Ionizing radiation affects protein composition of exosomes secreted in vitro from head and neck squamous cell carcinoma.

Karol Jelonek; Anna Wojakowska; Lukasz Marczak; Annika Muer; Ingeborg Tinhofer-Keilholz; Malgorzata Lysek-Gladysinska; Piotr Widlak; Monika Pietrowska

Karol Jelonek Center for Translational Research and Molecular Biology of Cancer, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland.;
Anna Wojakowska Center for Translational Research and Molecular Biology of Cancer, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland.;
Lukasz Marczak European Centre for Bioinformatics and Genomics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland.;
Annika Muer Department of Radiooncology and Radiotherapy, Charite University Hospital, Berlin, Germany.;
Ingeborg Tinhofer-Keilholz Department of Radiooncology and Radiotherapy, Charite University Hospital, Berlin, Germany.;
Malgorzata Lysek-Gladysinska Department of Cell Biology and Electron Microscopy, The Jan Kochanowski University in Kielce, Kielce, Poland.;
Piotr Widlak Center for Translational Research and Molecular Biology of Cancer, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland.;
Monika Pietrowska Center for Translational Research and Molecular Biology of Cancer, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland.;

Abstract

Exosomes are membrane vesicles of endocytic origin that participate in inter-cellular communication. Environmental and physiological conditions affect composition of secreted exosomes, their abundance and potential influence on recipient cells. Here, we analyzed protein component of exosomes released in vitro from cells exposed to ionizing radiation (2Gy dose) and compared their content with composition of exosomes released from control not irradiated cells. Exosomes secreted from FaDu cells originating from human squamous head and neck cell carcinoma were analyzed using LC-MS/MS approach. We have found that exposure to ionizing radiation resulted in gross changes in exosomal cargo. There were 217 proteins identified in exosomes from control cells and 384 proteins identified in exosomes from irradiated cells, including 148 "common" proteins, 236 proteins detected specifically after irradiation and 69 proteins not detected after irradiation. Among proteins specifically overrepresented in exosomes from irradiated cells were those involved in transcription, translation, protein turnover, cell division and cell signaling. This indicated that exosomal cargo reflected radiation-induced changes in cellular processes like transient suppression of transcription and translation or stress-induced signaling.