| 1. |
- Deneberg, Stefan, et al.
(author)
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microRNA-34b/c on chromosome 11q23 is aberrantly methylated in chronic lymphocytic leukemia
- 2014
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In: Epigenetics. - : Informa UK Limited. - 1559-2294 .- 1559-2308. ; 9:6, s. 910-917
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Journal article (peer-reviewed)abstract
- A commonly deleted region in chronic lymphocytic leukemia (CLL) is the 11q22-23 region, which encompasses the ATM gene. Evidence suggests that tumor suppressor genes other than ATM are likely to be involved in CLL with del(11q). A microRNA (miR) cluster including the miR-34b and miR-34c genes is located, among other genes, within the commonly deleted region (CDR) at 11q. Interestingly, these miRs are part of the TP53 network and have been shown to be epigenetically regulated. In this study, we investigated the expression and methylation status of these miRs in a well-characterized cohort of CLL, including cases with/without 11q-deletion. We show that the miR-34b/c promoter was aberrantly hypermethylated in a large proportion of CLL cases (48%, 25/52 cases). miR-34b/c expression correlated inversely to DNA methylation (P = 0.003), and presence of high H3K37me3 further suppressed expression regardless of methylation status. Furthermore, increased miR-34b/c methylation inversely correlated with the presence of 11q-deletion, indicating that methylation and del(11q) independently silence these miRs. Finally, 5-azacytidine and trichostatin A exposure synergistically increased the expression of miR-34b/c in CLL cells, and transfection of miR-34b or miR-34c into HG3 CLL cells significantly increased apoptosis. Altogether, our novel data suggest that miR-34b/c is a candidate tumor suppressor that is epigenetically silenced in CLL.
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| 2. |
- Deneberg, Stefan, et al.
(author)
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Prognostic DNA methylation patterns in cytogenetically normal acute myeloid leukemia are predefined by stem cell chromatin marks
- 2011
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In: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 118:20, s. 5573-5582
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Journal article (peer-reviewed)abstract
- Cytogenetically normal acute myeloid leukemia (CN-AML) comprise between forty and fifty percent of all adult acute myeloid leukemia (AML) cases. In this clinically diverse group molecular aberrations such as FLT3ITD, NPM1 and CEBPA mutations recently have added to the prognostic accuracy. Aberrant DNA methylation is a hallmark of cancer including AML. We investigated in total 118 CN-AML samples in a test and a validation cohort for genome-wide promoter DNA methylation with Illumina Methylation Bead arrays and compared them to normal myeloid precursors and global gene expression. IDH and NPM1 mutations were associated with different methylation patterns (p=0.0004 and 0.04, respectively). Genome-wide methylation levels were elevated in IDH mutated samples (p=0.006). We observed a negative impact of DNA methylation on transcription. Genes targeted by Polycomb group (PcG) proteins and genes associated with bivalent histone marks in stem cells showed increased aberrant methylation in AML (p<0.0001). Furthermore, high methylation levels of PcG target genes were independently associated with better progression free (OR 0.47, p=0.01) and overall survival (OR 0.36, p=0.001). In summary, genome wide methylation patterns show preferential methylation of PcG targets with prognostic impact in CN-AML.
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| 3. |
- Genovese, Giulio, et al.
(author)
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Clonal hematopoiesis and blood-cancer risk inferred from blood DNA sequence.
- 2014
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In: The New England journal of medicine. - 1533-4406 .- 0028-4793. ; 371:26, s. 2477-87
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Journal article (peer-reviewed)abstract
- Cancers arise from multiple acquired mutations, which presumably occur over many years. Early stages in cancer development might be present years before cancers become clinically apparent.
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| 4. |
- Lehmann, Sören, et al.
