Sören Lehmann

Karolinska University Hospital, Stockholm, Stockholm, Sweden

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Publications (13)94.46 Total impact

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    Article: Targeting p53 in Vivo: A First-in-Human Study With p53-Targeting Compound APR-246 in Refractory Hematologic Malignancies and Prostate Cancer.
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    ABSTRACT: PURPOSE APR-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 METHODS APR-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. Results MTD 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.
    Journal of Clinical Oncology 09/2012; 30(29):3633-9. · 18.37 Impact Factor
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    Article: Prognostic DNA methylation patterns in cytogenetically normal acute myeloid leukemia are predefined by stem cell chromatin marks.
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    ABSTRACT: Cytogenetically normal acute myeloid leukemia (CN-AML) compose between 40% and 50% of all adult acute myeloid leukemia (AML) cases. In this clinically diverse group, molecular aberrations, such as FLT3-ITD, 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 with normal myeloid precursors and global gene expression. IDH and NPM1 mutations were associated with different methylation patterns (P = .0004 and .04, respectively). Genome-wide methylation levels were elevated in IDH-mutated samples (P = .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 < .0001). Furthermore, high methylation levels of PcG target genes were independently associated with better progression-free survival (odds ratio = 0.47, P = .01) and overall survival (odds ratio = 0.36, P = .001). In summary, genome-wide methylation patterns show preferential methylation of PcG targets with prognostic impact in CN-AML.
    Blood 09/2011; 118(20):5573-82. · 9.90 Impact Factor
  • Article: APR-246 exhibits anti-leukemic activity and synergism with conventional chemotherapeutic drugs in acute myeloid leukemia cells.
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    ABSTRACT: APR-246 belongs to a new generation of the compounds that restore normal p53 function in cells with mutated or wild type p53. The purpose of this study was to examine the effects of APR-246 alone and in combination with other drugs in acute myeloid leukemia (AML) cells. Primary leukemic cells from patients with AML and AML cell lines were studied with respect to cytotoxic and apoptotic effects and mechanism of action of APR-246, alone and in combination with Ara-C, daunorubicin and fludarabine. APR-246 showed dose-dependent cytotoxic and apoptotic effects in AML cell lines as well as in primary AML patient cells. Cells from patients with TP53 mutation and complex karyotype were more resistant to conventional drugs while these factors did not significantly affect the sensitivity to APR-246. APR-246 increased active caspase-3, upregulated p53 protein levels, and increased the bax/bcl-2 ratio independently of TP53 mutational status in patient cells sensitive to APR-246. AML cells with high p14(ARF) expression were significantly more sensitive to APR-246. APR-246 induced significant synergistic effects in combination with conventional chemotherapeutic agents. Pre-incubation with APR-246 induced more synergistic effects compared to other schedules. In patient cells, pronounced synergism was found when combining APR-246 with danuorubicin. We conclude that APR-246 is effective in AML cells irrespectively of TP53 mutational status and that it has promising properties for combination studies in AML.
    European Journal Of Haematology 03/2011; 86(3):206-15. · 2.61 Impact Factor
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    Article: Hematopoietic stem cell transplantation rates and long-term survival in acute myeloid and lymphoblastic leukemia: real-world population-based data from the Swedish Acute Leukemia Registry 1997-2006.
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    ABSTRACT: Allogeneic stem cell transplantation (alloSCT) reduces relapse rates in acute leukemia, but outcome is hampered by toxicity. Population-based data avoid patient selection and may therefore substitute for lack of randomized trials. We evaluated alloSCT rates within the Swedish Acute Leukemia Registry, including 3899 adult patients diagnosed from 1997 through 2006 with a coverage of 98% and a median follow-up of 6.2 years. AlloSCT rates and survival decreased rapidly with age >55 years. The 8-year overall survival (OS) was 65% in patients <30 years and 38% in patients <60 years and was similar for acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Among 1073 patients <60 years, alloSCT was performed in 42% and 49% of patients with AML and ALL, respectively. Two-thirds of the alloSCTs were performed in first complete remission, and half used unrelated donors, the same in AML and ALL. Regional differences in management and outcome were found: 60% of AML patients <40 years received alloSCT in all parts of Sweden, but two-thirds of AML patients 40-59 years had alloSCT in one region compared with one-third in other regions (P<.001), with improved 8-year OS among all AML patients in this age cohort (51% vs 30%; P = .005). More Swedish AML patients received alloSCT, and long-term survival was better than in recently published large international studies, despite our lack of selection bias. There was no correlation between alloSCT rate and survival in ALL. In adult AML patients <60 years of age, a high alloSCT rate was associated with better long-term survival, but there was no such correlation in ALL.
