scholarly journals Using an in-Vivo Degron-Based Approach to Interrogate Dependencies of Serially Acquired Mutations - Including DNMT3a-R882 and NPM1c - in Acute Myeloid Leukemia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 12-13
Author(s):  
Andrew A Guirguis ◽  
Alexander Tepper ◽  
Max Jan ◽  
Quinlan Sievers ◽  
Benjamin L. Ebert

While a number of targeted therapies have recently become available in the treatment of acute myeloid leukemia (AML), it remains to be determined whether early acquired mutations are essential for ongoing leukemia maintenance in the face of sequential acquisition of additional mutations. In some cases, our ability to answer this question is hampered by the lack of targeted therapies to a number of these mutations. Of all AML mutations, those involving DNMT3a and NPM1c are some of the most frequent - often acquired before the final transforming event. Here we report the development of an in-vivo degron-based approach to interrogate the requirement for DNMT3a-R882 and NPM1c after leukemia development. Using an IKZF-based degron system offers us the opportunity to address the ongoing requirement of particular oncogenes for AML maintenance - by way of a conditional system that can be rapidly modulated. Thalidomide and its related analogues act by recruiting various substrates to the CRL4CRBN E3-ubiquitin ligase complex mediating subsequent ubiquitination and proteasomal degradation. In a majority of cases - the basis of this degradation has been determined to be the result of recognition and binding to a degron motif within C2H2 zinc fingers. Using more detailed analysis with single amino-acid resolution, we have engineered 'degrons' sensitive or resistant to degradation by thalidomide and its related analogues. In-vivo degradation using pomalidomide revealed a dependence of GMP cells on the presence of NPM1c but not DNMT3a R882. Using our cereblon (CRBN) knock-in mice engineered to mediate sensitivity to these compounds, we generated triple-mutant acute-myeloid leukemia - sequentially introducing DNMT3a-R882, NPM1c and N-RAS G12D mutations whilst altering the site of the degron tag in each case. Degradation-resistant degron constructs were used as a control in each case. Findings were subsequently correlated and validated with in-vitro treatments of triple mutant cells. RNA-seq was also performed after both in-vitro and in-vivo treatments to further delineate acute transcriptional changes in the absence of NPM1c - highlighting a number of changes including those within the Hox family of genes Together, these findings suggest triple mutant leukemia remains dependent on the leukemia-inducing mutation of NPM1c. In contrast, whilst epigenetic alterations induced by DNMT3a mutations are essential for leukemia development - these do not appear to be essential for ongoing leukemia maintenance. Further work is currently underway to determine how modulating NPM1c impacts long-term survival from leukemia and whether the epigenetic changes associated with DNMT3a R882 mutations are indeed reversible in the context of leukemia. This work highlights an approach to interrogate a protein of interest in-vivo using a conditional system that is reversible, rapidly acting and that uses a series of FDA-approved compounds with known kinetics. We envisage this will be generalisable as a tool to be used in other similar contexts. Disclosures No relevant conflicts of interest to declare.

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3941-3941 ◽  
Author(s):  
Nicole R. Grieselhuber ◽  
Shaneice R. Mitchell ◽  
Shelley Orwick ◽  
Bonnie K. Harrington ◽  
Virginia M. Goettl ◽  
...  

