Mesenchymal stem cells are resistant to carbon ion radiotherapy

// Nils H. Nicolay 1,2,3 , Yingying Liang 2,3 , Ramon Lopez Perez 3 , Tilman Bostel 1,2 , Thuy Trinh 1 , Sonevisay Sisombath 3 , Klaus-Josef Weber 1,2 , Anthony D. Ho 4 , Jürgen Debus 1,2 , Rainer Saffrich 4 and Peter E. Huber 1,2,3 1 Department of Radiation Oncology, Heidelberg University Hospital, Im Neuenheimer Feld, Heidelberg, Germany 2 Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology, Im Neuenheimer Feld, Heidelberg, Germany 3 Department of Molecular and Radiation Oncology, German Cancer Research Center (dkfz), Im Neuenheimer Feld, Heidelberg, Germany 4 Department of Hematology and Oncology, Heidelberg University Hospital, Im Neuenheimer Feld, Heidelberg, Germany Correspondence: Nils H. Nicolay, email: // Keywords : Mesenchymal stem cells, photon irradiation, carbon ion irradiation, radioresistance Received : September 22, 2014 Accepted : December 02, 2014 Published : December 03, 2014 Abstract Mesenchymal stem cells (MSCs) participate in regeneration of tissues damaged by ionizing radiation. However, radiation can damage MSCs themselves. Here we show that cellular morphology, adhesion and migration abilities were not measurably altered by photon or carbon ion irradiation. The potential for differentiation was unaffected by either form of radiation, and established MSC surface markers were found to be stably expressed irrespective of radiation treatment. MSCs were able to efficiently repair DNA double strand breaks induced by both high-dose photon and carbon ion radiation. We have shown for the first time that MSCs are relatively resistant to therapeutic carbon ion radiotherapy. Additionally, this form of radiation did not markedly alter the defining stem cell properties or the expression of established surface markers in MSCs.