scholarly journals IL-7 Activates a STAT5/PIM1 Axis to Promote T-Cell Acute Lymphoblastic Leukemia Proliferation and Viability in a Bcl-2-Independent Manner

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 914-914
Author(s):  
Ribeiro Daniel ◽  
Alice Melão ◽  
Ruben van Boxtel ◽  
Cristina Santos ◽  
Ana Silva ◽  
...  
Keyword(s):  
Cell Cycle ◽  
T Cells ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Cell Survival ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
Rna Seq ◽  
Pathway Activation ◽  
Cell Acute Lymphoblastic Leukemia

Abstract Background: T-cell acute lymphoblastic leukemia (T-ALL) constitutes an aggressive subset of ALL, the most frequent childhood malignancy. Although risk-adjusted chemotherapeutic regimens are currently extremely effective, their efficacy is associated with significant long-term side effects. Moreover, a significant fraction of the patients still relapse despite intensive chemotherapy, prompting the need for a deeper understanding of T-ALL biology in order to develop novel therapies. Interleukin-7 is a cytokine essential for normal T-cell development, where it has a pivotal role in promoting thymocyte survival via Bcl-2 upregulation. In this normal setting, Bcl-2 is under the control of STAT5 mediated signaling. Previously, we have shown that IL-7 promotes T-ALL expansion in vivo and leukemia cell survival and proliferation in vitro by activating PI3K/Akt/mTOR signaling pathway, consequently leading to p27kip1 downregulation and Bcl-2 upregulation. However, it is also known that T-cell lymphomas arising spontaneously in IL-7 transgenic mice depend on STAT5 activity and that leukemias displaying IL7R gain-of-function mutations are sensitive to JAK and STAT5 inhibitors. Thus, we investigated whether STAT5 could also be involved in the IL-7 pro-leukemia effects in human T-ALL cells. Methods: We used an IL-7-dependent leukemia T-cell line (TAIL7), an IL-7-responsive T-ALL cell line (HPB-ALL, with or without shRNA-mediated STAT5 silencing), primary T-ALL samples collected at diagnosis and patient-derived xenografts (PDX) and treated them with inhibitors of STAT5 (N-((4-Oxo-4H-chromen-3-yl) methylene) nicotinohydrazide) and PIM (AZD1208). Analysis of viability, cell size, cell cycle, surface CD71 and Bcl-2 expression was performed by flow cytometry. Signaling pathway activation, STAT5, PIM1, Bcl-xL, Mcl-1 and cell cycle protein expression was performed by immunoblot analysis. Proliferation was assessed by 3H-Thymidine incorporation. STAT5 ChIP-seq and RNA-seq were performed on TAIL7 cells. ChIP-PCR of histone marks H3K4me3, H3K27me, H3K27ac was performed in TAIL7 and HPB-ALL. Results: IL-7 induces JAK/STAT5 pathway activation in T-ALL cells and STAT5 genetic or pharmacological inactivation prevents IL-7-mediated T-ALL cell viability, growth and proliferation. At the molecular level, STAT5 is required for IL-7-induced downregulation of p27kip1, and upregulation of Cyclin A and TfR/CD71. Surprisingly, STAT5 inhibition does not significantly affect IL-7-mediated Bcl-2 upregulation, suggesting that, contrary to normal T-cells, STAT5 promotes leukemia cell survival via a Bcl-2-independent mechanism. In addition, IL-7-mediated increase in transcription of BCL2, BCL2L1 (Bcl-xL) and MCL1 is not affected by STAT5 silencing. To understand how STAT5 mediates the survival effects of IL-7 in T-ALL cells without affecting BCL2 transcription, we performed STAT5 ChIP-seq together with RNA-seq. Data cross-analysis reveal a diverse IL-7-driven STAT5-dependent transcriptional program in T-ALL cells, which includes transcription of the serine/threonine kinase PIM1. PIM1 is involved in cell cycle regulation and apoptosis, thereby constituting a possible alternative to Bcl-2-dependent prevention of apoptosis. We show that STAT5 silencing prevents IL-7-mediated PIM1 expression and the upregulation of active chromatin marks, H3K4me3 and H3K27ac, at the STAT5 binding region in the PIM1 gene. Notably, pharmacological inhibition of PIM kinase abrogates IL-7-mediated T-ALL cell growth and proliferation, however, without affecting cell survival. In agreement, PIM inhibition does not affect expression of Bcl-2 or Bcl-2 family anti-apoptotic members Bcl-xL and MCL1. Conclusion: Here we present evidence that T-ALL cells may have an alternative wiring of signaling networks downstream of IL-7 to that present in normal T-cells. In contrast to healthy lymphoid cells, IL-7-mediated control of survival of T-ALL cells via STAT5 does not rely on modulation of Bcl-2. Moreover, exploration of STAT5 downstream signaling reveals that PIM1 is required for IL-7-mediated proliferation of human T-ALL cells, indicating that strategies involving the use of PIM kinase small molecule inhibitors may have therapeutic potential against leukemias that rely on IL-7R and STAT5 signaling. Disclosures Barata: Instituto de Medicina Molecular João Lobo Antunes: Patents & Royalties: Patents.

