scholarly journals The Salt-Inducible Kinase inhibitor YKL-05-099 suppresses MEF2C function and acute myeloid leukemia progressionin vivo

2019 ◽  
Author(s):  
Yusuke Tarumoto ◽  
Shan Lin ◽  
Jinhua Wang ◽  
Joseph P. Milazzo ◽  
Yali Xu ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Disease Progression ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Clinical Investigation ◽  
Genetic Targeting ◽  
Acute Myeloid

AbstractLineage-defining transcription factors (TFs) are compelling targets for leukemia therapy, yet they are among the most challenging proteins to modulate directly with small molecules. We previously used CRISPR screening to identify a Salt-Inducible Kinase 3 (SIK3) requirement for the growth of acute myeloid leukemia (AML) cell lines that overexpress the lineage TF MEF2C. In this context, SIK3 maintains MEF2C function by directly phosphorylating histone deacetylase 4 (HDAC4), a repressive cofactor of MEF2C. Here, we evaluated whether inhibition of SIK3 with the tool compound YKL-05-099 can suppress MEF2C function and attenuate disease progression in animal models of AML. Genetic targeting of SIK3 or MEF2C selectively suppressed the growth of transformed hematopoietic cells underin vitroandin vivoconditions. Similar phenotypes were obtained when exposing cells to YKL-05-099, which caused cell cycle arrest and apoptosis in MEF2C-expressing AML cell lines. An epigenomic analysis revealed that YKL-05-099 rapidly suppressed MEF2C function by altering the phosphorylation state and nuclear localization of HDAC4. Using a gatekeeper allele ofSIK3, we found that the anti-proliferative effects of YKL-05-099 occurred through on-target inhibition of SIK3 kinase activity. Based on these findings, we treated two different mouse models of MLL-AF9 AML with YKL-05-099, which attenuated disease progressionin vivoand extended animal survival at well-tolerated doses. These findings validate SIK3 as a therapeutic target in MEF2C-positive AML and provide a rationale for developing drug-like inhibitors of SIK3 for definitive pre-clinical investigation and for studies in human patients with leukemia.Key PointsAML cells are uniquely sensitive to genetic or chemical inhibition of Salt-Inducible Kinase 3in vitroandin vivo.A SIK inhibitor YKL-05-099 suppresses MEF2C function and AMLin vivo.

scholarly journals Anti-leukemia properties of cadmium nanoparticles in the in vitro and in vivo condition: A chemobiological study

2021 ◽  
Author(s):  
Yudi Miao ◽  
Behnam Mahdavi ◽  
Mohammad Zangeneh
Keyword(s):  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Aqueous Extract ◽  
Myeloid Leukemia ◽  
Antioxidant Properties ◽  
Leukemia Cell ◽  
Sem Images ◽  
Acute Myeloid

IntroductionThe present study investigated the anti-acute myeloid leukemia effects of Ziziphora clinopodides Lam leaf aqueous extract conjugated cadmium nanoparticles.Material and methodsTo synthesize CdNPs, Z. clinopodides aqueous extract was mixed with Cd(NO3)2 .4H2O. The characterization of the biosynthesized cadmium nanoparticles was carried out using many various techniques such as UV-Vis. and FT-IR spectroscopy, XRD, FE-SEM, and EDS.ResultsThe uniform spherical morphology of NPs was proved by FE-SEM images with NPs the average size of 26.78cnm. For investigating the antioxidant properties of Cd(NO3)2, Z. clinopodides, CdNPs, and Daunorubicin, the DPPH test was used. The cadmium nanoparticles inhibited half of the DPPH molecules in a concentration of 196 µg/mL. To survey the cytotoxicity and anti-acute myeloid leukemia effects of Cd(NO3)2, Z. clinopodides, CdNPs, and Daunorubicin, MTT assay was used on the human acute myeloid leukemia cell lines i.e., Murine C1498, 32D-FLT3-ITD, and Human HL-60/vcr. The IC50 of the cadmium nanoparticles was 168, 205, and 210 µg/mL against Murine C1498, 32D-FLT3-ITD, and Human HL-60/vcr cell lines, respectively. In the part of in vivo study, DMBA was used for inducing acute myeloid leukemia in mice. CdNPs similar to daunorubicin ameliorated significantly (p≤0.01) the biochemical, inflammatory, RBC, WBC, platelet, stereological, histopathological, and cellular-molecular parameters compared to the other groups.ConclusionsAs mentioned, the cadmium nanoparticles had significant anti-acute myeloid leukemia effects. After approving the above results in the clinical trial studies, these cadmium nanoparticles can be used as a chemotherapeutic drug to treat acute myeloid leukemia in humans.

