Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 35
Filter
1.
J Immunol Methods ; 526: 113617, 2024 03.
Article in English | MEDLINE | ID: mdl-38215900

ABSTRACT

Immunotherapy using TCR and especially CAR transgenic T cells is a rapidly advancing field with the potential to become standard of care for the treatment of multiple diseases. While all current FDA approved CAR T cell products are generated using lentiviral gene transfer, extensive work is put into CRISPR/Cas mediated gene delivery to develop the next generation of safer and more potent cell products. One limitation of all editing systems is the size restriction of the knock-in cargo. Targeted integration under control of an endogenous promotor and/or signaling cascades opens the possibility to reduce CAR gene size to absolute minimum. Here we demonstrate that a first-generation CAR payload can be reduced to its minimum component - the antigen-binding domain - by targeted integration under control of the CD3ε promoter generating a CAR-CD3ε fusion protein that exploits the endogenous TCR signaling cascade. Miniaturizing CAR payload in this way results in potent CAR activity while simultaneously retaining the primary antigen recognition function of the TCR. Introducing CAR-specificity using a CAR binder only while maintaining endogenous TCR function may be an appealing design for future autologous CAR T cell therapies.


Subject(s)
Immunotherapy, Adoptive , T-Lymphocytes , Immunotherapy, Adoptive/methods , Immunotherapy , Receptors, Antigen, T-Cell
2.
Sci Rep ; 12(1): 6572, 2022 04 21.
Article in English | MEDLINE | ID: mdl-35449227

ABSTRACT

Large-scale target cell isolation from patient blood preparations is one of the critical operations during drug product manufacturing for personalized cell therapy in immuno-oncology. Use of high-affinity murine antibody coated magnetic nanoparticles that remain on isolated cells is the current standard applied for this purpose. Here, we present the transformation of previously described technology - non-magnetic immunoaffinity column chromatography-based cell selection with reversible reagents into a new clinical-grade cell isolation platform called Automated Traceless Cell affinity chromatography (ATC). ATC is a fully closed and GMP-compliant cell selection and manufacturing system. Reversibility of reagents enables (sequential) positive cell selection, optionally in combination with depletion columns, enabling capture of highly specific cell subsets. Moreover, synergy with other Streptamer-based technologies allows novel uses beyond cell isolation including integrated and automated on-column target cell activation. In conclusion, ATC technology is an innovative as well as versatile platform to select, stimulate and modify cells for clinical manufacturing and downstream therapies.


Subject(s)
Chromatography , Animals , Cell Separation/methods , Humans , Mice
3.
Brain Sci ; 11(11)2021 Nov 11.
Article in English | MEDLINE | ID: mdl-34827490

ABSTRACT

MRI studies have consistently identified atrophy patterns in Alzheimer's disease (AD) through a whole-brain voxel-based analysis, but efforts to investigate morphometric profiles using anatomically standardized and automated whole-brain ROI analyses, performed at the individual subject space, are still lacking. In this study we aimed (i) to utilize atlas-derived measurements of cortical thickness and subcortical volumes, including of the hippocampal subfields, to identify atrophy patterns in early-stage AD, and (ii) to compare cognitive profiles at baseline and during a one-year follow-up of those previously identified morphometric AD subtypes to predict disease progression. Through a prospectively recruited multi-center study, conducted at four Austrian sites, 120 patients were included with probable AD, a disease onset beyond 60 years and a clinical dementia rating of ≤1. Morphometric measures of T1-weighted images were obtained using FreeSurfer. A principal component and subsequent cluster analysis identified four morphometric subtypes, including (i) hippocampal predominant (30.8%), (ii) hippocampal-temporo-parietal (29.2%), (iii) parieto-temporal (hippocampal sparing, 20.8%) and (iv) hippocampal-temporal (19.2%) atrophy patterns that were associated with phenotypes differing predominately in the presentation and progression of verbal memory and visuospatial impairments. These morphologically distinct subtypes are based on standardized brain regions, which are anatomically defined and freely accessible so as to validate its diagnostic accuracy and enhance the prediction of disease progression.

