Altered expression of histone deacetylases (HDACs) is a common feature in several human malignancies and may represent an interesting target for cancer treatment, including haematological ...malignancies. We evaluated the mRNA gene expression profile of 12 HDAC genes by quantitative real-time polymerase chain reaction in 94 consecutive childhood acute lymphoblastic leukaemia (ALL) samples and its association with clinical/biological features and survival. ALL samples showed higher expression levels of HDAC2, HDAC3, HDAC8, HDAC6 and HDAC7 when compared to normal bone marrow samples. HDAC1 and HDAC4 showed high expression in T-ALL and HDAC5 was highly expressed in B-lineage ALL. Higher than median expression levels of HDAC3 were associated with a significantly lower 5-year event-free survival (EFS) in the overall group of patients (P = 0·03) and in T-ALL patients (P = 0.01). HDAC7 and HADC9 expression levels higher than median were associated with a lower 5-year EFS in the overall group (P = 0.04 and P = 0.003, respectively) and in B-lineage CD10-positive patients (P = 0.009 and P = 0·005, respectively). Our data suggest that higher expression of HDAC7 and HDAC9 is associated with poor prognosis in childhood ALL and could be promising therapeutic targets for the treatment of refractory childhood ALL.
Increased glycolytic metabolism plays an important role in B-cell precursor Acute Lymphoblastic Leukemia (BCP-ALL). We previously showed that IGFBP7 exerts mitogenic and prosuvival effects in ALL by ...promoting IGF1 receptor (IGF1R) permanence on the cell surface, thus prolonging Akt activation upon IGFs/insulin stimulation. Here, we show that sustained activation of the IGF1R-PI3K-Akt axis concurs with GLUT1 upregulation, which enhances energy metabolism and increases glycolytic metabolism in BCP-ALL. IGFBP7 neutralization with a monoclonal antibody or the pharmacological inhibition of the PI3K-Akt pathway was shown to abrogate this effect, restoring the physiological levels of GLUT1 on the cell surface. The metabolic effect described here may offer an additional mechanistic explanation for the strong negative impact seen in ALL cells in vitro and in vivo after the knockdown or antibody neutralization of IGFBP7, while reinforcing the notion that it is a valid target for future therapeutic interventions.
Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. Although its prognosis continually improves with time, a significant proportion of patients still relapse from the disease ...because of the leukemia’s resistance to therapy. Methotrexate (MTX), a folic-acid antagonist, is a chemotherapy agent commonly used against ALL and as an immune-system suppressant for rheumatoid arthritis that presents multiple and complex mechanisms of action and resistance. Previous studies have shown that MTX modulates the nuclear factor kappa B (NF-κB) pathway, an important family of transcription factors involved in inflammation, immunity, cell survival, and proliferation which are frequently hyperactivated in ALL. Using a gene set enrichment analysis of publicly available gene expression data from 161 newly diagnosed pediatric ALL patients, we found the Tumor necrosis factor α (TNF-α) signaling pathway via NF-κB to be the most enriched Cancer Hallmark in MTX-poor-responder patients. A transcriptomic analysis using a panel of ALL cell lines (six B-cell precursor acute lymphoblastic leukemia and seven T-cell acute lymphoblastic leukemia) also identified the same pathway as differentially enriched among MTX-resistant cell lines, as well as in slowly dividing cells. To better understand the crosstalk between NF-κB activity and MTX resistance, we genetically modified the cell lines to express luciferase under an NF-κB-binding-site promoter. We observed that the fold change in NF-κB activity triggered by TNF-α (but not MTX) treatment correlated with MTX resistance and proliferation across the lines. At the individual gene level, NFKB1 expression was directly associated with a poorer clinical response to MTX and with both an increased TNF-α-triggered NF-κB activation and MTX resistance in the cell lines. Despite these results, the pharmacological inhibition (using BAY 11-7082 and parthenolide) or stimulation (using exogenous TNF-α supplementation) of the NF-κB pathway did not alter the MTX resistance of the cell lines significantly, evidencing a complex interplay between MTX and NF-κB in ALL.
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•The degree of disorder in high-entropy alloys (HEA) is extended, by developing amorphous coatings.•A novel NbTaTiVZr(O) high-entropy metallic glass (HEMG) is ...synthetized.•NbTaTiVZr(O) HEMG showed superior cytocompatibility than its HEA counterpart.•The HEMG exhibits stable surface chemical states, hydrophilicity, and enhanced corrosion resistance.•These findings may open up for innovative design strategies for biocoatings.
