scholarly journals Dual targeting of acute myeloid leukemia progenitors by catalytic mTOR inhibition and blockade of the p110α subunit of PI3 kinase

Oncotarget ◽  
2015 ◽  
Vol 6 (10) ◽  
pp. 8062-8070 ◽  
Author(s):  
Marco Colamonici ◽  
Gavin Blyth ◽  
Diana Saleiro ◽  
Amy Szilard ◽  
Meghan Bliss-Moreau ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Pi3 Kinase ◽  
Mtor Inhibition ◽  
Dual Targeting ◽  
Acute Myeloid

Antileukemic activity of rapamycin in acute myeloid leukemia

Blood ◽  
2005 ◽  
Vol 105 (6) ◽  
pp. 2527-2534 ◽  
Author(s):  
Christian Récher ◽  
Odile Beyne-Rauzy ◽  
Cécile Demur ◽  
Gaëtan Chicanne ◽  
Cédric Dos Santos ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
De Novo ◽  
Mammalian Target Of Rapamycin ◽  
Cell Types ◽  
Mtor Inhibition ◽  
Growth And Survival ◽  
Clinical Responses ◽  
De Novo Aml ◽  
Acute Myeloid

AbstractThe mammalian target of rapamycin (mTOR) is a key regulator of growth and survival in many cell types. Its constitutive activation has been involved in the pathogenesis of various cancers. In this study, we show that mTOR inhibition by rapamycin strongly inhibits the growth of the most immature acute myeloid leukemia (AML) cell lines through blockade in G0/G1 phase of the cell cycle. Accordingly, 2 downstream effectors of mTOR, 4E-BP1 and p70S6K, are phosphorylated in a rapamycin-sensitive manner in a series of 23 AML cases. Interestingly, the mTOR inhibitor markedly impairs the clonogenic properties of fresh AML cells while sparing normal hematopoietic progenitors. Moreover, rapamycin induces significant clinical responses in 4 of 9 patients with either refractory/relapsed de novo AML or secondary AML. Overall, our data strongly suggest that mTOR is aberrantly regulated in most AML cells and that rapamycin and analogs, by targeting the clonogenic compartment of the leukemic clone, may be used as new compounds in AML therapy.

scholarly journals Dual Targeting of Aurora Kinases with AMG 900 Exhibits Potent Preclinical Activity Against Acute Myeloid Leukemia with Distinct Post-Mitotic Outcomes

2018 ◽  
Vol 17 (12) ◽  
pp. 2575-2585 ◽  
Author(s):  
Marc Payton ◽  
Hung-Kam Cheung ◽  
Maria Stefania S. Ninniri ◽  
Christian Marinaccio ◽  
William C. Wayne ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Aurora Kinases ◽  
Dual Targeting ◽  
Acute Myeloid

4E-Binding Protein 1 (4E-BP1) in CD34+ Cells as Measured by Quantitative Flow Cytometry Is an Independent Prognostic Factor in Patients with Acute Myeloid Leukemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2772-2772
Author(s):  
M. Gorre ◽  
I. Jilani ◽  
R. Chang ◽  
J. Bareng ◽  
H. Chan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Binding Protein ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Mtor Inhibition ◽  
Cd34 Cells ◽  
Acute Myeloid

Abstract The mammalian target of rapamycin (mTOR) is a serine/threonine kinase involved in the regulation of cell growth and proliferation. Once activated, mTOR can phosphorylate its downstream targets. One of these targets is the 4E-binding protein 1 (4E-BP1), which is phosphorylated and inactivated by mTOR in response to a growth signal. Phospho-4E-BP1 dissociates from the eukaryotic initiation factor 4E (eIF-4E), a translation initiation factor that subsequently binds the cap structure of 5′ mRNAs and initiates the translation of transcripts encoding genes involved in cell cycle control. Rapamycin and its analogs are immunosuppressant drugs that exert their activity by specific inhibition of mTOR. mTOR inhibition induces cell cycle arrest not only in normal lymphocytes but also in malignant cells. Using flow cytometry, we quantified the levels of 4E-BP1 and phosopho-4E-BP1 in CD34+ and CD3+ cells from bone marrow samples collected from patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). We then measured the antibody binding capacity of 100 CD34+ or CD3+ cells using QuantiBRITE and PE (phycoerythrin)-labeled antibodies in a 1:1 ratio. We demonstrated that CD34+ cells express significantly higher levels of 4E-BP1 (P=0.005) and phosphor-4E-BP1 (P=0.0001) as compared with CD3+ cells in patients with AML (n=49). In contrast, there was no significant difference in the levels of 4E-BP1 or phospho-4E-BP1 between CD34+ and CD3+ cells in patients with MDS (n=15). More importantly, in patients with AML, high expression of 4E-BP1 in CD34+ cells was associated with shorter survival (P=0.003) as well as shorter complete remission duration (CRD) (P=0.03). This association between survival and levels of 4E-BP1 was independent of cytogenetic abnormalities in this group of patients. This data not only suggests that the 4E-BP1 level, as measured in the CD34+ cells, can be an important prognostic indicator in AML but also suggests that 4E-BP1 plays a role in the biology of AML. Furthermore, targeting 4E-BP1 by mTOR inhibitors, or other means of down modulating 4E-BP1 levels, is a rational therapeutic approach in AML. Figure Figure