5.
Sci Rep ; 10(1): 17832, 2020 10 20.
Article in English | MEDLINE | ID: mdl-33082362

ABSTRACT

T cell activation is a cornerstone in manufacturing of T cell-based therapies, and precise control over T cell activation is important in the development of the next generation T-cell based therapeutics. This need cannot be fulfilled by currently available methods for T cell stimulation, in particular not in a time dependent manner. Here, we describe a modular activation reagent called Expamers, which addresses these limitations. Expamers are versatile stimuli that are intended for research and clinical use. They are readily soluble and can be rapidly bound and removed from the cell surface, allowing nearly instantaneous initiation and termination of activation signal, respectively. Hence, Expamers enable precise regulation of T cell stimulation duration and provide promise of control over T cell profiles in future products. Expamers can be easily adopted to different T cell production formats and have the potential to increase efficacy of T cell immunotherapeutics.


Subject(s)
Indicators and Reagents/pharmacology , Lymphocyte Activation/drug effects , T-Lymphocytes/drug effects , Animals , Cell Proliferation , Gene Expression Profiling , Humans , Immunotherapy, Adoptive , Mice , T-Lymphocytes/cytology , T-Lymphocytes/immunology , T-Lymphocytes/metabolism
6.
Front Microbiol ; 11: 1066, 2020.
Article in English | MEDLINE | ID: mdl-32528450

ABSTRACT

The thermophilic archaeon Sulfolobus acidocaldarius can use different carbon sources for growth, including the pentoses D-xylose and L-arabinose. In this study, we identified the activator XylR (saci_2116) responsible for the transcriptional regulation of the pentose transporter and pentose metabolizing genes in S. acidocaldarius. A xylR deletion mutant showed growth retardation on D-xylose/L-arabinose containing media and the lack of transcription of the respective ABC transporter. In contrast to so far used promoters for expression in S. acidocaldarius, the xylR responsive promoters have a very low background activity. Finally, two XylR dependent promoters next to the long-established maltose inducible promotor were used to construct a high-throughput expression vector system for S. acidocaldarius to efficiently clone and express proteins in S. acidocaldarius.

7.
Article in English | MEDLINE | ID: mdl-32461353

ABSTRACT

OBJECTIVE: Immunotherapy revolutionized melanoma treatment; however, immune-related adverse events, especially neurotoxicity, may be severe and require early and correct diagnosis as well as early treatment commencement. METHODS: We report an unusual severe multiorgan manifestation of neurotoxicity after treatment with the anti-PDL1 immune checkpoint inhibitor, nivolumab, and the anticytotoxic T-lymphocyte-associated antigen 4 immune checkpoint inhibitor, ipilimumab, in a 47-year-old male patient with metastatic melanoma. RESULTS: The patient developed immune-mediated synovitis and cranial neuritis, followed by longitudinal transverse myelitis, encephalitis, and optic neuritis. Early treatment with high-dose steroids and maintenance therapy with rituximab resulted in a favorable neurologic outcome. CONCLUSIONS: The frequency of spinal cord involvement and neuronal toxicity after cancer immunotherapy is very low and requires an extensive diagnostic workup to differentiate between disease progression and side effects. Immune checkpoint inhibitors should be discontinued and treatment with corticosteroids should be initiated early as the drug of first choice. Therapy may be escalated by other immune-modulating treatments, such as rituximab.


