Calcium, oxidative stress and connexin channels, a harmonious orchestra directing the response to radiotherapy treatment?

Elke Decrock, Delphine Hoorelbeke, Raghda Ramadan, Tinneke Delvaeye, Marijke De Bock, Nan Wang, Dmitry V Krysko, Sarah Baatout, Geert Bultynck, An Aerts, Mathieu Vinken, Luc Leybaert

    Research outputpeer-review


    Although radiotherapy is commonly used to treat cancer, its beneficial outcome is frequently hampered by the radiation resistance of tumor cells and adverse reactions in normal tissues. Mechanisms of cell-to-cell communication and how intercellular signals are translated into cellular responses, have become topics of intense investigation, particularly within the field of radiobiology. A substantial amount of evidence is available demonstrating that both gap junctional and paracrine communication pathways can propagate radiation-induced biological effects at the intercellular level, commonly referred to as radiation-induced bystander effects (RIBE). Multiple molecular signaling mechanisms involving oxidative stress, kinases, inflammatory molecules, and Ca2+ are postulated to contribute to RIBE. Ca2+ is a highly versatile and ubiquitous second messenger that regulates diverse cellular processes via the interaction with various signaling cascades. It furthermore provides a fast system for the dissemination of information at the intercellular level. Channels formed by transmembrane connexin (Cx) proteins, i.e. hemichannels and gap junction channels, can mediate the cell-to-cell propagation of increases in intracellular Ca2+ by ministering paracrine and direct cell-cell communication, respectively. We here review current knowledge on radiation-induced signaling mechanisms in irradiated and bystander cells, particularly focusing on the contribution of oxidative stress, Ca2+ and Cx channels. By illustrating the tight interplay between these different partners, we provide a conceptual framework for intercellular Ca2+ signaling as a key player in modulating the RIBE and the overall response to radiation. Copyright � 2017 Elsevier B.V. All rights reserved.
    Original languageEnglish
    Pages (from-to)1099-1120
    Number of pages21
    JournalBiochimica et Biophysica Acta
    Issue number6
    StatePublished - 1 Jun 2017

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