Redox regulation of STAT1 and STAT3 signaling

STAT1 and STAT3 are nuclear transcription factors that regulate genes involved in cell cycle, cell survival and immune response. The cross-talk between these signaling pathways determines how cells integrate the environmental signals received ultimately translating them in transcriptional regulation of specific sets of genes. Despite being activated downstream of common cytokine and growth factors, STAT1 and STAT3 play essentially antagonistic roles and the disruption of their balance directs cells from survival to apoptotic cell death or from inflammatory to anti-inflammatory responses. Different mechanisms are proposed to explain this yin-yang relationship. Considering the redox aspect of STATs proteins, this review attempts to summarize the current knowledge of redox regulation of STAT1 and STAT3 signaling focusing the attention on the post-translational modifications that affect their activity

Natural sesquiterpene lactones enhance chemosensitivity of tumor cells through redox regulation of STAT3 signaling

STAT3 is a nuclear transcription factor that regulates genes involved in cell cycle, cell survival, and immune response. Although STAT3 activation drives cells to physiological response, its deregulation is often associated with the development and progression of many solid and hematological tumors as well as with drug resistance. STAT3 is a redox-sensitive protein, and its activation state is related to intracellular GSH levels. Under oxidative conditions, STAT3 activity is regulated by S-glutathionylation, a reversible posttranslational modification of cysteine residues. Compounds able to suppress STAT3 activation and, on the other hand, to modulate intracellular redox homeostasis may potentially improve cancer treatment outcome. Nowadays, about 35% of commercial drugs are natural compounds that derive from plant extracts used in phytotherapy and traditional medicine. Sesquiterpene lactones are an interesting chemical group of plant-derived compounds often employed in traditional medicine against inflammation and cancer. This review focuses on sesquiterpene lactones able to downmodulate STAT3 signaling leading to an antitumor effect and correlates the anti-STAT3 activity with their ability to decrease GSH levels in cancer cells. These properties make them lead compounds for the development of a new therapeutic strategy for cancer treatment

Immunoprecipitation methods to identify S-glutathionylation in target proteins

S-glutathionylation is a reversible post-translational modification of proteins that generate a mixed disulfide between glutathione to thiolate anion of cysteine residues in target proteins. In the last ten years, S-glutathionylation has been extensively studied since it represents the cellular response to oxidative stress, in physiological as well as pathological conditions. This modification may be a protective mechanism from irreversible oxidative damage and, on the other hand, may modulate protein folding and function. Due to the importance of S-glutathionylation in cellular redox signaling, various methods have been developed to identify S-gluthationylated proteins. Herein, we describe two easy methods to recognized S-glutathionylation of a target protein after oxidative stress in cellular extracts based on different immunoprecipitation procedures. The immunoprecipitation assay allows the capture of one glutathionylated protein using a specific antibody that binds to the target protein. The presence of S-glutathionylation in the immunoprecipitated protein is identified using anti-glutathione antibody. The second type of approach is based on the detection of the glutathionylated protein with biotin/streptavidin technique. After different steps of protection of non-oxidized thiolic groups and reduction of S-glutathionylated groups, the newly-formed protein free-thiols are labeled with biotin-GSH. The modified protein can be isolate with streptavidin-beads and recognized using an antibody against target protein. \u2022S-glutathionylation is a reversible post-translational modification of proteins that recently has been emerged as important signaling in the redox regulation of protein function.\u2022Both methods to identify glutathionylated proteins are economic, easy and do not require particular equipment.\u2022The setups of both methods guarantee high reproducibility

Tumor dormancy and interplay with hypoxic tumor microenvironment

The tumor microenvironment is a key factor in disease progression, local resistance, immune-escaping, and metastasis. The rapid proliferation of tumor cells and the aberrant structure of the blood vessels within tumors result in a marked heterogeneity in the perfusion of the tumor tissue with regions of hypoxia. Although most of the tumor cells die in these hypoxic conditions, a part of them can adapt and survive for many days or months in a dormant state. Dormant tumor cells are characterized by cell cycle arrest in G0/G1 phase as well as a low metabolism, and are refractive to common chemotherapy, giving rise to metastasis. Despite these features, the cells retain their ability to proliferate when conditions improve. An understanding of the regulatory machinery of tumor dormancy is essential for identifying early cancer biomarkers and could provide a rationale for the development of novel agents to target dormant tumor cell populations. In this review, we examine the current knowledge of the mechanisms allowing tumor dormancy and discuss the crucial role of the hypoxic microenvironment in this process

