A possible role for oxidation stress in lymphoid leukaemias and therapeutic failure

Antitumor Effect of Brusatol in Acute Lymphoblastic Leukemia Models Is Triggered by Reactive Oxygen Species Accumulation

Acute lymphoblastic leukemia (ALL) is one of the most common hematological malignancies at pediatric ages and is characterized by different chromosomal rearrangements and genetic abnormalities involved in the differentiation and proliferation of lymphoid precursor cells. Brusatol is a quassinoid plant extract extensively studied due to its antineoplastic effect through global protein synthesis and nuclear factor erythroid 2-related factor-2 (NRF2) signaling inhibition. NRF2 is the main regulator of cellular antioxidant response and reactive oxygen species (ROS), which plays an important role in oxidative stress regulation. This study aimed to evaluate the effect of brusatol in in vitro models of ALL. KOPN-8 (B-ALL), CEM (T-ALL), and MOLT-4 (T-ALL) cell lines were incubated with increasing concentrations of brusatol, and the metabolic activity was evaluated using the resazurin assay. Flow cytometry was used to evaluate cell death, cell cycle, mitochondrial membrane potential (Δψmit), and to measure ROS and reduced glutathione (GSH) levels. Our results show that brusatol promoted a decrease in metabolic activity in ALL cell lines in a time-, dose-, and cell-line-dependent manner. Brusatol induced a cytostatic effect by cell cycle arrest in G0/G1 in all cell lines; however, cell death mediated by apoptosis was only observed in T-ALL cells. Brusatol leads to an oxidative stress imbalance by the increase in ROS levels, namely, superoxide anion. Redox imbalance and cellular apoptosis induced by brusatol are highly modulated by mitochondria disruption as a decrease in mitochondrial membrane potential is detected. These data suggest that brusatol might represent a new therapeutic approach for acute lymphoblastic leukemia, particularly for ALL T-cell lineage.

Impact of cancer metabolism on therapy resistance - Clinical implications

Despite an increasing arsenal of anticancer therapies, many patients continue to have poor outcomes due to the therapeutic failures and tumor relapses. Indeed, the clinical efficacy of anticancer therapies is markedly limited by intrinsic and/or acquired resistance mechanisms that can occur in any tumor type and with any treatment. Thus, there is an urgent clinical need to implement fundamental changes in the tumor treatment paradigm by the development of new experimental strategies that can help to predict the occurrence of clinical drug resistance and to identify alternative therapeutic options. Apart from mutation-driven resistance mechanisms, tumor microenvironment (TME) conditions generate an intratumoral phenotypic heterogeneity that supports disease progression and dismal outcomes. Tumor cell metabolism is a prototypical example of dynamic, heterogeneous, and adaptive phenotypic trait, resulting from the combination of intrinsic [(epi)genetic changes, tissue of origin and differentiation dependency] and extrinsic (oxygen and nutrient availability, metabolic interactions within the TME) factors, enabling cancer cells to survive, metastasize and develop resistance to anticancer therapies. In this review, we summarize the current knowledge regarding metabolism-based mechanisms conferring adaptive resistance to chemo-, radio-and immunotherapies as well as targeted therapies. Furthermore, we report the role of TME-mediated intratumoral metabolic heterogeneity in therapy resistance and how adaptations in amino acid, glucose, and lipid metabolism support the growth of therapy-resistant cancers and/or cellular subpopulations. We also report the intricate interplay between tumor signaling and metabolic pathways in cancer cells and discuss how manipulating key metabolic enzymes and/or providing dietary changes may help to eradicate relapse-sustaining cancer cells. Finally, in the current era of personalized medicine, we describe the strategies that may be applied to implement metabolic profiling for tumor imaging, biomarker identification, selection of tailored treatments and monitoring therapy response during the clinical management of cancer patients.