PP2A Activators Enhance Efficacy of FLT3 Inhibitors in FLT3-ITD Acute Myeloid Leukemia Cells through AKT Inactivation-Dependent Pim-1 and c-Myc Proteasomal Degradation

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1276-1276
Author(s):  
Mario Scarpa ◽  
Prerna Singh ◽  
Shivani Kapoor ◽  
Jonelle K. Lee ◽  
Sandrine Niyongere ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Proteasome Inhibitor ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Concurrent Treatment ◽  
Dual Targeting ◽  
Flt3 Inhibitor ◽  
Flt3 Inhibitors ◽  
Acute Myeloid ◽  
In Cells

Introduction fms-like tyrosine like kinase 3 internal tandem duplication (FLT3-ITD), present in acute myeloid leukemia (AML) cells of 30% of patients, results in constitutive and aberrant FLT3 signaling and, clinically, short disease-free survival. Efficacy of FLT3 inhibitors is limited and transient, but may be enhanced by dual targeting of FLT3-ITD signaling pathways. The tumor suppressor protein phosphatase 2A (PP2A) is inhibited in cells with FLT3-ITD. The oncogenic serine/threonine kinase Pim-1 is transcriptionally upregulated and also stabilized by PP2A inhibition in cells with FLT3-ITD. Pim-1 contributes directly to FLT3-ITD proliferative and anti-apoptotic effects, and also phosphorylates and stabilizes FLT3-ITD in a positive feedback loop. Moreover FLT3-ITD, PP2A and Pim-1 all regulate the transcription factor c-Myc. PP2A-activating drugs enhance efficacy of FLT3 inhibitors. We sought to identify mechanisms underlying the efficacy of this combination. Methods Ba/F3-ITD and MV4-11 cells, with FLT3-ITD, and blasts from patients with AML with FLT3-ITD were cultured with the FLT3 inhibitors gilteritinib (15 nM) or quizartinib (1 nM) and/or the PP2A-activating drugs FTY720 (2-4 µM) or DT-061 (10 µM), or with DMSO control. Pim-1, c-Myc, p-AKT (S473 and T308) and AKT protein expression was measured by immunoblotting, along with p-STAT5 (Y694), STAT5, p-PP2A (Y307) and PP2A expression. To study post-translational regulation, cells were cultured with cycloheximide (100 µg/mL) with and without the proteasome inhibitor MG-132 (20 µM). Ubiquitinated c-Myc was measured by co-immunoprecipitation and immunoblotting with c-Myc and ubiquitin antibodies. Ba/F3-ITD cells were stably transfected with estrogen receptor (ER)-c-Myc, kinase-dead Pim-1 or myristoylated AKT plasmids or corresponding empty vectors. Apoptosis was detected by Annexin V and propidium iodine staining, measured by flow cytometry. Cells were also cultured with the pan-Pim kinase inhibitor AZD1208 (1 µM), the Myc inhibitor 10058-F4 (100 µM) or the pan-AKT inhibitor MK-2206 (5 µM). Results Concurrent treatment of Ba/F3-ITD and MV4-11 cells and primary AML cells with FLT3-ITD with a FLT3 inhibitor (gilteritinib or quizartinib) and a PP2A-activating drug (FTY720 or DT-061) decreased growth and increased apoptosis induction, relative to treatment with single drugs. Concurrent FLT3 inhibitor and PP2A-activating drug treatment decreased expression of both Pim-1 and c-Myc protein. Concurrent treatment decreased Pim-1 half-life from 15 to 5 minutes, and c-Myc half-life from 30 to 5 minutes, while half-lives were restored by concurrent treatment with the proteasome inhibitor MG-132. Concurrent treatment was also shown to increase c-Myc ubiquitination. Effects of concurrent treatment on Pim-1 and c-Myc were independent, as transfection with kinase-dead Pim-1 or treatment with Pim inhibitor AZD1208 did not alter c-Myc downregulation, and c-Myc overexpression or treatment with Myc inhibitor 10058-F4 did not alter Pim-1 downregulation. Concurrent treatment with FLT3 inhibitor and PP2A-activating drug did not alter expression of c-Myc deubiquitinases, but rapidly decreased AKT S473 and T308 phosphorylation. FLT3 inhibitor and PP2A activator co-treatment did not induce downregulation or increased turnover of Pim-1 and c-Myc protein or apoptosis in cells with constitutive AKT activation caused by transfection of myristoylated AKT. Moreover, AKT inhibition downregulated Pim-1 and c-Myc protein expression, decreased Pim-1 and c-Myc protein half-lives from 15 to 5 minutes and 30 to 10 minutes, respectively, and induced apoptosis of cells with FLT3-ITD, replicating the effects of FLT3 inhibitor and PP2A activator co-treatment. Conclusion PP2A activators enhance the efficacy of FLT3 inhibitors in AML cells with FLT3-ITD through AKT inactivation-dependent increased Pim-1 and c-Myc proteasomal degradation, which is a novel mechanism. The data support further preclinical and clinical testing of this dual targeting approach to treatment of AML with FLT3-ITD. Disclosures Baer: Takeda: Research Funding; Incyte: Research Funding; Kite: Research Funding; Forma: Research Funding; AI Therapeutics: Research Funding; Abbvie: Research Funding; Astellas: Research Funding.