    Cancer 03/2011; 117(18):4238-46. · 4.77 Impact Factor
  • Article: Single nucleotide polymorphism genomic arrays analysis of t(8;21) acute myeloid leukemia cells.
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    ABSTRACT: Translocation of chromosomes 8 and 21, t(8;21), resulting in the AML1-ETO fusion gene, is associated with acute myeloid leukemia. We searched for additional genomic abnormalities in this acute myeloid leukemia subtype by performing single nucleotide polymorphism genomic arrays (SNP-chip) analysis on 48 newly diagnosed cases. Thirty-two patients (67%) had a normal genome by SNP-chip analysis (Group A), and 16 patients (33%) had one or more genomic abnormalities including copy number changes or copy number neutral loss of heterozygosity (Group B). Two samples had copy number neutral loss of heterozygosity on chromosome 6p including the PIM1 gene; and one of these cases had E135K mutation of Pim1. Interestingly, 38% of Group B and only 13% of Group A samples had a KIT-D816 mutation, suggesting that genomic alterations are often associated with a KIT-D816 mutation. Importantly, prognostic analysis revealed that overall survival and event-free survival of individuals in Group B were significantly worse than those in Group A.
    Haematologica 10/2009; 94(9):1301-6. · 6.42 Impact Factor
  • Article: Selenite is a potent cytotoxic agent for human primary AML cells.
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    ABSTRACT: Selenite is a potent inhibitor of malignant cell growth. Although the cytotoxic effects have been extensively investigated in vitro, there are only a limited number of studies using primary tumor cells with concomitant comparison to conventional drugs. An ex vivo model with primary cells from 39 consecutive patients with acute myeloid leukemia (AML) were exposed to a panel of conventional cytotoxic drugs, and the effects on viability were compared to those of clinically achievable concentrations of selenite. Selenite at 5 microM caused the lowest mean survival of primary tumor cells in the panel of all tested drugs (28.95% CI 18.60-39.30%). The cells showed a significant (p<0.05) correlation in the resistance to all tested conventional AML drugs whereas selenite did not, indicating sensitivity to selenite also in multi drug resistant cells. Exposure to selenite also resulted in an increased mRNA expression of the antioxidant proteins TrxR1 and Grx, while staining for TrxR1 showed decreased protein levels. The results strongly suggest a great potential for selenite in the treatment of multi drug resistant AML.
    Cancer letters 04/2009; 282(1):116-23. · 4.86 Impact Factor
  • Article: The FLT3 inhibitor PKC412 in combination with cytostatic drugs in vitro in acute myeloid leukemia.
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    ABSTRACT: An internal tandem duplication of FLT3 (FLT3/ITD) occurs in approximately 25% of newly diagnosed AML. PKC412 inhibits the growth of leukemic cell lines with FLT3 mutations such as the MV4-11. This study evaluated the in vitro effects of the combination of PKC412 and ara-C or daunorubicin, studying the effect of co-incubation, pre-incubation and sequential incubation of the drugs in patient samples and cell lines. Thirty-three patients with AML were included. Two cell lines were studied; MV4-11 that expresses the FLT3/ITD and HL-60 that does not. In the patient cells PKC412 exerted its effect at concentrations between 0.1 and 2.0 microM. For MV4-11 cells concentrations down to 1 nM were effective. In patient samples, the results of co-incubation of PKC412 with ara-C were synergistic in 5%, additive in 67%, sub additive in 17% and antagonistic in 11% of the cases. In patient cells, incubations with ara-C and PKC412 resulted in synergistic effects in 17% of the FLT3/ITD positive samples compared to 0% synergistic in the FLT3/ITD negative samples (p < 0.01). Antagonistic effects were more common in the FLT3/ITD negative samples. The timing of the drugs had little impact on the effect. In cell lines, antagonistic effects were seen frequently in HL-60 (90%) and less so in MV4-11 (60%) regardless of sequence or timing of the drugs. The combination of daunorubicin and PKC412 resulted in more synergistic and less antagonistic effects compared to combinations with ara-C, in both patient material and cell lines. The combination of Lonafarnib, a farnesyl-transferase inhibitor (FTI) and PKC412 had additive and synergistic effects in both FLT3/ITD positive and negative cell lines. In conclusion, the combination of PKC412 together with chemotherapeutic drugs is more effective in FLT3/ITD positive AML cells. Antagonistic effects can be seen, especially in patient samples without FLT3/ITD. Also, the combination of PKC412 and the farnesylinhibitor lonafarnib should be further explored.