The Investigational Multi-Targeted Kinase Inhibitor TAK-901 Antagonizes Acute Myeloid Leukemia Pathogenesis: Results of Preclinical Studies

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 581-581
Author(s):  
Patrick Griffin ◽  
Steffan T Nawrocki ◽  
Takashi Satou ◽  
Claudia M Espitia ◽  
Kevin R. Kelly ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Mouse Model ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Standard Of Care ◽  
Clonogenic Survival ◽  
Preclinical Studies ◽  
Acute Myeloid

Abstract Abstract 581 The long-term prognosis for the majority of patients diagnosed with acute myeloid leukemia (AML) is very poor due, in part, to pre-existing myelodysplasia, multidrug resistance, and co-existing morbidities that limit therapeutic options. Novel strategies are essential in order to improve clinical outcomes. TAK-901 is an investigational small molecule kinase inhibitor that is currently being evaluated in Phase I trials. In preclinical studies, TAK-901 has demonstrated significant effects against a number of kinases with important roles in cancer including the Aurora kinases, which are key regulators of mitosis and whose overexpression in cancer promotes genetic instability, malignant pathogenesis, and drug resistance. We hypothesized that simultaneously targeting the activity of the Auroras and other oncogenic kinases with TAK-901 would disrupt AML pathogenesis. In order to test our hypothesis, we investigated the efficacy and pharmacodynamic activity of TAK-901 human AML cell lines, primary AML specimens, and an orthotopic bioluminescent disseminated mouse model of AML. TAK-901 potently diminished the viability of a panel of 8 AML cell lines as well as primary cells obtained from patients with AML. Acute exposure to TAK-901 ablated clonogenic survival, triggered the accumulation of polyploid cells, and induced apoptosis. The cytostatic and cytotoxic effects of TAK-901 were associated with significantly increased expression of the cyclin-dependent kinase inhibitor p27, growth arrest and DNA-damage-inducible 45a (GADD45a), and the BH3-only pro-apoptotic protein PUMA. Chromatin immunoprecipitation (ChIP) assays revealed that the elevation in the expression of these genes caused by administration of TAK-901 was due to increased FOXO3a transcriptional activity. The in vivo anti-leukemic activity of TAK-901 was investigated in a disseminated xenograft mouse model of AML established by intravenous injection of luciferase-expressing MV4-11 cells. IVIS Xenogen imaging was utilized to monitor disease burden throughout the study. In this mouse model, administration of TAK-901 was very well-tolerated and significantly more effective than the standard of care drug cytarabine with respect to suppressing disease progression and prolonging overall survival. Analysis of specimens collected from mice demonstrated that TAK-901 inhibited the homing of AML cells to the bone marrow microenvironment and induced AML cell apoptosis in vivo. Our collective findings indicate that TAK-901 is a novel multi-targeted kinase inhibitor that has significant preclinical activity in AML models and warrants further investigation. Disclosures: Satou: Takeda Pharmaceuticals: Employment. Hasegawa:Takeda Pharmaceuticals: Employment. Romanelli:Millennium Pharmaceuticals: Employment. de Jong:Takeda San Diego: Employment. Carew:Millennium Pharmaceuticals: Research Funding.

