scholarly journals Low-Dose Triptolide Promotes MDM2 Inhibitor Nutlin3a to Induce Acute Myeloid Leukemia Cell Death Via p53-Dependent and -Independent Mechanisms

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 24-24
Author(s):  
Qinwei Chen ◽  
Suqi Deng ◽  
Zhijuan Lin ◽  
Manman Deng ◽  
Lihong Ding ◽  
...  
Keyword(s):  
Cell Death ◽  
Acute Myeloid Leukemia ◽  
Herbal Medicine ◽  
Myeloid Leukemia ◽  
Low Dose ◽  
Negative Regulator ◽  
Immune Disorders ◽  
Wild Type ◽  
Mdm2 Inhibitor ◽  
Acute Myeloid

The tumor suppressor p53 is central to hematopoietic stem cell function. Loss of p53 function is associated with poor prognosis of acute myeloid leukemia (AML). P53 negative regulator MDM2 is frequently overexpressed in AML, thus it becomes an attractive therapeutic target for the treatment of AML with wild-type p53 (Wt-p53). Targeting MDM2 to restore p53 activity has been assessed in AML, but clinical outcomes are less promising. Notably, p53-mutated AML still lacks effective treatment approaches. Therefore, our study strived to explore potent therapeutics to target AML with p53 wild-type and mutations. Triptolide (TPL), an ancient herbal medicine, has been used to treat immune disorders for centuries. Accumulating evidence including ours have proven that low dose of TPL potentiates the efficacy of chemotherapies in a broad range of tumor types. In this study, we evaluated the anti-leukemic efficacy of combining low dose TPL with Nutlin3a, a MDM2 inhibitor, against AML with p53 wild-type and mutations. We found that low-dose TPL synergized with Nutlin3a to induce mitochondrial apoptosis in AML cells with Wt-p53 bothin vitroandin vivo. Underlying mechanism for the synergy showed that Nutlin3a upregulated pro-apoptosis factors (e.g. PUMA, p21), while low-dose TPL suppressed MDM2 transcription and reduced anti-apoptosis proteins (e.g. XIAP, Mcl-1) in Wt-p53 AML cells. Interestingly, we also observed that TPL but not Nutlin3a induced cell death in p53 shRNA knockdown, p53 deficiency cell lines (e.g. THP-1, HL-60) and primary samples. Thus, the p53-independent role of TPL was consequently focused. Our RNA-Seq analysis identified 621 differential expression genes (DEGs) after TPL treatment. These genes, including MYC, ATF4 and 4EBP1, were enriched in intrinsic apoptosis pathway responding to ER stress and thus we concluded that Triptolide played its p53 independent role via MYC-ATF4 axis. Collectively, these findings suggest that coadministration of Nutlin3a with low dose TPL would benefit for AML patients. Disclosures Carter: AstraZeneca:Research Funding;Syndax:Research Funding;Ascentage:Research Funding;Amgen:Research Funding. OffLabel Disclosure: Triptolide (TPL), an ancient herbal medicine, is applying to treat immune disorders.

Degradation of TRAF6 by Bortezomib-Induced Autophagy Contributes to Cell Death in Acute Myeloid Leukemia and Myelodysplastic Syndrome

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2452-2452
Author(s):  
Jing Fang ◽  
Lyndsey Bolanos ◽  
Garrett Rhyasen ◽  
Carmen Rigolino ◽  
Agostino Cortelezzi ◽  
...  
Keyword(s):  
Cell Death ◽  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndrome ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
26S Proteasome ◽  
Negative Regulator ◽  
Myeloid Malignancies ◽  
Chromosome 5Q ◽  
Acute Myeloid

