Systems Modeling of Proliferation Mechanisms in Childhood Acute Lymphoblastic Leukemia

2013 ◽  
pp. 227-256
Author(s):  
George I. Lambrou ◽  
Apostolos Zaravinos ◽  
Maria Adamaki ◽  
Spiros Vlahopoulos
Keyword(s):  
Cell Proliferation ◽  
Acute Lymphoblastic Leukemia ◽  
Systems Approach ◽  
Current Knowledge ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cell ◽  
Systems Modeling ◽  
Global Patterns ◽  
Diseased State

Acute Lymphoblastic Leukemia (ALL) is the most common neoplasm in children, but the mechanisms underlying leukemogenesis are poorly understood, despite the existence of several theories regarding the mechanics of leukemic cell proliferation. However, with the advent of new biological principles, it appears that a systems approach could be used in an effective search of global patterns in biological systems, so as to be able to model the phenomenon of proliferation and gain a better understanding of how cells may progress from a healthy to a diseased state. This chapter reviews the current knowledge on proliferation dynamics, along with a discussion of the several existing theories on leukemogenesis and their comparison with the theories governing general oncogenesis. Furthermore, the authors present some “in-house” experimental data that support the view that it is possible to model leukemic cell proliferation and explain how this has been performed in in vitro experiments.

Proliferation and Nonlinear Dynamics of Childhood Acute Lymphoblastic Leukemia Revisited

2016 ◽  
pp. 315-348 ◽  
Author(s):  
George I. Lambrou
Keyword(s):  
Nonlinear Dynamics ◽  
Experimental Data ◽  
Cell Proliferation ◽  
Current Knowledge ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cell ◽  
In Vitro Experiments ◽  
Linear Dynamics ◽  
The Moment

Acute Lymphoblastic Leukaemia (ALL) is the most common neoplasm in children but the mechanisms underlying leukemogenesis along with the dynamics of leukemic cell proliferation are poorly understood. The importance in understanding the proliferation dynamics of leukaemia lies in the fact that our knowledge from the point of first appearance to the moment of clinical presentation, we know almost nothing. Further on, describing cell proliferation dynamics in a more mature, probably mathematical, way it could lead us to the understanding of disease ontogenesis and thus its aetion. This chapter reviews the current knowledge on proliferation dynamics and proliferation non-linear dynamics of the leukemic cell. Furthermore, we present some “in-house” experimental data that support the view that it is possible to model leukemic cell proliferation and explain how this has been performed in in vitro experiments.

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.

L-arginine depletion by PEG-arginase I, a new potential therapy for acute lymphoblastic leukemia.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 6580-6580
Author(s):  
Ofelia Crombet Ramos ◽  
Claudia Hernandez ◽  
Kevin Morrow ◽  
John T. Cole ◽  
Paulo Rodriguez
Keyword(s):  
Cell Proliferation ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
De Novo ◽  
Remission Rate ◽  
Lymphoblastic Leukemia ◽  
Arginase I

6580 Background: Advances in therapies have resulted in an overall complete remission rate of approximately 85% for childhood acute lymphoblastic leukemia (ALL). In contrast, the overall remission rate of adults with leukemia continues to be poor, only about 40% in cases of T cell-ALL (T-ALL). Therefore, it is imperative to generate new therapies that alone or in combination with other treatments could potentially increase the percentages of complete responders or be used to treat the refractory ALL population. Our published results show that a pegylated form of human arginase I (peg-Arg I) prevented T-ALL cell proliferation in vitro and in vivo through the induction of tumor cell apoptosis. Interestingly, the anti-leukemic effects induced by peg-Arg I did not affect the anti-tumor activity of normal T cells, suggesting an anti-tumor specific effect. Our hypothesis states that peg-Arg I has an anti-tumoral effect on B-ALL and T-ALL cells in vitro and that the sensitivity of ALL cells to peg-Arg I depends on their expression of argininosuccinate synthase (ASS) and their ability to produce L-arginine de novo from citrulline. Methods: Malignant T cell proliferation was tested using nonradioactive cell proliferation yellow tretrazolium salt kit. Apoptosis studies were based on the expression of annexin V. Western blot assays were conducted to determine enzymatic expression in different cell lines. Results: The results of our in vitro experiments showed that peg-Arg I had a pro-apoptotic and anti-proliferattive effect on B-ALL cells similar to the one previously seen on T-ALL cells. These effects can be overcome in cell lines able that express ASS and therefore to produce L-arginine de novo. Conclusions: Our results suggest the role of ASS in the ALL-apoptosis induced by peg-Arg-I. Our next steps include: _Understand why ASS-expressing ALL cells do not undergo apoptosis when cultured with peg-Arg-I_Determine the role of ASS in the anti-leukemic effect induced by peg-Arg-I in vivo. Completion of this research is expected to lead to a better understanding of how peg-Arg-I kills ALL cells and could provide the foundation for a novel therapy for ALL patients.