The BTK Inhibitor Ibrutinib Blocks SDF1/CXCR4 Mediated Migration of Acute Myeloid Leukemia Cells

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 915-915
Author(s):  
Stuart A Rushworth ◽  
Lyubov Zaitseva ◽  
Megan Y Murray ◽  
Matthew J Lawes ◽  
David J MacEwan ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Conflicts Of Interest ◽  
Lymphocytic Leukemia ◽  
Cell Trafficking ◽  
Acute Myeloid

Abstract Introduction Despite recent significant progress in the understanding of the biology of acute myeloid leukemia (AML) the clinical outcomes for the majority of patients diagnosed with AML presently remain poor. Consequently, there is an urgent need to identify pharmacological strategies in AML, which are not only effective but can be tolerated by the older, less well patient. Recently our group and others have shown that there is high Bruton’s Tyrosine Kinase (BTK) phosphorylation and RNA expression in AML. Moreover, our recent study described for the first time that ibrutinib and BTK-targeted RNA interference reduced factor-induced proliferation of both AML cell lines and primary AML blasts, as well as reducing AML blast adhesion to bone marrow stromal cells. Inhibition of BTK has been shown to regulate chronic lymphocytic leukemia, mantle cell lymphoma and multiple myeloma cell migration by inhibiting SDF1 (stromal derived factor 1) induced CXCR4 regulated cell trafficking. Here we report that in human AML ibrutinib in addition functions in a similar way to inhibit SDF1/CXCR4-mediated AML migration at concentrations achievable in vivo. Methods To investigate the role of BTK in regulating AML migration we used both pharmacological inhibitor ibrutinib and genetic knockdown using a lentivirus mediated BTK targeted miRNA in primary AML blasts and AML cell lines. We examined migration of AML blasts and AML cells to SDF-1 using Transwell permeable plates with 8.0µM pores. Western blotting was used to examine the role of SDF-1 in regulating BTK, AKT and MAPK activation in primary AML blasts. Results We initially examined the expression of CXCR4 in human AML cell lines and found that 4/4 cell lines were positive for CXCR4 expression. Next we examined the effects of ibrutinib on the migration of the AML cell lines U937, MV4-11, HL60 and THP-1 in response to SDF1. We found that ibrutinib can inhibit the migration of all AML cell lines tested. We tested the in-vitro activity of ibrutinib on SDF-1 induced migration in a spectrum of primary AML blasts from a wide age spectrum of adult patients and across a range of WHO AML subclasses and found that ibrutinib significantly inhibits primary AML blast migration (n=12). Next we found that ibrutinib can inhibit SDF-1 induced BTK phosphorylation and downstream MAPK and AKT signalling in primary AML blast. Finally to eliminate the problems associated with off target ibrutinib activity we evaluated migration of AML cells lines using genetic inhibition of BTK. The introduction of BTK-specific miRNA dramatically inhibited the expression of BTK in THP-1 and HL60 and reduced SDF1 mediated migration confirming that BTK is involved in regulating AML migration in response to SDF1. Conclusions These results reported here provide a molecular mechanistic rationale for clinically evaluating BTK inhibition in AML patients and suggests that in some AML patients the blasts count may initially rise in response to ibrutinib therapy, analgous to similar clinical observations in CLL. Disclosures No relevant conflicts of interest to declare.

The Novel Fluoropyrimidine FdUMP[10] Is Highly Active Against Acute Myeloid Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3302-3302
Author(s):  
Timothy Pardee ◽  
Evan Gomes ◽  
Jamie Jennings-Gee ◽  
David L. Caudell ◽  
William Gmeiner
Keyword(s):  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Single Agent ◽  
The Novel ◽  
Highly Active ◽  
Ic50 Values ◽  
Acute Myeloid