scholarly journals ORP4L is essential for T-cell acute lymphoblastic leukemia cell survival

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Wenbin Zhong ◽  
Qing Yi ◽  
Bing Xu ◽  
Shiqian Li ◽  
Tong Wang ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Cell Survival ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
Cell Acute Lymphoblastic Leukemia

Mechanism of CAG Regimen Eliminating Human T Cell Acute Lymphoblastic Leukemia Cell Line, A3

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5051-5051
Author(s):  
Aining Sun ◽  
Yanling Wu ◽  
Shengli Xue ◽  
Wu Depei ◽  
Weirong Chang
Keyword(s):  
Cell Cycle ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
S Phase ◽  
Leukemia Cell Line ◽  
Human T Cell ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Lymphoblastic Leukemia Cell Line

Abstract Objective To explore the mechanism of CAG regimen eliminating human T cell acute lymphoblastic leukemia cell line, A3 and evaluate the role played by G-CSF/G-CSFR system in this process. Methods The expression of G-CSFR on A3 cells was detected by flow cytometric analysis. Cell cycle parameters of A3 cells treated with different concentration of G-CSF(5ng/ml A10ng/ml A15ng/ml A20ng/ml G0ng/ml as control) were examined by propidium iodide staining. The inhibition and apoptosis rates of A3 cells caused by treatment with various combination of G-CSF, cytarabine (Ara-C), and aclarubicin (ACR) after incubation for 48h were analyzed by Cell Counting Kit (CCK-8) and AnnexinV staining, respectively. After incubation for 48 hours with G-CSF and PD98059(the specific inhibitor of MEK in Ras-MAPK signaling pathway), cell cycle and cell dynamic change were examined. Results The expression frenquency of G-CSFR on A3 cells was 94.2% which was comparable to that of KG-1 cells. The proportion of A3 cells in S-phase was elevated concomitantly with the increasing G-CSF concentrations within 0–20ng/ml, highest at 15ng/ml of G-CSF. After incubation with Ara-C and G-CSF for 48 hours, the proliferation of A3 cells was inhibited more significantly than incubation with incubation with Ara-C alone (P<0.05, Ara-C 10−5M and 10−6M) by CCK-8 assay. Incubated with Ara-C, ACR, and G-CSF for 48 hours, the apoptosis of A3 cells was increased than that treated with Ara-C and ACR. With the concentration of PD98059 increased gradually, the proportion of A3 cells in S-phase and OD values of A3 cells decreased, which was less than that of control group (p<0.05). Conclusion G-CSFR was expressed on A3 cells. G-CSF/G-CSFR system had a synergetic effect on eliminating A3 cells when administrated simultaneously with chemical agents by driving G0-phase cells into S-phase. Apoptosis was one of the mechanisms of CAG regimen eliminating A3 cells. The interaction between G-CSF and G-CSFR activates a series of signaling pathways which includes Ras-MAPK. The inhibition of MAPK phosphorylation by PD98059 contributed partially to the effect of G-CSF on A3 cells.

scholarly journals IL-7 Either Promotes or Inhibits Autophagy, Depending on the Stress Context, to Promote the Viability of T-Cell Acute Lymphoblastic Leukemia Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2822-2822
Author(s):  
Daniel Ribeiro ◽  
Inês Lopes ◽  
Marta Abreu ◽  
Carlos Custódia ◽  
Joao Barata
Keyword(s):  
Cell Death ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Cell Viability ◽  
Cell Survival ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
Culture Conditions ◽  
Cell Acute Lymphoblastic Leukemia

