Annette Kopp-Schneider

Histone deacetylase 8 in neuroblastoma tumorigenesis

Purpose: The effects of pan–histone deacetylase (HDAC) inhibitors on cancer cells have shown that HDACs are involved in fundamental tumor biological processes such as cell cycle control, differentiation, and apoptosis. However, because of the unselective nature of these compounds, little is known about the contribution of individual HDAC family members to tumorigenesis and progression. The purpose of this study was to evaluate the role of individual HDACs in neuroblastoma tumorigenesis. Experimental Design: We have investigated the mRNA expression of all HDAC1-11 family members in a large cohort of primary neuroblastoma samples covering the full spectrum of the disease. HDACs associated with disease stage and survival were subsequently functionally evaluated in cell culture models. Results: Only HDAC8 expression was significantly correlated with advanced disease and metastasis and down-regulated in stage 4S neuroblastoma associated with spontaneous regression. High HDAC8 expression was associated with poor prognostic markers and poor overall and event-free survival. The knockdown of HDAC8 resulted in the inhibition of proliferation, reduced clonogenic growth, cell cycle arrest, and differentiation in cultured neuroblastoma cells. The treatment of neuroblastoma cell lines as well as short-term-culture neuroblastoma cells with an HDAC8-selective small-molecule inhibitor inhibited cell proliferation and clone formation, induced differentiation, and thus reproduced the HDAC8 knockdown phenotype. Global histone 4 acetylation was not affected by HDAC8 knockdown or by selective inhibitor treatment. Conclusions: Our data point toward an important role of HDAC8 in neuroblastoma pathogenesis and identify this HDAC family member as a specific drug target for the differentiation therapy of neuroblastoma.

“ToxRTool”, a new tool to assess the reliability of toxicological data

Evaluation of the reliability of toxicological data is of key importance for regulatory decision-making. In particular, the new EU Regulations concerning the registration, evaluation, authorisation and restriction of chemicals (REACH) and classification, labelling and packaging (CLP) according to the new globally harmonised system (GHS) rely on the integration of all available toxicological information. The so-called Klimisch categories, although well established and widely used, lack detailed criteria for assigning data quality to categories. A software-based tool (ToxRTool) was developed within the context of a project funded by the European Commission to provide comprehensive criteria and guidance for reliability evaluations of toxicological data. It is applicable to various types of experimental data, endpoints and studies (study reports, peer-reviewed publications) and leads to the assignment to Klimisch categories 1, 2 or 3. The tool aims to increase transparency and to harmonise approaches of reliability assessment. The tool consists of two parts, one to evaluate in vivo and one to evaluate in vitro data. The prototypes of the tool were tested in two independent inter-rater experiments. This approach allowed the analysis of the performance of the tool in practice and the identification and minimisation of sources of heterogeneity in evaluation results. The final version, ToxRTool, is publicly available for testing and use.

HDAC5 and HDAC9 in Medulloblastoma: Novel Markers for Risk Stratification and Role in Tumor Cell Growth

Purpose: Medulloblastomas are the most common malignant brain tumors in childhood. Survivors suffer from high morbidity because of therapy-related side effects. Thus, therapies targeting tumors in a specific manner with small molecules such as histone deacetylase (HDAC) inhibitors are urgently warranted. This study investigated the expression levels of individual human HDAC family members in primary medulloblastoma samples, their potential as risk stratification markers, and their roles in tumor cell growth. Experimental Design: Gene expression arrays were used to screen for HDAC1 through HDAC11. Using quantitative real time reverse transcriptase-PCR and immunohistochemistry, we studied the expression of HDAC5 and HDAC9 in primary medulloblastoma samples. In addition, we conducted functional studies using siRNA-mediated knockdown of HDAC5 and HDAC9 in medulloblastoma cells. Results: HDAC5 and HDAC9 showed the highest expression in prognostically poor subgroups. This finding was validated in an independent set of medulloblastoma samples. High HDAC5 and HDAC9 expression was significantly associated with poor overall survival, with high HDAC5 and HDAC9 expression posing an independent risk factor. Immunohistochemistry revealed a strong expression of HDAC5 and HDAC9 proteins in most of all primary medulloblastomas investigated. siRNA-mediated knockdown of HDAC5 or HDAC9 in medulloblastoma cells resulted in decreased cell growth and cell viability. Conclusion: HDAC5 and HDAC9 are significantly upregulated in high-risk medulloblastoma in comparison with low-risk medulloblastoma, and their expression is associated with poor survival. Thus, HDAC5 and HDAC9 may be valuable markers for risk stratification. Because our functional studies point toward a role in medulloblastoma cell growth, HDAC5 and HDAC9 may potentially be novel drug targets. Clin Cancer Res; 16(12); 3240–52. ©2010 AACR.