scholarly journals NET1 Enhances Proliferation and Chemoresistance in Acute Lymphoblastic Leukemia Cells

2019 ◽  
Vol 27 (8) ◽  
pp. 935-944 ◽  
Author(s):  
Hongbo Sun ◽  
Zhifu Zhang ◽  
Wei Luo ◽  
Junmin Liu ◽  
Ye Lou ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Acute Lymphoblastic Leukemia ◽  
Western Blot ◽  
Colony Formation ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Lymphoblastic Leukemia ◽  
Luciferase Reporter ◽  
Tunel Staining

Acute lymphoblastic leukemia (ALL) is the most prevalent of pediatric cancers. Neuroepithelial cell-transforming 1 (NET1) has been associated with malignancy in a number of cancers, but the role of NET1 in ALL development is unclear. In the present study, we investigated the effect of NET1 gene in ALL cell proliferation and chemoresistance. We analyzed GEO microarray data comparing bone marrow expression profiles of pediatric B-cell ALL samples and those of age-matched controls. MTT and colony formation assays were performed to analyze cell proliferation. ELISA assays, Western blot analyses, and TUNEL staining were used to detect chemoresistance. We confirmed that NET1 was targeted by miR-206 using Western blot and luciferase reporter assays. We identified NET1 gene as one of the most significantly elevated genes in pediatric B-ALL. MTT and colony formation assays demonstrated that NET1 overexpression increases B-ALL cell proliferation in Nalm-6 cells. ELISA assays, Western blot analyses, and TUNEL staining showed that NET1 contributes to ALL cell doxorubicin resistance, whereas NET1 inhibition reduces resistance. Using the TargetScan database, we found that several microRNAs (miRNAs) were predicted to target NET1, including microRNA-206 (miR-206), which has been shown to regulate cancer development. To determine whether miR-206 targets NET1 in vitro, we transfected Nalm-6 cells with miR-206 or its inhibitor miR-206-in. Western blot assays showed that miR-206 inhibits NET1 expression and miR-206-in increases NET1 expression. Luciferase assays using wild-type or mutant 3′-untranslated region (3′-UTR) of NET1 confirmed these findings. We ultimately found that miR-206 inhibits B-ALL cell proliferation and chemoresistance induced by NET1. Taken together, our results provide the first evidence that NET1 enhances proliferation and chemoresistance in B-ALL cells and that miR-206 regulates these effects by targeting NET1. This study therefore not only contributes to a greater understanding of the molecular mechanisms underlying B-ALL progression but also opens the possibility for developing curative interventions.

scholarly journals Targeting High Dynamin2 Expression By Restoring Ikaros Function in Acute Lymphoblastic Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2713-2713
Author(s):  
Zheng Ge ◽  
Jianyong Li ◽  
Baoan Chen ◽  
Sinisa Dovat ◽  
Chunhua Song
Keyword(s):  
Cell Proliferation ◽  
Acute Lymphoblastic Leukemia ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cell ◽  
Leukemic Cells ◽  
Primary Cells ◽  
Proliferation Assay ◽  
High Relapse Rate ◽  
Leukemic Cell Lines ◽  
Ck2 Inhibitor

