scholarly journals Metabolic Alterations May Contribute to Cabozantinib Resistance in Acute Myeloid Leukemia Cells with FLT3-ITD

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2785-2785
Author(s):  
Fang-Yu Lo ◽  
Kit Man Ng ◽  
Wen-Chun Chen ◽  
Chung-Yi Hu ◽  
Hsin-An Hou ◽  
...  
Keyword(s):  
Cell Lines ◽  
Myeloid Leukemia ◽  
Lactate Production ◽  
Resistant Cell ◽  
Atp Content ◽  
Rna Seq ◽  
Metabolic Alterations ◽  
Gapdh Activity ◽  
Acute Myeloid ◽  
Resistant Cells

Abstract Background: Internal tandem duplication in the juxtamembranal region of FLT3 gene (FLT3-ITD) is one of the most common mutations in acute myeloid leukemia (AML), resulting in constitutive activation of FLT3 signaling pathway. Therefore FLT3 have been proved to be as a useful target for AML treatment. Previously, we demonstrated that cabozantinib, an oral multi-target tyrosine kinase inhibitor (TKI), could selectively cytotoxic to AML cells with FLT3-ITD (MV4-11 and Molm13). Recently, cabozantinib was reported to be well tolerated in AML patients with FLT3-ITD and potentially be useful in the treatment of AML with FLT3-ITD. However, it is known that TKI-resistance in AML often cause higher relapse rates and lower survival rates. In order to study the drug resistance mechanism, we established cabozantinib-resistant cell lines from MV4-11 and Molm13 cells, after gradual escalating concentration of cabozantinib incubation, with increasing IC50 from 9.5nM to 1.5μM and from 1.06nM to 473.36nM, respectively. The cabozantinib-resistance cell lines were named MV4-11 XR and Molm-13 XR, respectively. Aims: To elucidate the mechanism of survival advantage of cabozantinib-resistance of MV4-11-XR and Molm13-XR. Materials and Methods : The differential expression genes (DEGs) were examined using RNA-seq (Illumina NextSeq-500). Metascape recourse and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses were performed to predict the biological functions of DEGs. Quantitative PCR (Q-PCR) were used to validate the RNA-seq results. The extracellular acidification rate (ECAR) was measured using Seahorse bio-analyzer. In addition, to investigate the mitochondrial metabolism, analyses of oxygen consumption rate (OCR), glucose uptake, GAPDH activity, lactate production, ATP content were performed. Results: The gene expression profile in MV4-11 cells and Molm13 cells were used as baselines to establish the up- or down-regulated genes in MV4-11-XR and Molm13-XR cells, respectively. The FPKM were estimated with the selection criteria of q value<0.05 and [log2 (fold change0)>1 or <1 for significantly differential expression for up- and down-regulation, respectively. We identified a total of 1113 DEGs between the MV4-11 and MV4-11-XR cells, and a total of 1057 DEGs between the Molm13 and Molm13-XR cells. By using KEGG Mapper to interrogate pathways significance, we found that the metabolic pathway was the most significant in both up- and down-regulated DEGs in both resistant cells (MV4-11-XR up: 30 DEGs, down: 52 DEGs; Molm13-XR up: 27 DEGs, down: 58 DEGs). The information suggests that metabolic alterations occur in both drug resistant cell lines. Both MV4-11-XR and Molm13-XR cells showed higher glucose uptake, GAPDH activity, lactate production and ATP content than corresponding parental cells. Consistent with increased lactate export, analysis of glycolytic function showed a significant increase in glycolysis, glycolytic capacity and glycolytic reserve in both resistant cells. In addition, we showed increased basal mitochondrial and ATP-coupled respiration in both resistant cells, compared to their corresponding parental cells. Finally, decreased OCR / ECAR ratios indicated the relatively higher reliance on glycolysis in both resistant cells: 15.79 in Molm13-XR cells compared to 24.93 in Molm-13 cells, and 1.75 in MV4-11-XR cells compared to 9.97 in MV4-11 cells. Conclusion: Our study highlights that alteration of metabolic pathways may contribute cabozantinib resistance. We suggest that targeting these pathways may be a viable strategy to overcome cabozantinib resistance. Disclosures No relevant conflicts of interest to declare.

