Transcriptome profiling by RNA-sequencing of the AML cell line U937.
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ABSTRACT: All-trans retinoic acid (ATRA, RA) has powerful activity in APL; its efficacy in non-APL AML is still unclear, but may be boosted by epigenetic drugs such azanucleoside DNMT inhibitors (Blagitko-Dorfs et al. PLoS ONE 2013). In a randomized phase II study (DECIDER trial, NCT00867672) the addition of RA to decitabine (DAC) in newly diagnosed non-fit older AML patients resulted in a clinically meaningful extension of survival. We hypothesize that in vitro, the add-on of RA to DAC results in cooperative transcriptome changes (possibly associated with demethylation), which may explain at least in part this clinical result.
Project description:All-trans retinoic acid (ATRA, RA) has powerful activity in APL; its efficacy in non-APL AML is still unclear, but may be boosted by epigenetic drugs such azanucleoside DNMT inhibitors (Blagitko-Dorfs et al. PLoS ONE 2013). In a randomized phase II study (DECIDER trial, NCT00867672) the addition of RA to decitabine (DAC) in newly diagnosed non-fit older AML patients resulted in a clinically meaningful extension of survival. We hypothesize that in vitro, the add-on of RA to DAC results in cooperative transcriptome and chromatin accessibility changes (possibly associated with demethylation), which may explain at least in part this clinical result.
Project description:All-trans retinoic acid (ATRA, RA) has powerful activity in APL; its efficacy in non-APL AML is still unclear, but may be boosted by epigenetic drugs such azanucleoside DNMT inhibitors (Blagitko-Dorfs et al. PLoS ONE 2013). In a randomized phase II study (DECIDER trial, NCT00867672) the addition of RA to decitabine (DAC) in newly diagnosed non-fit older AML patients resulted in a clinically meaningful extension of survival. We hypothesize that in vitro, the add-on of RA to DAC results in cooperative transcriptome changes (possibly associated with demethylation), which may explain at least in part this clinical result.
Project description:The therapeutic effect of DNA-hypomethylating agents (HMAs) in AML/MDS is discussed to be via its effects on aberrant gene silencing by reactivation (e.g. through promoter demethylation). While this has been broadly studied in cell line models, only very few studies have addressed the global effects of HMAs in primary blasts serially isolated from AML patients (pts) undergoing HMA treatment (Claus et al., Leuk. Res. 2013, Klco et al., Blood 2013, Welch et al., N. Engl. J. Med. 2016). We therefore conducted prospective serial methylome and transcriptome analyses on AML blasts from pts of the DECIDER trial (NCT00867672), hypothesizing that both random and non-random effects of the HMA may be observed in vivo.
Project description:The therapeutic effect of DNA-hypomethylating agents (HMAs) in AML/MDS is discussed to be via its effects on aberrant gene silencing by reactivation (e.g. through promoter demethylation). While this has been broadly studied in cell line models, only very few studies have addressed the global effects of HMAs in primary blasts serially isolated from AML patients (pts) undergoing HMA treatment (Claus et al., Leuk. Res. 2013, Klco et al., Blood 2013, Welch et al., N. Engl. J. Med. 2016). We therefore conducted prospective serial methylome and transcriptome analyses on AML blasts from pts of the DECIDER trial (NCT00867672), hypothesizing that both random and non-random effects of the HMA may be observed in vivo.
Project description:The histone demethylase LSD1 is deregulated in several tumors, including leukemias, providing the rationale for the clinical use of LSD1 inhibitors. In acute promyelocytic leukemia (APL), pharmacological doses of retinoic acid (RA) induce differentiation of APL cells through degradation of the PML-RAR oncogene. APL cells are resistant to LSD1 inhibition or knock-out, but LSD1 inhibition sensitizes them to physiological doses of RA without altering the stability of PML-RAR, and extends survival of leukemic mice upon RA treatment. Non-enzymatic activities of LSD1 are essential to block differentiation of leukemic cells, while the combination of LSD1 inhibitors (or LSD1 knock-out) with low doses of RA releases a differentiation-associated gene expression program, not strictly dependent on changes in histone H3K4 methylation (known substrate of LSD1). An integrated proteomic/epigenomic/mutational analysis showed that LSD1 inhibitors alter the recruitment of LSD1-containing complexes to chromatin through inhibition of the interaction between LSD1 and GFI1, a relevant transcription factor in hematopoiesis.