    Cancer Chemotherapy and Pharmacology 08/2008; 62(3):439-48. · 2.83 Impact Factor
  • Article: Chromosomal aberrations in 17p predict in vitro drug resistance and short overall survival in acute myeloid leukemia.
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    ABSTRACT: Chromosomal aberrations are important prognostic parameters in acute myeloid leukemia (AML). Indicators of poor prognosis include del(5q)/-5, del(7q)/-7, abnormal 3q or complex karyotype. In recent years, it has become clear that aberrations in 17p represent one of the indicators of poor prognosis in haematological malignancies. In AML, deletions in 17p have been shown to indicate a dismal prognosis; genetic aberrations in 9p have also been discussed as influencing long-term survival in AML. In this study, we correlated genetic abnormalities in chromosomes 9 and 17 in patients with de novo AML to in vitro cytotoxicity of conventional anti-leukemic drugs, and long-term overall survival. Blast cells were isolated from 387 patients diagnosed with AML. Chromosomal analysis was successful in 336 cases. All samples were tested for in vitro cytotoxicity against fludarabine, amsacrine, mitoxantrone, etoposide, daunorubicin and Ara-C after being cultured for 4 days, using an ATP assay. Among the 336 patients, five main groups were identified. Abnormal chromosome 17 (n = 22), abnormal 9p (n = 13), monosomy 7 or deletion 7q (n = 35), complex karyotype (n = 52) and normal karyotype (n = 132). Patients with abnormalities of chromosome 17 showed significantly greater resistance to all drugs tested and significantly shorter overall survival compared with patients with normal and complex karyotypes (p = 0.0001 and 0.041, respectively). All patients with abnormalities of chromosome 17 died within 11 months of diagnosis. A tendency towards shorter overall survival and greater drug resistance was also noted when comparing chromosome 17 abnormalities with del(7q)/-7, but the differences did not reach statistical significance. Patients with abnormal 9p showed significantly shorter overall survival but did not differ significantly as regards in vitro drug resistance compared with patients presenting with a normal karyotype. Chromosomal abnormalities affecting the p53 pathway have a significant impact on cytostatic drug resistance and survival in AML. Developing new drugs targeting the p53 pathway could be a way to improve treatment of AML.
    Leukemia & lymphoma 04/2008; 49(3):508-16. · 2.40 Impact Factor
  • Article: Molecular allelokaryotyping of early-stage, untreated chronic lymphocytic leukemia.
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    ABSTRACT: To the authors' knowledge, genetic abnormalities in early-stage chronic lymphocytic leukemia (CLL) have not been examined fully. Single nucleotide polymorphism (SNP) genomic array (SNP-chip) is a new tool that can detect copy number changes and uniparental disomy (UPD) over the entire genome with very high resolution. The authors performed SNP-chip analysis on 56 samples from patients with early-stage, untreated CLL. To validate the SNP-chip data, fluorescence in situ hybridization (FISH) analysis was performed at selected sites. Expression levels of ZAP-70 and the mutational status of immunoglobulin heavy-chain gene also were examined. SNP-chip analysis easily detected nearly all changes that were identified by FISH, including trisomy 12, deletion of TP53 (17p13), deletion of ATM (11q22), and deletion of 13q14. Only 10 of 56 CLL samples (18%) had no genomic abnormalities. Excluding the 4 common abnormalities mentioned above, 25 CLL samples (45%) had a total of 45 copy number changes detected by SNP-chip analysis. Four samples had 6q deletion at 6q21 that involved the AIM1 gene. UPD was detected in 4 samples; 2 samples involved whole chromosome 13 resulting in homozygous deletion of micro-RNA-15a (miR-15a)/miR-16-1. CLL samples with deletion of 13q14 and trisomy 12 were mutually exclusive. Genetic abnormalities, including whole chromosome 13 UPD, are very common events in early-stage CLL. SNP-chip analysis can detect small genetic abnormalities in CLL and may be able to support or even supplant FISH and cytogenetics.