Subject(s)
Antineoplastic Agents, Immunological/adverse effects , Arthritis/chemically induced , Encephalomyelitis/chemically induced , Immune Checkpoint Inhibitors/adverse effects , Immune System Diseases/chemically induced , Ipilimumab/adverse effects , Melanoma/drug therapy , Neuritis/chemically induced , Nivolumab/adverse effects , Humans , Male , Middle Aged
8.
Brain Cogn ; 134: 1-8, 2019 08.
Article in English | MEDLINE | ID: mdl-31054405

ABSTRACT

Recent evidence has suggested that the hippocampus supports learning and retrieval of arithmetic facts during childhood and adolescence. Whether the hippocampus is also involved in retrieving overlearned arithmetic facts (such as 3 × 5 = 15) during adult age is open for investigation. In this study, we assessed whether patients with hippocampal atrophy due to Alzheimer's disease (AD) are still able to retrieve overlearned arithmetic facts from memory. Sixteen patients (n = 13 with AD, n = 3 with Mild Cognitive Impairment - MCI) were evaluated using standard radiological, neurological, and neuropsychological test procedures. We adopted a multiple single-case analysis in order to acknowledge possible dissociations between hippocampal degeneration and intact arithmetic fact retrieval. All patients performed a neuropsychological screening battery assessing episodic memory as well as arithmetic processing, and underwent a 3-Tesla MRI procedure. A morphometric analysis comprising estimation of both cortical thickness and hippocampal volume, which also included a subfield analysis, was conducted. All patients had marked hippocampal atrophy (bilateral n = 15, unilateral n = 1) in comparison to healthy matched controls and showed deficits in episodic memory (delayed recall). However, 13 out of 16 patients performed in the average range of standardised norms during retrieval of overlearned arithmetic facts (i.e. multiplication tables). Our results suggest that intact retrieval of consolidated arithmetic facts from memory does not depend on the integrity of the hippocampus. This is in line with the view that the hippocampus plays a dynamic and time-limited role in arithmetic processing. While the hippocampus seems to be necessary for learning and consolidating new arithmetic facts in memory, it might not be critically involved in retrieving arithmetic facts when these are well consolidated in memory.


Subject(s)
Alzheimer Disease/pathology , Hippocampus/pathology , Memory, Episodic , Temporal Lobe/pathology , Aged , Aged, 80 and over , Alzheimer Disease/psychology , Cognitive Dysfunction/pathology , Cognitive Dysfunction/psychology , Female , Humans , Magnetic Resonance Imaging , Male , Mental Recall , Neuropsychological Tests
9.
Parkinsonism Relat Disord ; 62: 210-214, 2019 05.
Article in English | MEDLINE | ID: mdl-30573412

ABSTRACT

INTRODUCTION: SYNE1 encodes nesprin-1, a scaffold protein which is involved in the binding between cytoskeleton, nuclear envelope and other subcellular compartments. In 2007, recessive truncating SYNE1 mutations have been linked to a genetic form of pure cerebellar ataxia with adult onset and mild phenotype. Subsequent reports described a number of patients with SYNE1-ataxia and widespread neurological involvement including features of motor neuron disease. Recently, heterozygote missense SYNE1 mutations have been associated with muscular disorders, such as Emery-Dreifuss muscular dystrophy, arthrogryposis multiplex congenita and dilated cardiomyopathy. METHODS: Herein we describe novel genotypic and phenotypic findings in an independent cohort of 5 patients with SYNE1-ataxia referring to the Department of Neurology of the Innsbruck Medical University and performed a review of the related literature. RESULTS: We report 3 novel mutations and describe for the first time myocardial involvement in a patient with a complicated spastic-ataxic phenotype and C-terminal mutation. In the literature, mutations associated with additional motor neuron signs spanned over the entire gene, but patients with a particularly severe phenotype and premature death bore C-terminal mutations. CONCLUSION: Our findings support a genotype-phenotype correlation in SYNE1-ataxia and suggest the need for a systematic cardiologic evaluation in the setting of complicated spastic-ataxia phenotypes.