Abstract Background: Dynamin-2 (DNM2) is a GTPase essential for intracellular vesicle formation and trafficking, cytokinesis and receptor endocytosis. Mutations in DNM2 are common in early T-cell precursor acute lymphoblastic leukemia (ALL). However, DNM2 expression in other types of ALL is not reported. Ikaros, encoded by IKZF1, is a transcriptor factor functioned as a tumor suppress gene, and its dysfunction is associated with poor survival and high relapse rate in ALL. Casein Kinase II (CK2) inhibition could restore Ikaros function in high-risk leukemia and CK2 inhibitor-CX4945 showed the therapeutic efficacy on high-risk leukemia with human-derived xenograft mouse model. It is still undetermined if Ikaros regulates DNM2 expression in the leukemic cells. Methods: The 151 patients' and 30 volunteers' BM samples were collected between June 2008 and June 2014 at the First Affiliated Hospital of Nanjing Medical University. The ALL diagnosis was made according to the morphologic, Immunophenotypic, cytogenetic, and molecular criteria of WHO Diagnosis and Classification of ALL (2008).Cytogenetic and molecular analyses as previously reported. The DNM2 expression was determined by qPCR in the patients. All the patients were divided into high or low DNM2 expression groups (Q4 vs Q1-3) and the cutoff was determined by SPSS 17.0. For quantitative parameters, overall differences between the cohorts were evaluated using a Mann - Whitney U -test. For qualitative parameters, overall group differences were analyzed using a χ2 test. All statistical analyses were performed using the SPSS 17.0 and P<0.05 was considered statistically significant. The effect of Ikaros on DNM2 gene expression was observed by qPCR in the leukemic cells expressed Ikaros or Ikaros ShRNA. Ikaros binding with promoter of DNM2 was evaluated by chromatin immunoprecipitation assay following quantitative real-time PCR in leukemic cells. The effect of DNM2 inhibitor on cell proliferation was performed by WST-1 cell proliferation assay, and the synergy of Casein Kinase inhibitor which restores Ikaros function with DNM2 inhibitor on cell proliferation of leukemic cells was analyzed by CalcuSyn. Results: We studied DNM2 mRNA level in adults with B- and T-cell ALL, and found DNM2 is more highly expressed compared with normals in both forms of ALL. High DNM2 expression is significantly associated with poor overall survival (OS), high relapse rate, and leukaemia cell proliferation markers particularly in B-ALL. DNM2 expression is significantly higher in the patients with IKZF1 deletion compared to that of without deletion. Ikaros directly binds the DNM2 promoter in Nalm6 (B-ALL) and CEM (T-ALL) leukemic cells. Ikaros suppresses the transcription of DNM2 with luciferase reporter assay. Retroviral transduction of Ikaros results in the down-regulation of DNM2 in the leukemic cells. CK2 inhibitor, TBB increases Ikaros binding to promoter of DNM2 and suppresses DNM2 expression in an Ikaros-dependent manner in both leukemic cell lines and primary cells. TBB induced-increase of H3K9me3 binding on the promoter of DNM2 was also observed in leukemic cell lines and primary cells. Finally, DNM2 inhibitor-MiTMAB significantly suppresses the cell proliferation of Nalm6 and CEM cells with the WST-1 cell proliferation assay and has significantly synergistic effect with Ck2 inhibitor, CX-4945 in the cells. Conclusion: High DNM2 expression is associated with Ikarosdys-regulation, revealing their potential roles on the development of ALL. DNM2 inhibitor MiTMAB inhibits cell proliferation and has synergistic effect with CK2 inhibitor CX4945 in leukemic cells. Disclosures No relevant conflicts of interest to declare.

TPEN Selectively Eliminates Lymphoblastic B cells from Bone Marrow Pediatric Acute Lymphoblastic Leukemia Patients

2021 ◽  
Author(s):  
Miguel Mendivil-Perez ◽  
Carlos Velez-Pardo ◽  
Lina Maria Quiroz-Duque ◽  
Alexandra Restrepo-Rincon ◽  
Natalia Andrea Valencia-Zuluaga ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Lymphoblastic Leukemia ◽  
Anticancer Agents ◽  
Pediatric Patients ◽  
De Novo ◽  
Ex Vivo ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cell ◽  
Leukemia Cells

