klaudia hettinger - Academia.edu (original) (raw)

Papers by klaudia hettinger

The Lancet, Nov 1, 1998

ABSTRACT Sensitive techniques for detection of minimal residual disease (MRD) at degrees of one l... more ABSTRACT Sensitive techniques for detection of minimal residual disease (MRD) at degrees of one leukaemic cell per 10(3)-10(6) cells (10(-3)-10(-6)) during follow-up of children with acute lymphoblastic leukaemia (ALL) can provide insight into the effectiveness of cytotoxic treatment. However, it is not yet clear how information on MRD can be applied to treatment protocols. We monitored 240 patients with childhood ALL who were treated according to national protocols of the International BFM Study Group. 60 patients relapsed and the patients in continuous complete remission (CCR) had a median event-free follow-up of 48 months. Bone-marrow samples were collected at up to nine time points during and after treatment. Standardised PCR analysis of patient-specific immunoglobulin and T-cell receptor gene rearrangements and TAL1 deletions were used as targets for semiquantitative estimation of MRD. Amount of MRD was classed as 10(-2) or more, 10(-3), and 10(-4) or less. MRD negativity at the various follow-up times was associated with low relapse rates (3-15% at 3 years), but five-fold to ten-fold higher relapse rates (39-86% at 3 years) were found in MRD-positive patients. The distinct degrees of MRD appeared to have independent prognostic value (p [trend]&lt;0.001) at all separate time points, especially at the first two time points (at the end of induction treatment and before consolidation treatment). At these two time points a high degree of MRD (&gt; or = 10(-2)) was associated with a three-fold higher relapse rate when compared with patients with a low degree of MRD (&lt; or = 10(-4)). At later time points (including the end of treatment) even a low degree of MRD was associated with a poor outcome. Positivity in patients in CCR after treatment was rare (&lt; 1%). With the combined MRD information from the first two follow-up time points, it was possible to recognise three different risk groups--55 (43%) were in a low-risk group and had a 3-year relapse rate of only 2% (95% CI 0.05-12%); 19 (15%) were in a high-risk group and had a relapse rate of 75% (55-95%); and 55 (43%) were in an intermediate-risk group and had a 3-year relapse rate of 23% (13-36%). Our collaborative MRD study shows that monitoring patients with childhood ALL at consecutive time points gives clinically relevant insight into the effectiveness of treatment. Combined information on MRD from the first 3 months of treatment distinguishes patients with good prognoses from those with poor prognoses, and this helps in decisions whether and how to modify treatment.

Regulatory Toxicology and Pharmacology, 2014

Cell Death & Differentiation, 2006

Activation of c-Jun, a component of the AP-1 family of transcription factors, leads to either pro... more Activation of c-Jun, a component of the AP-1 family of transcription factors, leads to either promotion or prevention of apoptosis. However, the molecular determinants of c-Jun-mediated cell survival are still unclear. We show here that inducible expression of c-Jun promotes cellular survival by negatively regulating the expression of the tumor-suppressor PTEN, resulting in the concomitant activation of the Akt survival pathway. Consistently, c-jun À/À fibroblasts, which are sensitive to nutrient deprivation, and human cell lines in which c-Jun expression is silenced, express elevated levels of PTEN. siRNA-mediated silencing of PTEN resulted in the reduction of cell-death owing to c-Jun deficiency. c-Jun was found to suppress PTEN expression by binding to a variant AP-1 site found in the 5 0 upstream sequences of PTEN promoter. Finally, an inverse correlation between c-Jun and PTEN levels was apparent in a panel of human tumor cell lines, independent of their p53 status. Together, the data demonstrate that c-Jun contributes to the promotion of cellular survival by regulating the expression of PTEN.

Cancer Chemotherapy and Pharmacology, 2010

In this preclinical study we examined the biodistribution of hypericin formulated as its watersol... more In this preclinical study we examined the biodistribution of hypericin formulated as its watersoluble PVP-hypericin complex in the different layers (urothelium, submucosa, muscle) of a normal rat bladder and a rat bladder bearing a malignant urothelium composed of syngeneic AY-27 tumor cells. The results were compared with the biodistribution of hexaminolevulinate (HAL) induced protoporphyrin IX (PpIX). Methods Freshly prepared PVP-hypericin and HAL solutions were instilled in both normal as well as tumor bearing rat bladders. Following instillation, bladders were removed and snap frozen in liquid nitrogen. Fluorescence of PVP-hypericin or PpIX induced HAL was measured in the bladder layers and quantified using image analysis software. Results The results of these experiments show that PVP-hypericin (30 µM) accumulated about 3.5fold more in malignant urothelial tissue as compared to normal urothelium, whereas PpIX accumulated to the same extent in malignant and normal urothelium, both after intra-bladder instillation of 8 or 16 mM HAL. Besides, PVP-hypericin and PpIX accumulated selectively in the urothelium with a tumor-to-muscle ratio of 30.6 for PVP-hypericin and 3.7 to 8.3 for 16 and 8 mM HAL, respectively. Conclusions This study shows that PVP-hypericin appears to have great potential as a photodynamic agent against non-muscle invasive bladder cancers after intravesical administration, with a limited risk of affecting the deeper layers of the bladder.