This study combines the brand new concept of high-entropy designed materials with the superior properties of metallic glasses to obtain a NbTaTiVZr high-entropy metallic glass (HEMG) coating for biomedical applications. The amorphous structure is achieved by a room temperature magnetron sputtering deposition, whereas a bcc crystalline phase, typical of high-entropy alloys (HEA), is obtained at 400 °C. X-ray photoelectron spectroscopy showed that the oxygen concentration on the coatings surface is > 50% and significantly higher than in the bulk (∼ 5%). The NbTaTiVZr(O) HEMG surface is completely passivated, in contrast to the metallic + oxide outermost layer found for the HEA. Potentiodynamic polarization tests attested an improved corrosion resistance of the HEMG surface, which showed also increased hydrophilicity compared to the crystalline sample. In vitro biocompatibility investigations using both the hTERT-immortalized bone marrow mesenchymal cells and MG-63 osteosarcoma cells showed excellent viability (∼ 98% and ∼ 96%, respectively) and adhesion onto the HEMG coating after 96 h of incubation, indicating the integrity and biosafety of this surface. The cell viability and proliferation on the HEA and Ti (used as a benchmark) surfaces were much inferior. The enhanced surface protection and the superior biocompatibility makes the HEMG promising to be employed as a biocoating on orthopedic implants.
Acute Lymphoblastic Leukemia (ALL) is the most frequent childhood malignancy. In the effort to find new anti-leukemic agents, we evaluated the small drug SB225002 ...(N-(2-hydroxy-4-nitrophenyl)-N'-(2-bromophenyl)urea). Although initially described as a selective antagonist of CXCR2, later studies have identified other cellular targets for SB225002, with potential medicinal use in cancer. We found that SB225002 has a significant pro-apoptotic effect against both B- and T-ALL cell lines. Cell cycle analysis demonstrated that treatment with SB225002 induces G2-M cell cycle arrest. Transcriptional profiling revealed that SB225002-mediated apoptosis triggered a transcriptional program typical of tubulin binding agents. Network analysis revealed the activation of genes linked to the JUN and p53 pathways and inhibition of genes linked to the TNF pathway. Early cellular effects activated by SB225002 included the up-regulation of GLIPR1, a p53-target gene shown to have pro-apoptotic activities in prostate and bladder cancer. Silencing of GLIPR1 in B- and T-ALL cell lines resulted in increased resistance to SB225002. Although SB225002 promoted ROS increase in ALL cells, antioxidant N-Acetyl Cysteine pre-treatment only modestly attenuated cell death, implying that the pro-apoptotic effects of SB225002 are not exclusively mediated by ROS. Moreover, GLIPR1 silencing resulted in increased ROS levels both in untreated and SB225002-treated cells. In conclusion, SB225002 induces cell cycle arrest and apoptosis in different B- and T-ALL cell lines. Inhibition of tubulin function with concurrent activation of the p53 pathway, in particular, its downstream target GLIPR1, seems to underlie the anti-leukemic effect of SB225002.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Interleukin 7 (IL-7) is a critical cytokine that plays a fundamental role in B- and T-cell development and in acute lymphoblastic leukemia (ALL). Its receptor (IL7R) is a transmembrane heterodimer ...formed by the IL7Rα and the IL2Rγ chain (γc). The IL7R signals through the JAK/STAT pathway. Loss-of-function mutations and some polymorphisms of the IL7Rα were associated to immunodeficiency and inflammatory diseases, respectively. Gain-of-function mutations were described in T-cell ALL and in high risk precursor B-cell ALL. Most confirmed loss-of-function mutations occur in the extracellular part of the IL7Rα while oncogenic mutations are exclusively found in the extracellular juxtamembrane (EJM) or transmembrane regions. Oncogenic mutations promote either IL7Rα/IL7Rα homodimerization and constitutive signaling, or increased affinity to γc or IL-7. This work presents a review on IL7Rα polymorphisms/mutations and attempts to present a classification based on their structural consequences and resulting biological activity.
Abstract
The role of tumour microenvironment in neoplasm initiation and malignant evolution has been increasingly recognized. However, the bone marrow mesenchymal stromal cell (
BMMSC
) contribution ...to disease progression remains poorly explored. We previously reported that the expression of serine protease inhibitor kunitz‐type2 (
SPINT
2/
HAI
‐2), an inhibitor of hepatocyte growth factor (
HGF
) activation, is significantly lower in
BMMSC
from myelodysplastic syndromes (
MDS
) patients compared to healthy donors (
HD
). Thus, to investigate whether this loss of expression was due to
SPINT
2/
HAI
‐2 methylation,
BMMSC
from
MDS
and de novo acute myeloid leukaemia (de novo
AML
) patients were treated with 5‐Azacitidine (Aza), a
DNA
methyltransferase inhibitor. In
MDS
‐ and de novo
AML
‐
BMMSC
, Aza treatment resulted in a pronounced
SPINT
2/
HAI
‐2
levels up‐regulation. Moreover, Aza treatment of
HD
‐
BMMSC
did not improve
SPINT
2/
HAI
‐2
levels. To understand the role of
SPINT
2/
HAI
‐2 down‐regulation in
BMMSC
physiology,
SPINT
2/
HAI
‐2 expression was inhibited by lentivirus.
