ORIGINAL ARTICLE

Patrick Ziegler & Hubert Schrezenmeier & Jamil Akkad &

Ute Brassat & Lucia Vankann & Jens Panse &

Stefan Wilop & Stefan Balabanov & Klaus Schwarz &

Uwe M. Martens & Tim H. Brümmendorf

Received: 7 March 2012 /Accepted: 16 March 2012 /Published online: 4 April 2012# Springer-Verlag 2012

Abstract Telomere length (TL) both reflects and limits thereplicative life span of normal somatic cells. As a conse-quence, critically shortened telomeres are associated with avariety of disease states. Telomere attrition can be counter-acted by a nucleoprotein complex containing telomerase.Mutations in subunits of telomerase, telomerase-bindingproteins as well as in members of the shelterin complexhave been described both in inherited and acquired bonemarrow failure syndromes. Here, we report on a patient withacquired aplastic anemia and a nonsynonymous variation ofcodon 1062 of the hTERT gene (p.Ala1062Thr) whosesubstantial and maintained hematologic response to long-term androgen treatment (including complete transfusionindependence) was paralleled by a significant and continuedincrease in TL in multilineage peripheral blood cells. To our

knowledge, this represents the first case of sustained telo-mere elongation in hematopoietic stem cells induced by apharmacological approach in vivo (141 words).

Keywords Telomere . Telomerase . Bone marrow failure .

Aplastic anemia . Androgen treatment

Introduction

Acquired bone marrow failure syndromes (aBMFS) arethought to result from (e.g., auto-immune-mediated) dam-age to the hematopoietic stem cell (HSC) compartment [1].As a consequence, telomere shortening in patients withaplastic anemia (AA) was found to be significantly correlated

Patrick Ziegler and Hubert Schrezenmeier contributed equally

P. Ziegler : L. Vankann : J. Panse : S. Wilop :T. H. Brümmendorf (*)Department of Oncology, Hematology and Stem CellTransplantation, University Hospital Aachen,RWTH Aachen University,Pauwelsstraße 30,52074 Aachen, Germanye-mail: tbruemmendorf@ukaachen.de

H. Schrezenmeier :K. SchwarzInstitut für Klinische Transfusionsmedizinund Immungenetik Ulm,DRK Blutspendedienst Baden-Württemberg – Hessen,Sandhofstraße,60528 Frankfurt, Germany

H. Schrezenmeier :K. SchwarzInstitut für Transfusionsmedizin, Universität Ulm,Helmholtzstraße 10,89081 Ulm, Germany

J. Akkad :U. M. MartensDepartment of Hematology and Oncology,Cancer Center Heilbronn-Franken, SLK Kliniken,Am Gesundbrunnen 20-26,74078 Heilbronn, Germany

U. Brassat : S. BalabanovKlinik für Onkologie, Hämatologie undKnochenmarktransplantation mit Sektion Pneumologie,Universitäres Cancer Center Hamburg (UCCH),Universitäts-Klinikum Hamburg-Eppendorf,Martinistraße 52,20246 Hamburg, Germany

Ann Hematol (2012) 91:1115–1120DOI 10.1007/s00277-012-1454-x

Telomere elongation and clinical response to androgentreatment in a patient with aplastic anemia and a heterozygoushTERT gene mutation

with the degree of pancytopenia, risk of relapse after immu-nosuppressive (IS) therapy, size of a glycosylphosphatidyli-nositol (GPI) anchor-deficient subclone [2, 3], clonalevolution, and overall survival [4–6]. Among hematopoieticdisorders associated with altered telomere maintenance [7],telomere shortening is most accelerated in cases ofinherited BMFS (iBMFS) such as dyskeratosis congenita(DKC) which are thought to result from genetic aberra-tions in the gene DKC1 or in subunits of the telomerase orshelterin complex [8].

Methods

Patient material

Patient material was obtained following informed consent.Analysis was either performed as part of routine clinical careor approved by the local institutional review board (IRB) ofthe University of Ulm.

Sequencing of the telomerase reverse transcriptase gene

Genomic deoxyribonucleic acid (DNA) was isolated fromthe respective samples using standard procedures. Polymerasechain reaction (PCR) products included the coding exons andadjacent intronic regions (±10 bp). Primer sequences areavailable upon request (e-mail: klaus.schwarz@uni-ulm.de).Products were directly sequenced with BigDye Terminatortechnology and run on an ABI PRISM 3100 genetic analyzer(both from Applied Biosystems, Carlsbad, CA, USA).