Subject(s)
Cerebellar Ataxia/genetics , Cytoskeletal Proteins/genetics , Genotype , Intellectual Disability/genetics , Muscle Spasticity/genetics , Nerve Tissue Proteins/genetics , Optic Atrophy/genetics , Phenotype , Spinocerebellar Ataxias/genetics , Adult , Cerebellar Ataxia/diagnostic imaging , Female , Follow-Up Studies , Humans , Intellectual Disability/diagnostic imaging , Male , Muscle Spasticity/diagnostic imaging , Mutation/genetics , Optic Atrophy/diagnostic imaging , Spinocerebellar Ataxias/diagnostic imaging
10.
Clin Auton Res ; 28(3): 341-346, 2018 06.
Article in English | MEDLINE | ID: mdl-29435867

ABSTRACT

PURPOSE: To assess whether autonomic failure belongs to the clinical spectrum of spinocerebellar ataxia type 2 (SCA2), an autosomal dominant genetic disorder showing progressive cerebellar and brainstem dysfunction. METHODS: We evaluated cardiovascular autonomic function in 8 patients with SCA2 and 16 age- and gender-matched healthy controls. Other autonomic domains were examined through standardized questionnaires and by testing the skin sympathetic reflex. RESULTS: Patients with SCA2 showed normal responses to cardiovascular autonomic function tests, with the exception of lower baroreflex sensitivity upon standing compared to controls. In questionnaires, 7 out of 8 patients reported bladder disturbances, while 3 out of 6 tested patients had no skin sympathetic reflex. CONCLUSIONS: We did not observe clinically overt cardiovascular autonomic failure in patients with SCA2. Other autonomic domains (i.e., bladder and sudomotor function) may be affected in the disease.


Subject(s)
Autonomic Nervous System/physiopathology , Spinocerebellar Ataxias/physiopathology , Adult , Baroreflex , Female , Hemodynamics , Humans , Male , Middle Aged , Reflex , Skin/innervation , Spinocerebellar Ataxias/diagnosis , Sympathetic Nervous System/physiopathology , Valsalva Maneuver
11.
Cephalalgia ; 38(6): 1167-1176, 2018 05.
Article in English | MEDLINE | ID: mdl-28856914

ABSTRACT

Background Familial hemiplegic migraine (FHM) is a rare, genetic form of migraine with aura. The severity of the aura imposes an effective prophylaxis that is currently based on standard anti-migraine drugs. To this concern, only short-term reports are currently available. Methods Eight patients from a multigenerational FHM type 1 family harbouring a T666M mutation in the CACNA1A gene were referred to our ataxia outpatient clinic. Medical history, general and neurological examination as well as therapeutic approaches were recorded regularly on a routine basis for an average period of 13 years (range 9-15 years). Brain imaging studies and EEG data were also collected. Results Our long-term follow-up revealed that ictal manifestations, which usually improve after the adolescence, may reoccur later in the adulthood. Permanent neurological signs as assessed by means of clinical evaluation as well as follow-up MRIs, EEGs and neuropsychological testing remained stable. Interval therapy with non-selective calcium antagonists reduced the burden of migraine attacks and was well tolerated in the long term.


Subject(s)
Migraine with Aura , Adolescent , Adult , Aged , Calcium Channels/genetics , Child , Female , Follow-Up Studies , Humans , Male , Middle Aged , Migraine with Aura/genetics , Migraine with Aura/pathology , Migraine with Aura/physiopathology , Mutation , Pedigree , Young Adult
12.
Appl Environ Microbiol ; 84(3)2018 02 01.
Article in English | MEDLINE | ID: mdl-29150511