Abstract T-cell acute lymphoblastic leukemia (T-ALL), an aggressive and common childhood hematological malignancy, arises from clonal expansion of T-cell progenitors. Autophagy is a homeostatic process characterized by the sequestration of cytoplasmic compartments within double-membrane vesicles (autophagosomes) to promote their degradation. Importantly, autophagy is upregulated during starvation and cellular stress, as a compensatory mechanism to provide nutrients and stress relief. By mitigating stress and allowing cell survival, autophagy may serve as a pro-tumoral mechanism. On the other hand, persistent autophagy can lead to cell death and thereby prevent tumor growth. Interleukin-7 (IL-7), a cytokine produced by the bone marrow and thymic stroma, is essential for normal T-cell development. However, IL-7-mediated signaling can also contribute to leukemogenesis. A majority of T-ALL patients (~70%) expresses the IL-7 receptor and IL-7 accelerates T-ALL progression in vivo and promotes T-ALL cell proliferation, survival and metabolic activation in vitro via PI3K/Akt/mTOR pathway (a master negative regulator of autophagy). IL-7 can also activate MEK/Erk pathway (which has been implicated in promotion of autophagy). Because IL-7 has the ability to activate signaling pathways with potentially opposing roles in autophagy regulation, we explored whether IL-7 impacted on the autophagic process in T-ALL cells and sought to elucidate the molecular mechanisms and functional consequences of IL-7-mediated autophagy regulation under different culture conditions: a) medium with 10% serum - a scenario where cells have optimal growth conditions, b) medium with low (1%) serum - to mimic a milieu with nutrient stress (which may happen in densely populated leukemic niches in vivo), and c) regular medium plus asparaginase (ASNase) - to induce treatment-imposed stress. Using IL-7-responsive T-ALL cell lines and patient-derived xenograft (PDX) samples, we show that, in optimal culture conditions, IL-7 leads to a decrease in LC3-I/-II conversion and a reduction in both LC3 puncta and autophagosome/autolysosome formation, as determined by immunoblot, confocal microscopy, flow cytometry and electron microscopy - indicating that IL-7 inhibits autophagy in T-ALL. Using signaling-specific small molecule inhibitors (UO126 for MEK/Erk; LY294002 and rapamycin for PI3K/Akt/mTOR) we found that IL-7-mediated regulation of autophagy occurs in a complex manner that involves concomitant triggering of both pro- (via MEK/Erk) and anti- (via PI3K/Akt/mTOR) autophagic signaling, with the effects of the latter prevailing over the former. In this scenario, IL-7-mediated viability relies on PI3K/Akt/mTOR pathway and, as expected, autophagy inhibition (using MRT68921) does not prevent the ability of IL-7 to promote leukemia cell survival. In contrast, under serum starvation IL-7 promotes autophagy, and IL-7-mediated leukemia cell viability partially relies on autophagy activation, and strictly requires MEK/Erk activation. Mechanistically, we provide evidence that depending on the culture conditions, IL-7 can balance the relative activation of PI3K/Akt/mTOR and MEK/Erk pathways, inhibiting or facilitating autophagy, in order to consistently promote T-ALL cell viability. We further extended our studies to a therapy-related scenario and found that under ASNase treatment, IL-7 still promotes increased survival of leukemic cells, a possible mechanism of treatment resistance. Functionally, we demonstrate that the IL-7-mediated increase in survival under ASNase treatment is, in part, mediated via activation of autophagy, suggesting that combining ASNase administration with autophagy inhibitors may be an attractive strategy to prevent resistance. In summary, our results indicate that IL-7 makes use of a 'flexible strategy' to promote T-ALL cell viability by activating both pro- and anti-autophagic pathways, which are differentially recruited, depending on the microenvironmental conditions, to prevent tumor cell death. Moreover, our findings strengthen the notion that combination therapies against PI3K/Akt/mTOR and MEK/Erk pathways may constitute a valid therapeutic avenue and highlight the potential of using autophagy inhibitors to prevent microenvironment-induced chemotherapy resistance in T-ALL. Disclosures Barata: Instituto de Medicina Molecular João Lobo Antunes: Patents & Royalties: Patents.

