scholarly journals Oxidative Stress and X-ray Exposure Levels-Dependent Survival and Metabolic Changes in Murine HSPCs

Antioxidants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Melis Karabulutoglu ◽  
Rosemary Finnon ◽  
Lourdes Cruz-Garcia ◽  
Mark A. Hill ◽  
Christophe Badie
Keyword(s):  
Oxidative Stress ◽  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Metabolic Changes ◽  
Target Cells ◽  
Dependent Manner ◽  
X Ray ◽  
Regulatory Systems ◽  
Dose Dependent ◽  
Acute Myeloid

Haematopoietic bone marrow cells are amongst the most sensitive to ionizing radiation (IR), initially resulting in cell death or genotoxicity that may later lead to leukaemia development, most frequently Acute Myeloid Leukaemia (AML). The target cells for radiation-induced Acute Myeloid Leukaemia (rAML) are believed to lie in the haematopoietic stem and progenitor cell (HSPC) compartment. Using the inbred strain CBA/Ca as a murine model of rAML, progress has been made in understanding the underlying mechanisms, characterisation of target cell population and responses to IR. Complex regulatory systems maintain haematopoietic homeostasis which may act to modulate the risk of rAML. However, little is currently known about the role of metabolic factors and diet in these regulatory systems and modification of the risk of AML development. This study characterises cellular proliferative and clonogenic potential as well as metabolic changes within murine HSPCs under oxidative stress and X-ray exposure. Ambient oxygen (normoxia; 20.8% O2) levels were found to increase irradiated HSPC-stress, stimulating proliferative activity compared to low oxygen (3% O2) levels. IR exposure has a negative influence on the proliferative capability of HSPCs in a dose-dependent manner (0–2 Gy) and this is more pronounced under a normoxic state. One Gy x-irradiated HSPCs cultured under normoxic conditions displayed a significant increase in oxygen consumption compared to those cultured under low O2 conditions and to unirradiated HSPCs. Furthermore, mitochondrial analyses revealed a significant increase in mitochondrial DNA (mtDNA) content, mitochondrial mass and membrane potential in a dose-dependent manner under normoxic conditions. Our results demonstrate that both IR and normoxia act as stressors for HSPCs, leading to significant metabolic deregulation and mitochondrial dysfunctionality which may affect long term risks such as leukaemia.

Immunoliposomes in Acute Myeloid Leukaemia Therapy: An Overview of Possible Targets and Obstacles

2019 ◽  
Vol 26 (28) ◽  
pp. 5278-5292 ◽  
Author(s):  
Aditi Singh ◽  
Nikolai Norevik Myklebust ◽  
Sarah Marie Vie Furevik ◽  
Ragnhild Haugse ◽  
Lars Herfindal
Keyword(s):  
Drug Delivery ◽  
Stem Cells ◽  
Bone Marrow ◽  
Side Effects ◽  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Drug Delivery System ◽  
Delivery System ◽  
Target Cells ◽  
Acute Myeloid

:Acute Myeloid Leukaemia (AML) is the neoplastic transformation of Hematopoietic Stem Cells (HSC) and relapsed disease is a major challenge in the treatment. Despite technological advances in the field of medicine and our heightened knowledge regarding the pathogenesis of AML, the initial therapy of “7+3” Cytarabine and Daunorubicin has remained mainly unchanged since 1973. AML is a disease of the elderly, and increased morbidity in this patient group does not allow the full use of the treatment and drug-resistant relapse is common.:Nanocarriers are drug-delivery systems that can be used to transport drugs to the bone marrow and target Leukemic Stem Cells (LSC), conferring less side-effects compared to the free-drug alternative. Nanocarriers also can be used to favour the transport of drugs that otherwise would not have been used clinically due to toxicity and poor efficacy. Liposomes are a type of nanocarrier that can be used as a dedicated drug delivery system, which can also have active ligands on the surface in order to interact with antigens on the target cells or tissues. In addition to using small molecules, it is possible to attach antibodies to the liposome surface, generating so-called immunoliposomes. By using immunoliposomes as a drug-delivery system, it is possible to minimize the toxic side effects caused by the chemotherapeutic drug on healthy organs, and at the same time direct the drugs towards the remaining AML blasts and stem cells.:This article aims to explore the possibilities of using immunoliposomes as a drug carrier in AML therapy. Emphasis will be on possible target molecules on the AML cells, leukaemic stem cells, as well as bone marrow constituents relevant to AML therapy. Further, some conditions and precautions that must be met for immunoliposomes to be used in AML therapy will be discussed.

