scholarly journals Growth Arrest-Specific 2 Promotes the Growth of T-Cell Acute Lymphoblastic Leukemia Cells Via Its Regulation of CXCR4

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4081-4081
Author(s):  
Wenjuan Ma ◽  
Yan Wan ◽  
Haixia Zhou ◽  
Li Zhu ◽  
Yun Zhao

Abstract Growth arrest-specific 2 (GAS2) has multiple functions including the regulation of cell morphology, cell cycle, apoptosis and calpain activity.GAS2 has a dual function in cancer cells, however its expression and underlying mechanism in human T-cell acute lymphoblastic leukemia (T-ALL) remain unclear. In the present study, qRT-PCR analysis showed that GAS2 has significantly higher expression (155.5-fold, P=0.0048) in CD3+ cells from T-ALL patients (n=25) than healthy donors (n=13). GAS2 was present in Jurkat cells, while absent in MOLT-4 or HPB-ALL cells. A tiny CpG island of GAS2 was almost fully methylated in both MOLT-4 (100%) and HPB-ALL cells (80%), while 40% methylation in Jurkat cells; suggesting that DNA methylation played a subtle role in regulating GAS2 expression. Two independent shRNA sequences were delivered into Jurkat cells with lentiviral vector. GAS2 silencing inhibited the growth and colony-forming cell (CFC) production significantly. Conversely, GAS2 overexpression enhanced the growth and CFC production of both MOLT-4 and HPB-ALL cells. In addition, GAS2 overexpression promoted HPB-ALL cell induced leukemia in a xenoengraftment model (5 mice in each control group). In GAS2 expressed group, the disease latency was shortened, the splenomegaly was more severe than control group (0.35±0.04g vs. 0.27±0.05g), and more leukemic cells were present in bone marrow (85±3% vs. 45±7%). To obtain the molecular insights of how GAS2 acts, RNA-seq data comparing GAS2 silenced Jurkat cells with control cells were generated. Several Notch signaling molecules were inhibited, including NOTCH1, HES1 and HES4. Despite the differential expression of these transcripts was validated in Jurkat cells, GAS2 overexpression did not elevated the expression of these transcripts in MOLT-4 or HPB-ALL cells, suggesting GAS2 did not have a consistent impact on Notch signaling. However, we found that GAS2 silencing reduced CXCR4 protein expression in Jurkat cells and GAS2 overexpression enhanced CXCR4 protein expression in MOLT-4 cells, while CXCR4 transcript was not altered upon GAS2 manipulation. Consequently, GAS2 silencing significantly reduced migration ability of Jurkat cells and GAS2 overexpression enhanced migration ability of MOLT-4 cells. Overexpression of CXCR4 "rescued" the inhibited CFC production and migration upon GAS2 silencing. A truncated GAS2 (Δ171-313) coined as GAS2DN (dominant negative form of GAS2) has been known to inhibit normal function of GAS2. Herein, we showed that GAS2DN inhibited the growth of Jurkat cells and the expression of CXCR4. To delineate the role of calpain1 and calpain2 in GAS2 function, shRNA sequences against calpain1 and calpain2 was delivered into GAS2DN expressed Jurkat cells respectively, the results showed that calpain2 but not calpain1 silencing was able to enhance the cell growth and CXCR4 expression. Taken together, the present study has demonstrated that GAS2 is aberrantly expressed in human T-ALL cells, which promotes the growth of T-ALL cells partially via its post-transcriptional regulation of CXCR4 depending on calpain2 activity. These data provide new insights of the pathogenesis of T-ALL and possibly new clues to improve the management of the disease. Disclosures No relevant conflicts of interest to declare.

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5197-5197
Author(s):  
Niroshaathevi Arumuggam ◽  
Nicole Melong ◽  
Catherine K.L. Too ◽  
Jason N. Berman ◽  
H.P. Vasantha Rupasinghe