SPINT
2 underexpression resulted in an increased production of
HGF
by
HS
‐5 stromal cells and improved survival of
CD
34
+
de novo
AML
cells. We also observed an increased adhesion of de novo
AML
hematopoietic cells to
SPINT
2/
HAI
‐2 silenced cells. Interestingly,
BMMSC
isolated from
MDS
and de novo
AML
patients had increased expression of the integrins
CD
49b,
CD
49d, and
CD
49e. Thus,
SPINT
2/
HAI
‐2 may contribute to functional and morphological abnormalities of the microenvironment niche and to stem/progenitor cancer cell progression. Hence, down‐regulation in
SPINT
2/
HAI
‐2
gene expression, due to methylation in
MDS
‐
BMMSC
and de novo
AML
‐
BMMSC
, provides novel insights into the pathogenic role of the leukemic bone marrow microenvironment.
Pediatric adrenocortical tumors (ACT) are rare aggressive neoplasms with heterogeneous prognosis. Despite extensive efforts, identifying reliable prognostic factors for pediatric patients with ACT ...remains a challenge. MicroRNA (miRNA) signatures have been associated with cancer diagnosis, treatment response, and prognosis of several types of cancer. However, the role of miRNAs has been poorly explored in pediatric ACT. In this study, we performed miRNA microarray profiling on a cohort of 37 pediatric ACT and nine nonneoplastic adrenal (NNA) samples and evaluated the prognostic significance of abnormally expressed miRNAs using Kaplan–Meier plots, log‐rank test, and Cox regression analysis. We identified a total of 98 abnormally expressed miRNAs; their expression profile discriminated ACT from NNAs. Among the 98 deregulated miRNAs, 17 presented significant associations with patients’ survival. In addition, higher expression levels of hsa‐miR‐630, ‐139‐3p, ‐125a‐3p, ‐574‐5p, ‐596, ‐564, ‐1321, and ‐423‐5p and lower expression levels of hsa‐miR‐377‐3p, ‐126‐3p, ‐410, ‐136‐3p, ‐29b‐3p, ‐29a‐3p, ‐337‐5p, ‐143‐3p, and 140‐5p were significantly associated with poor prognosis, tumor relapse, and/or death. Importantly, the expression profile of these 17 miRNAs stratified patients into two groups of ACTs with different clinical outcomes. Although some individual miRNAs exhibit potential prognostic values in ACTs, only the 17 miRNA‐based expression clustering was considered an independent prognostic factor for 5‐year event‐free survival (EFS) compared to other clinicopathological features. In conclusion, our study reports for the first time associations between miRNA profiles and childhood ACT prognosis, providing evidence that miRNAs could be useful biomarkers to discriminate patients with favorable and unfavorable clinical outcomes.
Methotrexate (MTX), a folic acid antagonist and nucleotide synthesis inhibitor, is a cornerstone drug used against acute lymphoblastic leukemia (ALL), but its mechanism of action and resistance ...continues to be unraveled even after decades of clinical use.
To better understand the mechanisms of this drug, we accessed the intracellular metabolic content of 13 ALL cell lines treated with MTX by 1H-NMR, and correlated metabolome data with cell proliferation and gene expression. Further, we validated these findings by inhibiting the cellular antioxidant system of the cells in vitro and in vivo in the presence of MTX.
MTX altered the concentration of 31 out of 70 metabolites analyzed, suggesting inhibition of the glycine cleavage system, the pentose phosphate pathway, purine and pyrimidine synthesis, phospholipid metabolism, and bile acid uptake. We found that glutathione (GSH) levels were associated with MTX resistance in both treated and untreated cells, suggesting a new constitutive metabolic-based mechanism of resistance to the drug. Gene expression analyses showed that eight genes involved in GSH metabolism were correlated to GSH concentrations, 2 of which (gamma-glutamyltransferase 1 GGT1 and thioredoxin reductase 3 TXNRD3) were also correlated to MTX resistance. Gene set enrichment analysis (GSEA) confirmed the association between GSH metabolism and MTX resistance. Pharmacological inhibition or stimulation of the main antioxidant systems of the cell, GSH and thioredoxin, confirmed their importance in MTX resistance. Arsenic trioxide (ATO), a thioredoxin inhibitor used against acute promyelocytic leukemia, potentiated MTX cytotoxicity in vitro in some of the ALL cell lines tested. Likewise, the ATO+MTX combination decreased tumor burden and extended the survival of NOD scid gamma (NSG) mice transplanted with patient-derived ALL xenograft, but only in one of four ALLs tested.
Altogether, our results show that the cellular antioxidant defense systems contribute to leukemia resistance to MTX, and targeting these pathways, especially the thioredoxin antioxidant system, may be a promising strategy for resensitizing ALL to MTX.
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