scholarly journals HOXA11 Regulates Chemoresistance By Modulating p53 Gene Expression in Acute Myeloid Leukemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5182-5182
Author(s):  
Xutao Guo ◽  
Bowen Yan ◽  
Yi Qiu
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Myeloid Leukemia ◽  
Drug Sensitivity ◽  
P53 Gene ◽  
Resistant Cell ◽  
Wild Type ◽  
P53 Expression ◽  
Acute Myeloid ◽  
Resistant Cells

Acute myeloid leukemia (AML) exhibits large intrinsic variation in drug responsiveness due to its inherent heterogeneity. Therefore, it is important to understand the resistant mechanism in order to improve the treatment. In our previously study, the OCI-AML2-resistant cell lines were established to resist cytarabine (Ara-C) in the concentration of 50 µM (OCI-AML2 R50). The RNA-seq results showed that many genes changed in the resistant cells compared to wild type OCI-AML2 cells. One of the most remarkably decreased gene in resistant cells was HOXA11 (Homeobox A11). It is the part of the A cluster on chromosome 7 and encodes a DNA-binding transcription factor which regulates gene expression, morphogenesis, and differentiation. In this study, we have evaluated the importance of HOXA11 in AML chemoresistance. We found that knockdown of HOXA11 repressed the WT OCI-AML2 cell proliferation and increased the population of cells expressing CD123 and CD47 LSC (Leukemia stem cell) markers and enhanced the resistance to Ara-C in vitro, while overexpression of HOXA11 showed the reverse effect. These results support the idea that HOXA11 promotes drug sensitivity and apoptosis in AML. However, the result also showed that overexpression of HOXA11 repressed the OCI-AML2 R50 cell proliferation and enhanced the resistance. Therefore, HOXA11 plays opposite role in sensitive cells and resistant cells. We further investigated the mechanism for these effects. We found that knockdown of HOXA11 decreased the p53 gene expression and overexpression of HOXA11 increased the expression of p53 in OCI-AML2 and R50 cells. Further, in OCI-AML2 R50 cells p53 has a hotspot mutation in DNA binding site and studies have shown that p53 mutation enhance cancer cell survival and chemoresistance. Therefore, our study shows dual roles for HOXA11 in cell survival. In p53 wild type parental AML2 cells, HOXA11 induces wild type p53 expression to enhance drug sensitivity while in resistant cell, HOXA11 promotes mutant p53 expression and enhances the resistance of chemotherapy. Disclosures No relevant conflicts of interest to declare.

scholarly journals Cytotoxic effects of bortezomib in myelodysplastic syndrome/acute myeloid leukemia depend on autophagy-mediated lysosomal degradation of TRAF6 and repression of PSMA1

Blood ◽  
2012 ◽  
Vol 120 (4) ◽  
pp. 858-867 ◽  
Author(s):  
Jing Fang ◽  
Garrett Rhyasen ◽  
Lyndsey Bolanos ◽  
Christopher Rasch ◽  
Melinda Varney ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndrome ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Gene Signature ◽  
Resistant Cell ◽  
Reversible Inhibitor ◽  
Cytotoxic Effects ◽  
Hematopoietic Stem ◽  
Acute Myeloid

Bortezomib (Velcade) is used widely for the treatment of various human cancers; however, its mechanisms of action are not fully understood, particularly in myeloid malignancies. Bortezomib is a selective and reversible inhibitor of the proteasome. Paradoxically, we find that bortezomib induces proteasome-independent degradation of the TRAF6 protein, but not mRNA, in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) cell lines and primary cells. The reduction in TRAF6 protein coincides with bortezomib-induced autophagy, and subsequently with apoptosis in MDS/AML cells. RNAi-mediated knockdown of TRAF6 sensitized bortezomib-sensitive and -resistant cell lines, underscoring the importance of TRAF6 in bortezomib-induced cytotoxicity. Bortezomib-resistant cells expressing an shRNA targeting TRAF6 were resensitized to the cytotoxic effects of bortezomib due to down-regulation of the proteasomal subunit α-1 (PSMA1). To determine the molecular consequences of loss of TRAF6 in MDS/AML cells, in the present study, we applied gene-expression profiling and identified an apoptosis gene signature. Knockdown of TRAF6 in MDS/AML cell lines or patient samples resulted in rapid apoptosis and impaired malignant hematopoietic stem/progenitor function. In summary, we describe herein novel mechanisms by which TRAF6 is regulated through bortezomib/autophagy–mediated degradation and by which it alters MDS/AML sensitivity to bortezomib by controlling PSMA1 expression.