British Journal of Haematology, 1998

The preferential occurrence of immature T-cell receptor (TCR) delta rearrangements (i.e. incomple... more The preferential occurrence of immature T-cell receptor (TCR) delta rearrangements (i.e. incomplete Ddelta2-Ddelta3 and Vdelta2-Ddelta3) in B-cell precursor acute lymphoblastic leukaemia (BCP ALL) and of predominantly mature rearrangements (incomplete Ddelta2-Jdelta1, complete Vdelta1, Vdelta2, Vdelta3 to Jdelta1) in T-lineage ALL prompted us to establish two separate multiplex PCR systems for the identification of clonal TCRdelta rearrangements. PCR products of the expected size for the specific rearrangements were detectable from a dilution of 100-1000 clonal cells in 150000 polyclonal cells. Both multiplex PCR systems were used to analyse samples from 86 childhood BCPALLs and 30 T-lineage ALLs. The results of the multiplex PCRs were controlled by standard PCR analyses for the individual rearrangements and Southern blots, which were identical. Only immature TCRdelta rearrangements were detected in BCP ALL (59%), whereas no rearrangement was found in the remaining BCP leukaemias, thus confirming the exclusive presence of immature TCRdelta rearrangements in B-lineage cells. 50% of the T-lineage ALLs contained mature rearrangements, but no immature rearrangements were found. These two multiplex PCR techniques appear to be reliable and fast aids in the analysis of clonal TCRdelta rearrangements in ALL.

Journal of Biomedical Optics, 2011

Polyvinylpyrrolidone (PVP)-hypericin is a potent photosensitizer that is used in the urological c... more Polyvinylpyrrolidone (PVP)-hypericin is a potent photosensitizer that is used in the urological clinic to photodiagnose with high-sensitivity nonmuscle invasive bladder cancer (NMIBC). We examined the differential accumulation and therapeutic effects of PVP-hypericin using spheroids composed of a human urothelial cell carcinoma cell line (T24) and normal human urothelial (NHU) cells. The in vitro biodistribution was assessed using fluorescence image analysis of 5-μm cryostat sections of spheroids that were incubated with PVP-hypericin. The results show that PVP-hypericin accumulated to a much higher extent in T24 spheroids as compared to NHU spheroids, thereby reproducing the clinical situation. Subsequently, spheroids were exposed to different PDT regimes with a light dose ranging from 0.3 to 18J/cm 2 . When using low fluence rates, only minor differences in cell survival were seen between normal and malignant spheroids. High light fluence rates induced a substantial difference in cell survival between the two spheroid types, killing ∼80% of the cells present in the T24 spheroids. It was concluded that further in vivo experiments are required to fully evaluate the potential of PVP-hypericin as a phototherapeutic for NMIBC, focusing on the combination of the compound with methods that enhance the oxygenation of the urothelium. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

Bone Marrow Transplantation, 2001

High MRD levels before transplantation in children receiving T cell-depleted unrelated grafts for... more High MRD levels before transplantation in children receiving T cell-depleted unrelated grafts for relapsed ALL were associated with a 100% relapse risk. We report on two children with relapsed ALL who underwent non T cell-depleted BMT from unrelated donors. Despite a high residual tumor load pretransplant and the occurrence of only aGVHD grade I, they are still in second complete remission 2.7 and 5.2 years after transplantation, respectively. Thus, we propose that the transplant regimens influence the prognostic significance of high MRD levels pre-BMT. Bone Marrow Transplantation (2001) 28, 1087-1089.

Blood, 2002

A hyperdiploid karyotype is found in 30% of B-cell precursor acute lymphoblastic leukemias in chi... more A hyperdiploid karyotype is found in 30% of B-cell precursor acute lymphoblastic leukemias in childhood. The time of nondisjunction of chromosomes leading to hyperdiploidy during leukemogenesis is unknown. We used the 3 clonotypic immunoglobulin heavy chain (IgH) gene rearrangements as molecular markers for each of the 3 chromosomes 14 in a case with hyperdiploid acute lymphoblastic leukemia to define the order of events—namely, somatic recombination and nondisjunction of chromosomes—during leukemia development. A partial sequence homology of the incomplete DJH rearrangement with 1 of the 2 nonfunctional VDJH rearrangements suggests that the doubling of chromosomes had occurred after this DJHrearrangement and thus during early B-cell differentiation. The occurrence of the nondisjunction of chromosomes as well as ongoing rearrangement processes in utero were confirmed by the presence of all 3 IgH rearrangements in neonatal blood spots, providing the first evidence that hyperdiploidy ...