TL measurement

The average telomere length (TL) in peripheral blood cells ofthe patient outlined below was measured by fluorescence insitu hybridization and flow cytometry (flow-FISH) [3, 5, 9,10] and by monochrome multiplex quantitative PCR (MM-QPCR) [11]. For flow-FISH, samples were analyzed in tripli-cate both with and without hybridization with FITC–(C3TA2)3PNA. Each sample included cow thymocytes as an internalcontrol and was counterstained with the DNA dye LDS751.Subfractions of peripheral blood cells were identified based ontwo parameters: forward light scatter and LDS751 fluores-cence. TL was calculated based on Southern blot analysisperformed on cow thymocytes as described previously [9].ForMM-QPCR, whole blood DNAwas isolated using a DNAblood kit (Quiagen, Hilden, Germany). For telomere amplifi-cation, the following primers were used—telg primer 5 -ACACTAAGGTTTGGGTTTGGGTTTGGGTTTGGGTTAGTGT-3 and telc primer 5 -TGTTAGGTATCCCTATCCCTATCCCTATCCCTATCCCTAACA-3 —as a referenceserving the beta-globin gene, which was amplified using hbgu

primer 5 -CGGCGGCGGGCGGCGCGGGCTGGGCGGCTTCATCCACGTTCACCTTG-3 and hbgd primer5 -GCCCGGCCCGCCGCGCCCGTCCCGCCGGAGGAGAAGTCTGCCGTT-3 . PCR was performed on a MyIQ2two-color real-time PCR detection system (Biorad) usingsignal acquisition at 74°C (telomere amplicon) and 88°C(beta-globin amplicon). For relative quantitation, six con-centrations of standard DNA sample were prepared byserial dilution and analyzed in the same 96-well plate asthe experimental DNA. Standard and experimental DNAwere assayed in triplicate. Amplification efficiency forthe data outlined here was between 90% and 100% forboth amplicons. Melt-curve analysis confirmed the specificityof the amplification. T/S ratio for experimental DNAsamples was calculated by dividing the copy number ofthe telomere template T by the copy number of the beta-globintemplate S.

Results and discussion

We report here on a 51-year-old male patient who was firstdiagnosed in February 2006 with moderate AA. The patientdeveloped slowly progressive pancytopenia affecting pre-dominantly erythropoiesis and megakaryopoiesis. Typicalextra-hematopoietic manifestations of DKC were excluded.TL was found to be significantly reduced below the 1%percentile of normal individuals [12], both in lymphocytes(4.28±0.02 kbp) and granulocytes (4.14±0.1 kbp). Sequenc-ing of the telomerase reverse transcriptase gene (hTERT)revealed a heterozygous mutation in exon 15 (ca. 3184 G>A)with a predicted nonsynonymous aminoacid change (p.Ala1062Thr) both in peripheral blood and buccalmucosa cells(data not shown). This mutation has been demonstrated tocause reduced telomerase activity by haploinsufficiency andhas been found to be associated with the development of acutemyeloid leukemia [8, 13]. Telomerase RNA subunit (hTERC)and DKC1 genes were found to be wild-type.

Based on the clinical presentation (i.e., moderate AAwithisolated red blood cell transfusion dependency) in conjunc-tion with a heterozygous hTERT mutation associated withsubstantial telomere shortening, we decided to initiate tes-tosterone undecanoat (Andriol® 80 mg tid) as first linetreatment rather than to initiate IS treatment with antithy-mocyte globulin (ATG) and cyclosporin (CSA) in April2007. Androgen treatment was well tolerated, and eventu-ally, after 12 months of treatment, the patient became redblood cell transfusion-independent (Fig. 1A). In parallel tohis hemoglobin levels rising to above 12 g/dl, the patient’splatelet count increased steadily and significantly over morethan 4 years (Fig. 1B). During this time period, the patientremained free of somatic symptoms and without apparentadverse events. Excitingly, this clinical and hematological

1116 Ann Hematol (2012) 91:1115–1120

improvement was mirrored by a steady increase of TL inmultilineage peripheral blood cells (Fig. 2A–B), suggestingthat continuous telomere lengthening has occurred invivo in the multipotent hematopoietic stem and progenitorcompartment. Whereas telomeres in granulocytes typicallyloose an average of about 30–50 bp/year in adulthood(reviewed in Drummond et al. [7]), we found a mean increaseof >400 bp/year during the treatment period. Results obtainedby two independent methods, i.e., flow FISH and MM-QPCRcorrelated well (Fig. 2C). To our knowledge, this representsthe first case of sustained telomere elongation in HSCsinduced by a pharmacological approach in vivo. However,more than 5 years after first diagnosis of AA, the patientsblood counts began to drop again and four months later, thepatient developed acute myelogeneous leukemia (AML) with

a 50% infiltration of the bone marrow with CD13+CD33+,CD34+, CD117+, HLA-DR+leukemic blasts. Cytogeneticsrevealed monosomy 7, molecular markers NPM1 and FLT3were negative. Following induction chemotherapy, blastswere cleared from the patient’s bone marrow at day 22.However, due to persistent bone marrow aplasia and lackof hematopoietic recovery probably reflecting limitedbone marrow reserve due to his underlying BMFS, thepatient proceeded to allogeneic stem cell transplantationfrom a matched related donor. Within the first 100 dayspostallogeneic stem cell transplantation, the patient diedfrom acute graft versus host disease accompanied byinfectious complications.

