages.

BACKGROUND: Macrophages play pivotal roles in tumor progression and the response to anticancer therapies, including radiotherapy (RT). Dual oxidase (DUOX) 1 is a transmembrane enzyme that plays a critical role in oxidant generation. METHODS: Since we found DUOX1 expression in macrophages from human lung samples exposed to ionizing radiation, we aimed to assess the involvement of DUOX1 in macrophage activation and the role of these macrophages in tumor development. RESULTS: Using Duox1-/- mice, we demonstrated that the lack of DUOX1 in proinflammatory macrophages improved the antitumor effect of these cells. Furthermore, intratumoral injection of Duox1-/- proinflammatory macrophages significantly enhanced the antitumor effect of RT. Mechanistically, DUOX1 deficiency increased the production of proinflammatory cytokines (IFNγ, CXCL9, CCL3 and TNFα) by activated macrophages in vitro and the expression of major histocompatibility complex class II in the membranes of macrophages. We also demonstrated that DUOX1 was involved in the phagocytotic function of macrophages in vitro and in vivo. The antitumor effect of Duox1-/- macrophages was associated with a significant increase in IFNγ production by both lymphoid and myeloid immune cells. CONCLUSIONS: Our data indicate that DUOX1 is a new target for macrophage reprogramming and suggest that DUOX1 inhibition in macrophages combined with RT is a new therapeutic strategy for the management of cancers.

Oxidative stress in thyroid carcinomas: biological and clinical significance.

At physiological concentrations, reactive oxygen species (ROS), including superoxide anions and H2O2, are considered as second messengers that play key roles in cellular functions, such as proliferation, gene expression, host defence and hormone synthesis. However, when they are at supraphysiological levels, ROS are considered potent DNA-damaging agents. Their increase induces oxidative stress, which can initiate and maintain genomic instability. The thyroid gland represents a good model for studying the impact of oxidative stress on genomic instability. Indeed, one particularity of this organ is that follicular thyroid cells synthesise thyroid hormones through a complex mechanism that requires H2O2. Because of their detection in thyroid adenomas and in early cell transformation, both oxidative stress and DNA damage are believed to be neoplasia-preceding events in thyroid cells. Oxidative DNA damage is, in addition, detected in the advanced stages of thyroid cancer, suggesting that oxidative lesions of DNA also contribute to the maintenance of genomic instability during the subsequent phases of tumourigenesis. Finally, ionizing radiation and the mutation of oncogenes, such as RAS and BRAF, play a key role in thyroid carcinogenesis through separate and unique mechanisms: they upregulate the expression of two distinct 'professional' ROS-generating systems, the NADPH oxidases DUOX1 and NOX4, which cause DNA damage that may promote chromosomal instability, tumourigenesis and dedifferentiation.

Selective modification of a native protein in a patient tissue homogenate using palladium nanoparticles.

We have developed new benign palladium nanoparticles able to catalyze the Suzuki-Miyaura cross-coupling reaction on human thyroglobulin (Tg), a naturally iodinated protein produced by the thyroid gland, in homogenates from patients' tissues. This represents the first example of a chemoselective native protein modification using transition metal nanoobjects in near-organ medium.