STAT5 Activation Is Mandatory for IL-7-Mediated Viability and Growth of T-Cell Acute Lymphoblastic Leukemia Cells

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3530-3530
Author(s):  
Daniel Ribeiro ◽  
Ana Silva ◽  
Bruno A. Cardoso ◽  
Joao T. Barata
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Cell Survival ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
Leukemia Cells ◽  
Dependent Manner ◽  
Dismal Prognosis ◽  
Cell Acute Lymphoblastic Leukemia

Abstract Abstract 3530 T-cell acute lymphoblastic leukemia (T-ALL) constitutes, in general, an aggressive subset of ALL, the most frequent childhood malignancy. Although risk-adjusted chemotherapeutic regimens are currently extremely effective, their efficacy is associated with significant long-term side effects and those cases that relapse have dismal prognosis. New, more specific, therapies are therefore required. To achieve this goal it is essential to have a better understanding of T-ALL biology, including the contribution of tumor microenvironmental factors for leukemia progression. Interleukin 7 (IL-7) is produced by stromal cells in the bone marrow and thymus. While IL-7 is essential for normal T-cell development, there is also considerable evidence that it can partake in leukemia expansion. Previously, we have shown that IL-7 promotes T-ALL expansion in vivo (Silva et al, Cancer Res. 2011) and leukemia cell survival and proliferation in vitro by activating PI3K/Akt/mTOR signaling pathway (Barata et al, J Exp Med. 2004), consequently leading to p27kip1 downregulation and Bcl-2 upregulation. However, it is also known that T-cell lymphomas arising spontaneously in IL-7 transgenic mice depend on STAT5 activity. Thus, we investigated whether STAT5 could also be involved in the IL-7 pro-leukemia effects in human T-ALL cells. Using an IL-7-dependent leukemia T-cell line (TAIL7), we show that IL-7 activates JAK-STAT5 pathway in a dose- and time-dependent manner, as measured by phosphorylation of JAK1, JAK3 and STAT5. We further demonstrate that IL-7 induces STAT5 DNA binding and transcriptional activity. To establish the role of STAT5, we stably transduced HPB-ALL cells with lentiviral vectors driving the expression of STAT5a shRNA or scramble control, and confirmed the efficiency of STAT5a knock down at the protein level. Flow cytometry analysis of cell size and annexin V binding, indicate that STAT5 is indispensable for IL-7-mediated T-ALL cell growth and viability. To test the potential clinical applicability of these observations, we treated TAIL7 and primary leukemia cells collected from pediatric T-ALL patients at diagnosis with pharmacological inhibitors of JAK3 (WHI-P131), STATs in general (parthenolide) and STAT5 in particular (N-((4-Oxo-4H-chromen-3-yl)methylene)nicotinohydrazide). All three inhibitors abrogate IL-7-mediated T-ALL cell viability, growth and proliferation. At the molecular level, these observations correlate with complete inhibition of IL-7-induced modulation of p27kip1, cyclin A and cyclin D2 expression and with prevention of transferrin receptor (CD71) upregulation. Interestingly, Bcl-2 expression does not appear to be significantly affected by inhibition of STAT5 activity. This contrasts with PI3K/Akt pathway and suggests that STAT5 regulates leukemia T-cell survival, at least in part, by an alternative, Bcl-2-independent mechanism. Overall, these results extend our observations that JAK/STAT5 pathway inhibitors can eliminate cells displaying IL-7Rα gain-of-function mutations that we recently found in T-ALL (Zenatti et al, Nat Genet. 2011), and indicate that STAT5 plays a major role in mediating IL-7/IL-7R signaling effects in T-ALL cells, therefore constituting a promising target for therapeutic intervention in this malignancy. Disclosures: No relevant conflicts of interest to declare.

scholarly journals BRD4 PROTAC Degrader ARV-825 Inhibits T-Cell Acute Lymphoblastic Leukemia by Targeting 'Undruggable' Myc-pathway Genes

2020 ◽  
Author(s):  
Shuiyan Wu ◽  
You Jiang ◽  
Yi Hong ◽  
Xinran Chu ◽  
Zimu Zhang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Lymphoblastic Leukemia ◽  
Rna Seq ◽  
Bet Inhibitors ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Bet Protein