Telomerase reverse transcriptase (hTERT) and its RNAtemplate (hTERC) are core components of the telomerase

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Fig. 1 Clinical response uponandrogen treatment. Timecourse of hemoglobin values(A), platelets (B), and whiteblood cell (wbc, C) counts in apatient before and duringtreatment with Andriol for redblood cell transfusion-dependent AA prior todiagnosis of secondary AML.Black arrows indicate packedred blood cell transfusions

Ann Hematol (2012) 91:1115–1120 1117

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Fig. 2 Telomere elongation invivo upon androgen treatment.Gain in telomere length(bp/year) in granulocytes andlymphocytes from peripheralblood during androgentreatment of a patient withacquired aplastic anemia and anonsynonmous mutation in thetelomerase gene measured byflow-FISH (A) and MM-QPCR(B). Correlation of the relativeT/S ratios obtained byMM-QPCR in whole bloodDNA samples with telomerefluorescence values determinedby flow-FISH

1118 Ann Hematol (2012) 91:1115–1120

complex together with other proteins [14]. Mutations in sev-eral telomere maintenance genes, including dyskerin (DKC1)[15], hTERC [16], hTERT, TINF2, NOP10 and NHP2, resultin inherited aBMFS such as DKC. Patients with DKC havebeen shown to have ultra-short telomeres associated with ahighly increased risk of developing iBMFS before the age of30 years [16]. Heterozygous hTERT mutations compromisetelomerase function mostly by haploinsufficiency and rarely,by a dominant negative effect [17]. Interestingly, hTERTcatalytic activity has been shown to be responsive to stimula-tion by sex hormones via upregulation of hTERTmRNA [18].Recently, hematopoietic cells from patients carrying muta-tions within the telomerase complex have been shown torespond to androgen treatment in vitro [19]. Obviously, sincebone marrow specimens were not available under treatment,we cannot provide formal proof of increased telomerase ac-tivity under andriol treatment eventually leading to elongationof TL in hTERT-mutated HSCs. However, the gradual natureof improvement in blood counts over more than 4 yearsparalleled by continued elongation of TL in peripheral bloodgranulocytes and lymphocytes is in support of this hypothesis.Alternatively, TL increase can be explained by favorableactivity of androgen treatment on subclone(s) with particularlylong telomeres [20] eventually leading to clonal selection ofsuch HSC(s). Whereas TL in peripheral blood cells amountedto 7.3 kb 5 months before diagnosis of AML, it was dramat-ically reduced in bone marrow blasts retrieved from the timepoint of AML diagnosis (3.7 kb). As expected [10], despite ofsignificantly reduced TL, TA was found to be significantlyincreased in myeloid leukemic blasts (not shown).

Taken together, these findings seem to suggest that evolutionto secondary AML occurred in a subclone of HSCs that eitherwas primarily unresponsive to androgen treatment (and there-fore telomeres remained short) or developed secondary resis-tance at some point during the years of andriol treatment leadingto accelerated telomere shortening and genetic instability.

Clinically, patients with AA refractory to IS treatmentrequire alternate treatment strategies such as allogeneic stemcell transplantation, a treatment option that is associatedwith significant risk and considerable comorbidities and(given the age distribution of the patients) not readily avail-able for all patients [21]. Alternatively, in addition to sup-portive care, corticosteroids and particularly syntheticandrogenic steroids have been used in individual caseseffectively. Recently, a Japanese study successfully investi-gated Danazol in Japanese individuals with AA refractory toIS [22]. Moreover, Danazol was used as first line treatmentin patients who were not eligible for allogeneic stem celltransplantation and did not have access to standard first linetreatment with ATG and CSA in Mexico [23]. In this study,the response rate in the Danazol arm was 46% (17 out of 37patients treated) and tolerability at a dose of 300–600 mg(median 400 mg) was favorable.

The role of androgen treatment in AA, in general, and in“telomeropathies,” in particular, will have to be tested pro-spectively and studies addressing this issue are alreadyongoing (ClinicalTrials.gov identifier: NCT01441037).Nevertheless and in line with these strategies, we feel thatevidence is increasing that screening TL analysis should beincorporated into the routine clinical work-up of patientswith BMFS to date and might not only serve as a valuableprognostic but eventually also as an important predictivebiomarker for patients receiving treatment with androgenderivatives in this disease.

Ann Hematol (2012) 91:1115–1120 1119

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