Screening microRNA-196 targets in 11q23-translocation acute myeloid leukemia reveal mechanisms maintaining leukemia stemness with therapeutic potential
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ABSTRACT:
ORGANISM(S): Mus musculus Homo sapiens
PROVIDER: GSE75843 | GEO | 2018/06/28
REPOSITORIES: GEO
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Project description:microRNA are aberrantly expressed in acute myeloid leukemia (AML), and clinically may have diagnostic, prognostic, and therapeutic value. We identify one such microRNA, miR-196b, is essential for MLL-AF9 leukemia initiation and maintenance. To discover how miR-196b contributes to leukemogenesis, we utilized multiple unbiased approaches that identified and functionally screened miR-196b target activity in AML. Our studies resolved how conflicting networks of miRNA-regulated targets are integrated during leukemogenesis. This work uncovered two miR-196b direct targets, the cell cycle regulator Cdkn1b (p27Kip1) and Polycomb group member Phc2, that independently cooperate with MLL-AF9 to promote leukemogenesis by regulating stem cell transcriptional programs. Finally, we found that therapeutic disruption of miR-196b direct targeting of Cdkn1b suppresses leukemogenesis.
2018-06-29 | GSE75842 | GEO
Project description:microRNA are aberrantly expressed in acute myeloid leukemia (AML), and clinically may have diagnostic, prognostic, and therapeutic value. We identify one such microRNA, miR-196b, is essential for MLL-AF9 leukemia initiation and maintenance. To discover how miR-196b contributes to leukemogenesis, we utilized multiple unbiased approaches that identified and functionally screened miR-196b target activity in AML. Our studies resolved how conflicting networks of miRNA-regulated targets are integrated during leukemogenesis. This work uncovered two miR-196b direct targets, the cell cycle regulator Cdkn1b (p27Kip1) and Polycomb group member Phc2, that independently cooperate with MLL-AF9 to promote leukemogenesis by regulating stem cell transcriptional programs. Finally, we found that therapeutic disruption of miR-196b direct targeting of Cdkn1b suppresses leukemogenesis.
2018-06-29 | GSE75841 | GEO
Project description:Screening microRNA-196 targets in 11q23-translocation acute myeloid leukemia reveal mechanisms maintaining leukemia stemness with therapeutic potential
| PRJNA305517 | ENA
Project description:We have shown that antagomiR inhibition of miRNA miR-21 and miR-196b activity is sufficient to ablate MLL-AF9 leukemia stem cells (LSC) in vivo. Here, we used an shRNA screening approach to mimic miRNA activity on experimentally verified miR-196b targets to identify functionally important and therapeutically relevant pathways downstream of oncogenic miRNA in MLL-r AML. We found Cdkn1b (p27Kip1) is a direct miR-196b target whose repression enhanced an embryonic stem cell-like signature associated with decreased leukemia latency and increased numbers of leukemia stem cells in vivo. Conversely, elevation of p27Kip1 significantly reduced MLL-r leukemia self-renewal, promoted monocytic differentiation of leukemic blasts, and induced cell death. Antagonism of miR-196b activity or pharmacologic inhibition of the Cks1-Skp2-containing SCF E3-ubiquitin ligase complex increased p27Kip1 and inhibited human AML growth. This work illustrates that understanding oncogenic miRNA target pathways can identify actionable targets in leukemia.
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Project description:Ovarian cancer is the most common and aggressive type of tumor of the female reproductive system. Two factors account for this detrimental clinical presentation: (i) the lack of early detection methods and (ii) the inherently aggressive nature of this malignancy. Currently, transcriptomic analyses have become important tools to identify new targets in different cancer types. In this study, by measuring expression levels in ovarian cancer samples and stem cell samples, we identified 24 tumor suppressor genes consistently associated with poor prognosis. Combined results further revealed a potential therapeutic candidate, BTG2, which belongs to the antiproliferative gene family. Our results showed that BTG2 expression regulated ovarian cancer cell proliferation via G1/S phase cell cycle arrest by regulating Cyclin D1, CDK4, p-AKT, and p-ERK expression. BTG2 also inhibited cell migration by modulating MMP-2 and MMP-9 expression. Furthermore, xenograft models confirmed a growth inhibitory effect of BTG2 in ovarian cancer in vivo. BTG2 was significantly associated with ovarian cancer FIGO stage and grade in the clinic. Our findings indicated that BTG2 exerts a suppressive impact on ovarian cancer and could be a potential biomarker.
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Project description:Translocases of the AAA+ (ATPases Associated with various cellular Activities) family are powerful molecular machines that use the mechano-chemical coupling of ATP hydrolysis and conformational changes to thread DNA or protein substrates through their central channel for many important biological processes. These motors comprise hexameric rings of ATPase subunits, in which highly conserved nucleotide-binding domains form active-site pockets near the subunit interfaces and aromatic pore-loop residues extend into the central channel for substrate binding and mechanical pulling. Over the past 2 years, 41 cryo-EM structures have been solved for substrate-bound AAA+ translocases that revealed spiral-staircase arrangements of pore-loop residues surrounding substrate polypeptides and indicating a conserved hand-over-hand mechanism for translocation. The subunits' vertical positions within the spiral arrangements appear to be correlated with their nucleotide states, progressing from ATP-bound at the top to ADP or apo states at the bottom. Studies describing multiple conformations for a particular motor illustrate the potential coupling between ATP-hydrolysis steps and subunit movements to propel the substrate. Experiments with double-ring, Type II AAA+ motors revealed an offset of hydrolysis steps between the two ATPase domains of individual subunits, and the upper ATPase domains lacking aromatic pore loops frequently form planar rings. This review summarizes the critical advances provided by recent studies to our structural and functional understanding of hexameric AAA+ translocases, as well as the important outstanding questions regarding the underlying mechanisms for coordinated ATP-hydrolysis and mechano-chemical coupling.
