Alteration of glucose metabolism and expression of glucose transporters in ovarian cancer

Aerobic glycolysis also known as the Warburg effect, remains a hallmark of various cancers, including ovarian cancer. Cancer cells undergo metabolic changes to sustain their tumorigenic properties and adapt to environmental conditions, such as hypoxia and nutrient starvation. Altered metabolic pathways not only facilitate ovarian cancer cells’ survival and proliferation but also endow them to metastasize, develop resistance to chemotherapy, maintain cancer stem cell phenotype, and escape anti-tumor immune responses. Glucose transporters (GLUTs), which play a pivotal role as the rate-limiting step in glycolysis, are frequently overexpressed in a variety of tumors, including ovarian cancer. Multiple oncoproteins can regulate GLUT proteins, promoting tumor proliferation, migration, and metastasis, either dependent or independent of glycolysis. This review examines the alteration of GLUT proteins, particularly GLUT1, in ovarian cancer and its impact on cancer initiation, progression, and resistance to treatment. Additionally, it highlights the role of these proteins as biomarkers for diagnosis and prognosis in ovarian cancer, and delves into novel therapeutic strategies currently under development that target GLUT isoforms

When an Intramolecular Disulfide Bridge Governs the Interaction of DUOX2 with Its Partner DUOXA2

Aims: The dual oxidase 2 (DUOX2) protein belongs to the NADPH oxidase (NOX) family. As H2O2 generator, it plays a key role in both thyroid hormone biosynthesis and innate immunity. DUOX2 forms with its maturation factor, DUOX activator 2 (DUOXA2), a stable complex at the cell surface that is crucial for the H2O2-generating activity, but the nature of their interaction is unknown. The contribution of some cysteine residues located in the N-terminal ectodomain of DUOX2 in a surface protein?protein interaction is suggested. We have investigated the involvement of different cysteine residues in the formation of covalent bonds that could be of critical importance for the function of the complex. Results: We report the identification and the characterization of an intramolecular disulfide bond between cys-124 of the N-terminal ectodomain and cys-1162 of an extracellular loop of DUOX2, which has important functional implications in both export and activity of DUOX2. This intramolecular bridge provides structural support for the formation of interdisulfide bridges between the N-terminal domain of DUOX2 and the two extracellular loops of its partner, DUOXA2. Innovation: Both stability and function of the maturation factor, DUOXA2, are dependent on the oxidative folding of DUOX2, indicating that DUOX2 displays a chaperone-like function with respect to its partner. Conclusions: The oxidative folding of DUOX2 that takes place in the endoplasmic reticulum (ER) appears to be a key event in the trafficking of the DUOX2/DUOXA2 complex as it promotes an appropriate conformation of the N-terminal region, which is propitious to subsequent covalent interactions with the maturation factor, DUOXA2. Antioxid. Redox Signal. 23, 724?733.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140308/1/ars.2015.6265.pd

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 \u2018HMIMV\u2019 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 \u2018PTC\u2019 with a prevalence of 28% (8 PTC out 29 PTC). Like international trends, Papillary Thyroid Carcinomas \u2019PTC\u2019 is more frequent than Follicular Thyroid Carcinomas \u2018FTC\u2019 and Anaplastic Thyroid Carcinomas \u2018ATC\u2019 (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

Detection of Intracellular Reactive Oxygen Species (CM-H2DCFDA)