Abstract Abstract 2452 Deletion of chromosome 5q in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) patients results in loss of miR-146a, which is a negative regulator of the innate immune pathway by targeting TNF receptor associated factor-6 (TRAF6). Therefore, MDS and AML patients with reduced miR-146a expression concomitantly exhibit elevated TRAF6 protein. TRAF6 is an E3 ubiquitin ligase that catalyzes K63-linked polyubiquitin chains on substrates that lead to pathway activation, one of which includes NF-kB. Mice lacking miR-146a, or with overexpression of TRAF6, develop AML- and MDS-like features. Bortezomib (Velcade©), which shows promise alone or in combination with chemotherapy in certain groups of MDS and AML patients, is a selective and reversible inhibitor of the 26S proteasome. Studies on the mechanism of action of Bortezomib have shown that pro-apoptotic proteins are stabilized following proteasome inhibition and contribute to the anti-cancer effect. In this report, paradoxically, we find that Bortezomib induces rapid and complete degradation of TRAF6 protein, but not mRNA, in MDS/AML cell lines and human CD34+ cells. A similar finding was observed when AML cells were treated with MG132, another proteasome inhibitor, indicating that degradation of TRAF6 is secondary to proteasomal inhibition. Interestingly, the reduction in TRAF6 protein coincides with Bortezomib-induced autophagy, as indicated by conversion of LC3B-I to LC3B-II and degradation of SQSTM1/p62, and subsequently with apoptosis in MDS/AML cells. Addition of an autophagy inhibitor (3-methyladenine [3-MA]) to Bortezomib-treated AML cells maintained TRAF6 protein expression and enhanced cell viability. Similarly, TRAF6 degradation was blocked by 3-MA when cells were treated with Rapamycin, an mTOR inhibitor and inducer of autophagy. These findings suggest that a mechanism of Bortezomib-induced cell death in myeloid malignancies involves elimination of TRAF6 protein by autophagosomes. Forced expression of TRAF6 in two AML cell lines partially blocked the cytotoxic effect of Bortezomib, suggesting that TRAF6 is an important target of Bortezomib. To determine whether loss of TRAF6 is sufficient to impede growth of MDS and AML, we used a genetic approach to inhibit TRAF6 in MDS/AML cell lines and bone marrow cells from MDS patients with deletion of chromosome 5q. RNAi-mediated depletion of TRAF6 in MDS and AML samples resulted in impaired malignant hematopoietic stem/progenitor function and rapid apoptosis. To uncover the molecular consequences following loss of TRAF6, we applied gene expression profiling and identified genes relevant to the survival of MDS and AML cells. In summary, these findings implicate TRAF6 in Bortezomib-induced cell death and in the maintenance of myeloid malignancies, and reveal a novel mechanism of TRAF6 regulation through autophagic degradation. Disclosures: Oliva: Celgene: Consultancy.

scholarly journals Randomised evaluation of quizartinib and low-dose ara-C vs low-dose ara-C in older acute myeloid leukemia patients

2021 ◽  
Author(s):  
Mike Dennis ◽  
Ian Thomas ◽  
Cono Ariti ◽  
Laura Upton ◽  
Alan K Burnett ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Overall Survival ◽  
Acute Myeloid Leukemia ◽  
Older Patients ◽  
Myeloid Leukemia ◽  
Low Dose ◽  
Intensive Chemotherapy ◽  
Wild Type ◽  
Flt3 Inhibitor ◽  
Acute Myeloid

Survival for older patients with acute myeloid leukaemia (AML) unsuitable for intensive chemotherapy is unsatisfactory. Standard non intensive therapies have low response rates and only extend life by a few months. Quizartinib is an oral Fms-like tyrosine kinase 3 (FLT3) inhibitor with reported activity in wild type patients. As part of the AML LI trial we undertook a randomised evaluation of low dose ara-C (LDAC) with or without quizartinib in patients not fit for intensive chemotherapy. Overall, survival was not improved (202 patients), but in the 27 FLT3-ITD patients the addition of quizartinib to LDAC improved response (p=0.05) with CR/CRi for quizartinib + LDAC in 5/13 (38%) v 0/14 (0%) in patients receiving LDAC alone. Overall survival (OS) in these FLT3-ITD positive patients was also significantly improved at 2 years for quizartinib + LDAC; hazard ratio 0.36 (95% confidence intervals 0.16, 0.85), (p=0.04). Median OS was 13.7 months compared to 4.2 months with LDAC alone. This is the first report of a FLT3 targeted therapy added to standard non-intensive chemotherapy that has improved survival in this population. Quizartinib merits consideration for future triplet based treatment approaches. (Clinical trial numbers: ISRCTN No: ISRCTN40571019 EUDRACT Number: 2011-000749-19).