Abstract Abstract 3302 Acute Myeloid Leukemia (AML) is an aggressive myeloid malignancy that leads to marrow failure and death. This disease affects approximately 12,000 people per year in the United States, causing 9,000 deaths. Despite decades of research, therapy remains essentially unchanged and outcomes are poor. In patients over the age of 60 less then 10% of patients survive 5 years from diagnosis. There is a desperate need for the identification of new active agents with favorable toxicity profiles. The novel polymeric fluoropyrimidine (FP) FdUMP[10] is an oligodeoxynucleotide pro-drug of the thymidylate synthase (TS)-inhibitory FP metabolite 5-fluoro-2'-deoxyuridine-5`-O-monophosphate (FdUMP). The observation that this compound was highly active against several leukemia lines in the NCI 60 cell line screen prompted us to evaluate its activity in several preclinical models of AML. In vitro, FdUMP[10] exhibited remarkable activity against 3 human acute leukemia cell lines, HL60, Jurkat and THP-1, with IC50 values of 3.378 nM (95% CI 2.984 to 3.825), 5.438 nM (4.609 to 6.417) and 4.093 nM (3.413 to 4.907) respectively. We next tested its efficacy against a more genetically defined murine model of AML driven by expression of MLL-ENL. FdUMP[10] exhibited even greater activity against all murine lines tested. The IC50 values of FdUMP[10] against two MLL-ENL driven murine AML cell lines were 214 pM (95%CI 178.9 to 255.9) and 292.3 pM (251.8 to 339.4). The IC50 values observed for FdUMP[10] for all the murine lines tested were lower than both Ara-C (30-40 nM) and doxorubicin (2-4 nM). We then determined the cytotoxic mechanism for FdUMP[10] in vitro. Upon treatment with FdUMP[10] both the human and murine cell lines undergo extensive apoptosis as indicated by Annexin V and propidium iodide staining. Treated cells developed γH2AX foci, rapid and complete TS inhibition and display trapped Topoisomerase I (Topo I) cleavage complexes. FdUMP[10]-mediated induction of apoptosis was p53 independent as murine AML cells that had p53 knocked down by RNAi demonstrated resistance to both Ara-C and doxorubicin, but not to FdUMP[10]. We next tested the efficacy of FdUMP[10] in vivo. The MLL-ENL driven murine AML model results in blasts that can be transplanted into sublethally irradiated, immunocompetent, syngeneic recipients. The recipients develop a fatal and therapy-resistant AML. Lines were generated that expressed a luciferase reporter. Animals were imaged 6–7 days after injection of the leukemias to ensure engraftment and then began treatment with either the combination of Ara-C plus doxorubicin, single-agent FdUMP[10], or observation. Studies were performed using 2 doses of FdUMP[10] at 150 or 300 mg/kg injected on days 1 and 3 and compared to animals treated with 100 mg/kg Ara-C and 3mg/kg doxorubicin injected on days 1 through 5. Both treatments resulted in a statistically significant survival advantage over observation. A preliminary toxicology study compared FdUMP[10], 150 mg/kg daily, to 5-fluorouracil (5 FU), 150 mg/kg daily, or the combination of Ara-C at 100 mg/kg plus doxorubicin at 3 mg/kg daily. All groups were treated for 3, 4 or 5 days. On day 6 animals were sacrificed and organs harvested, sectioned, and stained. Slides were then reviewed by a veterinary pathologist. Tissues most affected were the small intestine, colon, and the bone marrow. The 5FU-treated animals had severe villous blunting and fusion with crypt necrosis in both large and small intestine. In contrast, FdUMP[10]-treated animals had only mild crypt epithelial apoptosis with mitoses. The 5 FU and Ara-C plus doxorubicin groups had a severe pan-cytopenia in the marrow compared to FdUMP[10] treated animals that showed only minimal to mild apoptosis. These data support the assertion that FdUMP[10] has lower toxicity then either Ara-C plus doxorubicin or identically dosed 5 FU. In summary FdUMP[10] exhibited remarkable activity against AML cells in vitro and in vivo. Additionally, FdUMP[10] had decreased toxicity compared to treatment with either single agent 5 FU or combination treatment with Ara-C plus doxorubicin. Disclosures: Gmeiner: Salzburg Therapeutics: Equity Ownership.

