Project description:Acute myeloid leukemia (AML) is an aggressive hematologic malignancy, often characterized by poor prognosis following standard induction therapy. The DNA methyltransferase inhibitor decitabine (DAC) is an alternative to intensive chemotherapy in elderly and relapsed/refractory AML patients. Despite some efficacy, DAC monotherapy does not promote complete remission and overall survival rates are very poor. Therefore, novel therapeutic regimens for AML are warranted. CD105 (endoglin), a receptor for the TGF-β superfamily, is expressed in various hematopoietic malignancies, including AML in which high expression correlates with poor prognosis. We have recently demonstrated that targeting CD105+ AML blasts with the TRC105 monoclonal antibody abrogates leukemogenesis in vivo. Based on these encouraging findings, here we investigated whether TRC105 in combination with DAC could represent a novel therapeutic option to treat relapsed/refractory AML. Treatment of leukemic mice with DAC in combination with TRC105 resulted in superior survival and significant reduction of leukemia burden in the bone marrow (BM) of AML xenografts compared to DAC monotherapy. To determine if TRC105 anti-leukemogenic effect is mediated by NK cells, we performed in vitro and in vivo studies. In the latter, we tested TRC105 in the context of NK depletion by injecting mice with an antibody to CD122. TRC105 treatment resulted in comparable reduction of leukemia burden in xenografts regardless of NK depletion, demonstrating that the anti-leukemogenic effect of TRC105 in AML is independent of NK cells. Altogether, our findings provide proof-of-principle for the clinical evaluation of TRC105 in combination with DAC in AML patients.
Project description:The Affymetrix Human Genome U133 Plus 2.0 Array was used to examine the Genome wide transcriptional changes which follow the treatment of AML xenografts with either PBS control or combination of decitabine (DAC) and cytarabine (Ara-C). Animals were treated with PBS, DAC alone, Ara-C alone, DAC and Ara-C combined (D+A), DAC followed by Ara-C (D/A) or Ara-C followed by DAC (A/D). PBS vs each drug combination
Project description:The Affymetrix Human Genome U133 Plus 2.0 Array was used to examine the Genome wide transcriptional changes which follow the treatment of AML xenografts with either PBS control or combination of decitabine (DAC) and cytarabine (Ara-C). Animals were treated with PBS, DAC alone, Ara-C alone, DAC and Ara-C combined (D+A), DAC followed by Ara-C (D/A) or Ara-C followed by DAC (A/D).
Project description:Sequential assessment of global mRNA expression in myeloblasts isolated from peripheral blood of eight AML patients treated with Decitabine within a phase II study (trial 00331). Total RNA was isolated after enrichment of peripheral blood myeloblasts directly before and directly after (median day 3) Decitabine administration
Project description:Acute myeloid leukemia (AML), and other myeloid malignancies, are frequently treated with hypomethylating agents like decitabine. Alterations in the epigenome, induced by decitabine, are likely to result in gene expression changes. The effects of decitabine have not been systemically studied using primary AML samples. We cultured 18 different primary AML samples for 7 days, the last 3 days of which included 100 nM decitabine (DAC) or 100 nm cytarabine (AraC). We hypothesized that decitabine treatment would result in detectable and consistent gene expression changes. For comparison, we also analyzed mRNA from cells treated with DMSO control (mock) and mRNA from uncultured cells taken at the time of diagnosis.
Project description:Acute myeloid leukemia (AML), and other myeloid malignancies, are frequently treated with hypomethylating agents like decitabine. Alterations in the epigenome, induced by decitabine, are likely to result in gene expression changes. The effects of decitabine have not been systemically studied using primary AML samples.
Project description:Genome-wide DNA methylation profiling of primary AML samples treated with 100nM decitabine (DAC), cytarabine (AraC), or DMSO. Eight distinct AML samples were grown using an in vitro stromal co-culture system for 4 days and then treated with either DAC, Ara-C or DMSO for 3 days. DNA was prepared for genome-wide methylation analysis with the Illumina Infinium 450k Human DNA methylation BeadChip. DNA from each sample/treatment was analyzed on duplicate arrays. Bisulfite-converted DNA from 24 samples was hybridised to the Illumina Infinium 450k Human Methylation Beadchip in duplicate (replicates are indicated by array plate number).
Project description:We found previously that the effect of decitabine (DAC) on hematopoietic stem cell viability differed between Mll5 wildtype and null cells. We therefore investigated the role of MLL5 expression levels on outcome of AML patients who were treated with decitabine. High MLL5 expressing AML patients have improved overall survival when treated with decitabine. In transformed murine cells, loss of Mll5 was associated with resistance to low-dose decitabine, less frequent promoter methylation, and reduced demethylation upon decitabine treatment. These data suggest a biological link between MLL5 expression and decitabine response involving regulation of DNA methylation. Leukemia cell model was generated by co-transfer of HOXA9 and MEIS1 into Mll5 wildtype or knockout mouse bone marrow cells. MeDIP was performed in Mll5+/+ HOXA9/MEIS1 and Mll5-/- HOXA9/MEIS1 leukemic cells, untreated or treated with 3-day exposure of 20 nM decitabine, triplicate for each condition. MeDIP-enriched DNA was amplified with the GenomePlex Complete Whole Genome Amplification (WGA) Kit (Sigma-Aldrich). DNA from three MeDIP and WGA of each cell type and treatment was pooled for subsequent microarray analysis. The enriched DNA and corresponding input genomic DNA was labeled, hybridized and scanned on Agilent custom mouse promoter microarrays (Agilent-025976 AP_1M_Custom_CH3, assembly build mm9). The methylation value of individual probes was defined by the signal intensity ratio of MeDIP DNA (Cy3) compared to input DNA (Cy5) . Methylated DNA immunoprecipitation coupled with Agilent mouse promoter CpG arrays (MeDIP-chip)
Project description:Genome-wide DNA methylation profiling of primary AML samples treated with 100nM decitabine (DAC), cytarabine (AraC), or DMSO. Eight distinct AML samples were grown using an in vitro stromal co-culture system for 4 days and then treated with either DAC, Ara-C or DMSO for 3 days. DNA was prepared for genome-wide methylation analysis with the Illumina Infinium 450k Human DNA methylation BeadChip. DNA from each sample/treatment was analyzed on duplicate arrays.
Project description:Understanding the contribution of abnormal genetic and epigenetic programs to acute myeloid leukemia (AML) is necessary for the integrated design of targeted therapies. To investigate this, we determined the effect of epigenetic reprogramming on leukemic behavior by generating induced pluripotent stem cells (iPSCs) from AML patient samples harboring MLL rearrangements. AML-derived iPSCs (AML-iPSCs) retained leukemic mutations, but reset leukemic DNA methylation/gene expression patterns and lacked leukemic potential. However, when differentiated into hematopoietic cells, AML-iPSCs reacquired the ability to give rise to leukemia in vivo and reestablished leukemic methylation/gene expression patterns, including an aberrant MLL signature, indicating that epigenetic reprogramming was insufficient to eliminate leukemic behavior. In one case, we identified distinct AML-iPSC KRAS mutant and wildtype subclones that demonstrated differential growth properties and therapeutic susceptibilities, predicting KRAS wildtype clonal relapse due to increased cytarabine resistance. Increased cytarabine resistance was further observed in a cohort of KRAS wildtype MLL-rearranged AML samples, demonstrating the utility of AML-iPSCs in predicting subclonal relapse and facilitating clonal targeting in AML. This SuperSeries is composed of the SubSeries listed below.