scholarly journals Statins Potentiate Aminopeptidase Inhibitor (pro)Drug Activity in Acute Myeloid Leukemia Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3945-3945 ◽  
Author(s):  
Jacqueline Cloos ◽  
Godefridus J Peters ◽  
Marjon Al ◽  
Yehuda G Assaraf ◽  
Lixia Wang ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Elderly Patients ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Cholesterol Metabolism ◽  
Mtor Inhibition ◽  
Toxic Concentrations ◽  
Aminopeptidase Inhibitors ◽  
Acute Myeloid

Abstract Tosedostat represents a next generation oral aminopeptidase inhibitor prodrug that has recently demonstrated promising activity in elderly patients with relapsed and refractory acute myeloid leukemia (AML). This prodrug is bio-activated to its hydrophilic active metabolite by intracellular esterases including carboxylesterase 1 (CES1) hence enhancing its cellular retention and promoting targeting of multiple aminopeptidases. Aminopeptidase inhibition provokes an amino acid deprivation response, inhibition of mTOR activity and blockade of protein synthesis. The fact that CES1 also has an important physiological function in cholesterol metabolism (i.e. conversion of cholesteryl-esters to cholesterol), and the notion that AML cells display an aberrant cholesterol metabolism, prompted us to explore whether or not statins, as inhibitors of the mevalonate-cholesterol biosynthesis pathway, can potentiate the cytotoxic activity of aminopeptidase inhibitor prodrugs. Here, we discovered that the antitumor activity of CHR2863, a close structural analogue of Tosedostat, is markedly potentiated by non-toxic and clinically achievable concentrations of statins. These findings were supported by the following lines of experimental evidence; (i) A strong synergy in cell growth inhibition (combination indices < 0.1) of CHR2863 with various statins (simvastatin, fluvastatin, lovastatin and pravastatin) was demonstrated for U937 AML cells and U937 sublines displaying acquired resistance to CHR2863. (ii) This potent synergy between CHR2863 and simvastatin was also observed with a spectrum of human AML cell lines including THP1, MV4-11, and KG1, but not with acute lymphocytic leukemia (CCRF-CEM) or solid tumor cell lines (MCF7 breast cancer, KB nasopharyngeal carcinoma and SW1573 non-small cell lung cancer). (iii) The synergistic effects with non-toxic concentrations of statins were specific for aminopeptidase inhibitors, either prodrugs (CHR2863) or direct inhibitors (e.g. Bestatin), but not for other unrelated cytotoxic agents, including daunorubicin and an esterase-dependent prodrug of a histone deacetylase inhibitor. (iv) The synergy of CHR2863 with statins was also corroborated by enhanced apoptosis induction and cell cycle arrest which increased the sub-G1 fraction. (v) Statin potentiation of CHR2863 activity was abrogated by co-administration with mevalonate or farnesylpyrophosphate, and partly by geranylgeranylpyrophosphate, suggesting the involvement of protein prenylation. Consistenly, the farnesyltransferase inhibitor FTI-277 also synergized with CHR2863 activity. (vi) Mechanistically, non-toxic concentrations of simvastatin impaired Rheb prenylation which is required for lysosomal membrane association and activation of mTOR. Hence, we propose that the dual inhibitory effect