(author)
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Targeting p53 in Vivo : a First-in-Human Study With p53-Targeting Compound APR-246 in Refractory Hematologic Malignancies and Prostate Cancer
- 2012
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In: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 30:29, s. 3633-3639
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Journal article (peer-reviewed)abstract
- PURPOSEAPR-246 (PRIMA-1MET) is a novel drug that restores transcriptional activity of unfolded wild-type or mutant p53. The main aims of this first-in-human trial were to determine maximum-tolerated dose (MTD), safety, dose-limiting toxicities (DLTs), and pharmacokinetics (PK) of APR-246.PATIENTS AND METHODSAPR-246 was administered as a 2-hour intravenous infusion once per day for 4 consecutive days in 22 patients with hematologic malignancies and prostate cancer. Acute myeloid leukemia (AML; n = 7) and prostate cancer (n = 7) were the most frequent diagnoses. Starting dose was 2 mg/kg with dose escalations up to 90 mg/kg.RESULTSMTD was defined as 60 mg/kg. The drug was well tolerated, and the most common adverse effects were fatigue, dizziness, headache, and confusion. DLTs were increased ALT/AST (n = 1), dizziness, confusion, and sensory disturbances (n = 2). PK showed little interindividual variation and were neither dose nor time dependent; terminal half-life was 4 to 5 hours. Tumor cells showed cell cycle arrest, increased apoptosis, and upregulation of p53 target genes in several patients. Global gene expression analysis revealed changes in genes regulating proliferation and cell death. One patient with AML who had a p53 core domain mutation showed a reduction of blast percentage from 46% to 26% in the bone marrow, and one patient with non-Hodgkin's lymphoma with a p53 splice site mutation showed a minor response.CONCLUSION We conclude that APR-246 is safe at predicted therapeutic plasma levels, shows a favorable pharmacokinetic profile, and can induce p53-dependent biologic effects in tumor cells in vivo.
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| 5. |
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| 6. |
- Willander, Kerstin
(author)
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Molecular genetic studies on Chronic Lymphocytic Leukemia and Acute Myeloid Leukemia - with focus on prognostic markers
- 2014
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Doctoral thesis (other academic/artistic)abstract
- The present thesis is focused on the prognostic value of genetic variations and alterations in the initiation and development of chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML) patients. Several prognostic markers based on genetic or chromosomal aberrations are today used in clinic in these heterogeneous diseases. Novel biomarkers have been identified through next generation sequencing techniques and some of them may be useful as prognostic markers in clinical diagnostic. In papers I-IV we have investigated some of this markers in CLL and AML tumor cells.In papers I and III we investigated the prognostic value of the MDM2 SNP309 in relation to the presence of TP53 mutations in tumor cells from CLL and AML patients. The SNP309 G-allele was associated with a shorter overall survival in TP53 wildtype CLL and non-normal karyotype AML patients. Mutations in the TP53 gene were found in 6.2% in CLL and 21.7% in AML and were always associated with adverse overall survival. This was most significant observed among the AML patients, where the three year survival was zero.In paper II we investigated mutations in NOTCH1 and NOTCH2 as prognostic biomarkers in CLL. Notch1 and Notch2 play critical roles in lineage differentiation of white blood cells. We found mutation only in NOTCH1 in a frequency of 6.7% and our analysis revealed a shorter overall survival for these. NOTCH1 mutations were almost mutually exclusive with TP53 mutations and represented together 12.9% in CLL patients, and they may both be strong prognostic biomarkers in CLL.In paper IV we studied mutations in the tricarboxylic acid cycle. Metabolic disturbances in cancer cells have been known for many years, but recently mechanistic explanations have been identified. Hot spot mutations in IDH1/2 genes, result in neomorphic enzyme activities that results in global hypermethylation of the cancer cell genome. We found mutations in 21% of the AML patients. Among the CN-AML patients there is a lack of prognostic markers and in this subgroup we found patients with IDH2 mutations to have a shorter overall survival (3 vs. 21 months (p=0.009) for mutated and wild-type patients, respectively). Additionally, we also studied a SNP in the IDH1 gene, and both the IDH2 mutations and the SNP showed to have a potential as a new prognostic markers in CN-AML.In summary, the results in papers I-IV have a potential to function as novel prognostic biomarkers in the clinic for therapeutic considerations and may also be targets for novel drugs for CLL and AML patients.
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