Implications of somatic mutations in the AML1 gene in radiation-associated and therapy-related myelodysplastic syndrome/acute myeloid leukemia

Blood ◽  
2003 ◽  
Vol 101 (2) ◽  
pp. 673-680 ◽  
Author(s):  
Hironori Harada ◽  
Yuka Harada ◽  
Hideo Tanaka ◽  
Akiro Kimura ◽  
Toshiya Inaba
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndrome ◽  
Myeloid Leukemia ◽  
Low Dose ◽  
Alkylating Agents ◽  
Point Mutations ◽  
Wild Type ◽  
Low Dose Radiation ◽  
Dose Radiation ◽  
Acute Myeloid

Somatically acquired point mutations of AML1/RUNX1 gene have been recently identified in rare cases of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Moreover, germ line mutations of AML1 were found in an autosomal dominant disease, familial platelet disorder with predisposition to AML (FPD/AML), suggesting that AML1 mutants, as well as AML1 chimeras, contribute to the transformation of hematopoietic progenitors. In this report, we showed that AML1 point mutations were found in 6 (46%) of 13 MDS patients among atomic bomb (A-bomb) survivors in Hiroshima. Unlike acute or chronic leukemia patients among A-bomb survivors, MDS patients exposed relatively low-dose radiation and developed the disease after a long latency period. AML1 mutations also were found in 5 (38%) of 13 therapy-related AML/MDS patients who were treated with alkylating agents with or without local radiation therapy. In contrast, frequency of AML1 mutation in sporadic MDS patients was 2.7% (2 of 74). Among AML1 mutations identified in this study, truncated-type mutants lost DNA binding potential and trans-activation activity. All missense mutations with one exception (Gly42Arg) lacked DNA binding ability and down-regulated the trans-activation potential of wild-type AML1 in a dominant-negative fashion. The Gly42Arg mutation that was shared by 2 patients bound DNA even more avidly than wild-type AML1 and enhanced thetrans-activation potential of normal AML1. These results suggest that AML1 point mutations are related to low-dose radiation or alkylating agents and play a role distinct from that of leukemogenic chimeras as a result of chromosomal translocations caused by sublethal radiation or topoisomerase II inhibitors.

scholarly journals Pharmacological Inhibition of WIP1 Sensitizes Acute Myeloid Leukemia Cells to the MDM2 Inhibitor Nutlin-3a

Biomedicines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 388
Author(s):  
Maria Chiara Fontana ◽  
Jacopo Nanni ◽  
Andrea Ghelli Luserna di Rorà ◽  
Elisabetta Petracci ◽  
Antonella Padella ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Single Agent ◽  
Young Patients ◽  
Negative Regulator ◽  
Dependent Manner ◽  
Acute Myeloid Leukemia Cells ◽  
Induced Apoptosis ◽  
Mdm2 Inhibitor ◽  
Acute Myeloid

In acute myeloid leukemia (AML), the restoration of p53 activity through MDM2 inhibition proved efficacy in combinatorial therapies. WIP1, encoded from PPM1D, is a negative regulator of p53. We evaluated PPM1D expression and explored the therapeutic efficacy of WIP1 inhibitor (WIP1i) GSK2830371, in association with the MDM2 inhibitor Nutlin-3a (Nut-3a) in AML cell lines and primary samples. PPM1D transcript levels were higher in young patients compared with older ones and in core-binding-factor AML compared with other cytogenetic subgroups. In contrast, its expression was reduced in NPM1-mutated (mut, irrespective of FLT3-ITD status) or TP53-mut cases compared with wild-type (wt) ones. Either Nut-3a, and moderately WIP1i, as single agent decreased cell viability of TP53-wt cells (MV-4-11, MOLM-13, OCI-AML3) in a time/dosage-dependent manner, but not of TP53-mut cells (HEL, KASUMI-1, NOMO-1). The drug combination synergistically reduced viability and induced apoptosis in TP53-wt AML cell line and primary cells, but not in TP53-mut cells. Gene expression and immunoblotting analyses showed increased p53, MDM2 and p21 levels in treated TP53-wt cells and highlighted the enrichment of MYC, PI3K-AKT-mTOR and inflammation-related signatures upon WIP1i, Nut-3a and their combination, respectively, in the MV-4-11 TP53-wt model. This study demonstrated that WIP1 is a promising therapeutic target to enhance Nut-3a efficacy in TP53-wt AML.

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.

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