Reactive oxygen species (ROS) play a critical role in cellular physiopathology. ROS are implicated in cell proliferation, signaling pathways, oxidative defense mechanisms responsible for killing of bacteria, thyroid hormonosynthesis, etc. The cellular Redox homeostasis is balanced by oxidants and antioxidants systems. In several diseases (cancer, neurodegenerative diseases, cardiovascular diseases), the Redox balance is disturbed. In fact, excessive amounts of ROS can damage proteins, lipids and DNA at cellular level. The choose of a sensitive method for detection of intracellular ROS is very important for detecting the disturbed Redox balance in pathological cells and after exposition of cells to different genotoxic agents (Irradiation, Oxidative stress, etc).The detection of ROS in biological systems is difficult for several reasons: Method sensibility and probe specificity. The 2′, 7′-dichlorodihydrofluorescein diacetate (H2DCF-DA) fluorescent probe is commonly employed and may react with several ROS including hydrogen peroxide, hydroxyl radicals and peroxynitrite. The cell-permeant H2DCFDA passively diffuses into cells and is retained in the intracellular level after cleavage by intracellular esterases. Upon oxidation by ROS, the nonfluorescent H2DCFDA is converted to the highly fluorescent 2',7'-dichlorofluorescein (DCF). The chloromethyl derivative of H2DCFDA (CM-H2DCFDA) provides much better retention in live cells than H2DCFDA. Dead or dying cells produces ROS. When we want to detect ROS in living cells, we have to stain cells by propidium iodide (PI) and evaluate ROS production only in living cells which are PI negative. In fact, PI intercalates into double-stranded nucleic acids. It is excluded by viable cells but can penetrate cell membranes of dying or dead cells. PI is excited at 488 nm and emits at a maximum wavelength of 617 nm. Because of these spectral characteristics, PI can be used in combination with other fluorescent probe such as CM-H2DCFDA (excitation/emission: 492–495/517–527 nm).A probe fluorescence emission can be assessed by Flow cytometry, a standard fluorometer or fluorescence microscopy using appropriate filter.Flow cytometry is commonly employed to detect intracellular ROS production. Flow cytometry measures fluorescence per cell. The cells is excited by the light source and emitted light from cells are converted to electrical pulses by optical detectors. Emitted Light is send to different detectors by using optical filters: 525 nm Band Pass Filter for FL-1 and 620 nm Band Pass Filter for FL-3. A 525 nm band pass filter (FL-1) placed in the light path prior to the detector will only allow “green” light into the detector. So, FL-1 is used in our protocol to collect green light corresponding to the oxidation of dichlorodihydrofluorescein (DCF) by ROS. FL-1 is the Green (FL-1) channel on flow cytometers. 620 nm Band Pass Filter (FL-3) only allow “red” light into the detector. Red fluorescence emission is measured in the Red (FL-3) channel on most flow cytometers

Oxidative stress in thyroid carcinomas: biological and clinical significance

International audienc

Conformation of the N-Terminal Ectodomain Elicits Different Effects on DUOX Function: A Potential Impact on Congenital Hypothyroidism Caused by a H 2 O 2 Production Defect

International audienc

NADPH oxidase DUOX1 sustains TGF-β1 signalling and promotes lung fibrosis

International audienceInterstitial lung fibroblast activation coupled with extracellular matrix production is a pathological signature of pulmonary fibrosis, and is governed by transforming growth factor (TGF)-β1/Smad signalling. TGF-β1 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 (H 2 O 2­­ )-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-β1 upregulates DUOX1 and its maturation factor DUOXA1 and that DUOX1-derived H 2 O 2 promoted the duration of TGF-β1-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 H 2 O 2 in a positive feedback that amplifies the signalling output of the TGF-β1 pathway and identify DUOX1 as a new therapeutic target in pulmonary fibrosis

BRCA1 Promoter Hypermethylation in Malignant Breast Tumors and in the Histologically Normal Adjacent Tissues to the Tumors: Exploring Its Potential as a Biomarker and Its Clinical Significance in a Translational Approach

The hypermethylation status of the promoter region of the breast cancer 1 (BRCA1), a well-known tumor suppressor gene, has been extensively investigated in the last two decades as a potential biomarker for breast cancer. In this retrospective study, we investigated the prevalence of BRCA1 promoter methylation in 84 human breast tissues, and we correlated this epigenetic silencing with the clinical and histopathological parameters of breast cancer. We used methylation-specific PCR (MSP) to analyze BRCA1 promoter hypermethylation in 48 malignant breast tumors (MBTs), 15 normal adjacent tissues (NATs), and 21 benign breast lesions (BBLs). The results showed that BRCA1 promoter hypermethylation was higher in MBTs (20/48; 41.67%) and NATs (7/15; 46.67%) compared to BBLs (4/21; 19.05%). The high percentage of BRCA1 hypermethylation in the histologically normal adjacent tissues to the tumors (NATs) suggests the involvement of this epigenetic silencing as a potential biomarker of the early genomic instability in NATs surrounding the tumors. The detection of BRCA1 promoter hypermethylation in BBLs reinforces this suggestion, knowing that a non-negligible rate of benign breast lesions was reported to evolve into cancer. Moreover, our results indicated that the BRCA1 promoter hypermethylated group of MBTs exhibited higher rates of aggressive features, as indicated by the SBR III grade (14/19; 73.68%), elevated Ki67 levels (13/16; 81.25%), and Her2 receptor overexpression (5/20; 25%). Finally, we observed a concordance (60%) in BRCA1 promoter hypermethylation status between malignant breast tumors and their paired histologically normal adjacent tissues. This study highlights the role of BRCA1 promoter hypermethylation as a potential useful biomarker of aggressiveness in MBTs and as an early marker of genomic instability in both histological NATs and BBLs