Essential oils and their nanoformulations for breast cancer therapy

Breast Cancer (BC) is the most prevalent type of cancer in the world. Current treatments include surgery, radiation, and chemotherapy but often are associated with high toxicity to normal tissues, chemoresistance, and relapse. Thus, developing novel therapies which could combat these limitations is essential for effective treatment. In this context, phytochemicals are increasingly getting popular due to their safety profile, ability to efficiently target tumors, and circumvent limitations of existing treatments. Essential Oils (EOs) are mixtures of various phytochemicals which have shown potential anticancer activity in preclinical BC models. However, their clinical translation is limited by factors such as high volatility, low stability, and poor solubility. Nanotechnology has facilitated their encapsulation in a variety of nanostructures and proven to overcome these limitations. In this review, we have efficiently summarized the current knowledge on the anticancer effect of EOs and constituents in both in in vitro and in in vivo BC models. Further, we also provide a descriptive account on the potential of nanotechnology in enhancing the anti-BC activity of EOs and their constituents. The papers discussed in this review were selected using the keywords "antiproliferative Essential Oils in breast cancer," "anticancer activity of Essential Oil in breast cancer," and "cytotoxicity of Essential Oils in breast cancer" performed in PubMed and ScienceDirect databases

Pro-apoptotic activity of α-bisabolol in preclinical models of primary human acute leukemia cells

<p>Abstract</p> <p>Background</p> <p>We previously demonstrated that the plant-derived agent α-bisabolol enters cells <it>via </it>lipid rafts, binds to the pro-apoptotic Bcl-2 family protein BID, and may induce apoptosis. Here we studied the activity of α-bisabolol in acute leukemia cells.</p> <p>Methods</p> <p>We tested <it>ex vivo </it>blasts from 42 acute leukemias (14 Philadelphia-negative and 14 Philadelphia-positive B acute lymphoid leukemias, Ph^-/Ph⁺B-ALL; 14 acute myeloid leukemias, AML) for their sensitivity to α-bisabolol in 24-hour dose-response assays. Concentrations and time were chosen based on CD34⁺, CD33⁺my and normal peripheral blood cell sensitivity to increasing α-bisabolol concentrations for up to 120 hours.</p> <p>Results</p> <p>A clustering analysis of the sensitivity over 24 hours identified three clusters. Cluster 1 (14 ± 5 μM α-bisabolol IC₅₀) included mainly Ph^-B-ALL cells. AML cells were split into cluster 2 and 3 (45 ± 7 and 65 ± 5 μM IC₅₀). Ph⁺B-ALL cells were scattered, but mainly grouped into cluster 2. All leukemias, including 3 imatinib-resistant cases, were eventually responsive, but a subset of B-ALL cells was fairly sensitive to low α-bisabolol concentrations. α-bisabolol acted as a pro-apoptotic agent <it>via </it>a direct damage to mitochondrial integrity, which was responsible for the decrease in NADH-supported state 3 respiration and the disruption of the mitochondrial membrane potential.</p> <p>Conclusion</p> <p>Our study provides the first evidence that α-bisabolol is a pro-apoptotic agent for primary human acute leukemia cells.</p

Synthesis and biological evaluation of new N-alkylcarbazole derivatives as STAT3 inhibitors: preliminary study

The signalling pathway of Janus tyrosine Kinases-Signal Transducers and Activators of Transcription (JAKSTAT) is activated by a number of cytokines, hormones (GH, erythropoietin and prolactin), and growth factors. JAK-STAT signalling is involved in regulation of cell proliferation, differentiation and apoptosis. These activities are due to different members of JAK-STAT family consisting of: JAK1, JAK2, JAK3, Tyk2 and STAT1, STAT2, STAT3, STAT4, STAT5a, STAT5b, STAT6. Recent studies suggest a key role for STAT family proteins, in particular for STAT3, in selectively inducing and maintaining a pro-carcinogenic inflammatory microenvironment, that promote tumour cells transformation. Moreover, a striking correlation between cancer development/progression and STAT3 persistent activation exists, probably due to STAT3 promoting of the pro-oncogenic inflammatory pathways, like NF-kB, IL-6 and JAK family kinases. Recent study demonstrated that carbazoles can inhibit STAT3 mediated transcription. From these evidences, STAT3 represents a therapeutic target, so we have synthesized a new set of N-alkylcarbazole derivatives substituted in positions 2, 4 and 6, to evaluate their activity on STAT3. Some of these compounds showed an interesting activity as STAT3 selective inhibitors; in particular, compounds 9a 9b and 9c revealed to inhibit the STAT3 activation for the 50%, 90% and 95%, respectively