Assessment of morphological MRI for pulmonary changes in cystic fibrosis (CF) patients: Comparison to thin-section CT and chest x-ray

Objectives:As pulmonary complications are life limiting in patients with cystic fibrosis (CF), repeated chest imaging [chest x-ray, computed tomography (CT)] is needed for follow up. With the continuously rising life expectancy of CF patients, magnetic resonance imaging (MRI) as a radiation-free imaging modality might become more and more attractive. The goal of this study was to prospectively assess the value of MRI for evaluation of morphologic pulmonary CF-changes in comparison to established imaging modalities. Materials and Methods:Thirty-one CF patients (19 female, 12 male; mean age 16.7 years) with stable lung disease were examined by MRI: HASTE, coronal/transversal (TR/TE/α/TA: infinite/28 ms/180°/18 s), multi-detector computed tomography (MDCT) (30 patients): 120 kV, dose modulated mAs, and chest x-ray (21 patients). Image evaluation: random order, 4 chest radiologists in consensus; chest x-ray: modified Chrispin-Norman score; CT and MRI: modified Helbich score. The maximal attainable score for chest x-ray was 34, for MRI and CT 25. Median scores, Pearson correlation coefficients, Bland-Altman plots, and concordance of MRI to CT on a lobar and segmental basis were calculated. Results:The median MRI and MDCT scores were 13 (min 3, max 20) respectively 13.5 (min 0, max 20). The median chest x-ray score was 14 (min 5, max 32). Pearson correlation coefficients: MRI/CT = 0.80, P < 0.0001; MRI/chest x-ray = 0.63, P < 0.0018; chest x-ray/CT = 0.75, P < 0.0001. The median lobe related concordance was 80% for bronchiectasis, 77% for mucus plugging, 93%, for sacculation/abscesses, and 100% for collapse/consolidation. Conclusions:Morphologic MRI of the lung in CF patients demonstrates comparable results to MDCT and chest x-ray. Because radiation exposure is an issue in CF patients, MRI might have the ability to be used as an appropriate alternative method for pulmonary imaging.

Magnetic Resonance Imaging Detects Changes in Structure and Perfusion, and Response to Therapy in Early Cystic Fibrosis Lung Disease