Abstract BackgroundT-cell acute lymphoblastic leukemia (T-ALL) is an aggressive disease with a high risk of induction failure and poor outcomes, with relapse due to drug resistance. Targeting bromodomains and extra-terminal (BET) protein inhibitors are promising anti-cancer agents, and ARV-825, comprising a BET inhibitor conjugated with cereblon, was recently shown to attenuate the growth of multiple tumors in vitro and in vivo. However, the functional and molecular mechanisms of ARV-825 in T-ALL remain unclear. This study aimed to investigate the therapeutic efficacy and potential mechanism of ARV825 in T-ALL.MethodsExpression levels of the BET protein BRD4 were determined in pediatric T-ALL samples and differential gene expression after ARV-825 treatment was explored by RNA-seq and quantitative reverse transcription-polymerase chain reaction. T-ALL cell viability was measured by CCK8 assay after ARV-825 administration. Cell cycle was analyzed by propidium iodide (PI) staining and apoptosis was assessed by Annexin V/PI staining. The functional and molecular pathways involved in ARV-825 treatment of T-ALL were verified by western blot and chromatin immunoprecipitation (ChIP).ResultsBRD4 expression was higher in pediatric T-ALL samples compared with T-cells from healthy donors. High BRD4 expression indicated a poor outcome. ARV-825 suppressed cell proliferation in vitro by arresting the cell cycle and inducing apoptosis, with elevated poly-ADP ribose polymerase and cleaved caspase 3. BRD4, BRD3, and BRD2 were degraded in line with reduced cereblon expression in T-ALL cells. ARV-825 had a lower IC50 in T-ALL cells compared with the BET inhibitors JQ1 and dBET1. ARV-825 perturbed the H3K27Ac-Myc pathway and reduced c-Myc protein levels in T-ALL cells according to RNA-seq and ChIP. Moreover, ARV-825 inhibited cell proliferation by depleting BET and c-Myc proteins in T cell lines and in pediatric T-ALL patients. ConclusionsBRD4 indicates a poor prognosis in T-ALL. The BRD4 degrader ARV-825 can effectively suppress the proliferation and promote apoptosis of T-ALL cells via BET protein depletion and c-Myc inhibition, thus providing a new strategy for the treatment of T-ALL.

scholarly journals BRD4 PROTAC degrader ARV-825 inhibits T-cell acute lymphoblastic leukemia by targeting 'Undruggable' Myc-pathway genes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shuiyan Wu ◽  
You Jiang ◽  
Yi Hong ◽  
Xinran Chu ◽  
Zimu Zhang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Acute Lymphoblastic Leukemia ◽  
Caspase 3 ◽  
Lymphoblastic Leukemia ◽  
Rna Seq ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Bet Protein

Abstract Background T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive disease with a high risk of induction failure and poor outcomes, with relapse due to drug resistance. Recent studies show that bromodomains and extra-terminal (BET) protein inhibitors are promising anti-cancer agents. ARV-825, comprising a BET inhibitor conjugated with cereblon ligand, was recently developed to attenuate the growth of multiple tumors in vitro and in vivo. However, the functional and molecular mechanisms of ARV-825 in T-ALL remain unclear. This study aimed to investigate the therapeutic efficacy and potential mechanism of ARV-825 in T-ALL. Methods Expression of the BRD4 were determined in pediatric T-ALL samples and differential gene expression after ARV-825 treatment was explored by RNA-seq and quantitative reverse transcription-polymerase chain reaction. T-ALL cell viability was measured by CCK8 assay after ARV-825 administration. Cell cycle was analyzed by propidium iodide (PI) staining and apoptosis was assessed by Annexin V/PI staining. BRD4, BRD3 and BRD2 proteins were detected by western blot in cells treated with ARV-825. The effect of ARV-825 on T-ALL cells was analyzed in vivo. The functional and molecular pathways involved in ARV-825 treatment of T-ALL were verified by western blot and chromatin immunoprecipitation (ChIP). Results BRD4 expression was higher in pediatric T-ALL samples compared with T-cells from healthy donors. High BRD4 expression indicated a poor outcome. ARV-825 suppressed cell proliferation in vitro by arresting the cell cycle and inducing apoptosis, with elevated poly-ADP ribose polymerase and cleaved caspase 3. BRD4, BRD3, and BRD2 were degraded in line with reduced cereblon expression in T-ALL cells. ARV-825 had a lower IC50 in T-ALL cells compared with JQ1, dBET1 and OTX015. ARV-825 perturbed the H3K27Ac-Myc pathway and reduced c-Myc protein levels in T-ALL cells according to RNA-seq and ChIP. In the T-ALL xenograft model, ARV-825 significantly reduced tumor growth and led to the dysregulation of Ki67 and cleaved caspase 3. Moreover, ARV-825 inhibited cell proliferation by depleting BET and c-Myc proteins in vitro and in vivo. Conclusions BRD4 indicates a poor prognosis in T-ALL. The BRD4 degrader ARV-825 can effectively suppress the proliferation and promote apoptosis of T-ALL cells via BET protein depletion and c-Myc inhibition, thus providing a new strategy for the treatment of T-ALL.