Anti-Leukemia Effect of FF-10501-01, a Novel Inosine 5'-Monophosphate Dehydrogenase Inhibitor, in Acute Myeloid Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2756-2756
Author(s):  
Hui Yang ◽  
Zachary S. Bohannan ◽  
Zhihong Fang ◽  
Irene Gañán-Gómez ◽  
Yue Wei ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
De Novo ◽  
Resistant Cell ◽  
Nucleotide Synthesis ◽  
Cell Numbers ◽  
Induced Apoptosis ◽  
Dose Dependent ◽  
Acute Myeloid

Abstract Introduction Inosine 5'- monophosphate dehydrogenase (IMPDH) plays a critical role in nucleotide synthesis by serving as a rate-limiting step for the de novo production of guanine from its precursors. Overexpression of IMPDH has been observed in both solid and hematologic malignancies. FF-10501-01 is a potent new competitive IMPDH inhibitor. In this study, we systematically investigated the anti-leukemia effect of FF-10501-01 in acute myeloid leukemia (AML) cell lines, including hypomethylating agent (HMA)-resistant derivative cells. Methods Thirteen leukemia cell lines were studied, including 5 parental AML cell lines and their HMA-resistant derivatives (MOLM13, SKM1, HL60, TF1, and U937) as well as three other AML cell lines (KG1, HEL, and OCI-AML3). Cell proliferation was determined using trypan blue analysis. Flow cytometry was performed to detect drug-induced apoptosis and cell cycle status. High-performance liquid chromatography (HPLC) was performed to detect the intracellular concentration of guanine nucleotides, with mycophenolic acid (MPA) treated cells used as positive control. We also studied the effect of guanosine supplementation on FF-10501-01-treated cells. Results To understand whether FF-10501-01 was able to effectively limit AML cell proliferation, we subjected a variety of cell lines to 72 hours of FF-10501-01 treatment at various concentrations. We also included a large number of HMA-resistant cell lines in an effort to understand whether or not FF-10501-01 could be a useful secondary or complimentary treatment to HMA therapy. FF-10501-01 inhibited the proliferation of all 13 AML cell lines studied with 72 hours of treatment. The IC-50 of FF-10501-01 ranged between 4.3 and 144.5 µM. The IC50 values for HMA-resistant cells were all higher than those values in their HMA-sensitive counterparts, except SKM1, in which the HMA-sensitive line had a higher IC50 than the HMA-resistant SKM1 line. To further understand the mechanism by which FF-10501-01 effectively reduced cell numbers in these cell lines, we assessed the level of apoptosis in each line after FF-10501-01 exposure. FF-10501-01-induced apoptosis was observed in all of the studied cell lines in a dose-dependent manner except for the HMA-resistant TF-1 cell line. We then assessed whether FF-10501-01 affected cell cycle progression. This effect was highly variable. Increased numbers of cells in G1 phase and decreased numbers of cells in S phase were observed in MOLM13, SKM1, and TF-1 cell lines treated with less than 100 µM FF-10501-01. To understand the mechanistic effects of FF-10501-01, we performed rescue experiments with both HMA-resistant and HMA-sensitive MOLM13 and HL60 cells. Concurrent treatment with FF-10501-01 and guanosine in these cells partially rescued the antiproliferation effect of FF-10501-01. To further characterize the effect of FF-10501-01 on guanosine metabolism, we then performed HPLC experiments to analyze the levels of phosphoguanosine in treated MOLM13 and SKM1 cells. FF-10501-01 treatment effectively reduced the intracellular phosphoguanosine levels in both cell lines. This effect was seen for GMP, GDP, and GTP. We then sought to assess whether the combination of FF-10501-01 and HMAs could be effective in limiting MOLM13 and HL-60 cell proliferation, especially in their HMA resistant derivatives. The combination of HMA and FF-10501-01 showed little synergy beyond the effects of FF-10501-01 alone, regardless of HMA sensitivity, except in HMA-resistant HL-60 cells, in which FF-10501-01 showed moderate synergy with HMA. We further assessed the antiproliferative effect of FF-10501-01 in bone marrow blast samples taken from 3 AML patients. There was a minor dose-dependent antiproliferation effect seen in these samples, but this was not statistically significant. Notably, one patient showed a sharp increase in cell counts at the lowest concentration of FF-10501-01, but that sample's cell numbers decreased more rapidly as FF-10501-01 concentration increased. This implies that FF-10501-01 treatment response may be related to cell proliferation. Conclusions The IMPDH inhibitor FF-10501-01 can produce potent anti-proliferative and apoptotic induction effects on AML cell lines, including HMA-resistant cell lines, through inhibition of de novo guanine nucleotide synthesis. These results indicate that FF-10501-01 might be a promising new therapeutic agent for AML. Disclosures Paradiso: Strategia Therapeutics, Inc.: Employment. Iwamura:FUJIFILM Corporation: Employment.