Oxidative Stress Parameters Can Predict the Response to Erythropoiesis-Stimulating Agents in Myelodysplastic Syndrome Patients

Oxidative stress has been implicated in the development of several types of cancer, including myelodysplastic syndromes (MDS), as well as in the resistance to treatment. In this work, we assessed the potential of oxidative stress parameters to predict the response to erythropoiesis-stimulating agents (ESAs) in lower-risk MDS patients. To this end, we analyzed the systemic levels of reactive species (peroxides and NO), antioxidant defenses (uric acid, vitamin E, vitamin A, GSH, GSSG, TAS, as well as GPX and GR activities], and oxidative damage (8-OH-dG and MDA) in 66 MDS patients, from those 44 have been treated with ESA. We also calculated the peroxides/TAS and NO/TAS ratios and analyzed the gene expression of levels of the redox regulators, NFE2L2 and KEAP1. We found that patients that respond to ESA treatment showed lower levels of plasma peroxides (p < 0.001), cellular GSH (p < 0.001), and cellular GR activity (p = 0.001) when compared to patients who did not respond to ESA treatment. ESA responders also showed lower levels of peroxides/TAS ratio (p < 0.001) and higher levels of the expression of the NFE2L2 gene (p = 0.001) than those that did not respond to ESA treatment. The levels of plasmatic peroxides shown to be the most accurate biomarker of ESA response, with good sensitivity (80%) and specificity (100%) and is an independent biomarker associated with therapy response. Overall, the present study demonstrated a correlation between oxidative stress levels and the response to ESA treatment in lower-risk MDS patients, with the plasmatic peroxides levels a good predictive biomarker of drug (ESA) response.

Simultaneous determination of three endogenous chiral thiol compounds in serum from humans at normal and stress states using ultrahigh-performance liquid chromatography coupled to quadrupole-Orbitrap high resolution mass spectrometry

Measurement of chiral thiol compounds such as glutathione (GSH), cysteine (Cys), and homocysteine (Hcy) in human serum plays an important role in the early diagnosis and warning of cardiovascular disease, neurodegenerative disease, and cancer. We developed a novel chiral mass spectrometry derivatization reagent, (R)-(5-(3-isothiocyanatopyrrolidin-1-yl)-5-oxopentyl) triphenylphosphonium (NCS-OTPP), with triphenylphosphine (TPP) as a basic structure carrying a permanent positive charge for the diastereomeric separation of chiral thiol compounds by ultrahigh-performance liquid chromatography coupled to quadrupole-Orbitrap high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS). A novel method was developed for simultaneous determination of three kinds of chiral thiol compounds based on the NCS-OTPP derivatization method. Three kinds of chiral thiol compounds on a YMC Triart C18 (2.0 × 150 mm, 1.9 μm) column with Rs were 1.56-1.68. The protonated precursor to product ion transitions monitored for GSH was m/z 780.16→747.24/473.18, Cys was m/z 594.20→561.18/473.18, and Hcy was m/z 608.21→575.19/473.18. An excellent linearity for all the analytes with correlation coefficients ≥ 0.9995 and suitable precision with inter-day and intra-day coefficients of variation RSDs was 0.83-4.06% and 0.95-3.11%. Satisfactory accuracy with recoveries between 83.73 and 103.35% was observed. The limit of detection (S/N = 3) was 2.4-7.2 fmol. Furthermore, the method was successfully applied to the simultaneous determination of three kinds of free and total thiol compounds in serum from 10 healthy volunteers at normal and stress states.

Impact of the induction phase chemotherapy on cytokines and oxidative markers in peripheral and bone marrow plasma of children with acute lymphocytic leukemia

B-cell acute lymphocytic leukemia (B-ALL) is the main neoplasia affecting children worldwide, in which cytotoxic chemotherapy remains the main treatment modality. In this study, we analyzed the profile of inflammatory markers concerning oxidative stress and cytokines in 17 B-ALL patients. Peripheral blood (PB) and bone marrow (BM) samples were collected and evaluated for the pro-oxidative status (nitric oxide products-NOx and hydroperoxides), antioxidants (sulfhydryl groups-SH and total radical-trapping antioxidant parameter-TRAP), and cytokines (TNF-α, IFN-γ), at diagnosis (D0) to and the end of the induction phase (D28). At D28, hydroperoxides were higher in PB, concomitant to TNF-α levels. INF-γ was increased in the BM at D28. Hydroperoxides were higher in patients presenting malignant cells in BM and/or PB after treatment, a condition named minimal residual disease (MRD) when compared to those without MRD at D28. These findings suggest that oxidative stress and cytokines vary across the B-ALL induction phase, and lipid peroxidation is a potential marker associated with MRD status.