ABSTRACT

Sulfolobus spp. possess a great metabolic versatility and grow heterotrophically on various carbon sources, such as different sugars and peptides. Known sugar transporters in Archaea predominantly belong to ABC transport systems. Although several ABC transporters for sugar uptake have been characterized in the crenarchaeon Sulfolobus solfataricus, only one homologue of these transporters, the maltose/maltooligomer transporter, could be identified in the closely related Sulfolobus acidocaldarius Comparison of the transcriptome of S. acidocaldarius MW001 grown on peptides alone and peptides in the presence of d-xylose allowed for the identification of the ABC transporter for d-xylose and l-arabinose transport and the gaining of deeper insights into pentose catabolism under the respective growth conditions. The d-xylose/l-arabinose substrate binding protein (SBP) (Saci_2122) of the ABC transporter is unique in Archaea and shares more similarity to bacterial SBPs of the carbohydrate uptake transporter-2 (CUT2) family than to any characterized archaeal one. The identified pentose transporter is the first CUT2 family ABC transporter analyzed in the domain of Archaea Single-gene deletion mutants of the ABC transporter subunits exemplified the importance of the transport system for d-xylose and l-arabinose uptake. Next to the transporter operon, enzymes of the aldolase-independent pentose catabolism branch were found to be upregulated in N-Z-Amine and d-xylose medium. The α-ketoglutarate semialdehyde dehydrogenase (KGSADH; Saci_1938) seemed not to be essential for growth on pentoses. However, the deletion mutant of the 2-keto-3-deoxyarabinoate/xylonate dehydratase (KDXD [also known as KDAD]; Saci_1939) was no longer able to catabolize d-xylose or l-arabinose, suggesting the absence of the aldolase-dependent branch in S. acidocaldariusIMPORTANCE Thermoacidophilic microorganisms are emerging model organisms for biotechnological applications, as their optimal growth conditions resemble conditions used in certain biotechnologies such as industrial plant waste degradation. Because of its high genome stability, Sulfolobus acidocaldarius is especially suited as a platform organism for such applications. For use in (ligno)cellulose degradation, it was important to understand pentose uptake and metabolism in S. acidocaldarius This study revealed that only the aldolase-independent Weimberg pathway is required for growth of S. acidocaldarius MW001 on d-xylose and l-arabinose. Moreover, S. acidocaldarius employs a CUT2 ABC transporter for pentose uptake, which is more similar to bacterial than to archaeal ABC transporters. The identification of pentose-inducible promoters will expedite the metabolic engineering of S. acidocaldarius for its development into a platform organism for (ligno)cellulose degradation.


Subject(s)
Archaeal Proteins/genetics , Carbohydrate Metabolism , Fructose-Bisphosphate Aldolase/metabolism , Pentoses/metabolism , Sulfolobus acidocaldarius/genetics , Sulfolobus acidocaldarius/metabolism , Archaeal Proteins/metabolism , Biological Transport
13.
PLoS One ; 12(7): e0181458, 2017.
Article in English | MEDLINE | ID: mdl-28749974

ABSTRACT

BACKGROUND: Paroxysmal (PS) and unusual symptoms (US) account for approximately 1.6% of initial manifestations of multiple sclerosis (MS) and have comparable conversion rates to clinically definite MS (CDMS) as classical bout onset symptoms (CS). However, long-term prognosis and clinical outcome of patients experiencing PS or US as first clinical manifestation are unclear. METHODS: Clinical, MRI and cerebrospinal fluid data were obtained retrospectively and patients presenting with PS or US were compared to patients with CS presentation. RESULTS: In a cohort of 532 relapsing onset MS patients followed for a mean period of 11.4 years (SD 3.6), 10 (1.9%) patients initially presented with PS/US. PS/US patients received disease modifying treatment (DMT) in a significantly smaller proportion immediately after the first clinical symptom (30% vs. 61.7%; p = 0.021) and during the observation period (60% vs. 83.5%; p = 0.033). In multivariate models correcting for sex, age at initial symptoms, complete remission of initial symptoms, total number of T2 and contrast-enhancing lesions, presence of oligoclonal bands and DMT exposure, PS/US were not associated with lower annualized relapse rate or lower EDSS over time. CONCLUSION: In addition to a similar conversion rate to CDMS, patients presenting with PS/US at disease onset display very similar relapse and disability rates as patients with CS onset. Consequently, initial presentation with PS/US does not indicate benign or atypical MS, but requires DMT initiation based on the same criteria as in CS patients.