Biopsychosocial model of resilience in young adults with multiple sclerosis (BPS-ARMS): an observational study protocol exploring psychological reactions early after diagnosis

INTRODUCTION: Multiple sclerosis (MS), the most common neurological disease causing disability in young adults, is widely recognised as a major stress factor. Studies have shown that the first years after the diagnosis are distressing in terms of adjustment to the disease and that MS negatively affects patients' psychological well-being, quality of life (QoL) and social functioning. However, the links between disease-specific variables at diagnosis, resilience and psychological adjustment of patients with MS remain largely unexplored, especially in adolescents and young adults. This observational study aims to fill the gap of knowledge on biopsychosocial characteristics and resilience of young adults with MS to evaluate the relationship among these variables and to develop a biopsychosocial model of resilience. METHODS AND ANALYSIS: Biological and clinical characteristics of young adults newly diagnosed with MS will be investigated by collecting clinical information, performing neurological examinations, MRI and analysing cerebrospinal fluid and blood biomarkers (eg, measures of inflammation), body composition, gut microbiota and movement/perceptual markers. Psychosocial characteristics (eg, psychological distress, coping strategies), QoL, psychological well-being and resilience will be assessed by self-report questionnaires. Comparative statistics (ie, analysis of variance or unpaired samples t-test, correlation and regression analyses) will be applied to evaluate the relationship among biological, psychological and social factors. The results are expected to allow a comprehensive understanding of the determinants of resilience in young patients with MS and to inform resilience interventions, tailored to young patients' specific needs, aiming to reduce the risk of maladaptive reactions to the disease and to improve psychological well-being and QoL. ETHICS AND DISSEMINATION: The study has been approved by the Verona University Hospital Ethics Committee (approval number: 2029CESC). The findings will be disseminated through scientific publications in peer-reviewed journals, conference presentations, social media and specific websites. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov (NCT03825055)

Rehabilitation and biomarkers of stroke recovery: study protocol for a randomized controlled trial

Background: Stroke is a leading cause of disability. Nonetheless, the care pathway for stroke rehabilitation takes partially into account the needs of chronic patients. This is due in part to the lack of evidence about the mechanisms of recovery after stroke, together with the poor knowledge of related and influencing factors. Here we report on the study protocol \u201cRehabilitation and Biomarkers of Stroke Recovery,\u201d which consists of 7 work-packages and mainly aim to investigate the effects of long-term neurorehabilitation on stroke patients and to define a related profile of (clinical-biological, imaging, neurophysiological, and genetic-molecular) biomarkers of long-term recovery after stroke. The work-package 1 will represent the main part of this protocol and aims to compare the long-term effects of intensive self-rehabilitation vs. usual (rehabilitation) care for stroke. Methods: We planned to include a total of 134 adult subacute stroke patients (no more than 3 months since onset) suffering from multidomain disability as a consequence of first-ever unilateral ischemic stroke. Eligible participants will be randomly assigned to one of the following groups: intensive self-rehabilitation (based on the principles of \u201cGuided Self-Rehabilitation Contract\u201d) vs. usual care (routine practice). Treatment will last 1 year, and patients will be evaluated every 3 months according to their clinical presentation. The following outcomes will be considered in the main work-package: Fugl-Meyer assessment, Cognitive Oxford Screen Barthel Index, structural and functional neuroimaging, cortical excitability, and motor and somatosensory evoked potentials. Discussion: This trial will deal with the effects of an intensive self-management rehabilitation protocol and a related set of biomarkers. It will also investigate the role of training intensity on long-term recovery after stroke. In addition, it will define a set of biomarkers related to post-stroke recovery and neurorehabilitation outcome in order to detect patients with greater potential and define long-term individualized rehabilitation programs. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT04323501

Targeting STAT1 by myricetin and delphinidin provides efficient protection of the heart from ischemia/reperfusion-induced injury

AbstractFlavonoids exhibit a variety of beneficial effects in cardiovascular diseases. Although their therapeutic properties have been attributed mainly to their antioxidant action, they have additional protective mechanisms such as inhibition of signal transducer and activator of transcription 1 (STAT1) activation. Here, we have investigated the cardioprotective mechanisms of strong antioxidant flavonoids such as quercetin, myricetin and delphinidin. Although all of them protect the heart from ischemia/reperfusion-injury, myricetin and delphinidin exert a more pronounced protective action than quercetin by their capacity to inhibit STAT1 activation. Biochemical and computer modeling analysis indicated the direct interaction between STAT1 and flavonoids with anti-STAT1 activity