A Machine-Learning Analysis Suggests That FLX925, a FLT3/CDK4/6 Kinase Inhibitor, Is Potent Against FLT3-Wild Type Tumors Via Its CDK4/6 Activity

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3520-3520
Author(s):  
Gene Cutler ◽  
Jordan S Fridman
Keyword(s):  
Cell Cycle ◽  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Rna Seq ◽  
Cell Cycle Genes ◽  
Equity Ownership ◽  
Anti Tumor Activity ◽  
Acute Myeloid

Abstract Fms-like tyrosine kinase 3 (FLT3) is universally expressed in Acute Myeloid Leukemia (AML) blast cells (Zheng R, et al. FLT3 ligand causes autocrine signaling in acute myeloid leukemia cells. Blood. 2004) and activating mutations of FLT3 are amongst the most common genetic lesions in AML (Levis M. FLT3 mutations in acute myeloid leukemia: what is the best approach in 2013? ASH Education Program Book. 2013). FLX925, a small molecule inhibitor of FLT3 would be expected to have antitumor efficacy against FLT3-driven AML tumors. However, FLX925 also inhibits two closely related cyclin-dependent kinases (CDKs), CDK4 and CDK6 (described together as CDK4/6). Since CDK4/6 are important cell cycle genes and CDK4/6 inhibitors have demonstrated anti-tumor activity, the anti-CDK4/6 activity of FLX925 may drive anti-tumor efficacy in additional and potentially overlapping patient populations. To generate hypotheses about which tumors would be sensitive to FLX925 treatment and to understand the relative contributions of FLX925's FLT3- and CDK4/6-inhibitory activities, a panel of XXX tumor-derived cell lines were screened for sensitivity to FLX925. We performed a Gradient Boosting Machine (GBM) analysis, a machine-learning approach, to generate a model that predicts sensitivity to FLX925 based on RNA-Seq expression data. This sensitivity model can predict which cell lines and tumors are likely to be sensitive to FLX925 and also which gene expression patterns contribute to that sensitivity. The GBM analysis was performed on 133 (75%) of the assayed cell lines with a random 45 (25%) of the cell line datasets reserved for model validation. Pearson's correlations of r=0.96 on the test cell lines and r=0.68 on the validation cell lines were observed, indicating good predictive performance with modest overfitting. The two most important predictive genes in the model were Retinoblastoma 1 (RB1) and by Cyclin-Dependent Kinase Inhibitor 2A (CDKN2A). RB1 and CDKN2A are important cell cycle genes immediately downstream and upstream, respectively, of CDK4/6, suggesting that sensitivity to FLX925 in these cell lines is driven by FLX925's CDK4/6 inhibitory activity. To strengthen this conclusion, the modeling was repeated but gene sets covering cell cycle genes or genes in the FLT3/STAT5 signaling pathway were separately excluded from the analysis. While excluding the FLT3/STAT5 pathway genes had no impact on the predictive power of the model, excluding the cell cycle gene set completely abrogated the ability of the GBM to predict sensitivity to FLX925. Thus, we conclude that in this panel of largely FLT3-wild type (FLT3-WT) cell lines, FLX925-sensitivity is driven solely by the compound's CDK4/6 activity. These results suggest that independent, but potentially overlapping, sets of tumors will be responsive to FLX925 due to both its FLT3- and its CDK4/6-inhibitory activities. To predict which tumor types would be most sensitive to FLX925 treatment, we applied our GBM model to the RNA-Seq expression data for 10,537 tumors from The Cancer Genome Atlas (TCGA) consortium. Even though this model is indifferent to FLT3/STAT5-pathway gene expression, it nevertheless identifies AML tumors as having the highest median predicted sensitivity to FLX925. This is true even when all haem/lymph malignancy-derived cell lines are excluded from the training set. Thus, both FLT3-WT and FLT3-activated tumors are expected to have sensitivity to FLX925 treatment, the former due to FLX925's CDK4/6 activity alone and the latter due to the independent FLT3 and CDK4/6 activities of the drug. The anti-tumor activity of FLX925 is currently being investigated in a Ph1/b dose-escalation study in subject with relapsed or refractory AML (NCT02335814). Disclosures Cutler: Amgen, Inc: Equity Ownership; FLX Bio: Employment, Equity Ownership. Fridman:FLX Bio: Employment, Equity Ownership.