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B-ALL is the main neoplasia in childhood.

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Chemotherapy is the main modality for B-ALL treatment, and the success in the initial phase is determinant on the rates of cure.

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Oxidative stress is one of the main known mechanisms of action of chemotherapy.

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We showed that the initial chemotherapy of B-ALL is mediated by oxidative stress fluctuations

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Lipid peroxides are associated to disease elimination in the induction phase.

Development of C60-based labeling reagents for the determination of low-molecular-weight compounds by matrix assisted laser desorption ionization mass spectrometry (II): Determination of thiols in human serum

Perturbation of thiol homeostasis in biological fluids are thought to be associated with several diseases, and reliable analytical methods for the determination of low molecular weight (LMW) thiols in human plasma or serum are thus required. In this study, a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) method is described for high throughput determination of four LMW thiols (glutathione, cysteine, homocysteine and cysteinylglycine) in human serum. It is based on the use of a bromoacetyl functionalized C60 (Br-C60) as a derivatization reagent to label thiols. The Br-C60 labeling can add an 832-Da tag to thiols, which moves thiol signals to high mass region and effectively avoids the signal interference generated by the traditional MALDI matrix below 800 Da. The labeling can be completed within 5 min under microwave-assisted condition. Thereby, the Br-C60 labeling based MALDI-TOF MS analytical method can achieve high throughput analysis of LMW thiols in serum. Good linearities of the method for the thiols in human serum were obtained in the range of 0.5-500.0 μM with correlation coefficient (R) greater than 0.9960. The limit of detection is in the range of 0.07-0.18 μM for the investigated thiols in human serum with relative standard deviations of lower than 13.5% and recoveries ranging from 81.9 to 117.1%. Using the method, four thiols in microliter serum samples of breast cancer (BC) patients were determined. The result showed that the contents of the four thiols in BC serum samples significantly changed compared to the healthy control (HC).

Oxidative Stress in Tunisian Patients With Acute Lymphoblastic Leukemia and Its Involvement in Leukemic Relapse

The aim of the present study was to evaluate in patients with acute lymphoblastic leukemia (ALL), the oxidative status and antioxidant defense and its involvement in the relapse of ALL. The plasmatic levels of malondialdehyde, advanced oxidation of protein products and reduced glutathione (GSH), and the plasmatic activities of catalase, superoxide dismutase (SOD), and glutathione peroxidase were determined in 34 patients who were newly diagnosed with ALL and compared with 92 healthy individuals. The plasmatic concentrations of malondialdehyde and advanced oxidation of protein products were higher in ALL patients than in controls and increased during chemotherapy. A decrease in glutathione peroxidase activity and an increase in catalase and SOD activities and GSH plasma levels were observed in ALL patients, as compared with sex-matched controls. Moreover, SOD activity and GSH levels were significantly correlated with the relapse of ALL patients. These data suggest the involvement of oxidative stress in acute lymphoid leukemias and leukemic relapse.

Analytical methods involving separation techniques for determination of low-molecular-weight biothiols in human plasma and blood

Low-molecular-weight biothiols such as homocysteine, cysteine, and glutathione are metabolites of the sulfur cycle and play important roles in biological processes such as the antioxidant defense network, methionine cycle, and protein synthesis. Thiol concentrations in human plasma and blood are related to diseases such as cardiovascular disease, neurodegenerative disease, and cancer. The concentrations of homocysteine, cysteine, and glutathione in plasma samples from healthy human subjects are approximately in the range of 5-15, 200-300, and 1-5 μM, respectively. Glutathione concentration in the whole blood is in the millimolar range. Measurement of biothiol levels in plasma and blood is thought to be important for understanding the physiological roles and biomarkers for certain diseases. This review summarizes the relationship of biothiols with certain disease as well as pre-analytical treatment and analytical methods for determination of biothiols in human plasma and blood by using high-performance liquid chromatography and capillary electrophoresis coupled with ultraviolet, fluorescence, or chemiluminescence detection; or mass spectrometry.