Vgamma9Vdelta2 T Cells-Based Immunotherapy Targeting BTN3 Molecules in Acute Myeloid Leukemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3726-3726
Author(s):  
Daniel Olive ◽  
Audrey Benyamine ◽  
Aude Le Roy ◽  
Rémy Castellano ◽  
Julie Gertner-Dardenne ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Mevalonate Pathway ◽  
Conflicts Of Interest ◽  
Tumor Burden ◽  
Acute Myeloid

Abstract As they can kill Acute Myeloid Leukemia (AML) blasts in vitro and in vivo, Vg9Vd2T cells are key players in the design of new strategies of immunotherapy. AminoBisphonates (NBP) can enhance their activation in vitro and in vivo. Their combination with low-dose IL2 has shown promising results in 2 patients with AML who underwent partial remission. NBP treatment of blasts inhibits the Mevalonate pathway. The subsequent accumulation of Isopentenyl Diphosphate sensitize AML blasts to Vg9Vd2T cells killing but some AML cell lines blasts are resistant to this TCR mediated-lysis. Butyrophilin 3 A1 (BTN3A1) has been shown to be involved in IPP recognition and Vg9Vd2 T cells activation. Agonist monoclonal antibodies (mAb) recognizing the 3 isoforms of BTN3, can trigger BTN3 on tumor cell lines and sensitize them to Vg9Vd2 T cells lysis. We show that primary AML blasts from patient at diagnosis are heterogeneously killed by allogenic-IL-2-NBP-expanded Vg9Vd2 T. Some are resistant to this lysis and/or poorly sensitized by NBP. BTN3 molecules are highly expressed by blasts of AML cell lines and primary AML samples. We show that treatment of primary AML blasts with agonist anti-BTN3 mAb can overcome the resistance to Vg9Vd2 cells lysis in vitro. We assess this effect in vivo, showing that the addition of agonist anti-BTN3 mAb to Vg9Vd2 cells infusion decreased the tumor burden and increased the survival of NOG mice xenografted with luciferase-transduced U937 cell line. We confirm this effect in a model of mice xenografted with primary AML blasts, showing that treatment with anti-BTN3 mAb added to Vg9Vd2 cells infusion can decrease the number of blastic cells in the spleen, bone marrow and the blood, without requiring additional cytokine infusion. This drastic effect on sensitization of primary AML blasts to Vg9Vd2T cells killing could be of great interest especially in cases of refractory or relapsing AML. Disclosures No relevant conflicts of interest to declare.

scholarly journals The pan-class I phosphatidyl-inositol-3 kinase inhibitor NVP-BKM120 demonstrates anti-leukemic activity in acute myeloid leukemia

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Matteo Allegretti ◽  
Maria Rosaria Ricciardi ◽  
Roberto Licchetta ◽  
Simone Mirabilii ◽  
Stefania Orecchioni ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Phosphatidyl Inositol ◽  
Class I ◽  
Clinical Activity ◽  
Dependent Manner ◽  
Acute Myeloid

Abstract Aberrant activation of the PI3K/Akt/mTOR pathway is a common feature of acute myeloid leukemia (AML) patients contributing to chemoresistance, disease progression and unfavourable outcome. Therefore, inhibition of this pathway may represent a potential therapeutic approach in AML. The aim of this study was to evaluate the pre-clinical activity of NVP-BKM120 (BKM120), a selective pan-class I PI3K inhibitor, on AML cell lines and primary samples. Our results demonstrate that BKM120 abrogates the activity of the PI3K/Akt/mTOR signaling, promoting cell growth arrest and significant apoptosis in a dose- and time-dependent manner in AML cells but not in the normal counterpart. BKM120-induced cytotoxicity is associated with a profound modulation of metabolic behaviour in both cell lines and primary samples. In addition, BKM120 synergizes with the glycolitic inhibitor dichloroacetate enhancing apoptosis induction at lower doses. Finally, in vivo administration of BKM120 to a xenotransplant mouse model of AML significantly inhibited leukemia progression and improved the overall survival of treated mice. Taken together, our findings indicate that BKM120, alone or in combination with other drugs, has a significant anti-leukemic activity supporting its clinical development as a novel therapeutic agent in AML.

scholarly journals Therapeutic inhibition of GAS6-AS1/YBX1/MYC axis suppresses cell propagation and disease progression of acute myeloid leukemia

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Hao Zhou ◽  
Wei Liu ◽  
Yongming Zhou ◽  
Zhenya Hong ◽  
Jian Ni ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Disease Progression ◽  
Myeloid Leukemia ◽  
Target Genes ◽  
Leukemia Cell ◽  
Treatment Strategies ◽  
Network Analyses ◽  
Acute Myeloid