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Project description:BackgroundIrreversible inhibition of Bruton's tyrosine kinase (BTK) by ibrutinib represents an important therapeutic advance for the treatment of chronic lymphocytic leukemia (CLL). However, ibrutinib also irreversibly inhibits alternative kinase targets, which potentially compromises its therapeutic index. Acalabrutinib (ACP-196) is a more selective, irreversible BTK inhibitor that is specifically designed to improve on the safety and efficacy of first-generation BTK inhibitors.MethodsIn this uncontrolled, phase 1-2, multicenter study, we administered oral acalabrutinib to 61 patients who had relapsed CLL to assess the safety, efficacy, pharmacokinetics, and pharmacodynamics of acalabrutinib. Patients were treated with acalabrutinib at a dose of 100 to 400 mg once daily in the dose-escalation (phase 1) portion of the study and 100 mg twice daily in the expansion (phase 2) portion.ResultsThe median age of the patients was 62 years, and patients had received a median of three previous therapies for CLL; 31% had chromosome 17p13.1 deletion, and 75% had unmutated immunoglobulin heavy-chain variable genes. No dose-limiting toxic effects occurred during the dose-escalation portion of the study. The most common adverse events observed were headache (in 43% of the patients), diarrhea (in 39%), and increased weight (in 26%). Most adverse events were of grade 1 or 2. At a median follow-up of 14.3 months, the overall response rate was 95%, including 85% with a partial response and 10% with a partial response with lymphocytosis; the remaining 5% of patients had stable disease. Among patients with chromosome 17p13.1 deletion, the overall response rate was 100%. No cases of Richter's transformation (CLL that has evolved into large-cell lymphoma) and only one case of CLL progression have occurred.ConclusionsIn this study, the selective BTK inhibitor acalabrutinib had promising safety and efficacy profiles in patients with relapsed CLL, including those with chromosome 17p13.1 deletion. (Funded by the Acerta Pharma and others; ClinicalTrials.gov number, NCT02029443.).
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Project description:Cancer stemness, referring to the stem-cell-like phenotype of cancer cells, has been recognised to play important roles in different aspects of hepatocarcinogenesis. A number of well-established cell-surface markers already exist for liver cancer stem cells, with potential new markers of liver cancer stem cells being identified. Both genetic and epigenetic factors that affect various signalling pathways are known to contribute to cancer stemness. In addition, the tumour microenvironment-both physical and cellular-is known to play an important role in regulating cancer stemness, and the potential interaction between cancer stem cells and their microenvironment has provided insight into the regulation of the tumour-initiating ability as well as the cellular plasticity of liver CSCs. Potential specific therapeutic targeting of liver cancer stemness is also discussed. With increased knowledge, effective druggable targets might be identified, with the aim of improving treatment outcome by reducing chemoresistance.
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Project description:The 26S proteasome is the primary eukaryotic degradation machine and thus is critically involved in numerous cellular processes. The heterohexameric adenosine triphosphatase (ATPase) motor of the proteasome unfolds and translocates targeted protein substrates into the open gate of a proteolytic core while a proteasomal deubiquitinase concomitantly removes substrate-attached ubiquitin chains. However, the mechanisms by which ATP hydrolysis drives the conformational changes responsible for these processes have remained elusive. Here we present the cryo-electron microscopy structures of four distinct conformational states of the actively ATP-hydrolyzing, substrate-engaged 26S proteasome. These structures reveal how mechanical substrate translocation accelerates deubiquitination and how ATP-binding, -hydrolysis, and phosphate-release events are coordinated within the AAA+ (ATPases associated with diverse cellular activities) motor to induce conformational changes and propel the substrate through the central pore.
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Project description:Isolating and maintaining the appropriate stem cell for large scale cell culture is essential in tissue engineering or food production. For bovine satellite cells an optimized isolation and purification protocol is lacking and there is also no detailed understanding on the factors that maintain stemness of these cells. Here, we set up a fluorescence-activated cell sorting strategy to enrich bovine satellite cells. We found that p38-MAPK signalling is activated and PAX7 expression is gradually lost during satellite cell proliferation. The p38 inhibitor (SB203580) treatment maintained PAX7 expression but inhibited the fusion of satellite cells in a concentration-dependent way in short-term incubation. The mechanism of p38 inhibition was confirmed by inhibiting canonical p38 signalling, i.e. HSP27. Long-term culture with an appropriate concentration of p38i enhanced the proliferation and PAX7 expression, while the differentiation capacity recovered and was enhanced compared to vehicle control. These studies indicate that bovine satellite cells maintenance depends on cell purity and p38 MAPK signalling. Inhibition of p38 MAPK signaling is a promising strategy to facilitate large scale cell expansion of primary cells for tissue engineering and cultured meat purposes.
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