Abstract Background: Acute myeloid leukemia (AML) has very poor long-term survival with traditional therapies. AML has a diverse pathogenesis and likely represents multiple different diseases. Various epigenetic effector proteins are altered in AML by mutation, over-expression, or compartmental displacement and these changes maintain transcriptional programs important for leukemogenesis. The bromodomain and extra-terminal domain (BET) proteins, including BRD2, BRD3 and BRD4, play roles in many cellular functions important to leukemogenesis, such as super-enhancer function, transcriptional elongation, histone acetylation and cell cycle progression. In particular, AML cells depend on BRD4 for expression of the pro-survival proteins MYC and BCL2. BRD4 has therefore become an attractive target for novel therapeutics. PLX51107 is a novel BET inhibitor with a unique binding mode in the acetylated lysine binding pocket of BRD4 that differentiates it from other compounds under investigation. Our group has previously shown this compound to have antineoplastic activity in models of aggressive B cell malignancies. We have now investigated the anti-leukemic properties of PLX51107 in both in vitro and in vivo models of AML. Results: PLX51107 treatment potently reduced viability and proliferation of the human AML cell lines MV4-11, MOLM-13, OCI-AML3, and Kasumi-1, with IC50 of 0.17, 1.8, 0.2 and 0.2 μM, respectively. We then evaluated the in vitro activity of PLX51007 in primary human AML samples. PLX51107 inhibited the proliferation of primary human AML cells co-cultured with HS5 stromal cells. For nearly all samples tested (n=9), the IC50 of PLX51007 was less than 1 μM (average = 0.41 μM, range 0.039 - 1.5 μM). Notably, PLX51107 showed efficacy across a broad range of AML risk groups, including samples with adverse risk features such as 11q23 abnormalities and FLT3-ITD mutations. In comparison, for the same AML samples, the average IC50 for JQ1 was 0.71 μM (range 0.02 - 3.3 μM) and for cytarabine was 3.5 μM (range 0.33 to >10 μM). Furthermore, PLX51107 treatment reduced the clonogenicity of primary AML cells. Following incubation of AML cells in 1 μM PLX51107, there was significantly decreased colony formation (p<0.05) in drug-free, cytokine-supplemented methylcellulose media. We next examined the efficacy of PLX51107 in vivo, utilizing luciferase labeled MV4-11 AML cells xenotransplanted into NOD / SCID / IL2rgnull (NSG) immunodeficient mice. Daily oral dosing with 20 mg/kg PLX51107 resulted in prolonged survival (median 47 days) compared to vehicle treated control animals (median 30 days, p< 0.001). Weekly measurement of bioluminescence showed decreased disease burden in PLX51107 treated mice. In addition, human peripheral blood CD45 / CD33 double positive cells were significantly decreased in treated animals. Histologic analysis conducted at day 16 showed decreased leukemic burden in the bone marrow of the PLX51107 treated animals. In addition, examination of tissues from moribund mice at time of euthanasia demonstrated fewer leukemia cells in the spleen, liver and bone marrow. Conclusions: Collectively, our results show pre-clinical activity of PLX51107 in AML, supporting further development of this compound in clinical trials for relapsed or refractory myeloid malignancies. We are currently working to define downstream targets of PLX51107 action and developing patient derived AML xenografts to further characterize the in vivo effects of PLX51107. Disclosures Walker: Gilead Sciences: Research Funding. Bhatnagar:Karyopharm: Research Funding.


Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3385
Author(s):  
Axel H. Schönthal ◽  
Steve Swenson ◽  
Radu O. Minea ◽  
Hye Na Kim ◽  
Heeyeon Cho ◽  
...  

Despite progress in the treatment of acute myeloid leukemia (AML), the clinical outcome remains suboptimal and many patients are still dying from this disease. First-line treatment consists of chemotherapy, which typically includes cytarabine (AraC), either alone or in combination with anthracyclines, but drug resistance can develop and significantly worsen prognosis. Better treatments are needed. We are developing a novel anticancer compound, NEO212, that was created by covalent conjugation of two different molecules with already established anticancer activity, the alkylating agent temozolomide (TMZ) and the natural monoterpene perillyl alcohol (POH). We investigated the anticancer activity of NEO212 in several in vitro and in vivo models of AML. Human HL60 and U937 AML cell lines, as well as different AraC-resistant AML cell lines, were treated with NEO212 and effects on cell proliferation, cell cycle, and cell death were investigated. Mice with implanted AraC-sensitive or AraC-resistant AML cells were dosed with oral NEO212, and animal survival was monitored. Our in vitro experiments show that treatment of cells with NEO212 results in growth inhibition via potent G2 arrest, which is followed by apoptotic cell death. Intriguingly, NEO212 was equally potent in highly AraC-resistant cells. In vivo, NEO212 treatment strikingly extended survival of AML mice and the majority of treated mice continued to thrive and survive without any signs of illness. At the same time, we were unable to detect toxic side effects of NEO212 treatment. All in all, the absence of side effects, combined with striking therapeutic activity even in an AraC-resistant context, suggests that NEO212 should be developed further toward clinical testing.


2016 ◽  
Vol 113 (43) ◽  
pp. E6669-E6678 ◽  
Author(s):  
Mark A. Gregory ◽  
Angelo D’Alessandro ◽  
Francesca Alvarez-Calderon ◽  
Jihye Kim ◽  
Travis Nemkov ◽  
...  