B-cell acute lymphoblastic leukemia (B-ALL) is a hematologic disorder characterized by the abnormal proliferation and accumulation of immature B-lymphoblasts arrested at various stages of differentiation. Despite advances in treatment, a significant percentage of pediatric patients with precursor B-ALL still relapse. Therefore, alternative therapies are needed to improve the cure rates for pediatric patients. TPEN (N, N, N&rsquo;, N&rsquo;-tetrakis(2-pyridylmethyl)-ethylenediamine).is a pro-oxidant agent capable of selectively inducing apoptosis in leukemia cells. Consequently, it has been suggested that TPEN could be a potential agent for oxidative therapy. However, it is not yet known whether TPEN can selectively destroy leukemia cells in a more disease-like model, for example, the bloodstream and bone marrow (BM), in vitro. This investigation is an extension of a previous study that dealt with the effect of TPEN on ex vivo isolated/purified refractory B-ALL cells. Here, we evaluated the effect of TPEN on whole BM from nonleukemic patients (control) or pediatric patients diagnosed with de novo B-ALL or refractory B-ALL cells by analyzing the hematopoietic cell lineage marker CD34/CD19. Although TPEN was innocuous to nonleukemic BM (n=3), we found that TPEN significantly induced apoptosis in de novo (n = 5) and refractory B-ALL (n = 6) leukemic cell populations. Moreover, TPEN significantly increased the counts of cells positive for the oxidation of the stress sensor protein DJ-1, a sign of the formation of H2O2, and significantly increased the counts of cells positive for the pro-apoptotic proteins TP53, PUMA, and CASPASE-3 (CASP-3), indicative of apoptosis, in B-ALL cells. We demonstrate that TPEN selectively eliminates B-ALL cells independent of age, diagnosis status (de novo or refractory), sex, karyotype, or immunophenotype. Understanding TPEN-induced cell death in leukemia cells provides insight into more effective therapeutic oxidation-inducing anticancer agents.

Polo-Like Kinase 1 (PLK1) Inhibition Reduces Cell Proliferation and Induces Apoptosis in Childhood Acute Lymphoblastic Leukemia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3529-3529 ◽  
Author(s):  
Stefanie A. Hartsink-Segers ◽  
Carla Exalto ◽  
Steven C. Clifford ◽  
Huib N. Caron ◽  
Rob Pieters ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Acute Lymphoblastic Leukemia ◽  
Protein Expression ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cell ◽  
Response To Therapy ◽  
Childhood Acute Lymphoblastic Leukemia ◽  
Pediatric All ◽  
Plk1 Expression ◽  
Low Expression

Abstract Abstract 3529 Polo-like Kinase 1 (PLK1) is an essential regulator of mitosis. It is often overexpressed and a predictor of poor prognosis in different types of solid tumours and adult hematopoietic malignancies, making PLK1 an interesting therapeutic target in these cancer types. No PLK1 inhibitor has entered clinical trials in pediatric malignancies yet. This study therefore aimed to determine the potential of PLK1 as a new target in the treatment of childhood acute lymphoblastic leukemia (ALL), the most common type of childhood cancer. Reverse phase protein arrays were performed to analyze levels of PLK1 protein expression and phosphorylation at T210, the major activating phosphorylation site, in ALL patient samples (n=174) and normal bone marrow mononuclear cells (nBM) (n=11). Both PLK1 expression and T210 phosphorylation were elevated (2.6-fold and 1.8-fold, respectively) in patients compared to nBM (p<0.0001). Furthermore, PLK1 protein expression levels were 1.3-fold higher in ALL cells carrying an E2A-PBX1 translocation than in other ALL genetic subtypes (p<0.0001). Knockdown of PLK1 expression by lentivirally delivered short hairpins led to inhibition of cell proliferation and induction of apoptosis in three precursor B-ALL cell lines and one T-ALL cell line, as indicated by decreased cell numbers and increased cleavage of PARP. This suggests an essential role for PLK1 in maintenance of the leukemic cell. An MTS cell viability assay was used to test the efficacy of the PLK1-specific inhibitor NMS-P937 (NMS-1286937) in primary ALL samples (n=15). When exposed to 120nM of NMS-P937 for 96 hours, there was a significant reverse correlation between PLK1 protein expression and leukemic cell survival (rs=−0.58; p=0.024): patient cells with a high expression were more sensitive than cells with a low expression, whereas nBM cells were resistant up to concentrations in the micromolar range. Cumulative incidence of relapse and non-response to therapy (CIR) did not significantly differ between ALL patients with high and low levels of PLK1 protein (CIR=25.9% vs 15.7%; p=0.215). Patients with a high PLK1 T210 phosphorylation level, however, showed a trend towards a higher CIR than those with a low expression (CIR=27.5% vs 14.0%; p=0.078). Finally, Sanger sequencing of PLK1 mutational hot-spots led to the identification of a new non-synonymous mutation in 1 out of 38 patients. This mutation was located in exon 5 of the PLK1 gene, resulting in Ser335Arg, and did not lead to unusual levels of PLK1 protein or T210 phosphorylation, nor to NMS-P937 sensitivity. Taken together, these results show that PLK1 is overexpressed in pediatric ALL and plays a pivotal role in the proliferation and survival of pediatric ALL cells. Moreover, they underline the potency of PLK1-inhibiting drugs as a valuable addition to current ALL treatment strategies, especially for cases expressing high levels of PLK1 protein. Disclosures: No relevant conflicts of interest to declare.