    Cancer 04/2008; 112(6):1296-305. · 4.77 Impact Factor
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    Article: Higher plasma but not intracellular concentrations after infusion with liposomal daunorubicin compared with conventional daunorubicin in adult acute myeloid leukemia.
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    ABSTRACT: To investigate the plasma and intracellular pharmacokinetics of liposomal daunorubicin (DaunoXome) in comparison with conventional daunorubicin, 14 patients aged 28 to 60 years with newly diagnosed acute myeloid leukemia were treated for 1 day with DaunoXome (50 mg/m) and for 2 days with daunorubicin (50 mg/m) with concomitant Ara-C (7 days, 200 mg/m, continuous IV). Eleven of the 14 patients entered complete remission; 9 are still alive. Pharmacokinetic profiles were obtained by blood sampling at appropriate intervals on days 1 to 4. Daunorubicin and daunorubicinol concentrations in plasma and in peripheral leukemic blast cells were measured by high-performance liquid chromatography. Following liposomal daunorubicin administration, the peak values and plasma area under the curve (AUC) were more than 100 times higher than after administration of conventional daunorubicin (AUC, 176 vs. 0.98 micromol/L x hour), but the intracellular AUCs were comparable (759 vs. 715 micromol/L x hour). Intracellular concentrations after DaunoXome peaked later and half as high as after daunorubicin. After DaunoXome versus daunorubicin, plasma clearance was 0.001 versus 0.4 micromol/h, respectively. The volume of distribution was 5.5 L for DaunoXome, versus 3640 L for daunorubicin, indicating low tissue affinity for the liposomal formulation. The authors conclude that liposomal daunorubicin, DaunoXome, yields 2-log higher plasma concentrations but similar intracellular concentrations of daunorubicin and its metabolite daunorubicinol than does free daunorubicin.
    Therapeutic Drug Monitoring 11/2007; 29(5):626-31. · 2.49 Impact Factor
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    Article: Capsaicin, a component of red peppers, inhibits the growth of androgen-independent, p53 mutant prostate cancer cells.
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    ABSTRACT: Capsaicin is the major pungent ingredient in red peppers. Here, we report that it has a profound antiproliferative effect on prostate cancer cells, inducing the apoptosis of both androgen receptor (AR)-positive (LNCaP) and -negative (PC-3, DU-145) prostate cancer cell lines associated with an increase of p53, p21, and Bax. Capsaicin down-regulated the expression of not only prostate-specific antigen (PSA) but also AR. Promoter assays showed that capsaicin inhibited the ability of dihydrotestosterone to activate the PSA promoter/enhancer even in the presence of exogenous AR in LNCaP cells, suggesting that capsaicin inhibited the transcription of PSA not only via down-regulation of expression of AR, but also by a direct inhibitory effect on PSA transcription. Capsaicin inhibited NF-kappa activation by preventing its nuclear migration. In further studies, capsaicin inhibited tumor necrosis factor-alpha-stimulated degradation of IkappaBalpha in PC-3 cells, which was associated with the inhibition of proteasome activity. Taken together, capsaicin inhibits proteasome activity which suppressed the degradation of IkappaBalpha, preventing the activation of NF-kappaB. Capsaicin, when given orally, significantly slowed the growth of PC-3 prostate cancer xenografts as measured by size [75 +/- 35 versus 336 +/- 123 mm(3) (+/-SD); P = 0.017] and weight [203 +/- 41 versus 373 +/- 52 mg (+/-SD); P = 0.0006; capsaicin-treated versus vehicle-treated mice, respectively]. In summary, our data suggests that capsaicin, or a related analogue, may have a role in the management of prostate cancer.