scholarly journals AXL/MERTK inhibitor ONO-7475 potently synergizes with venetoclax and overcomes venetoclax resistance to kill FLT3-ITD acute myeloid leukemia

Haematologica ◽  
2021 ◽  
Author(s):  
Sean M. Post ◽  
Huaxian Ma ◽  
Prerna Malaney ◽  
Xiaorui Zhang ◽  
Marisa J.L. Aitken ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Leukemia Cell ◽  
Leukemia Cell Lines ◽  
Acute Myeloid ◽  
Myeloid Leukemia Cell ◽  
Resistant Cells

FMS-like Tyrosine Kinase 3 (FLT3) mutation is associated with poor survival in AML. The specific Anexelekto/MER Tyrosine Kinase (AXL) inhibitor ONO-7475 kills FLT3-mutant acute myeloid leukemia cells with targets including Extracellular-signal Regulated Kinase (ERK) and Myeloid Cell Leukemia 1 (MCL1). ERK and MCL1 are known resistance factors for Venetoclax (ABT-199), a popular drug for AML therapy, prompting the investigation of the efficacy of ONO-7475 in combination with ABT-199 in vitro and in vivo. ONO-7475 synergizes with ABT-199 to potently kill FLT3-mutant acute myeloid leukemia cell lines and primary cells. ONO-7475 is effective against ABT-199-resistant cells including cells that overexpress MCL1. Proteomic analyses revealed that ABT-199-resistant cells expressed elevated levels of pro-growth and anti-apoptotic proteins compared to parental cells, and that ONO-7475 reduced the expression of these proteins in both the parental and ABT-199-resistant cells. ONO-7475 treatment significantly extended survival as a single agent in vivo using acute myeloid leukemia cell lines and PDX models. Compared to ONO-7474 monotherapy, the combination of ONO- 7475/ABT-199 was even more potent in reducing leukemic burden and prolonging survival of mice in both model systems. These results suggest the ONO-7475/ABT-199 combination may be effective for acute myeloid leukemia therapy.

scholarly journals Efficient Elimination of Acute Myeloid Leukemia Cells through Inhibition of KDM4A in Combination with PARP Inhibition

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3756-3756
Author(s):  
Laura Monaghan ◽  
Matthew Edward Massett ◽  
Roderick P Bunschoten ◽  
Petrisor Alin Pirvan ◽  
Alex Hoose ◽  
...  
Keyword(s):  
Cell Lines ◽  
Myeloid Leukemia ◽  
Essential Role ◽  
Therapeutic Strategy ◽  
Leukemic Cell ◽  
Leukemic Cells ◽  
Enrichment Score ◽  
Rna Seq ◽  
Q Value ◽  
Acute Myeloid

