European Journal of Nuclear Medicine and Molecular Imaging

, Volume 32, Issue 3, pp 274–285

Cell death triggered by alpha-emitting 213Bi-immunoconjugates in HSC45-M2 gastric cancer cells is different from apoptotic cell death

Authors

    • Department of Nuclear MedicineTechnische Universität München
  • Hedwig Schröck
    • Department of Nuclear MedicineTechnische Universität München
  • Sabine Seidenschwang
    • Department of Nuclear MedicineTechnische Universität München
  • Roswitha Beck
    • Department of Nuclear MedicineTechnische Universität München
  • Ernst Schmid
    • Institute of Radiation Biology, GSFNational Research Center for Environment and Health
  • Michael Abend
    • Institute of RadiobiologyGerman Armed Forces
  • Karl-Friedrich Becker
    • Institute of PathologyTechnische Universität München
    • Institute of Pathology, GSFNational Research Center for Environment and Health
    • Institute of Molecular Immunology, GSFNational Research Center for Environment and Health
  • Christos Apostolidis
    • Institute for Transuranium ElementsEuropean Commission
  • Tuomo K. Nikula
    • Institute for Transuranium ElementsEuropean Commission
  • Elisabeth Kremmer
    • Institute of Molecular Immunology, GSFNational Research Center for Environment and Health
  • Markus Schwaiger
    • Department of Nuclear MedicineTechnische Universität München
  • Reingard Senekowitsch-Schmidtke
    • Department of Nuclear MedicineTechnische Universität München
Original Article

DOI: 10.1007/s00259-004-1653-3

Cite this article as:
Seidl, C., Schröck, H., Seidenschwang, S. et al. Eur J Nucl Med Mol Imaging (2005) 32: 274. doi:10.1007/s00259-004-1653-3

Abstract

Purpose

Radioimmunotherapy with α-particle-emitting nuclides, such as 213Bi, is a promising concept for the elimination of small tumour nodules or single disseminated tumour cells. The aim of this study was to investigate cellular damage and the mode of cell death triggered by 213Bi-immunoconjugates.

Methods

Human gastric cancer cells (HSC45-M2) expressing d9-E-cadherin were incubated with different levels of activity of 213Bi-d9MAb targeting d9-E-cadherin and 213Bi-d8MAb, which does not bind to d9-E-cadherin. Micronucleated (M) cells, abnormal (A) cells and apoptotic (A) [(MAA)] cells were scored microscopically in the MAA assay following fluorescent staining of nuclei and cytoplasm. Chromosomal aberrations were analysed microscopically following Giemsa staining. The effect of z-VAD-fmk, known to inhibit apoptosis, on the prevention of cell death was investigated following treatment of HSC45-M2 cells with sorbitol as well as 213Bi-d9MAb. Activation of caspase 3 after incubation of HSC45-M2 cells with both sorbitol and 213Bi-d9MAb was analysed via Western blotting.

Results

Following incubation of HSC45-M2 human gastric cancer cells expressing d9-E-cadherin with 213Bi-d9MAb the number of cells killed increased proportional to the applied activity concentration. Microscopically visible effects of α-irradiation of HSC45-M2 cells were formation of micronuclei and severe chromosomal aberrations. Preferential induction of these lesions with specific 213Bi-d9MAb compared with unspecific 213Bi-d8MAb (not targeting d9-E-cadherin) was not observed if the number of floating, i.e. unbound 213Bi-immunoconjugates per cell exceeded 2×104, most likely due to intense crossfire. In contrast to sorbitol-induced cell death, cell death triggered by 213Bi-immunoconjugates was independent of caspase 3 activation and could not be inhibited by z-VAD-fmk, known to suppress the apoptotic pathway.

Conclusion

213Bi-immunoconjugates seem to induce a mode of cell death different from apoptosis in HSC45-M2 cells.

Keywords

Alpha-emitter 213BiTumour-specific antibodyMAA assayChromosomal aberrationsCaspase 3 activation

Copyright information

© Springer-Verlag 2004