Abstract T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignant disease that accounts for about 15% of pediatric and 25% of adult ALL. Although risk stratification has provided more tailored therapy and improved the overall survival of T-ALL patients, clinical challenges such as suboptimal drug responses, morbidity from drug toxicities, and drug resistance still exist. Plant polyphenols have therapeutic efficacy as pharmacological adjuvants to help overcome these challenges. They can be acylated with fatty acids to overcome issues concerning bioavailability, such as poor intestinal absorption and low metabolic stability. Phloridzin (PZ), a flavonoid found in apple peels, was acylated with an omega-3 fatty acid, docosahexaenoic acid (DHA), to generate a novel ester called phloridzin docosahexaenoate (PZ-DHA). The cytotoxic effect of PZ-DHA was studied in the human Jurkat T-ALL cell line. PZ-DHA significantly reduced the viability and cellular ATP levels of treated cells. PZ-DHA was found to selectively induce apoptosis in Jurkat cells, while sparing normal murine T-cells. Apoptosis was further confirmed by demonstrating the ability of PZ-DHA to induce morphological alterations, DNA fragmentation, caspase activation, and the release of intracellular lactate dehydrogenase. PZ-DHA also significantly inhibited cell division in Jurkat cells. Furthermore, interferon-α-induced phosphorylation of the transcription factor, STAT3, was downregulated following PZ-DHA treatment. The in vitro efficacy of PZ-DHA was recapitulated in vivo in an established zebrafish xenograft model, where the proliferation of transplanted Jurkat cells was inhibited when PZ-DHA was added to the embryo water. Overall, these findings provide evidence for PZ-DHA as a novel therapeutic agent with activity in T-ALL. Studies examining the effect of PZ-DHA on patient-derived ALL cells engrafted in zebrafish are currently underway. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4630-4630
Author(s):  
Samuel D Gusscott ◽  
Florian Kuchenbauer ◽  
Andrew P Weng

Abstract Abstract 4630 T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive cancer of immature T cells that often shows aberrant activation of the Notch1 signaling pathway. Several studies have utilized mRNA expression profiling to identify downstream mediators of oncogenic Notch signaling in this context. Since microRNAs (miRNAs) have in recent years been shown to play important roles in hematological maliganancy, we performed a microarray-based screen for Notch-dependent miRNA expression in T-ALL. Jurkat and P12-Ichikawa cell lines were treated with gamma-secretase inhibitor to block Notch signaling vs. DMSO control for 4 days and profiled using Exigon miRCURY LNA miRNA microarrays. Surprisingly few miRNAs were found to be regulated by this approach; however, one of the hits, miR-223, showed consistent upregulation after gamma-secretase treatment in Jurkat cells and 5 additional human T-ALL cell lines assessed by miRNA qPCR. This observation was unique to human T-ALL as murine models of T-ALL showed no evidence for Notch-dependent miR-223 expression. Given that canonical Notch signaling results in transcriptional activation, our observation that Notch signaling is associated with reduced miR-223 expression suggests an intermediary repressor may be involved. miR-223 has been reported to play an important role in normal granulopoiesis, to be expressed relatively highly in T-ALL with myeloid-like gene features, and most recently to accelerate Notch-mediated T-cell leukemogenesis. To explore potential functional consequences for Notch-dependent miR-223 repression in T-ALL, candidate miR-223 targets identified by TargetScan software were analyzed with Ingenuity Pathway Analysis software, which indicated IGF-1, insulin receptor, PTEN, and ERK5 signaling pathways as the top hits. We recently reported IGF1R signaling to be important for growth and viability of bulk T-ALL cells as well as for leukemia-initiating cell activity. Additionally, we reported that Notch signaling directly upregulates IGF1R transcription by binding to an intronic enhancer which is present between exons 21/22 in the human, but not mouse IGF1R locus. As miR-223 has previously been reported to target IGF1R mRNA and reduce its translation, we hypothesized that Notch signaling may also upregulate net IGF1R protein expression by repressing miR-223. To test this hypothesis, we transduced several human T-ALL cell lines with miR-223 retrovirus and observed a modest decrease in total IGF1R protein levels by western blot; however, no significant change was observed in surface IGF1R levels as assessed by flow cytometry. Addtionally, knockdown of miR-223 by lentiviral expression miR-223 target sequences (miR-223 “sponge”) resulted in modestly increased total IGF1R protein levels, but again showed no demonstrable effect on surface IGF1R levels. Of note, we also observed no apparent effect of either overexpression or knockdown of miR-223 on bulk cell growth or viability. We interpret these findings to suggest that Notch signaling does not have major effects on the miR transcriptome, and that up- or down-modulation of miR-223 in established T-ALL cells does not have significant effects on overall cell growth/viability. Further studies will be required to determine if miR-223 may act in concert with other Notch target genes to modulate cell physiology. Disclosures: No relevant conflicts of interest to declare.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Mattia Mori ◽  
Luca Tottone ◽  
Deborah Quaglio ◽  
Nadezda Zhdanovskaya ◽  
Cinzia Ingallina ◽  
...  