Activating mutations in FMS-like tyrosine kinase 3 (FLT3) are common in acute myeloid leukemia (AML) and drive leukemic cell growth and survival. Although FLT3 inhibitors have shown considerable promise for the treatment of AML, they ultimately fail to achieve long-term remissions as monotherapy. To identify genetic targets that can sensitize AML cells to killing by FLT3 inhibitors, we performed a genome-wide RNA interference (RNAi)-based screen that identified ATM (ataxia telangiectasia mutated) as being synthetic lethal with FLT3 inhibitor therapy. We found that inactivating ATM or its downstream effector glucose 6-phosphate dehydrogenase (G6PD) sensitizes AML cells to FLT3 inhibitor induced apoptosis. Examination of the cellular metabolome showed that FLT3 inhibition by itself causes profound alterations in central carbon metabolism, resulting in impaired production of the antioxidant factor glutathione, which was further impaired by ATM or G6PD inactivation. Moreover, FLT3 inhibition elicited severe mitochondrial oxidative stress that is causative in apoptosis and is exacerbated by ATM/G6PD inhibition. The use of an agent that intensifies mitochondrial oxidative stress in combination with a FLT3 inhibitor augmented elimination of AML cells in vitro and in vivo, revealing a therapeutic strategy for the improved treatment of FLT3 mutated AML.


2018 ◽  
Vol 51 (2) ◽  
pp. 886-896 ◽  
Author(s):  
Xiaoya Dong ◽  
Zhigang Fang ◽  
Mingxue Yu ◽  
Ling Zhang ◽  
Ruozhi Xiao ◽  
...  

Background/Aims: Among different molecular candidates, there is growing data to support that long noncoding RNAs (lncRNAs) play a significant role in acute myeloid leukemia (AML). HOXA-AS2 is significantly overexpressed in a variety of tumors and associated with anti-cancer drug resistance, however, little is known regarding the expression and function of HOXA-AS2 in the chemoresistance of AML. In this study, we aimed to determine the role and molecular mechanism of HOXA-AS2 in adriamycin-based chemotherapy resistance in AML cells. Methods: Quantitative real-time PCR was used to detect HOXA-AS2 expression in the BM samples and ADR cell lines, U/A and T/A cells. Furthermore, the effects of HOXA-AS2 silencing on cell proliferation and apoptosis were assessed in vitro by CCK8 and flow cytometry, and on tumor growth in vivo. Furthermore, bioinformatics online programs predicted and luciferase reporter assay were used to validate the association of HOXA-AS2 and miR-520c-3p in AML. Results: In this study, we showed that HOXA-AS2 is significantly upregulated in BM samples from AML patients after treatment with adriamycin-based chemotherapy and in U/A and T/A cells. Knockdown of HOXA-AS2 inhibited ADR cell proliferation in vitro and in vivo and promoted apoptosis. Bioinformatics online programs predicted that HOXA-AS2 sponge miR-520c-3p at 3’-UTR with complementary binding sites, which was validated using luciferase reporter assay and anti-Ago2 RIP assay. HOXA-AS2 could negatively regulate the expression of miR-520c-3p in ADR cells. S100A4 was predicted as a downstream target of miR-520c-3p, which was confirmed by luciferase reporter assay. Conclusion: Our results suggest that HOXA-AS2 plays an important role in the resistance of AML cells to adriamycin. Thus, HOXA-AS2 may represent a therapeutic target for overcoming resistance to adriamycin-based chemotherapy in AML.


Author(s):  
Yudi Miao ◽  
Behnam Mahdavi ◽  
Mohammad Zangeneh

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.


2019 ◽  
Author(s):  
Yusuke Tarumoto ◽  
Shan Lin ◽  
Jinhua Wang ◽  
Joseph P. Milazzo ◽  
Yali Xu ◽  
...  

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.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Xuejie Jiang ◽  
Ling Jiang ◽  
Jiaying Cheng ◽  
Fang Chen ◽  
Jinle Ni ◽  
...  

Abstract Background Epigenetic dysregulation plays important roles in leukemogenesis and the progression of acute myeloid leukemia (AML). Histone acetyltransferases (HATs) and histone deacetylases (HDACs) reciprocally regulate the acetylation and deacetylation of nuclear histones. Aberrant activation of HDACs results in uncontrolled proliferation and blockade of differentiation, and HDAC inhibition has been investigated as epigenetic therapeutic strategy against AML. Methods Cell growth was assessed with CCK-8 assay, and apoptosis was evaluated by flow cytometry in AML cell lines and CD45 + and CD34 + CD38- cells from patient samples after staining with Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI). EZH2 was silenced with short hairpin RNA (shRNA) or overexpressed by lentiviral transfection. Changes in signaling pathways were detected by western blotting. The effect of chidamide or EZH2-specific shRNA (shEZH2) in combination with adriamycin was studied in vivo in leukemia-bearing nude mouse models. Results In this study, we investigated the antileukemia effects of HDAC inhibitor chidamide and its combinatorial activity with cytotoxic agent adriamycin in AML cells. We demonstrated that chidamide suppressed the levels of EZH2, H3K27me3 and DNMT3A, exerted potential antileukemia activity and increased the sensitivity to adriamycin through disruption of Smo/Gli-1 pathway and downstream signaling target p-AKT in AML cells and stem/progenitor cells. In addition to decreasing the levels of H3K27me3 and DNMT3A, inhibition of EZH2 either pharmacologically by chidamide or genetically by shEZH2 suppressed the activity of Smo/Gli-1 pathway and increased the antileukemia activity of adriamycin against AML in vitro and in vivo. Conclusions Inhibition of EZH2 by chidamide has antileukemia activity and increases the chemosensitivity to adriamycin through Smo/Gli-1 pathway in AML cells (Fig. 5). These findings support the rational combination of HDAC inhibitors and chemotherapy for the treatment of AML.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A893-A893
Author(s):  
Laurent Gauthier ◽  
Angela Virone-Oddos ◽  
Angela Virone-Oddos ◽  
Jochen Beninga ◽  
Benjamin Rossi ◽  
...  