RATIONALE Studies demonstrating early structural lung damage in infants and preschool children with cystic fibrosis (CF) suggest that noninvasive monitoring will be important to identify patients who may benefit from early therapeutic intervention. Previous studies demonstrated that magnetic resonance imaging (MRI) detects structural and functional abnormalities in lungs from older patients with CF without radiation exposure. OBJECTIVES To evaluate the potential of MRI to detect abnormal lung structure and perfusion in infants and preschool children with CF, and to monitor the response to therapy for pulmonary exacerbation. METHODS MRI studies were performed in 50 children with CF (age, 3.1 ± 2.1 yr; range, 0-6 yr) in stable clinical condition (n = 40) or pulmonary exacerbation before and after antibiotic treatment (n = 10), and in 26 non-CF control subjects (age, 2.9 ± 1.9 yr). T1- and T2-weighted sequences before and after intravenous contrast and first-pass perfusion imaging were acquired, and assessed on the basis of a dedicated morphofunctional score. MEASUREMENTS AND MAIN RESULTS MRI demonstrated bronchial wall thickening/bronchiectasis, mucus plugging, and perfusion deficits from the first year of life in most stable patients with CF (global score, 10.0 ± 4.0), but not in non-CF control subjects (score, 0.0 ± 0.0; P < 0.001). In patients with exacerbations, the global MRI score was increased to 18.0 ± 2.0 (P < 0.001), and was significantly reduced to 12.0 ± 3.0 (P < 0.05) after antibiotic therapy. CONCLUSIONS MRI detected abnormalities in lung structure and perfusion, and response to therapy for exacerbations in infants and preschool children with CF. These results support the development of MRI for noninvasive monitoring and as an end point in interventional trials for early CF lung disease. Clinical trial registered with www.clinicaltrials.gov (NCT00760071).

E6 and E7 from Beta Hpv38 Cooperate with Ultraviolet Light in the Development of Actinic Keratosis-Like Lesions and Squamous Cell Carcinoma in Mice

Cutaneous beta human papillomavirus (HPV) types appear to be involved in the development of non-melanoma skin cancer (NMSC); however, it is not entirely clear whether they play a direct role. We have previously shown that E6 and E7 oncoproteins from the beta HPV type 38 display transforming activities in several experimental models. To evaluate the possible contribution of HPV38 in a proliferative tissue compartment during carcinogenesis, we generated a new transgenic mouse model (Tg) where HPV38 E6 and E7 are expressed in the undifferentiated basal layer of epithelia under the control of the Keratin 14 (K14) promoter. Viral oncogene expression led to increased cellular proliferation in the epidermis of the Tg animals in comparison to the wild-type littermates. Although no spontaneous formation of tumours was observed during the lifespan of the K14 HPV38 E6/E7-Tg mice, they were highly susceptible to 7,12-dimethylbenz(a)anthracene (DMBA)/12-0-tetradecanoylphorbol-13-acetate (TPA) two-stage chemical carcinogenesis. In addition, when animals were exposed to ultraviolet light (UV) irradiation, we observed that accumulation of p21WAF1 and cell-cycle arrest were significantly alleviated in the skin of Tg mice as compared to wild-type controls. Most importantly, chronic UV irradiation of Tg mice induced the development of actinic keratosis-like lesions, which are considered in humans as precursors of squamous cell carcinomas (SCC), and subsequently of SCC in a significant proportion of the animals. In contrast, wild-type animals subjected to identical treatments did not develop any type of skin lesions. Thus, the oncoproteins E6 and E7 from beta HPV38 significantly contribute to SCC development in the skin rendering keratinocytes more susceptible to UV-induced carcinogenesis.

Morphologic and functional scoring of cystic fibrosis lung disease using MRI

Magnetic resonance imaging (MRI) gains increasing importance in the assessment of cystic fibrosis (CF) lung disease. The aim of this study was to develop a morpho-functional MR-scoring-system and to evaluate its intra- and inter-observer reproducibility and clinical practicability to monitor CF lung disease over a broad severity range from infancy to adulthood. 35 CF patients with broad age range (mean 15.3 years; range 0.5-42) were examined by morphological and functional MRI. Lobe based analysis was performed for parameters bronchiectasis/bronchial-wall-thickening, mucus plugging, abscesses/sacculations, consolidations, special findings and perfusion defects. The maximum global score was 72. Two experienced radiologists scored the images at two time points (interval 10 weeks). Upper and lower limits of agreement, concordance correlation coefficients (CCC), total deviation index and coverage probability were calculated for global, morphology, function, component and lobar scores. Global scores ranged from 6 to 47. Intra- and inter-reader agreement for global scores were good (CCC: 0.98 (R1), 0.94 (R2), 0.97 (R1/R2)) and were comparable between high and low scores. Our results indicate that the proposed morpho-functional MR-scoring-system is reproducible and applicable for semi-quantitative evaluation of a large spectrum of CF lung disease severity. This scoring-system can be applied for the routine assessment of CF lung disease and maybe as endpoint for clinical trials.