scholarly journals 583 Exploring the potential of T cell acute lymphoblastic leukemia (T-ALL) for generating leukemia-specific T cell responses that can be therapeutically harnessed with immunotherapy

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A613-A613
Author(s):  
Todd Triplett ◽  
Joshua Rios ◽  
Alexander Somma ◽  
Sarah Church ◽  
Khrystyna North ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Lymphoblastic Leukemia ◽  
Systemic Disease ◽  
Flow Cytometric Analysis ◽  
T Cell Responses ◽  
Lymphoid Tissues ◽  
Cell Responses ◽  
Cell Acute Lymphoblastic Leukemia

BackgroundT cell Acute Lymphoblastic Leukemia (T-ALL) is a devastating malignancy found primarily in pediatric populations. Unfortunately, standard of care for T-ALL has not progressed from highly toxic, intensive regimens of chemotherapy, which fails to cure all patients. Immunotherapies designed to activate patients‘ leukemia-specific T cells may provide a new therapeutic avenue to increase complete response rates, reduce toxicity without the need to engineer (e.g. CAR) cells. However, it is unknown whether T-ALL is capable of being recognized by T cells due given its relatively low mutation-rate. These studies therefore sought to investigate whether signs of leukemia-specific T cell responses are generated by T-ALL. Because T-ALL results in systemic disease and infiltrates multiple lymphoid and non-lymphoid tissues, these studies also determined how the divergent immune contextures of these TMEs impacts T cell responses to T-ALL. From this, we aim to identify immunotherapeutic targets capable of activating T cells across tissues to eradicate leukemia systemically.MethodsPrimary leukemia cells isolated from a spontaneous murine model (LN3 mice) into immune-competent, congenic (CD45.1) recipient mice. Tissues were harvested at distinct stages of disease for analysis by flow cytometry or utilizing NanoString Technologies’ GeoMX Digital Spatial Profiling (DSP) platform.ResultsFlow cytometric analysis of T cells revealed extensive changes in response to T-ALL that included multiple features of exhaustion typically associated with anti-tumor responses as determined by upregulation of co-inhibitory receptors and TOX. This included a surprisingly high-frequency of PD1+ T cells, which was accompanied by PDL1- and PDL2-expressing myeloid cells that likely are restraining these subsets. Importantly, combination immunotherapy with OX40 agonists while inhibiting PD1 resulted in drastically reduced tumor burden and concomitant expansion of proliferating granzyme-expressing CD8 T cells. To gain better insight into T cell responses within distinct organs, we analyzed tissue sections using DSP. This technique enabled us to evaluate T cells in direct contact with leukemia infiltrates compared to T cells in regions without T-ALL, which further revealed an enrichment of activated subsets. Importantly, these studies have provided critical insight needed to better understand how T cells responding to T-ALL diverge between distinct types of tissues.ConclusionsThe results from these studies collectively suggest that T cells are activated by T-ALL and that they can be therapeutically harnessed despite relatively low mutation-rates. Future studies will continue analysis of individual organs and use these results to rationally design combinations of immunotherapies by tailoring to activate T cells in all tissue types.AcknowledgementsSpecial thanks to all the support and analysis from everyone at NanoString, along with financial support provided by a SITC-NanoString DSP Fellowship awarded to Dr. Todd Triplett used for DSP analysis of all frozen tissues in these studies. Salary support for Dr. Triplett and pilot funding was provided by departmental funds via a Cancer Prevention and Research Institute of Texas (CPRIT) Scholar Award (Grant #RR160093; awarded to Dr. Gail Eckhardt).

scholarly journals The oxidation of (−)-epigallocatechin-3-gallate inhibits T-cell acute lymphoblastic leukemia cell line HPB-ALL via the regulation of Notch1 expression

RSC Advances ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 1679-1684 ◽  
Author(s):  
Yu-Na Wang ◽  
Jing Wang ◽  
Hao-Nan Yang ◽  
Bang-Lei Zhang ◽  
Pan Zhang ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Cell Line ◽  
Hematological Malignancy ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
Leukemia Cell Line ◽  
Activating Mutations ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Lymphoblastic Leukemia Cell Line

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy, and commonly associated with activating mutations in the Notch1 pathway.

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