Abstract Background Acute myeloid leukemia (AML) is the most common type of leukemia in adults. Its therapy has not significantly improved during the past four decades despite intense research efforts. New molecularly targeted therapies are in great need. The proto-oncogene c-Myc (MYC) is an attractive target due to its transactivation role in multiple signaling cascades. Deregulation of the MYC is considered one of a series of oncogenic events required for tumorigenesis. However, limited knowledge is available on which mechanism underlie MYC dysregulation and how long non-coding RNAs (lncRNAs) are involved in MYC dysregulation in AML. Methods AML microarray chips and public datasets were screened to identify novel lncRNA GAS6-AS1 was dysregulated in AML. Gain or loss of functional leukemia cell models were produced, and in vitro and in vivo experiments were applied to demonstrate its leukemogenic phenotypes. Interactive network analyses were performed to define intrinsic mechanism. Results We identified GAS6-AS1 was overexpressed in AML, and its aberrant function lead to more aggressive leukemia phenotypes and poorer survival outcomes. We revealed that GAS6-AS1 directly binds Y-box binding protein 1 (YBX1) to facilitate its interaction with MYC, leading to MYC transactivation and upregulation of IL1R1, RAB27B and other MYC target genes associated with leukemia progression. Further, lentiviral-based GAS6-AS1 silencing inhibited leukemia progression in vivo. Conclusions Our findings revealed a previously unappreciated role of GAS6-AS1 as an oncogenic lncRNA in AML progression and prognostic prediction. Importantly, we demonstrated that therapeutic targeting of the GAS6-AS1/YBX1/MYC axis inhibits AML cellular propagation and disease progression. Our insight in lncRNA associated MYC-driven leukemogenesis may contribute to develop new anti-leukemia treatment strategies.

Selective Abrogation of STAT5 Expression Impairs the Proliferation of Acute Myeloid Leukemia Cells with Various Cytogenetic Alterations

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5024-5024
Author(s):  
Youngsoo Kim ◽  
Tianyuan Zhou ◽  
Shuling Guo ◽  
Andy Siwkowski ◽  
Donna Witchell ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Signaling Pathways ◽  
Cell Lines ◽  
Proliferative Activity ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Significant Inhibition ◽  
Acute Myeloid

Abstract STAT5 is a key common downstream mediator of multiple signaling pathways which are often dysregulated in various hematologic malignancies, including acute myeloid leukemia (AML). Due to the heterogeneity and high relapse rate of the disease, the treatment options for AML are currently limited. Although the approach of treating the disease by inhibiting upstream kinases such as FLT3 within these signaling pathways appeared promising, the clinical efficacy of these drugs as mono-therapy have been disappointing. We hypothesized that this lack of efficacy might be due to the residual STAT5 activity that is present even in the presence of these inhibitors in vivo. Therefore, abrogating the expression of the final regulator of these pathways, STAT5, might be a much more efficient way of blocking signaling, thus inhibiting the proliferation and survival of AML cells. In this study, we first investigated the role of STAT5 in the proliferation of AML cells by selectively suppressing the expression of the gene using 2nd-Generation antisense oligonucleotides (ASOs). Suppression of STAT5 following ASO treatment (>80% over control ASO) led to a significant inhibition of cell proliferation (50~70% over control ASO), a decrease in colony formation, and a modest induction of apoptosis in a range of AML lines including KG-1α, MV-4-11, and MOLM-13. STAT5 ASO treatment was highly specific for the STAT5 target and produced predictable effects on gene expression, as demonstrated by the downregulation of Pim-1 and cyclin D1, well-known STAT5 regulated genes. No changes in the expression levels of Bcl-XL, STAT1, and STAT3 were observed. Furthermore, relative anti-proliferative activity within the various AML lines correlated well with the relative levels of STAT5 activity. Interestingly, there was a strong correlation between the extent of STAT5/Pim-1 downregulation and the degree of anti-proliferation, suggesting a possible role of Pim-1 as a downstream effector of STAT5 ASO anti-proliferative activity. Studies comparing the relative effects of the STAT5 ASO inhibitor with the potent multi kinase inhibitor CEP701 in various AML cell lines demonstrated potent anti-proliferative activity for the STAT5 inhibitor in the cell lines including KG-1α that display resistance to the multi kinase inhibitor. Taken together, these results suggest that a STAT5 ASO therapeutic approach may have utility for the treatment of AML and related hematologic disorders.