Optimization and prevalidation of the in vitro ERα CALUX method to test estrogenic and antiestrogenic activity of compounds

Estrogenicity of chemicals has received significant attention and is linked to endocrine-disrupting activities. However, there is a paucity of validated methods to assess estrogenicity in vitro. We have established a robust method to test estrogenic and antiestrogenic activity of compounds in vitro, as an alternative to using animal models such as the uterotrophic assay. To this end we optimized protocols to be used in combination with CALUX reporter gene assays and carried out an in house prevalidation, followed by two rounds of tests to establish transferability. Problems in the initial test with transferability were solved by isolation of a novel cell clone of the ERalpha CALUX line with greatly improved stability and luciferase levels. This cell line proved to be a very suitable and reliable predictor of estrogenicity of chemicals and was able to readily rank a range of chemicals on the basis of their EC50 values.

4D-CT-based target volume definition in stereotactic radiotherapy of lung tumours: Comparison with a conventional technique using individual margins

PURPOSE To investigate the dosimetric benefit of integration of 4D-CT in the planning target volume (PTV) definition process compared to conventional PTV definition using individual margins in stereotactic body radiotherapy (SBRT) of lung tumours. MATERIAL AND METHODS Two different PTVs were defined: PTV(conv) consisting of the helical-CT-based clinical target volume (CTV) enlarged isotropically for each spatial direction by the individually measured amount of motion in the 4D-CT, and PTV(4D) encompassing the CTVs defined in the 4D-CT phases displaying the extremes of the tumour position. Tumour motion as well as volumetric and dosimetric differences and relations of both PTVs were evaluated. RESULTS Volumetric examinations revealed a significant reduction of the mean PTV by 4D-CT from 57.7 to 40.7 cm(3) (31%) (p<0.001). A significant inverse correlation was found for the motion vector and the amount of inclusion of PTV(4D) in PTV(conv) (r=-0.69, 90% confidence limits: -0.87 and -0.34, p=0.007). Mean lung dose (MLD) was decreased significantly by 17% (p<0.001). CONCLUSIONS In SBRT of lung tumours the mere use of individual margins for target volume definition cannot compensate for the additional effects that the implementation of 4D-CT phases can offer.

Semi-automated volumetric analysis of lymph node metastases in patients with malignant melanoma stage III/IV-A feasibility study

Therapy monitoring in oncological patient care requires accurate and reliable imaging and post-processing methods. RECIST criteria are the current standard, with inherent disadvantages. The aim of this study was to investigate the feasibility of semi-automated volumetric analysis of lymph node metastases in patients with malignant melanoma compared to manual volumetric analysis and RECIST. Multislice CT was performed in 47 patients, covering the chest, abdomen and pelvis. In total, 227 suspicious, enlarged lymph nodes were evaluated retrospectively by two radiologists regarding diameters (RECIST), manually measured volume by placement of ROIs and semi-automated volumetric analysis. Volume (ml), quality of segmentation (++/−−) and time effort (s) were evaluated in the study. The semi-automated volumetric analysis software tool was rated acceptable to excellent in 81% of all cases (reader 1) and 79% (reader 2). Median time for the entire segmentation process and necessary corrections was shorter with the semi-automated software than by manual segmentation. Bland-Altman plots showed a significantly lower interobserver variability for semi-automated volumetric than for RECIST measurements. The study demonstrated feasibility of volumetric analysis of lymph node metastases. The software allows a fast and robust segmentation in up to 80% of all cases. Ease of use and time needed are acceptable for application in the clinical routine. Variability and interuser bias were reduced to about one third of the values found for RECIST measurements.