Topoisomerase II Inhibitor Voreloxin Causes Cell Cycle Arrest and Apoptosis in Acute Myeloid Leukaemia Cells and Acts in Synergy with Cytarabine.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4152-4152
Author(s):  
Elisabeth J Walsby ◽  
Steven Coles ◽  
Steven Knapper ◽  
Chris Pepper ◽  
Alan K Burnett
Keyword(s):  
Acute Myeloid Leukaemia ◽  
Topoisomerase Ii ◽  
Caspase 3 ◽  
Annexin V ◽  
Double Strand Breaks ◽  
Dna Integrity ◽  
Dependent Manner ◽  
Strand Breaks ◽  
Dose Dependent ◽  
Acute Myeloid

Abstract Abstract 4152 Topoisomerase II is essential for the maintenance of DNA integrity and the survival of proliferating cells. This enzyme functions as a homodimer to modulate DNA supercoiling and the unknotting and untangling of DNA. It acts via the creation of transient double strand breaks in the DNA that allow the resolution of DNA tangles prior to the rejoining of the double strand breaks. In cells with insufficient topoisomerase II activity DNA remains entangled resulting in reduced gene transcription. Conversely if a cell has excessive topoisomerase II activity the cleavage intermediates it forms with DNA can be converted into permanent strand breaks resulting in the loss of DNA integrity. Topoisomerase II poisons, including etoposide and doxorubicin, inhibit enzyme-mediated DNA ligation causing the accumulation of double strand breaks. These agents have been frontline drugs for the treatment of leukaemia for many years. Voreloxin (formerly SNS-595) is a first-in-class anticancer quinolone derivative that intercalates DNA and poisons topoisomerase II, inducing replication-dependent, site-selective DNA double-strand breaks. Primary acute myeloid leukaemia (AML) blasts isolated from patients at diagnosis (n = 88) had a mean LD50 (± SD) for voreloxin of 2.30μM (± 1.87). The mean Ara-C LD50 was 4.90μM (± 5.00) in the same population while the myeloid cell lines, NB4 and HL-60, had LD50 values for voreloxin of 0.23μM and 0.94μM respectively. The lower LD50 values for voreloxin in the cell lines is likely to be due to the fact that they are more actively dividing in culture than primary AML blasts and this agent is, at least to some extent, replication-dependent. Synergy experiments between voreloxin and Ara-C, (voreloxin1:2 Ara-C) identified synergism in 22 of 25 primary AML samples tested, with a mean combination index of 0.79. Apoptosis, measured by increases in Annexin V/propidium iodide (PI) staining and caspase-3 activation, was shown to increase in a dose-dependent manner. Annexin V/PI positivity was significantly increased by concentrations of voreloxin over 0.06μM (P = 0.02) while caspase-3 activation was evident at concentrations of voreloxin greater than 0.25μM (P = 0.0009). Furthermore, voreloxin was active in the p53 null K562 cell line, showing a dose-dependent increase in Annexin V/PI staining and an LD50 0.52μM. These data agree with previous reports suggesting that the action of voreloxin is not affected by p53 status. The action of voreloxin on topoisomerase II was confirmed using a DNA relaxation assay. In the presence of voreloxin the ability of topoisomerase II to relax a supercoiled DNA substrate was reduced in a dose-dependent manner. Voreloxin may provide an interesting addition to the cache of drugs available for the treatment of AML; a disease with poor long term survival. In addition to its potent action as a single agent in dividing cells, the synergy we demonstrated between voreloxin and AraC recommend it for further investigation Disclosures: No relevant conflicts of interest to declare.