of impaired Rheb prenylation by statins and CHR2863-induced mTOR inhibition achieves a potent synergistic inhibition on human AML cells. (viii) Finally, retrospective analysis in a clinical trial of relapsed and refractory elderly AML patients treated with combination chemotherapy including Tosedostat (Cortes et al, Lancet Oncol 2013), revealed a clinical benefit for patients who used a statin. AML patients on statins (n=8) and Tosedostat (switching from 240 to 120 mg/m2) had a 50% probability of 6 months survival as compared to 3 months survival for patients not on statins (n= 27). The two-year overall survival (20%) was not impacted by statin administration. Collectively, these novel findings uncover a potent therapeutic combination of statins and aminopeptidase inhibitors for the treatment of AML. This drug combination warrants further clinical evaluation, particularly in the context of elderly patients using statins for other comorbidities. Disclosures Cloos: Takeda: Research Funding; Merus: Research Funding; Novartis: Research Funding; Helsinn: Research Funding; Johnson&Johnson: Research Funding. Wang:CTI BioPharma: Employment, Equity Ownership. Singer:CTI BioPharma: Employment, Other: Stock options. Cortes:Novartis: Consultancy, Research Funding; Astellas Pharma: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Arog: Research Funding. Ossenkoppele:Pfizer: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Jazz: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Research Funding; Roche: Consultancy, Honoraria; Celgene: Honoraria, Research Funding; Johnson & Johnson: Consultancy, Honoraria, Research Funding; Genmab: Research Funding.

Survival of acute myeloid leukemia cells requires PI3 kinase activation

Blood ◽  
2003 ◽  
Vol 102 (3) ◽  
pp. 972-980 ◽  
Author(s):  
Qing Xu ◽  
Serge-Emile Simpson ◽  
Timothy J. Scialla ◽  
Adam Bagg ◽  
Martin Carroll
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Pi3 Kinase ◽  
Growth And Survival ◽  
Kinase Activation ◽  
Constitutive Activation ◽  
Acute Myeloid Leukemia Cells ◽  
Dose Dependent Decrease ◽  
Acute Myeloid

Abstract The mechanisms that regulate the growth and survival of acute myeloid leukemia (AML) cells are largely unknown. We hypothesized that constitutive activation of phosphatidyl-inositide 3 kinase (PI3 kinase) could regulate survival in primary cells from patients with AML. Here we demonstrate that Akt, a critical substrate of PI3 kinase, is activated in AML blasts. In a short-term culture system, most AML patient samples showed a dose-dependent decrease in survival after incubation with the PI3 kinase inhibitor LY294002. This decrease in survival was partially due to the induction of apoptosis. Furthermore, we have shown that p70 S6 kinase and 4EBP-1, downstream mediators of Akt signaling, also are phosphorylated in AML blasts. Phosphorylation of these proteins is inhibited by the mTOR inhibitor RAD001. Incubation of AML blasts with RAD001 induces only a small decrease in survival of the cells; however, when combined with Ara-C, RAD001 enhances the toxicity of Ara-C. These results demonstrate that constitutive activation of the PI3 kinase pathway is necessary for the survival of AML blasts and that targeting of this pathway with pharmacologic inhibitors may be of clinical benefit in treatment of AML.