BackgroundThere is a clear need for targeted therapies to treat acute myeloid leukemia (AML), the most common acute leukemia in adults. CD123 (IL-3 receptor alpha chain) is an attractive target for AML treatment.1 However, cytotoxic antibody targeting CD123 proved insufficiently effective in a combination setting in phase II/III clinical trials.2 T-cell engagers targeting CD123 displayed some clinical efficacy but were often associated with cytokine release syndrome and neurotoxicity.3 Interest in the use of NK cells for therapeutic interventions has increased in recent years, as a potential safer alternative to T cells. Several NK-cell activating receptors, such as CD16a, NKG2D, and the natural cytotoxicity receptors NKp30 and NKp46, can be targeted to induce antitumor immunity. We previously reported the development of trifunctional NK-cell engagers (NKCEs) targeting a tumor antigen on cancer cells and co-engaging NKp46 and CD16a on NK cells.4MethodsWe report here the design, characterization and preclinical development of a novel trifunctional NK cell engager (NKCE) targeting CD123 on AML cells and engaging the activating receptors NKp46 and CD16a on NK cells. The CD123 NKCE therapeutic molecule was engineered with humanized antibodies targeting NKp464 and CD123.5 We compared CD123-NKCE and a cytotoxic ADCC-enhanced antibody (Ab) targeting CD123, in terms of antitumor activity in vitro, ex vivo and in vivo. Pharmacokinetic, pharmacodynamic and safety profile of CD123-NKCE were evaluated in non-human primate (NHP) studies.ResultsThe expression of the high affinity Fc gamma receptor CD64 on patient-derived AML cells inhibited the ADCC of the Ab targeting CD123 in vitro and ex vivo, but not the antitumor activity of CD123-NKCE. CD123-NKCE had potent antitumor activity against primary AML blasts and AML cell lines, promoted strong NK-cell activation and induced cytokine secretion only in the presence of AML target cells. Its antitumor activity in mouse model was greater than that of the comparator antibody. Moreover, CD123-NKCE had strong and prolonged pharmacodynamic effects in NHP when used at very low doses, was well-tolerated up to high 3 mg/kg dose and triggered only minor cytokine release.ConclusionsThe data for activity, safety, pharmacokinetics, and pharmacodynamics provided here demonstrate the superiority of CD123-NKCE over comparator cytotoxic antibody, in terms of antitumor activity in vitro, ex vivo, in vivo, and its favorable safety profile, as compared to T-cell therapies. These results constitute proof-of-principle for the efficacy of CD123-NKCE for controlling AML tumors in vivo, and provide consistent support for their clinical development.ReferencesEhninger A, Kramer M, Rollig C, et al. Distribution and levels of cell surface expression of CD33 and CD123 in acute myeloid leukemia. Blood Cancer J 2014;4:e218.Montesinos P, Gail J Roboz GJ, et al. Safety and efficacy of talacotuzumab plus decitabine or decitabine alone in patients with acute myeloid leukemia not eligible for chemotherapy: results from a multicenter, randomized, phase 2/3 study. Leukemia 2021;35(1):62–74.Uy GL, Aldoss I, Foster MC, et al. Flotetuzumab as salvage immunotherapy for refractory acute myeloid leukemia. Blood 2021;137(6):751–762.Gauthier L, Morel A, Anceriz N, et al. Multifunctional natural killer cell engagers targeting NKp46 trigger protective tumor immunity. Cell 2019;177(7):1701–13.Jin L, Lee EM, Ramshaw HS, et al. Monoclonal antibody-mediated targeting of CD123, IL-3 receptor alpha chain, eliminates human acute myeloid leukemic stem cells. Cell Stem Cell 2009;5:31–42.


Sign in / Sign up

Export Citation Format

Share Document