CSL-TREX: A Novel Alternatively Spliced Isoform of CSL (RBPJ-K) Predominates Over the Full-Length Isoform in Many Patients with Acute Myeloid Leukaemia, Can Activate Notch Signalling and Is Associated with Improved Outcome.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3364-3364 ◽  
Author(s):  
Marc R Mansour ◽  
Rosemary Gale ◽  
Asim Khwaja ◽  
Martin Pule ◽  
Robert Hills ◽  
...  
Keyword(s):  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Remission Rate ◽  
Disease Free Survival ◽  
Full Length ◽  
Dependent Manner ◽  
Notch 1 ◽  
Cd34 Cells ◽  
Alternatively Spliced ◽  
Acute Myeloid

Abstract Notch activation can both inhibit myeloid differentiation and enhance self-renewal of haematopoietic progenitors, both key features of acute myeloid leukaemia (AML) pathogenesis. Activating mutations of Notch-1, frequent in T-cell acute lymphoblastic leukaemia, are rare in AML, although a subgroup of patients over-express the Notch ligand Jagged-1 and Notch-1 itself. Once activated, intracellular Notch binds to and releases the transcription factor CSL (RBPJ-K) from its co-repressor complex, whereupon it recruits the co-activator MAML1 and initiates downstream transcription of various genes including Hes-1. By RT-PCR, we found CSL was expressed in normal T-lymphocytes, neutrophils, CD34+ cells and primary AML samples. Interestingly, most AML patients expressed an alternatively spliced isoform of CSL where the last 78bp of exon 10 had been spliced out at a cryptic GC donor site (termed CSL-TREX TRuncated Exon X) coding for a portion of the beta-trephoil domain. Comparison with the crystal structure suggests this would not alter DNA-binding, but potentially affect complex formation in either its co-repressor or co-activating state. When primary AML blasts were stimulated in vitro to differentiate using IL-3, G-CSF and GM-CSF, CSL-TREX levels markedly decreased, median CSL-TREX % (as a % of total CSL) 36% and 8% respectively (n=6, P.0003), suggesting it was a feature of undifferentiated cells. Although the levels of CSL-TREX were significantly higher in AML blasts (median relative % of CSL-TREX 58%, range 0–100%) than in normal CD34+ cells (P.0004, n=10, median 22%, range 4–41%), they were very low in normal neutrophils (n=6, median 3%, range 0–8%) and absent in T-cells (n=6). In order to assess its biological relevance, we quantified CSL-TREX levels in 236 young adult patients treated on the UK MRC AML trials. There was no association between CSL-TREX level with AML subtype, age or sex, but high CSL-TREX levels were significantly correlated with lower presenting white cell count (P.001, Pearson test for correlation). There were no obvious cut off values and therefore clinical data was analysed for groups divided into quartiles. Median follow-up was 40 months. The overall remission rate was 86%, and was not significantly associated with CSL-TREX levels (P.16). However, patients with higher proportions of CSL-TREX had improved disease free survival (DFS) (highest quartile vs lowest quartile for CSL-TREX, 63% vs 51% at 5 years, HR across all quartiles 0.77 [CI 0.62–0.96], P.02), lower relapse rates (25% vs 40% HR 0.74 [CI 0.58–0.95], P.02) and improved overall survival (OS) (65% Vs 44%, HR 0.77 [CI 0.63–0.94], P.009). When adjusted for WCC, age, performance status and cytogenetics there was a trend for improved OS (P.04). There was no association between levels of CSL-TREX and either FLT3-ITD positivity (P.62) or NPM mutations (P.80). To assess its ability to activate transcription, CSL-TREX and full length (FL) CSL were cloned into an MSCV vector and transiently expressed in U20S cells together with a CSL-reporter (luciferase cloned downstream of 10xCSL-binding sites). CSL-TREX increased luciferase activity with similar potency to full-length CSL, and did so in a Notch-dependent manner, demonstrating it is able to bind both DNA and Notch. Furthermore, CSL-TREX was able to upregulate Hes-1 expression as determined by qPCR. Immunofluorescence in HEK-293T cells showed CSL-TREX was localised to both the nuclear and cytoplasmic compartments, similar to full-length CSL. In summary, we have identified a novel functional alternatively spliced isoform of CSL that constitutes the predominant isoform in many AML patients, where it associated with low presenting WCC and improved OS.