Temsirolimus, An mTOR Inhibitor, In Combination with Low-Dose Clofarabine in Older Patients with Advanced Acute Myeloid Leukemia: Results of a Phase 2 GIMEMA Study (AML-1107)

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 510-510
Author(s):  
Sergio Amadori ◽  
Adriano Venditti ◽  
Emanuele Ammatuna ◽  
Alberto M. Martelli ◽  
Giovanna Meloni ◽  
...  
Keyword(s):  
Overall Survival ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Low Dose ◽  
Disease Free Survival ◽  
Phase 2 ◽  
Mtor Inhibition ◽  
First Relapse ◽  
Acute Myeloid ◽  
Refractory Aml

Abstract Abstract 510 Background: Elderly patients with refractory or relapsed AML have a dismal prognosis and new treatments are needed for these patients.The PI3K/AKT signaling pathway is frequently dysregulated in AML and contributes to cell proliferation and survival through activation of the mTOR kinase and its downstream effectors. mTOR inhibition with Sirolimus or its analogs, such as Temsirolimus, has been associated with clinical responses in AML and may enhance the sensitivity of leukemic cells to cytotoxics. Clofarabine is a second-generation nucleoside analog with activity in AML. Based on this, a multicenter, phase 2, open label, two-stage study was conducted to assess the efficacy and safety of Temsirolimus in combination with low-dose Clofarabine as salvage therapy for older pts with AML. Methods: Eligible were pts older than 60 years of age with first relapse or primary refractory AML. Induction consisted of a single course of Clofarabine 20 mg/m2 iv d 1–5 and Temsirolimus 25 mg (flat dose) iv d 1, 8 and 15; a second course was allowed in pts achieving PR. Pts entering CR/CRi receive up to 12 monthly courses of maintenance with Temsirolimus (25 mg iv d 1 and 8 per course). The primary endpoint was complete remission with (CR) or without (CRi) hematopoietic recovery; secondary endpoints were overall survival, disease-free survival and toxicity. Pre and post-therapy bone marrow samples were obtained from a subset of pts to assess biomarkers. Results: Accrual began April 2009 and was completed in June 2010. To date, 52 of 54 enrolled pts are evaluable for response and toxicity (1 too early; 1 died pre-therapy): median age 70 yrs (range 60–78); 58% males; 17 pts with primary refractory AML; 35 pts with AML in first relapse (duration of CR1 < 6 mos 34%, ≥ 6 mos 66%); cytogenetics (MRC criteria): favorable in 4, intermediate in 37, adverse in 6, and unavailable in 5 pts. In all, 11 pts (21%; 95% CI 11–35%) have achieved CR (n=4) or CRi (n=7); 1 achieved PR; 7 (13%) died within 30 days of induction therapy (3 from infection, 3 from disease progression, 1 from cerebrovascular accident); 33 were resistant. CR or CRi was achieved in 9/35 pts (26%) in first relapse, and 2/17 (12%) with primary refractory disease. CR+CRi rates among: age < 70 and ≥ 70, 19% and 25%; first CR duration shorter and longer than 6 mos, 17% and 30%; favorable, intermediate, adverse and unknown cytogenetics, 50%, 22%, 0% and 20%. The median duration of remission for the 11 responders was 3.5 mos; 7 pts have relapsed to date and 4 (2 CR, 2 CRi) are currently maintaining a response at 2+, 4+, 11+ and 12+ mos from remission. With a median follow-up of 5 mos (range 0.3–14), the median overall survival for the entire population was 4.3 mos, and for responders 7.6 mos. Besides myelosuppression, most common grade 3–4 adverse events included infection (48%), febrile neutropenia (35%), transaminase elevation (11%), nausea and vomiting (8%), and fatigue (8%). Median times to recovery of neutrophils to 500/cmm and platelets to 50,000/cmm in responders were 28 and 32 days, respectively. Inhibition of phospho-S6RP, a downstream effector of mTOR, was documented in 12/21 (57%) pts analysed, and correlated with an improved rate of clinical response: 7/12 (58%) responded vs 0/9 pts with no detectable target inhibition. Conclusion: These data indicate that a regimen combining Temsirolimus with low-dose Clofarabine can be safely administered to elderly pts with advanced AML. Encouraging anti-leukemic activity was recorded in this difficult-to-treat patient population, particularly in pts showing evidence of an on-target effect on mTOR signaling. Further investigation of this novel regimen as front-line therapy in older pts with AML considered unsuitable for intensive chemotherapy is planned. Disclosures: Off Label Use: Clinical trial investigating Clofarabine and Temsirolimus in patients with acute myeloid leukemia.

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