2019 ◽  
Author(s):  
Kirsti L. Walker ◽  
Sabrina A. Kabakov ◽  
Fen Zhu ◽  
Myriam N. Bouchlaka ◽  
Sydney L Olson ◽  
...  

AbstractRelapsed/refractory T cell acute lymphoblastic leukemia (T-ALL) is difficult to salvage especially in heavily pretreated patients, thus novel targeted agents are sorely needed. Hyperactivated JAK/STAT and BCL2 overexpression promote increased T-ALL proliferation and survival, and targeting these pathways with ruxolitinib and venetoclax may provide an alternative approach to achieve clinical remissions. Ruxolitinib and venetoclax show a dose-dependent effect individually, but combination treatment synergistically reduces survival and proliferation of Jurkat and Loucy cells in vitro. Using a xenograft CXCR4+ Jurkat model, the combination treatment fails to improve survival, with death from hind limb paralysis. Despite on-target inhibition by the drugs, histopathology demonstrates increased leukemic infiltration into the central nervous system (CNS), which expresses CXCL12, as compared to liver or bone marrow. Liquid chromatography-tandem mass spectroscopy shows that neither ruxolitinib nor venetoclax can effectively cross the blood-brain barrier, limiting efficacy against CNS T-ALL. Deletion of CXCR4 on Jurkat cells by CRISPR/Cas9 results in prolonged survival and a reduction in overall and neurologic clinical scores. While combination therapy with ruxolitinib and venetoclax shows promise for treating T-ALL, additional inhibition of the CXCR4-CXCL12 axis will be needed to eliminate both systemic and CNS T-ALL burden and maximize the possibility of complete remission.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1470-1470
Author(s):  
Takaomi Sanda ◽  
Jeffrey W Tyner ◽  
Alejandro Gutierrez ◽  
Vu N Ngo ◽  
Jason M Glover ◽  
...  

Abstract Abstract 1470 To discover oncogenic pathways that are characteristically deregulated in T-cell acute lymphoblastic leukemia (T-ALL), we performed RNA interference screens both in T-ALL cell lines and primary specimens. We found that the JAK tyrosine kinase family member, TYK2, and its downstream effector, STAT1, are each required for the survival of T-ALL cells. To identify the effector molecules downstream of the TYK2-STAT1 pathway in T-ALL, we analyzed global gene expression profiles in TYK2-dependent T-ALL cell lines after silencing of TYK2 or STAT1. As expected, gene set enrichment analysis revealed that genes downregulated by TYK2 knockdown were generally also downregulated by knockdown of STAT1. Importantly, we found that expression of the anti-apoptotic gene BCL2 was significantly downregulated after silencing of both TYK2 and STAT1. Analysis by quantitative PCR of additional T-ALL cell lines revealed that silencing of TYK2 resulted in significant reductions of BCL2 mRNA expression in multiple TYK2-dependent cell lines. Expression of the wild-type but not the kinase-dead TYK2 protein was sufficient to rescue BCL2 protein expression and to prevent apoptosis after knockdown of endogenous TYK2, indicating that the tyrosine kinase activity of TYK2 is required for BCL2 upregulation. Similarly, expression of the shRNA-resistant wild-type STAT1A protein partially rescued BCL2 protein expression and prevented apoptosis, while a variant of STAT1A (Y701F) that is incapable of becoming phosphorylated on a requisite tyrosine residue did not rescue BCL2 levels. Taken together, our findings indicate that aberrant activation of a TYK2-STAT1 pathway upregulates BCL2 expression in T-ALL cells, and that the T-ALL cells develop pathway dependence, in that they require these sustained high levels BCL2 expression for survival. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3646-3646
Author(s):  
Saara Laukkanen ◽  
Thomas Liuksiala ◽  
Matti Nykter ◽  
Merja Heinäniemi ◽  
Olli Lohi