Epigenetic therapies are emerging as a promising therapeutic strategy for acute myeloid leukemia (AML), exemplified by advances in the development of inhibitors targeting DNMT3A, DOT1L and LSD1. We identified an essential role for the H3K9me3 histone demethylase, KDM4A, in maintaining AML cell survival with genetic depletion of KDM4A having no effect on normal hematopoiesis. Therefore, we hypothesise KDM4A inhibition may represent a novel and effective strategy to treat AML. To address this, we developed a series of novel KDM4A inhibitors (KDM4Ai), based on the structure of pan inhibitor IOX1, and fully characterised their functional potential in AML cells representing major molecular subtypes, and primary patient blasts in comparison with healthy donor cells, as single agents or in combination with other anti-cancer drugs. To evaluate these compounds in physiological conditions, we utilised a stromal co-culture system mimicking the bone marrow microenvironment. Furthermore, we carried out global transcriptomic profiling by RNA-seq to elucidate the molecular consequences responsible for KDM4Ai induced leukemic killing. As a mono-therapy, KDM4Ai induced leukemic cell differentiation and apoptosis in a broad spectrum of human AML cells, with an IC50 of 3.2µM ± 0.2 in MLL-AF9 driven THP1 cells after 48hr treatment (n=3), similar efficacy was observed in other human AML cell lines (n= ≤3) including Kasumi1 (2.69µM ± 0.1) , OCI-AML3 (4.9 µM ± 1.0) and MOLM13 (1.7 µM ± 0.7) and in primary patient blasts (3.8µM). A complete removal of colony forming potential was observed upon treatment (n = 2). The global expression of KDM4A's established substrate, H3K9me3 was upregulated by immunofluorescence and transcriptional changes in a 9-gene signature identified previously as direct KDM4A downstream targets, is indicative of an on-target effect by KDM4Ai. Importantly, KDM4Ai specifically reduced CD34+leukemic stem cell enriched population ( reduced by 6%). In contrast, a non significant reduction was observed on donor CD34+hematopoietic stem and progenitor cells proliferation and apoptosis suggesting a therapeutic window. Cytoprotection provided by stromal co-culture in both AML cell lines and primary samples resulted in a 50% decrease in apoptotic cells with maintenance of the CD34+compartment . Taking these results into account we identify importance of the microenvironment in drug mechanism and resistance. To better understand the mechanism driving this selective anti-leukemic effect, we performed transcriptomic analysis on KDM4Ai treated THP1 cells (n=3). Corroborating the differentiation phenotype, pathway analysis showed an enrichment of IL4 & IL13 signalling (Enrichment score (ES) = - 0.53, q value = 0.025), and neutrophil degranulation (Enrichment score (ES) = - 0.51, q value = 0.025), this was accompanied by significant up-regulation of DNA damage response pathways (ES = 0.66, q value = 0.025) . These results were confirmed in AML cell lines, displaying accumulation > 20% of γH2AX by intracellular flow cytometry and PARP cleavage by western blot following treatment. Based on these results we hypothesised that KDM4Ai may sensitise leukemic cells to DNA damage pathway inhibitors, such as PARP inhibitors (PARPi) (n = ≤3). While standard chemotherapies, such as cytarabine and azacitidine, in combination with KDM4Ai showed a largely additive effect, a dual inhibition of KDM4Ai at 3mM with 5mM olaparib (PARPi), exhibited a Combination Index of ~0.69 with a decrease in proliferation (>15% reduction) and increased apoptosis (>20%) in MLLr-AML cell lines compared with KDM4Ai alone (p=0.005). This effect was corroborated ex vivo using cells isolated from a patient derived xenograft model of MLL-AF10 (n=3). Taken together these results suggest a synergistic leukemic cell killing and have subsequently been subjected to global RNA-seq to confirm the detailed molecular mechanism underlying the synergistic effect. Pharmacological inhibition of KDM4A using novel compounds effectively eliminated leukemic cells sparing normal hematopoietic cells with a synthetic lethality observed through combination with PARPi offering a promising therapeutic strategy in AML. Our data further support the essential role for KDM4A in myeloid oncogenesis, promoting future clinical evaluation of KDM4Ai its associated downstream targets as potential tractable therapeutic vulnerabilities in AML. Disclosures No relevant conflicts of interest to declare.