Subject(s)
Multiple Sclerosis/diagnosis , Multiple Sclerosis/pathology , Adult , Female , Humans , Magnetic Resonance Imaging , Male , Multiple Sclerosis/cerebrospinal fluid , Multiple Sclerosis/diagnostic imaging , Multivariate Analysis , Prognosis , Recurrence
14.
Mult Scler Relat Disord ; 9: 150-4, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27645364

ABSTRACT

BACKGROUND: Paroxysmal (PS) and unusual symptoms (US) as initial manifestation of multiple sclerosis (MS) are rare and often thought to indicate "benign" MS. OBJECTIVE: To investigate prevalence and clinical disease course of patients experiencing PS or US as first clinical manifestation. METHODS: Clinical, MRI and cerebrospinal fluid data of patients presenting with PS and US were obtained retrospectively and compared to patients with classical bout onset (CS). RESULTS: In a cohort of 1396 relapsing onset patients, 15 (1.1%) were identified as presenting with PS and 7 (0.5%) with US. Groups were comparable regarding gender, age at onset and intrathecal immunoglobulin synthesis (p>0.05). During a mean follow-up period of 13.6 years, all patients presenting with PS or US converted to CDMS (mean duration 3.4 years; 95% CI 1.9-4.8) as compared to 1374 patients (94%) presenting with CS (mean duration 3.2 years; 95% CI 3.0-3.4; p=0.759). CONCLUSION: In a cohort of 1396 MS patients, 1.6% presented with PS or US at disease onset. Irrespective of the initial transient symptoms, patients were at the same risk of developing CDMS as CS patients, thereby underlining the importance of identifying PS and US as possible first clinical symptoms of MS.


Subject(s)
Multiple Sclerosis/diagnostic imaging , Multiple Sclerosis/physiopathology , Adult , Disease Progression , Female , Follow-Up Studies , Humans , Male , Multiple Sclerosis/epidemiology , Phenotype , Prospective Studies , Retrospective Studies
15.
Blood ; 127(4): 436-48, 2016 Jan 28.
Article in English | MEDLINE | ID: mdl-26508782

ABSTRACT

The crucial dependence of chronic lymphocytic leukemia (CLL) cells on signals derived from the B cell receptor (BCR) has encouraged the development of new inhibitors, which interfere with BCR signaling and demonstrate clinical benefits in nearly all patients. In addition, signaling through Toll-like receptor (TLR) 9 of the innate immune system has been shown to further contribute to the activation of CLL cells. However, responses to TLR9 engagement are not uniform, but diametrically opposed with cell death in some patients and cell proliferation in others. We now provide evidence that heterogeneous responses to TLR agonists are related to differences in the ability of CLL cells to activate the BCR-associated kinase Syk. Notably, expression of ZAP-70 appears to be of crucial importance for TLR9-mediated activation of Syk. We show that the activation of Syk provides an antiapoptotic signal, which is independent of Mcl-1, Bcl-2, and Bcl-XL, but related to the degradation of the proapoptotic Bim. Mechanistically, TLR9-mediated antiapoptotic signals in ZAP-70-positive CLL trigger secretion of immunoglobulin M, which then serves as (auto-) antigen for a prosurvival BCR signal. Thus, our data show that single activation of the innate immune receptor TLR9 is sufficient to fully engage BCR signaling in ZAP-70-positive CLL, protecting malignant cells from apoptosis. We conclude that the integration of TLR signaling into an adaptive immune response can further promote survival of CLL cells and may contribute to the unfavorable prognosis of ZAP-70-positive CLL.