Blood, 2002

We performed sensitive polymerase chain reaction-based minimal residual disease (MRD) analyses on... more We performed sensitive polymerase chain reaction-based minimal residual disease (MRD) analyses on bone marrow samples at 9 follow-up time points in 71 children with T-lineage acute lymphoblastic leukemia (T-ALL) and compared the results with the precursor B-lineage ALL (B-ALL) results (n ‫؍‬ 210) of our previous study. At the first 5 follow-up time points, the frequency of MRD-positive patients and the MRD levels were higher in T-ALL than in precursor-B-ALL, reflecting the more frequent occurrence of resistant disease in T-ALL. Subsequently, patients were classified according to their MRD level at time point 1 (TP1), taken at the end of induc-tion treatment (5 weeks), and at TP2 just before the start of consolidation treatment (3 months). Patients were considered at low risk if TP1 and TP2 were MRD negative and at high risk if MRD levels at TP1 and TP2 were 10 ؊3 or higher; remaining patients were considered at intermediate risk. The relative distribution of patients with T-ALL (n ‫؍‬ 43) over the MRDbased risk groups differed significantly from that of precursor B-ALL (n ‫؍‬ 109). Twenty-three percent of patients with T-ALL and 46% of patients with precursor B-ALL were classified in the low-risk group (P ‫؍‬ .01) and had a 5-year relapsefree survival (RFS) rate of 98% or greater.

Purpose In this preclinical study, we examined the bio-distribution of hypericin formulated as it... more Purpose In this preclinical study, we examined the bio-distribution of hypericin formulated as its water-soluble PVP-hypericin complex in the diVerent layers (urothelium, submucosa, muscle) of a normal rat bladder and a rat bladder bearing a malignant urothelium composed of syngeneic AY-27 tumor cells. The results were compared with the biodistribution of hexaminolevulinate (HAL)-induced pro-toporphyrin IX (PpIX). Methods Freshly prepared PVP-hypericin and HAL solutions were instilled in both normal as well as tumor-bearing rat bladders. Following instillation, bladders were removed and snap frozen in liquid nitrogen. Fluorescence of PVP-hypericin or PpIX-induced HAL was measured in the bladder layers and quantiWed using image analysis software. Results The results of these experiments show that PVP-hypericin (30 M) accumulated about 3.5-fold more in malignant urothelial tissue when compared to normal uro-thelium, whereas PpIX accumulated to the same extent in malignant and normal urothelium, both after intrabladder instillation of 8 or 16 mM HAL. Besides, PVP-hypericin and PpIX accumulated selectively in the urothelium with a tumor-to-muscle ratio of 30.6 for PVP-hypericin and 3.7-8.3 for 16 and 8 mM HAL, respectively. Conclusions This study shows that PVP-hypericin appears to have great potential as a photodynamic agent against non-muscle-invasive bladder cancers after intraves-ical administration, with a limited risk of aVecting the deeper layers of the bladder.

Activation of c-Jun, a component of the AP-1 family of transcription factors, leads to either pro... more Activation of c-Jun, a component of the AP-1 family of transcription factors, leads to either promotion or prevention of apoptosis.
However, the molecular determinants of c-Jun-mediated cell survival are still unclear. We show here that inducible expression of
c-Jun promotes cellular survival by negatively regulating the expression of the tumor-suppressor PTEN, resulting in the
concomitant activation of the Akt survival pathway. Consistently, c-jun/ fibroblasts, which are sensitive to nutrient
deprivation, and human cell lines in which c-Jun expression is silenced, express elevated levels of PTEN. siRNA-mediated
silencing of PTEN resulted in the reduction of cell-death owing to c-Jun deficiency. c-Jun was found to suppress PTEN
expression by binding to a variant AP-1 site found in the 50 upstream sequences of PTEN promoter. Finally, an inverse correlation
between c-Jun and PTEN levels was apparent in a panel of human tumor cell lines, independent of their p53 status. Together, the
data demonstrate that c-Jun contributes to the promotion of cellular survival by regulating the expression of PTEN.