scholarly journals T cell engaging bispecific antibodies targeting CD33 IgV and IgC domains for the treatment of acute myeloid leukemia

2021 ◽  
Vol 9 (5) ◽  
pp. e002509
Author(s):  
Sayed Shahabuddin Hoseini ◽  
Mallika Vadlamudi ◽  
Madelyn Espinosa-Cotton ◽  
Hoa Tran ◽  
Yi Feng ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Bispecific Antibodies ◽  
Immunodeficient Mice ◽  
Cytotoxicity Assays ◽  
Acute Myeloid

BackgroundAcute myeloid leukemia (AML) remains one of the most challenging hematological malignancies. Despite progress in therapeutics, majority of patients succumb to this neoplasm. CD33 is a proven therapeutic target, given its expression on most AML cells. Almost all anti-CD33 antibodies target the membrane distal immunoglobulin V (IgV) domain of the CD33 extracellular domain.MethodsIn this manuscript, we present data on three bispecific antibodies (BsAbs) against the CD33 IgV and membrane proximal immunoglobulin C (IgC) domains. We use in vitro binding and cytotoxicity assays to show the effect of these BsAbs on AML cell lines. We also use immunodeficient mice-bearing leukemias from cell lines and patient-derived xenografts to show the effect of these BsAbs in vivo.ResultsIn vitro, the IgV-targeting BsAb had higher binding to AML cell lines using flow cytometry and delivered more potent cytotoxicity in T-cell-dependent cytotoxicity assays; importantly, the IgC domain-targeting outperformed the IgV domain-targeting BsAb in medullary and extramedullary leukemia animal models.ConclusionsThese data support further clinical development of this BsAb for first-in-human phase I clinical trial.

scholarly journals Gilteritinib-induced upregulation of S100A9 is mediated through BCL6 in Acute Myeloid Leukemia

2021 ◽  
Author(s):  
Megan E Zavorka Thomas ◽  
Jae Yoon Jeon ◽  
Zahra Talebi ◽  
Daelynn R Buelow ◽  
Josie Silvaroli ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Calcium Binding ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Genetic Manipulation ◽  
Free Calcium ◽  
S100a9 Expression ◽  
Acute Myeloid

Drug resistance and relapse are common challenges in acute myeloid leukemia (AML), particularly in an aggressive subset bearing internal tandem duplications (ITD) of the FLT3 receptor (FLT3-ITD+). The tyrosine kinase inhibitor gilteritinib is approved for the treatment of relapse/refractory AML with FLT3 mutations, yet resistance to gilteritinib remains a clinical concern of which the underlying mechanisms remain incompletely understood. Using transcriptomic analyses and functional validation studies, we identified the calcium-binding proteins, S100A8 and S100A9 (S100A8/A9), as contributors to gilteritinib resistance in FLT3-ITD+ AML. Exposure of FLT3-ITD+ AML cells to gilteritinib increased S100A8/A9 expression in vivo and in vitro, decreased free calcium levels, and genetic manipulation of S100A9 was associated with altered sensitivity to gilteritinib. Using a transcription factor screen, we identified the transcriptional corepressor BCL6, as a regulator of S100A9 expression, and found that gilteritinib decreased BCL6 binding to the S100A9 promoter, thereby increasing S100A9 expression. Furthermore, pharmacological inhibition of BCL6 accelerated the growth rate of gilteritinib-resistant FLT3-ITD+ AML cells, suggesting that S100A9 is a functional target of BCL6. These findings shed light on mechanisms of resistance to gilteritinib through regulation of a target that can be therapeutically exploited to enhance gilteritinib's anti-leukemic effects.

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