Subject(s)
Adaptive Immunity , Immunity, Innate , Leukemia, Lymphocytic, Chronic, B-Cell/immunology , ZAP-70 Protein-Tyrosine Kinase/immunology , B-Lymphocytes/immunology , B-Lymphocytes/pathology , Cell Line , Cell Survival , Humans , Intracellular Signaling Peptides and Proteins/immunology , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Protein-Tyrosine Kinases/immunology , Receptors, Antigen, B-Cell/immunology , Signal Transduction , Syk Kinase , Toll-Like Receptor 9/immunology
16.
Sci Rep ; 5: 18411, 2015 Dec 17.
Article in English | MEDLINE | ID: mdl-26674118

ABSTRACT

The bone marrow microenvironment is physiologically hypoxic with areas being as low as 1% O2, e.g. the stem cell niche. Acute myeloid leukaemia (AML) blasts misuse these bone marrow niches for protection by the local microenvironment, but also might create their own microenvironment. Here we identify IL-8 as a hypoxia-regulated cytokine in both AML cell lines and primary AML samples that is induced within 48 hours of severe hypoxia (1% O2). IL-8 lacked effects on AML cells but induced migration in mesenchymal stromal cells (MSC), an integral part of the bone marrow. Accordingly, MSC were significantly increased in AML bone marrow as compared to healthy bone marrow. Interestingly, mononuclear cells obtained from healthy bone marrow displayed both significantly lower endogenous and hypoxia-induced production of IL-8. IL-8 mRNA expression in AML blasts from 533 patients differed between genetic subgroups with significantly lower expression of IL-8 in acute promyelocytic leukaemia (APL), while in non APL-AML patients with FLT ITD had the highest IL-8 expression. In this subgroup, high IL-8 expression was also prognostically unfavourable. In conclusion, hypoxia as encountered in the bone marrow specifically increases IL-8 expression of AML, which in turn impacts niche formation. High IL-8 expression might be correlated with poor prognosis in certain AML subsets.


Subject(s)
Bone Marrow/metabolism , Interleukin-8/genetics , Leukemia, Myeloid, Acute/genetics , Stem Cell Niche/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Bone Marrow/pathology , Bone Marrow Cells/metabolism , Cell Line, Tumor , Enzyme-Linked Immunosorbent Assay , Female , Gene Expression Regulation, Leukemic , Humans , Hypoxia , Immunohistochemistry , Interleukin-8/metabolism , Leukemia, Myeloid, Acute/metabolism , Leukemia, Myeloid, Acute/pathology , Leukemia, Promyelocytic, Acute/genetics , Leukemia, Promyelocytic, Acute/metabolism , Leukemia, Promyelocytic, Acute/pathology , Male , Mesenchymal Stem Cells/metabolism , Middle Aged , Prognosis , Reverse Transcriptase Polymerase Chain Reaction , Survival Analysis , Young Adult
17.
Sci Rep ; 5: 17550, 2015 Nov 30.
Article in English | MEDLINE | ID: mdl-26617391

ABSTRACT

Fms-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase constitutively expressed by acute myeloid leukaemia (AML) blasts. In addition, 25% of AML patients harbour a FLT3-ITD mutation, associated with inferior outcome due to increased relapse rate. Relapse might be propagated by interactions between AML blasts and the bone marrow microenvironment. Besides cellular elements of the microenvironment (e.g. mesenchymal stromal cells), bone marrow hypoxia has emerged as an additional crucial component. Hence, effects of hypoxia on FLT3 expression and biology could provide novel insight into AML biology. Here we show that 25% of AML patients down-regulate FLT3 expression on blasts in response to in vitro hypoxia (1% O2), which was independent of its mutational state. While virtually no AML cell lines regulate FLT3 in response to hypoxia, the down-regulation could be observed in Ba/F3 cells stably transfected with different FLT3 mutants. Hypoxia-mediated down-regulation was specific for FLT3, reversible and proteasome-dependent; with FLT3 half-life being significantly shorter at hypoxia. Also, PI-3K inhibition could partially abrogate down-regulation of FLT3. Hypoxia-mediated down-regulation of FLT3 conferred resistance against cytarabine in vitro. In conclusion, FLT3 expression in AML is dependent on the oxygen partial pressure, but response to hypoxia differs.