    Cancer Research 04/2006; 66(6):3222-9. · 7.86 Impact Factor
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    Article: Distinct patterns of hematopoietic stem cell involvement in acute lymphoblastic leukemia.
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    ABSTRACT: The cellular targets of primary mutations and malignant transformation remain elusive in most cancers. Here, we show that clinically and genetically different subtypes of acute lymphoblastic leukemia (ALL) originate and transform at distinct stages of hematopoietic development. Primary ETV6-RUNX1 (also known as TEL-AML1) fusions and subsequent leukemic transformations were targeted to committed B-cell progenitors. Major breakpoint BCR-ABL1 fusions (encoding P210 BCR-ABL1) originated in hematopoietic stem cells (HSCs), whereas minor BCR-ABL1 fusions (encoding P190 BCR-ABL1) had a B-cell progenitor origin, suggesting that P190 and P210 BCR-ABL1 ALLs represent largely distinct tumor biological and clinical entities. The transformed leukemia-initiating stem cells in both P190 and P210 BCR-ABL1 ALLs had, as in ETV6-RUNX1 ALLs, a committed B progenitor phenotype. In all patients, normal and leukemic repopulating stem cells could successfully be separated prospectively, and notably, the size of the normal HSC compartment in ETV6-RUNX1 and P190 BCR-ABL1 ALLs was found to be unaffected by the expansive leukemic stem cell population.
    Nature Medicine 07/2005; 11(6):630-7. · 22.46 Impact Factor
  • Article: Drug-resistant human lung cancer cells are more sensitive to selenium cytotoxicity. Effects on thioredoxin reductase and glutathione reductase.
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    ABSTRACT: The human U-1285 and GLC(4) cell lines, both derived from small cell carcinoma of the lung, are present in doxorubicin-sensitive (U-1285 and GLC(4)) and doxorubicin-resistant MRP-expressing (U-1285dox and GLC(4)/ADR) variants. These sublines were examined here with respect to their susceptibilities to the toxic effects of selenite and compared to the toxic effects of selenite on the promyelocytic leukemia cell line HL-60 and its doxorubicin-resistant P-glycoprotein expressing variant. The drug-resistant U-1285dox and GLC(4)/ADR sublines proved to be 3- and 4-fold, respectively, more sensitive to the cytotoxicity of selenite than the drug-sensitive U-1285 and GLC(4) sublines, whereas no difference was observed between the HL-60 sublines. The presence of doxorubicin at a concentration equal to the IC(10) did not significantly potentiate the toxic effects of selenite. The presence of selenite did not significantly affect the expression of the multi-drug resistant proteins (MRP1, LRP and topoisomerase IIalpha) in the drug-resistant cells. The activities of thioredoxin reductase (TrxR) were higher (50 and 25%, respectively) in the drug resistant cell sublines U-1285dox and GLC(4)/ADR compared to the drug-sensitive parental lines. The activity of glutathione reductase (GR) was essentially the same in the drug-sensitive and -resistant cell lines. Exposure to selenite resulted in a 4-fold increase in both TrxR and GR activities in U-1285 cells, an effect, which was less pronounced in the presence of doxorubicin. Under similar conditions the increase in the TrxR activity in the resistant U-1285dox cell line, was only 30% and the activity of GR was unaltered. Different responses in the activity of the key enzymes in selenium metabolism are one possible mechanism explaining the differential cytotoxicity of selenium in these cells.
    Biochemical Pharmacology 06/2002; 63(10):1875-84. · 4.70 Impact Factor

Institutions

  • 2011–2012
    • Karolinska University Hospital
      Stockholm, Stockholm, Sweden
  • 2009
    • Kanazawa University
      • Department of Stem Cell Biology
      Kanazawa-shi, Ishikawa-ken, Japan
  • 2006–2008
    • University of California, Los Angeles
      • Division of Hematology and Medical Oncology
      Los Angeles, CA, USA