Acute myeloid leukaemia with t(8;16)(p11;p13) in a child after intrauterine X‐ray exposure

1996 ◽  
Vol 94 (4) ◽  
pp. 702-704 ◽  
Author(s):  
Süreyya Savaşan ◽  
Anwar N. Mohamed ◽  
David R. Lucas ◽  
Michael C. Dugan ◽  
James R. Ryan ◽  
...  
Keyword(s):  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
X Ray ◽  
Acute Myeloid

L-Gossypol Inhibits NF- κB, Down Regulates Mcl-1 and Induces Apoptosis of Primary Acute Myeloid Leukaemia Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4813-4813
Author(s):  
Chris J Pepper ◽  
Hani Y Osman ◽  
Saman Hewamana ◽  
Elisabeth J Walsby ◽  
Alan K Burnett ◽  
...  
Keyword(s):  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Conflicts Of Interest ◽  
White Cell Count ◽  
Annexin V ◽  
Binding Activity ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Acute Myeloid

Abstract Abstract 4813 Standard treatments for acute myeloid leukaemia (AML) result in a median survival of approximately 1 year. There is now a realisation that in order to significantly improve outcomes in this disease more targeted therapies that take account of the specific biology of the tumour cell are required. L-Gossypol is a polyphenolic oil cotton seed extract that has anti-tumour activity against a range of haematological malignancies but has never been evaluated in AML cells. It is known to act as a BH3-mimetic, binding to the BH3 pocket of anti-apoptotic proteins and displacing pro-death partners to induce apoptosis. However, knowledge of the molecular events that underpin its downstream effects is limited. In this study we analysed the in vitro effects of L-Gossypol in 50 primary AML samples in order to determine its efficacy and mode of action. Apoptosis was induced in all the samples tested in a dose- and time-dependent manner as evidenced by increased Annexin V / propidium iodide labelling and the activation of caspase-9 and caspase-3. The median LD50 value (the concentration of drug required to kill 50% of the cells) was 27.5μM ± 18.3μM. There was no association between LD50 and age, sex, presenting white cell count, FLT3 mutation status or karyotype. Mechanistically, L-gossypol decreased the DNA binding activity of the NF-κB subunit, Rel A, in a concentration-dependent manner; this inhibition was evident after only 4 hours and preceded the induction of apoptosis. Furthermore, treatment with L-Gossypol inhibited the transcription of the NF-κB-regulated genes CFLAR, BCL2, BIRC5 and MCL1 in the same timeframe. Finally, studies of Mcl-1 protein expression showed down regulation in a dose-dependent manner but this was only apparent after 8 hours exposure to L-Gossypol. Taken together, our data demonstrate that L-Gossypol works, at least in part, through the inhibition of NF-κB and our data provides a rationale for clinical investigations of this agent in AML patients. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Diphenyleneiodonium Triggers Cell Death of Acute Myeloid Leukaemia Cells by Blocking the Mitochondrial Respiratory Chain and Synergizes with Cytarabine

2021 ◽  
Author(s):  
Hassan Dakik ◽  
Maya El Dor ◽  
Jérôme Bourgeais ◽  
Farah Kouzi ◽  
Olivier Herault ◽  
...  
Keyword(s):  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Respiratory Chain ◽  
Chemotherapy Resistance ◽  
Mitochondrial Respiratory Chain ◽  
Leukemic Cells ◽  
Dependent Manner ◽  
Ros Production ◽  
Acute Myeloid ◽  
Mitochondrial Respiratory

Acute myeloid leukaemia (AML) is characterized by the accumulation of undifferentiated blast cells in the bone marrow and blood. In most AMLs, relapse frequently occurs due to resistance to chemotherapy. Compelling research results indicate that drug resistance in cancer cells is highly dependent on the intracellular levels of reactive oxygen species (ROS). Modulating ROS levels is therefore a valuable strategy to overcome the chemotherapy resistance of leukemic cells. In this study, we evaluated the efficiency of diphenyleneiodonium (DPI), a well-known inhibitor of ROS production, in targeting AML cells. Results showed that although inhibiting cytoplasmic ROS production, DPI triggered an increase in the mitochondrial ROS levels caused by the disruption of the mitochondrial respiratory chain. We also demonstrated that DPI blocks the mitochondrial oxidative respiration (OxPhos) in a dose-dependent manner and that AML cells with high OxPhos status were highly sensitive to treatment with DPI, which synergizes with the chemotherapeutic agent cytarabine (Ara-C). Thus, our results suggest that targeting mitochondrial function by DPI might be exploited to target AML cells with high OxPhos status.

The acute myeloid leukaemia market

2019 ◽  
Vol 19 (4) ◽  
pp. 233-234
Author(s):  
Jorrit Schaefer ◽  
Sorcha Cassidy ◽  
Rachel M. Webster
Keyword(s):  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Acute Myeloid
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