Subject(s)
Gene Expression Regulation, Leukemic , Hypoxia/genetics , Hypoxia/metabolism , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/metabolism , Tumor Microenvironment/genetics , fms-Like Tyrosine Kinase 3/genetics , Blood Gas Analysis , Cell Line, Tumor , Down-Regulation , Gene Expression , Humans , Leukemia, Myeloid, Acute/mortality , Mutation , Oxygen Consumption , Prognosis , Transfection , fms-Like Tyrosine Kinase 3/metabolism
18.
Case Rep Pediatr ; 2015: 358164, 2015.
Article in English | MEDLINE | ID: mdl-26558127

ABSTRACT

Background. The causes of cerebral venous thrombosis (CVT) are manifold as is its clinical presentation. Case. We report the case of a CVT following lumbar puncture and intravenous glucocorticosteroid therapy in a female adolescent with a clinically isolated syndrome and risk factors for thrombosis. Conclusion. In adolescent patients with acute inflammatory disease undergoing lumbar puncture followed by intravenous high-dose glucocorticosteroid therapy, one should be aware of the elevated risk for thrombosis. A persistent headache with change in the headache pattern and loss of a postural component might be a sign for CVT, requiring emergency imaging of the brain.

19.
Leuk Res ; 39(7): 779-85, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25982178

ABSTRACT

Reduced oxygen partial pressure (pO2, hypoxia) is an important component of the bone marrow microenvironment and the hematopoietic stem cell niche. It is unclear whether this applies to the leukemic stem cell as well and if differences in pO2 between the normal hematopoetic and the leukemic stem cell niche exits. Here, we demonstrate that while there is no detectable difference in the hypoxic level of bone marrow infiltrated by acute myeloid leukemia (AML) and healthy bone marrow, physiological hypoxia of 1% O2 itself leads to cell cycle arrest of AML blasts (both cell lines and primary AML samples) in the G0/G1 phase with upregulation of p27 and consecutive decrease of cells in the S phase. Hence, susceptibility of AML blasts toward cytarabine as S phase dependent drug is significantly decreased as shown by decreased cytotoxicity in vitro. In addition, cells exposed to hypoxia activate PI3K/Akt and increase expression of anti-apoptotic XIAP. Inhibition of PI3K can restore cytarabine sensitivity of AML blasts at hypoxic conditions. In conclusion, hypoxia mediated effects encountered in the bone marrow might contribute to chemoresistance of AML blasts.


Subject(s)
Antineoplastic Agents/therapeutic use , Cell Hypoxia , Leukemia, Myeloid, Acute/pathology , Antineoplastic Agents/administration & dosage , Humans , Leukemia, Myeloid, Acute/drug therapy
20.
Leuk Res ; 39(2): 257-62, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25542695

ABSTRACT

Immune therapy for acute myeloid leukaemia (AML) has been largely disappointing. One possible explanation might lie in the microenvironment of the bone marrow, comprising cellular (e.g. mesenchymal stromal cells, MSC) and non-cellular components (e.g. hypoxia). The purpose of this study was to investigate the effects of these components in the immune response against AML in vitro. In vitro exposure of lymphocytes to hypoxia resulted in an increased expression of CD69 as an activation marker in NK cells only, with subsequently enhanced cell lysis of K-562 cell line by NK cells but not in lysis of primary blast. However, co-culture of AML cells with MSC significantly protected leukemic blasts from NK cell mediated lysis, mainly in a specific manner requiring cell-to-cell contact with supportive MSC. These data imply a relevant but unequivocal role of hypoxia and MSC the immune response against AML blasts.


Subject(s)
Bone Marrow/immunology , Cell Communication/immunology , Immunity, Cellular , Killer Cells, Natural/immunology , Leukemia, Myeloid, Acute/immunology , Tumor Microenvironment/immunology , Animals , Bone Marrow/pathology , Cell Hypoxia/immunology , HL-60 Cells , Humans , K562 Cells , Killer Cells, Natural/pathology , Leukemia, Myeloid, Acute/pathology , Mice
SELECTION OF CITATIONS
SEARCH DETAIL
...