Prednisolone Resistance in Pediatric Acute Lymphoblastic Leukemia Can Be Synergistically Overcome by Inhibition of Anti-Apoptotic MCL1 and Glycolysis

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3528-3528
Author(s):  
Ingrid M. Ariës ◽  
Bo R. Hansen ◽  
Troels Koch ◽  
William E. Evans ◽  
Rob Pieters ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cell ◽  
Glucose Consumption ◽  
Leukemic Cells ◽  
Anaerobic Glycolysis ◽  
Bcl2 Family ◽  
Protein Levels ◽  
Pediatric All

Abstract Abstract 3528 Background: Unsuccessful treatment of pediatric precursor B acute lymphoblastic leukemia (ALL) can be ascribed to cellular resistance to antileukemic drugs. In particular, resistance towards prednisolone is associated with poor prognosis in pediatric ALL. For three reasons, we hypothesized that anti-apoptosis sustained by the BCL2 family member MCL1 and glycolysis are linked processes and concomitantly induce resistance to prednisolone: 1) Glycolysis and apoptosis are closely related survival pathways both associated with prednisolone resistance, 2) Increased glucose metabolism has been directly linked to MCL1 stabilization and attenuation of apoptosis, and 3) BCL2 family members can adjust oxidative phosphorylation, a process that together with anaerobic glycolysis, is responsible for cellular respiration and ATP production. In this study, we functionally determined the synergistic contribution of MCL1 and glycolysis to prednisolone resistance in childhood ALL. Methods: Leukemic cells of pediatric ALL patients, >90% blasts, were treated in vitro with prednisolone for 48 hours. Changes in MCL1 protein levels were measured by reverse phase protein array. MCL1 knockdown was achieved by locked nucleic acid oligonucleotides (LNAs) and lentiviral silencing in two different prednisolone resistant leukemic cell lines, and the effect was assessed with RTQ-PCR and Western blot. Cell viability and cell count were analyzed by MACSQuant. Glucose consumption was measured using the GAGO20 glucose assay, in which glucose is oxidized to form the spectrophotometric end-product Oxidized o-Dianisidine. 2-deoxyglucose (2DG) was used to inhibit glycolysis. Cytotoxicity of prednisolone in leukemic cells was determined by the in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) drug-resistance assay. Sensitivity and resistance to prednisolone was assessed using previously established LC50 cut-off values, shown to be linked to the prognosis of patients. Results: MCL1 protein expression decreased by 2.9-fold after in vitro prednisolone treatment in prednisolone sensitive patients' leukemic cells (p<0.001). In contrast, MCL1 protein expression increased in prednisolone resistant ALL patient cells by maximum 2.3-fold (p<0.01). Three MCL1 LNA oligonucleotides efficiently diminished MCL1 protein levels by 82±16% compared to MCL1 levels measured in non-silencing control cells (p<0.05). This decrease was similar to the reduction by 72±12% seen for 2 lentivirally delivered shMCL1 (p<0.05). Silencing of MCL1 decreased leukemic cell proliferation by 9-fold and sensitized leukemic cells to prednisolone by maximum 80-fold (p<0.05). MCL1 silencing by either MCL1 LNA or shMCL1 upregulated the glucose consumption of leukemic cells by 2.5-fold (p<0.05), indicating a rescue mechanism mediated by anaerobic glycolysis. Inhibition of the anaerobic glycolysis by 2-DG diminished the proliferation rate of MCL1-silenced cells by 3.9-fold compared to MCL1-silenced cells alone (p<0.05). Most importantly, the combination of 2DG and silencing of MCL1 synergistically sensitized to prednisolone by 33±16% compared to the prednisolone response of leukemic cells treated with 2DG or MCL1 LNA alone (p<0.05, n=3). Conclusion: MCL1 is a potent target to sensitize to prednisolone in pediatric ALL. However, MCL1-silenced cells increase anaerobic glycolysis to avoid prednisolone-induced apoptosis. MCL1 and glycolysis should therefore be targeted simultaneously to effectively and synergistically reverse prednisolone resistance in ALL. Disclosures: No relevant conflicts of interest to declare.