An international expert group which includes 30 organisations (pharmaceutical companies, contract... more An international expert group which includes 30 organisations (pharmaceutical companies, contract research organisations, academic institutions and regulatory bodies) has shared data on the use of recovery animals in the assessment of pharmaceutical safety for early development. These data have http://dx. been used as an evidence-base to make recommendations on the inclusion of recovery animals in toxicology studies to achieve scientific objectives, while reducing animal use. Recovery animals are used in pharmaceutical development to provide information on the potential for a toxic effect to translate into long-term human risk. They are included on toxicology studies to assess whether effects observed during dosing persist or reverse once treatment ends. The group devised a questionnaire to collect information on the use of recovery animals in general regulatory toxicology studies to support first-inhuman studies. Questions focused on study design, the rationale behind inclusion or exclusion and the impact this had on internal and regulatory decisions. Data on 137 compounds (including 53 biologicals and 78 small molecules) from 259 studies showed wide variation in where, when and why recovery animals were included. An analysis of individual study and programme design shows that there are opportunities to reduce the use of recovery animals without impacting drug development.

High MRD levels before transplantation in children receiving T cell-depleted unrelated grafts for... more High MRD levels before transplantation in children receiving T cell-depleted unrelated grafts for relapsed ALL were associated with a 100% relapse risk. We report on two children with relapsed ALL who underwent non T cell-depleted BMT from unrelated donors. Despite a high residual tumor load pre-transplant and the occurrence of only aGVHD grade I, they are still in second complete remission 2.7 and 5.2 years after transplantation, respectively. Thus, we propose that the transplant regimens influence the prognos-tic significance of high MRD levels pre-BMT. Bone Marrow Transplantation (2001) 28, 1087-1089.

The preferential occurrence of immature T-cell receptor (TCR) d rearrangements (i.e. incomplete D... more The preferential occurrence of immature T-cell receptor (TCR) d rearrangements (i.e. incomplete Dd2-Dd3 and Vd2-Dd3) in B-cell precursor acute lymphoblastic leukaemia (BCP ALL) and of predominantly mature rearrangements (incomplete Dd2-Jd1, complete Vd1, Vd2, Vd3 to Jd1) in T-lineage ALL prompted us to establish two separate multiplex PCR systems for the identification of clonal TCRd rearrangements. PCR products of the expected size for the specific rearrangements were detectable from a dilution of 100-1000 clonal cells in 150 000 polyclonal cells. Both multiplex PCR systems were used to analyse samples from 86 childhood BCPALLs and 30 T-lineage ALLs. The results of the multiplex PCRs were controlled by standard PCR analyses for the individual rearrangements and Southern blots, which were identical. Only immature TCRd rearrangements were detected in BCP ALL (59%), whereas no rearrangement was found in the remaining BCP leukaemias, thus confirming the exclusive presence of immature TCRd rearrangements in B-lineage cells. 50% of the T-lineage ALLs contained mature rearrangements, but no immature rearrangements were found. These two multi-plex PCR techniques appear to be reliable and fast aids in the analysis of clonal TCRd rearrangements in ALL.

The Lancet, Nov 1, 1998

Regulatory Toxicology and Pharmacology, 2014

Cell Death & Differentiation, 2006

Cancer Chemotherapy and Pharmacology, 2010

British Journal of Haematology, 1998

Journal of Biomedical Optics, 2011

Bone Marrow Transplantation, 2001

Blood, 2002

Activation of c-Jun, a component of the AP-1 family of transcription factors, leads to either pro... more Activation of c-Jun, a component of the AP-1 family of transcription factors, leads to either promotion or prevention of apoptosis.
However, the molecular determinants of c-Jun-mediated cell survival are still unclear. We show here that inducible expression of
c-Jun promotes cellular survival by negatively regulating the expression of the tumor-suppressor PTEN, resulting in the
concomitant activation of the Akt survival pathway. Consistently, c-jun/ fibroblasts, which are sensitive to nutrient
deprivation, and human cell lines in which c-Jun expression is silenced, express elevated levels of PTEN. siRNA-mediated
silencing of PTEN resulted in the reduction of cell-death owing to c-Jun deficiency. c-Jun was found to suppress PTEN
expression by binding to a variant AP-1 site found in the 50 upstream sequences of PTEN promoter. Finally, an inverse correlation
between c-Jun and PTEN levels was apparent in a panel of human tumor cell lines, independent of their p53 status. Together, the
data demonstrate that c-Jun contributes to the promotion of cellular survival by regulating the expression of PTEN.

High MRD levels before transplantation in children receiving T cell-depleted unrelated grafts for... more High MRD levels before transplantation in children receiving T cell-depleted unrelated grafts for relapsed ALL were associated with a 100% relapse risk. We report on two children with relapsed ALL who underwent non T cell-depleted BMT from unrelated donors. Despite a high residual tumor load pre-transplant and the occurrence of only aGVHD grade I, they are still in second complete remission 2.7 and 5.2 years after transplantation, respectively. Thus, we propose that the transplant regimens influence the prognos-tic significance of high MRD levels pre-BMT. Bone Marrow Transplantation (2001) 28, 1087-1089.