Abstract Acute lymphoblastic leukemia (ALL) is the most common childhood cancer and one of the leading causes of death in children with tumors. Genetic changes in T-cell acute lymphoblastic leukemia (T-ALL) are relatively well known, but the underlying molecular processes driving the disease remain insufficiently understood. Better knowledge of molecular events in T-ALL would improve our understanding of the development and maintenance of the disease and could also lead to the development of targeted and more effective treatments. We have compiled a large gene expression data-set from microarray studies of various hematological and lymphoid malignancies and healthy tissues that use a uniform technical platform (Affymetrix HG U133 Plus 2.0) (see abstract by Liuksiala et al). Data-set includes 1302 healthy samples and 4418 leukemia samples: 1713 acute myeloid leukemias, 1648 precursor B-ALLs, 801 chronic lymphocytic leukemias, 385 T-ALLs, and 215 chronic myeloid leukemias. From this data-set, we identified a number of transcription factors (TFs) that were differentially expressed in T-ALL, including high expression of NOTCH1 and BCL11B as previously reported (Weng et al Science 2004; Gutierrez et al Blood 2011). Several novel candidate TFs with specific expression in T-ALLs were also discovered, including strong expression of two poorly characterized TFs, SIX6 and PCBP3. These findings were validated using real-time quantitative PCR (RT-qPCR) in a cell line panel consisting of T-ALL and pre-B-ALL cell lines as well as healthy controls. We next sought to identify novel drug targets in T-ALL by comparing our leukemia expression data-set with the therapeutic target database (TTD). TTD is a database providing information about the known and explored therapeutic protein and nucleic acid targets, and the corresponding drugs aimed at these targets. We identified high expression of a nicotinic acetylcholine receptor (nAChR) subunit CHRNA3 (cholinergic receptor, nicotinic, alpha 3), which is a target of nAChR inhibitor bupropion. RT-qPCR confirmed the high expression of CHRNA3 in T-ALL cell lines but not in pre-B-ALL cells or healthy controls. The effect of bupropion was tested in Jurkat cells which represent T-ALL cell line with high expression of CHRNA3. Increasing concentrations of bupropion (1-100µM) resulted in dose-dependent decrease in proliferation of Jurkat cells as measured by cell viability assay AlamarBlue. As a control, cell lines with low level of CHRNA3 expression (CCRF-CEM and REH) were treated as well but these cells did not show any changes in the rate of proliferation. In summary, we have identified several candidate transcription factors which could have a leukemic role in T-ALL. Furthermore, we identified high expression of CHRNA3 in T-ALL, suggesting a role for the cholinergic system in T-cell leukemia, and thus a novel avenue in search of putative therapeutic options. Disclosures No relevant conflicts of interest to declare.


2017 ◽  
Vol 42 (4) ◽  
pp. 1458-1468 ◽  
Author(s):  
Cong-Meng Lin ◽  
Yan-Ling Zeng ◽  
Min Xiao ◽  
Xu-Qiao Mei ◽  
Lv-Ying Shen ◽  
...  

Background: T-cell acute lymphoblastic leukemia (T-ALL) is a malignant hematological disease and is often accompanied by a variety of genetic abnormalities. Hence, our study aims to investigate the relationship between MMP-2 -1306C>T and MMP-9 -1562C>T polymorphisms and the risk and prognosis of T-ALL. Methods: From April 2009 to February 2011, a total of 376 T-ALL patients were chosen as the case group. Meanwhile, 352 healthy people who passed routine health examinations were selected as the control group. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to detect the frequency of MMP-2 -1306C>T (rs243865) and MMP-9 -1562C>T (rs3918242) polymorphisms in the study subjects. The serum levels of MMP-2 and MMP-9 were detected using enzyme-linked immunosorbent assay (ELISA). A Kaplan-Meier analysis was employed to analyze the event-free survival (EFS) rates of the T-All patients with different MMP-2 and MMP-9 genotypes. A multivariate COX model was applied to analyze the relationship between MMP-2 and MMP-9 polymorphisms and the prognosis of T-ALL patients. A C-statistic and net reclassification index (NRI) was carried out to evaluate the predictive value of MMP-2 and MMP-9 gene polymorphisms using the Cox model. Results: Compared to the control group, the genotypic frequency of MMP-2 -1306C>T (CT + TT) and MMP-9 -1562C>T (CT + TT) in the case group was significantly higher. The serum level of MMP-9 was markedly elevated in T-ALL patients with the CT + TT genotype compared to patients with the CC genotype. The results of the Kaplan-Meier analysis showed that the median EFS was lower in T-ALL patients with the CT + TT genotype of MMP-9 -1562C>T compared to patients with the CC genotype. The results of a multivariate analysis using the Cox proportional hazard model indicated that the MMP-9 -1562C>T polymorphism was associated with the prognosis of T-ALL patients. Conclusion: These results indicated that MMP-2 -1306C/T and MMP-9 -1562C/T polymorphisms might be associated with an increased risk of T-ALL. The MMP-9 -1562C>T polymorphism may also be related to the prognosis of T-ALL patients.


Sign in / Sign up

Export Citation Format

Share Document