Project description:Acute myeloid leukemia (AML) is characterized by the accumulation of immature leukemic blasts. The application of all-trans retinoic acid (ATRA) treatments have markedly transformed acute promyelocytic leukemia (APL, the M3 subtype of AML) to a highly manageable disease, and research strategies that seek to extend the application of ATRA-based treatment to other AML subtypes are an important area of investigation. Here, we found CASP1/GSDMD was lower expressed in APL and most other subtypes of primary de novo AML patients and increased in ATRA-treated APL cells. We showed that ATRA increased and activated CASP1 to trigger pyroptosis and differentiation of APL cells. Mechanistically, ATRA could induce CASP1 expression via IFNγ/STAT1 in APL and non-APL AML cells, while do not activate CASP1 in non-APL AML cells. Accordingly, pharmacological activation of CASP1 by Val-boroPro (DPP8/9 inhibitor) enhanced pyroptosis and differentiation induced by ATRA in AML cells. Moreover, the combination of ATRA and Val-boroPro enhanced anti-leukemia activity in primary AML cells. Our study demonstrates that the ATRA-mediated anti-leukemia effect requires a functional activated CASP1 and provides a highly attractive therapeutic strategy for the treatment of AML.
Project description:Leukemic stem cells (LSCs) of acute myeloid leukemia (AML) are enriched in CD34+CD38- fraction, and self-renewing LSCs hierarchically organize and maintain the AML populations. In acute promyelocytic leukemia (APL), which is driven by PML-RARα fusion genes, the presence of LSCs has long been unidentified, due to the difficulty of efficient reconstitution of human APL in the immunodeficient mice. Here, we show that LSCs of short type isoform APL, subtype of APL defined by different breakpoint of PML gene, concentrate in CD34+CD38- fraction and express T cell immunoglobulin mucin-3 (TIM-3) as in other non-APL AML. Short type APL cells exhibited distinct gene expression signatures including LSCs-related genes from other types of APL. Moreover, CD34+CD38-TIM-3+ short type APL cells efficiently reconstituted huma APL in xenograft models with high penetration, whereas CD34- more differentiated APL cells did not. Furthermore, CD34+CD38-TIM-3+ short type APL cells also reconstituted leukemia in the serial transplantation. Thus, short type APL is showing hierarchically organized by self-renewing APL-LSCs same as in other types of AML. The identification of LSCs in a subset of APL and establishment of efficient patient derived xenograft model would contribute to further understanding of APL leukemogenesis and devising individual treatment for eradication of APL LSCs.
Project description:The therapy-induced PML/RARA catabolism elicits the loss of APL-initiating cell self-renewal through PML NB reformation and P53 activation. These results explain the curative activity of the RA/arsenic combination, the resistance to RA of PLZF/RARA-driven APLs and they raise the prospect that activation of this PML/P53 checkpoint might have therapeutic values in other malignancies. Gene expression profiles of 36 transgenic induced APL and 36 viral transduction APL were hybridized using Affymetrix Mouse Gene 1.0 ST Arrays
Project description:Genome wide DNA methylation profiling of AML patient samples treated with PBS or DAC. The Illumina Infinium 450 Human DNA methylation was used to examine the methylation profile of 8 patient samples and 2 cell lines. Genome wide DNA methylation profiling of AML xenografts treated with either PBS control or with decitacine (DAC) alone, cytarabine (Ara-C) alone, DAC and Ara-C together (D+A), DAC followed by Ara-C (D/A) or with Ara-C followed by DAC (A/D).
Project description:Background: Acute myeloid leukemia (AML) is a heterogeneous disease characterized by diverse genetic abnormalities. The standard of care remains to be chemotherapy and stem cell transplantation. In acute promyelocytic leukemia (APL), differentiation therapy with all-trans retinoic acid (ATRA) has significantly improved outcomes. Despite this, the success of ATRA has yet to be transferred to non-APL AML. Exploring combinations to enhance the efficacy of ATRA in non-APL AML remains a key focus. Objective: To investigate the therapeutic effect of ATRA in combination with cyclin-dependent kinase 4/6 (CDK4/6) inhibitors in non-APL AML. Methods: Non-APL AML cells and primary patient samples were treated with ATRA and CDK4/6 inhibitors. Key outcomes included differentiation, proliferation, cell viability, and colony-forming capacity. Combination synergy was evaluated, and gene expression analysis identified pathways associated with therapeutic effects. Results: The combination demonstrated dose-dependent effects, enhancing differentiation and reducing proliferation, cell viability, and colony-forming capacity. A synergistic effect was observed across AML cell lines. Gene expression profiling revealed the co-regulation of differentiation-associated genes, unveiling the mechanisms driving therapeutic synergy. Conclusion: Combination of CDK4/6 inhibitors with ATRA shows potential for differentiation-based AML treatment. This approach offers a promising avenue for improved outcomes in non-APL AML.