Susanne Bohnenberger

Publications (6)17.1 Total impact

• Article: Photo catalogue for the classification of foci in the BALB/c 3T3 cell transformation assay.

  Kiyoshi Sasaki, Susanne Bohnenberger, Kumiko Hayashi, Thorsten Kunkelmann, Dai Muramatsu, Albrecht Poth, Ayako Sakai, Susan Salovaara, Noriho Tanaka, B Claire Thomas, Makoto Umeda
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  ABSTRACT: This catalogue is a display of focus photos representative of the BALB/c 3T3 cell transformation assay (CTA). It is intended as a visual aid for the identification and the scoring of foci in the conduct of the assay. A proper training from experienced personnel together with the protocol reported in this issue and the present photo catalogue will support method transfer and consistency in the assay results.
  Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 02/2012; 744(1):42-53. · 2.85 Impact Factor
• Article: Photo catalogue for the classification of cell colonies in the Syrian hamster embryo (SHE) cell transformation assay at pH 6.7.

  Susanne Bohnenberger, Shannon Wilson Bruce, Thorsten Kunkelmann, Kamala Pant, Sabine Perschbacher, Karl-Rainer Schwind, Jamie Sly, Albrecht Poth
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  ABSTRACT: This catalogue is a display of Syrian hamster embryo (SHE) cell colony photos representative of the cell transformation assay (CTA) carried out at pH 6.7. It is intended as a visual aid for the identification and the scoring of cell colonies in the conduct of the assay. A proper training from experienced personnel together with the protocol reported in this issue and the present photo catalogue will support method transfer and consistency in the assay results.
  Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 12/2011; 744(1):82-96. · 2.85 Impact Factor
• Article: Recommended protocol for the BALB/c 3T3 cell transformation assay.

  Kiyoshi Sasaki, Susanne Bohnenberger, Kumiko Hayashi, Thorsten Kunkelmann, Dai Muramatsu, Pascal Phrakonkham, Albrecht Poth, Ayako Sakai, Susan Salovaara, Noriho Tanaka, B Claire Thomas, Makoto Umeda
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  ABSTRACT: The present protocol has been developed for the BALB/c 3T3 cell transformation assay (CTA), following the prevalidation study coordinated by the European Centre for the Validation of Alternative Methods (ECVAM) and reported in this issue (Tanaka et al. [16]). Based upon the experience gained from this effort and as suggested by the Validation Management Team (VMT), some acceptance and assessment criteria have been refined compared to those used during the prevalidation study. The present protocol thus describes cell culture maintenance, the dose-range finding (DRF) experiment and the transformation assay, including cytotoxicity and morphological transformation evaluation. Use of this protocol and of the associated photo catalogue included in this issue (Sasaki et al. [17]) is recommended for the future conduct of the BALB/c 3T3 CTA.
  Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 12/2011; 744(1):30-5. · 2.85 Impact Factor
• Article: Recommended protocol for the Syrian hamster embryo (SHE) cell transformation assay.

  Marie-Aline Maire, Kamala Pant, Pascal Phrakonkham, Albrecht Poth, Karl-Rainer Schwind, Claudine Rast, Shannon Wilson Bruce, Jamie E Sly, Susanne Bohnenberger, Thorsten Kunkelmann, Markus Schulz, Paule Vasseur
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  ABSTRACT: The Syrian hamster embryo (SHE) cell transformation assay (CTA) is a short-term in vitro assay recommended as an alternative method for testing the carcinogenic potential of chemicals. SHE cells are "normal" cells since they are diploid, genetically stable, non-tumourigenic, and have metabolic capabilities for the activation of some classes of carcinogens. The CTA, first developed in the 1960s by Berwald and Sachs (1963,1964) [3,4], is based on the change of the phenotypic feature of cell colonies expressing the first steps of the conversion of normal to neoplastic-like cells with oncogenic properties. Pienta et al. (1977) [22] developed a protocol using cryopreserved cells to enhance practicality of the assay and limit sources of variability. Several variants of the assay are currently in use, which mainly differ by the pH at which the assay is performed. We present here the common version of the SHE pH 6.7 CTA and SHE pH 7.0 CTA protocols used in the ECVAM (European Centre for the Validation of Alternative Methods) prevalidation study on CTA reported in this issue. It is recommended that this protocol, in combination with the photo catalogues presented in this issue, should be used in the future and serve as a basis for the development of the OECD test guideline.
  Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 12/2011; 744(1):76-81. · 2.85 Impact Factor
• Article: Prevalidation study of the BALB/c 3T3 cell transformation assay for assessment of carcinogenic potential of chemicals.