C3aR1 Contributed to Acute Myeloid Leukemia Acquired Resistance to ABT-737 and Involved In the Process of AML

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1435-1435 ◽  
Author(s):  
Shaoyan Hu ◽  
Saied Mirshahidi ◽  
Chong-Lei Bi ◽  
Wee-Joo Chng ◽  
Heng-Wei Hsu ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Real Time ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Acquired Resistance ◽  
Resistant Cell ◽  
Rt Pcr ◽  
Resistant Lines ◽  
Parental Lines ◽  
Acute Myeloid

Abstract Abstract 1435 Abstract ABT-737 is a small molecule antagonist of BCL-2, BCL-XL, and BCL-w currently under evaluation in clinical trials in the oral form of ABT-263 (Navitoclax). Acquired resistance to BCL-2 inhibitors will inevitably emerge. Published pre-clinical data showed increased levels of BFL-1 and/or MCL-1 proteins in lymphoma, and concurrent up-regulation of BCL-XL and BCL2A1 in chronic lymphocytic leukemia, which are not targeted by ABT-737. To investigate potential mechanisms of resistance to BCL-2 inhibitors in acute myeloid leukemia, we developed resistant cell lines by long-term culture of HL-60 and MV4-11 cells with ABT-737, designated as HL-60R and MV4-11R. Parental lines, HL-60 and MV4-11 which were highly sensitive to ABT-737 with IC50 values of 30 nM and 90nM respectively, whereas those for HL-60R and MV4-11R were 10μM and 4.7μM respectively. Annexin V binding assay revealed that both resistant lines were resistant to ABT-737 induced apoptosis as compared to the parental HL-60 and MV4-11 cells. To explore the common pathway mediating acquired resistance to ABT-737, genes differentially expressed 2-fold or greater between parental and resistant lines on HL-60 and MV4-11 were studied. Interestingly, significant changes for BCL-2 family members were not found, suggesting that non-BCL2 family genes could play important roles in mediating the drug resistance to ABT-737. Among them, C3aR1 [Complement component 3a receptor 1] was significantly over-expressed in both resistant cell lines when compared to parental lines and verified with real-time RT-PCR. C3aR1 inhibitor, SB 290157, showed preferential cytotoxicity to both HL-60R and MV4-11R in a dose-dependent way and spared parental cells during 48 hrs in vitro MTT assay. Our findings suggest C3aR1 plays a key role in the resistance phenotype to Bcl-2 inhibitor and blocking C3aR1 revert the resistance. C3aR1 encodes a G-protein coupled seven trans-membrane receptor for C3a, an important inflammatory mediator. The C3a-C3aR axis modulated SDF-1–CXCR4 axis-dependent responses and regulated the homing of hematopoietic stem/progenitor cells into bone marrow. C3aR1 over expression has been associated with FLT3 and D835/I836 mutation cytogenetically normal acute myeloid leukemia, renal cancer and melanoma. We further investigate the role of C3aR1 in 138 cases of AML including 50 cases in initial diagnosis, 68 cases in remission and 20 cases in relapse with real-time RT-PCR. The result showed that C3aR1 expression is highest in initial stage and lowest in remission (p=0.006), there was no significant difference between initial and relapse stages (p=0.384). [Table 1] For newly diagnosed AML patients, high C3aR1 is statistically associated with younger age [median: 34 vs 43 years old], higher presenting WBC [median: 39K vs 27K], higher marrow % blasts [70 vs 55%], but not related to efficacy of first induction treatment, FAB classification or conventional chromosome risk groups.Table 1C3aR1 expression in AML clinical casesAML casesAge (year)C3AR1malefemalemedianrangeM-estimatorrangepInitial2822367-79199.777.49-2514.6P1 = 0.006Remission37313412-7092.2523.45-2286P2 = 0.046Relapse11944.513-54142.7512.4-2372.04P3 = 0.384Note: M-estimator was used for evaluating the differential expression of AML samples and the value was amplified by 104p1: initial vs remission; p2: relapse vs remission; p3 initial vs relapse The biological significant of C3a-C3aR axis in AML and resistance phenotype is intriguing and may suggest a novel mechanism of evading the apoptotic regulation by Bcl-2 gene family as suggested by our current study. Ongoing studies will further elucidate relationship of C3a-C3aR axis in AML. Disclosures: No relevant conflicts of interest to declare.