The glutathione peroxidase 1-protein tyrosine phosphatase 1B-protein phosphatase 2A axis. A key determinant of airway inflammation and alveolar destruction

Protein phosphatase-2A (PP2A) is a primary serine-threonine phosphatase that modulates inflammatory responses in asthma and chronic obstructive pulmonary disease (COPD). Despite its importance, the mechanisms that regulate lung PP2A activity remain to be determined. The redox-sensitive enzyme protein tyrosine phosphatase-1B (PTP1B) activates PP2A by dephosphorylating the catalytic subunit of the protein at tyrosine 307. This study aimed to identify how the interaction between the intracellular antioxidant glutathione peroxidase-1 (GPx-1) and PTP1B affected lung PP2A activity and airway inflammation. Experiments using gene silencing techniques in mouse lung or human small airway epithelial cells determined that knocking down PTP1B expression blocked GPx-1's activation of PP2A and negated the anti-inflammatory effects of GPx-1 protein in the lung. Similarly, the expression of human GPx-1 in transgenic mice significantly increased PP2A and PTP1B activities and prevented chronic cigarette smoke-induced airway inflammation and alveolar destruction. GPx-1 knockout mice, however, exhibited an exaggerated emphysema phenotype, correlating with a nonresponsive PP2A pathway. Importantly, GPx-1-PTP1B-PP2A signaling becomes inactivated in advanced lung disease. Indeed, PTP1B protein was oxidized in the lungs of subjects with advanced emphysema, and cigarette smoke did not increase GPx-1 or PTP1B activity within epithelial cells isolated from subjects with COPD, unlike samples of healthy lung epithelial cells. In conclusion, these findings establish that the GPx-1-PTP1B-PP2A axis plays a critical role in countering the inflammatory and proteolytic responses that result in lung-tissue destruction in response to cigarette smoke exposure.

Serum human leukocyte antigen-G and soluble interleukin 2 receptor levels in acute lymphoblastic leukemic pediatric patients

AIMS AND BACKGROUND

Human leukocyte antigen-G and interleukin-2 receptor play pivotal roles in the proliferation of lymphocytes, and thus generation of immune responses. Their overexpression has been evidenced in different malignant hematopoietic diseases. This study aimed to validate serum soluble human leukocyte antigen-G (sHLA-G) and serum soluble interleukin-2 receptor (sIL-2R) as an additional tool for the diagnosis and follow up of acute lymphoblastic leukemia (ALL).

SUBJECTS AND METHODS

Both markers were determined by ELISA in the serum of 33 ALL pediatric patients before treatment and after intensification phase of chemotherapy as well as in the serum of 14 healthy donors that were selected as a control group.

RESULTS

ALL patients showed abnormal CBC and high serum lactate dehydrogenase, which were improved after chemotherapy. Also, there was a non-significant increase in serum sHLA-G in ALL patients compared with the control group. However, after chemotherapy, sHLA-G was increased significantly compared with before treatment. On the other hand, serum sIL-2R in ALL patients was increased significantly compared with the control group. After chemotherapy, sIL-2R decreased significantly compared with before treatment.

CONCLUSIONS

From these results it could be suggested that measurement of serum sHLA-G might be helpful in diagnosis of ALL, while sIL-2R might be useful in diagnosis and follow-up of ALL in pediatric patients.

Chronic lymphocytic leukaemia--the role of the microenvironment pathogenesis and therapy

Chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL) is one of the more common forms of B cell malignancy. Although the condition has a variable clinical course, the trend is towards eventual relapse and the disease is considered incurable. Whilst the majority of the circulating CD5-positive neoplastic B cells are arrested in the G0 phase of the cell cycle, those in the bone marrow and lymphoid tissues proliferate at a rate of 0·1-1% of the entire clone per day. This proliferation is supported by the tissue microenvironment, which has been shown to induce upregulation of anti-apoptotic proteins and enhance the survival of the neoplastic cells. Microenvironmental factors are also thought to be important in tumour relapse and resistance to therapy. This review outlines the main signalling pathways involved in these tumour cell-stromal interactions, and includes potential therapeutic strategies based on the manipulation of key components within the CLL microenvironment.