  Noriho Tanaka, Susanne Bohnenberger, Thorsten Kunkelmann, Barbara Munaro, Jessica Ponti, Albrecht Poth, Enrico Sabbioni, Ayako Sakai, Susan Salovaara, Kiyoshi Sasaki, B Claire Thomas, Makoto Umeda
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  ABSTRACT: The cell transformation assays (CTAs) have attracted attention within the field of alternative methods due to their potential to reduce the number of animal experiments in the field of carcinogenicity. The CTA using BALB/c 3T3 cells has proved to be able to respond to chemical carcinogens by inducing morphologically transformed foci. Although a considerable amount of data on the performance of the assay has been collected, a formal evaluation focusing particularly on reproducibility, and a standardised protocol were considered important. Therefore the European Centre for the Validation of Alternative Methods (ECVAM) decided to coordinate a prevalidation study of the BALB/c 3T3 CTA. Three different laboratories from Japan and Europe participated. In the study the following modules were assessed stepwise: test definition (Module 1) consisted of the standardisation of the protocol, the selection of the cell lineage, and the preparation of a photo catalogue on the transformed foci. The within-laboratory reproducibility (Module 2) and the transferability (Module 3) were assessed using non-coded and coded 3-methylcholanthrene. Then, five coded chemicals were tested for the assessment of between-laboratory reproducibility (Module 4). All three laboratories obtained positive results with benzo[a]pyrene, phenanthrene and o-toluidine HCl. 2-Acetylaminofluorene was positive in two laboratories and equivocal in one laboratory. Anthracene was negative in all three laboratories. The chemicals except phenanthrene, which is classified by IARC (http://monographs.iarc.fr) as group 3 "not classifiable as to its carcinogenicity to human", were correctly predicted as carcinogens. Further studies on phenanthrene will clarify this discrepancy. Thus, although only a few chemicals were tested, it can be seen that the predictive capacity of the BALB/c 3T3 CTA is satisfactory. On the basis of the outcome of this study, an improved protocol, incorporating some changes related to data interpretation, has been developed. It is recommended that this protocol be used in the future to provide more data that may confirm the robustness of this protocol and the performance of the assay itself. During the study it became clear that selecting the most appropriate concentrations for the transformation assay is crucial.
  Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 12/2011; 744(1):20-9. · 2.85 Impact Factor
• Article: An international validation study of a Bhas 42 cell transformation assay for the prediction of chemical carcinogenicity.

  Ayako Sakai, Kiyoshi Sasaki, Kumiko Hayashi, Dai Muramatsu, Shoko Arai, Nobuko Endou, Sachiko Kuroda, Albrecht Poth, Susanne Bohnenberger, Thorsten Kunkelmann, [......], Nana Ishii, Fukutaro Mizuhashi, Sawako Kasamoto, Miho Nagai, Kamala Pant, Shannon W Bruce, Jamie E Sly, Shojiro Yamazaki, Makoto Umeda, Noriho Tanaka
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  ABSTRACT: The Bhas 42 cell transformation assay is a sensitive short-term system for predicting chemical carcinogenicity. Bhas 42 cells were established from BALB/c 3T3 cells by the transfection of v-Ha-ras gene and postulated to have acquired an initiated state in the two-stage carcinogenesis theory. The Bhas 42 cell transformation assay is capable of detecting both tumor-initiating and tumor-promoting activities of chemical carcinogens. The full assay protocol consists of two components, the initiation assay and the promotion assay, to detect the initiating activity and the promoting activity, respectively. An international study was carried out to validate this cell transformation assay in which six laboratories from three countries participated. Twelve coded chemicals were examined in total and each chemical was tested by three laboratories. In the initiation assay, concordant results were obtained by three laboratories for eight out of ten chemicals and in the promotion assay, concordant results were achieved for ten of twelve chemicals. The positive results were obtained in all three laboratories with the following chemicals: 2-acetylaminofluorene was positive in both initiation and promotion assays; dibenz[a,h]anthracene was positive in the initiation assay; sodium arsenite, lithocholic acid, cadmium chloride, mezerein and methapyrilene hydrochloride were positive in the promotion assay. o-Toluidin hydrochloride was positive in the both assays in two of the three laboratories. d-Mannitol, caffeine and l-ascorbic acid were negative in both assays in all the laboratories, and anthracene was negative in both assays in two of the three laboratories except one laboratory obtaining positive result in the promotion assay. Consequently, the Bhas 42 cell transformation assay correctly discriminated all six carcinogens and two tumor promoters from four non-carcinogens. Thus, the present study demonstrated that the Bhas 42 cell transformation assay is transferable and reproducible between laboratories and applicable to the prediction of chemical carcinogenicity. In addition, by comparison of the present results with intra-laboratory data previously published, within-laboratory reproducibility using the Bhas 42 cell transformation assay was also confirmed.
  Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 07/2011; 725(1-2):57-77. · 2.85 Impact Factor