Antitumor Effect of Pomolic Acid in Acute Myeloid Leukemia Cells Involves Cell Death, Decreased Cell Growth and Topoisomerases Inhibition

2019 ◽  
Vol 18 (10) ◽  
pp. 1457-1468
Author(s):  
Michelle X.G. Pereira ◽  
Amanda S.O. Hammes ◽  
Flavia C. Vasconcelos ◽  
Aline R. Pozzo ◽  
Thaís H. Pereira ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Natural Compound ◽  
Dna Topoisomerases ◽  
Human Dna ◽  
Pomolic Acid ◽  
Acute Myeloid

Background: Acute myeloid leukemia (AML) represents the largest number of annual deaths from hematologic malignancy. In the United States, it was estimated that 21.380 individuals would be diagnosed with AML and 49.5% of patients would die in 2017. Therefore, the search for novel compounds capable of increasing the overall survival rate to the treatment of AML cells is urgent. Objectives: To investigate the cytotoxicity effect of the natural compound pomolic acid (PA) and to explore the mechanism of action of PA in AML cell lines with different phenotypes. Methods: Three different AML cell lines, HL60, U937 and Kasumi-1 cells with different mechanisms of resistance were used to analyze the effect of PA on the cell cycle progression, on DNA intercalation and on human DNA topoisomerases (hTopo I and IIα) in vitro studies. Theoretical experiments of the inhibition of hTopo I and IIα were done to explore the binding modes of PA. Results: PA reduced cell viability, induced cell death, increased sub-G0/G1 accumulation and activated caspases pathway in all cell lines, altered the cell cycle distribution and inhibited the catalytic activity of both human DNA topoisomerases. Conclusion: Finally, this study showed that PA has powerful antitumor activity against AML cells, suggesting that this natural compound might be a potent antineoplastic agent to improve the treatment scheme of this neoplasm.

scholarly journals Chidamide increases the sensitivity of refractory or relapsed acute myeloid leukemia cells to anthracyclines via regulation of the HDAC3 -AKT-P21-CDK2 signaling pathway

2020 ◽  
Vol 39 (1) ◽  
Author(s):  
Hao Wang ◽  
Yu-chen Liu ◽  
Cheng-ying Zhu ◽  
Fei Yan ◽  
Meng-zhen Wang ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Signaling Pathway ◽  
Salvage Therapy ◽  
Myeloid Leukemia ◽  
Complete Response ◽  
Dependent Manner ◽  
Induce Cell Cycle Arrest ◽  
Anthracycline Resistance ◽  
Acute Myeloid ◽  
Resistant Cells

Abstract Background Induction therapy for acute myeloid leukemia (AML) is an anthracycline-based chemotherapy regimen. However, many patients experience a relapse or exhibit refractory disease (R/R). There is an urgent need for more effective regimens to reverse anthracycline resistance in these patients. Methods In this paper, Twenty-seven R/R AML patients with anthracycline resistance consecutively received chidamide in combination with anthracycline-based regimen as salvage therapy at the Chinese PLA General Hospital. Results Of the 27 patients who had received one course of salvage therapy, 13 achieved a complete response and 1 achieved a partial response. We found that the HDAC3-AKT-P21-CDK2 signaling pathway was significantly upregulated in anthracycline-resistant AML cells compared to non-resistant cells. AML patients with higher levels of HDAC3 had lower event-free survival (EFS) and overall survival (OS) rates. Moreover, anthracycline-resistant AML cells are susceptible to chidamide, a histone deacetylase inhibitor which can inhibit cell proliferation, increase cell apoptosis and induce cell-cycle arrest in a time- and dose-dependent manner. Chidamide increases the sensitivity of anthracycline-resistant cells to anthracycline drugs, and these effects are associated with the inhibition of the HDAC3-AKT-P21-CDK2 signaling pathway. Conclusion Chidamide can increase anthracycline drug sensitivity by inhibiting HDAC3-AKT-P21-CDK2 signaling pathway, thus demonstrating the potential for application.

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