Hydrocortisone does Not Influence in Vitro Glucocorticoid Sensitivity of Acute Lymphoblastic Leukemia Blasts

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5228-5228
Author(s):  
Lidewij T. Warris ◽  
Marry M. van den Heuvel-Eibrink ◽  
Ingrid M. Ariës ◽  
Rob Pieters ◽  
Erica L.T. van den Akker ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Side Effects ◽  
Cell Lines ◽  
Fluorescence Intensity ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cell ◽  
Leukemic Cells ◽  
Glucocorticoid Sensitivity ◽  
Leukemic Cell Lines

Abstract Introduction: Dexamethasone-induced neuropsychological side effects on mood, behavior and cognition seriously affect quality of life in children with acute lymphoblastic leukemia (ALL) during a long treatment period. Based on recent studies in animals, we hypothesized that these neuropsychological side effects are mediated by dexamethasone-induced cortisol depletion of the mineralocorticoid receptor (MR) in the brain. Therefore, we hypothesize that these side effects could be ameliorated by an intervention with hydrocortisone. For clinical application settings however, an absolute prerequisite is that MR activation does not interfere with the efficacy of the glucocorticoids, dexamethasone and prednisolone, on ALL cells. Materials and Methods: To investigate responsiveness of leukemic cell lines and fresh patients’ leukemic cells to dexamethasone and prednisolone in the presence of hydrocortisone, MTT-assays were performed. In addition MR and the glucocorticoid receptor (GR) expression on leukemic cells of different ALL subtypes was studied with a microarray-based gene expression profiling and validated by quantitative real-time PCR. Results: Leukemic cells expressed the MR at a very low level with a significantly higher (P≤0.001) expression in ETV6-RUNX1+ patients (median: 160.7 [AU] of fluorescence intensity, range: 38.1 - 760.6 [AU]) versus other ALL subtypes (median: 41.8 [AU] of fluorescence intensity, range: 25.1 - 276.2 [AU]). MR expression did not differ between glucocorticoid resistant and sensitive patients’ cells. Hydrocortisone addition did not affect glucocorticoid sensitivity of leukemic cell lines and patients’ leukemic cells of different leukemic subtypes also including ETV6-RUNX1+. Glucocorticoid sensitive patients’ cells became significantly more sensitive by hydrocortisone addition (prednisolone: P≤0.01, dexamethasone: P≤0.05). Conclusion: This present study shows that hydrocortisone does not interfere with efficacy of dexamethasone and prednisolone in vitro. These findings support a clinical randomized trial to study whether addition of hydrocortisone decreases the neuropsychological side effects of dexamethasone in children with ALL. Acknowledgments: The financial support of the KiKa® (Kinderen Kankervrij) foundation is highly appreciated. Disclosures No relevant conflicts of interest to declare.

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