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57th Annual Meeting of the German Society for Neuropathology and Neuroanatomy (DGNN)

German Society for Neuropathology and Neuroanatomy

12. - 15.09.2012, Erlangen

57th Annual Meeting of the German Society for Neuropathology and Neuroanatomy (DGNN)

DNA damage and repair in glioblastoma cell lines after antitumor drugs

Meeting Abstract

  • presenting/speaker Laura Annovazzi - University of Pavia, Neuro-Bio-Oncology Center, Policlinico di Monza Foundation (Vercelli) and Consorzio di Neuroscienze, Pavia, Italy
  • V. Caldera - University of Pavia, Neuro-Bio-Oncology Center, Policlinico di Monza Foundation (Vercelli) and Consorzio di Neuroscienze, Pavia, Italy
  • M. Mellai - University of Pavia, Neuro-Bio-Oncology Center, Policlinico di Monza Foundation (Vercelli) and Consorzio di Neuroscienze, Pavia, Italy
  • A. Piazzi - University of Pavia, Neuro-Bio-Oncology Center, Policlinico di Monza Foundation (Vercelli) and Consorzio di Neuroscienze, Pavia, Italy
  • O. Monzeglio - University of Pavia, Neuro-Bio-Oncology Center, Policlinico di Monza Foundation (Vercelli) and Consorzio di Neuroscienze, Pavia, Italy
  • D. Schiffer - University of Pavia, Neuro-Bio-Oncology Center, Policlinico di Monza Foundation (Vercelli) and Consorzio di Neuroscienze, Pavia, Italy

Deutsche Gesellschaft für Neuropathologie und Neuroanatomie. 57th Annual Meeting of the German Society for Neuropathology and Neuroanatomy (DGNN). Erlangen, 12.-15.09.2012. Düsseldorf: German Medical Science GMS Publishing House; 2012. Doc12dgnnPP3.9

DOI: 10.3205/12dgnn053, URN: urn:nbn:de:0183-12dgnn0536

Published: September 11, 2012

© 2012 Annovazzi et al.
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Outline

Text

Glioblastoma cell resistance to chemotherapy is due mainly to the MDR efflux pump and to the impairment of DNA repair mechanisms such as MGMT and PARP1. Tumor stem cells are responsible for cell resistance. We studied in glioblastoma cell lines, neurospheres or adherent cells, the effects of two antiblastic drugs, Temozolomide (TMZ) and Doxorubicin (DOXO),i.e.an alkylating agent and an antibiotic.

Methods:Cultures were established by adding growth factors or bovine serum and cells were counted in controls and after adding to the culture TMZ and DOXO in different concentrations and with different times. The following antibodies were used both by immunofluorescence with FITC and TRITC and by immunohistochemistry: Ki67/MIB.1, P53, p-ATM, gH2AX, 53BP1, p-Chk2, Ku70/80, DNA-PK, RAD51. Comet assay, Western blotting and TUNEL kit.

Results:IC50 is reached by TMZ with doses of 50-100 mM. The dose is lower for adherent cells than for neurospheres and for MGMT hypermethylated neurospheres than for MGMT wild-type. The gene status of TP53 influences the IC50. Comet assay varies correspondingly. The DNA repair cascade is very sensitive to the DNA damage: sensors, such as p-ATM, gH2AX and 53BP1, are activated first and followed by effectors, such as p-Chk2, Ku70/80, DNA-PK, RAD51 and apoptosis. Lower doses and shorter times are required for DOXO.

Conclusions:Adherent cells are more sensitive than neurospheres and DOXO is more powerful than TMZ. The non homologous repair pathway is activated more and earlier than the homologous one. The high concentrations of TMZ and the long action time are to be taken into account for the treatment of glioblastoma.