Lack of evidence for low-LET radiation induced bystander response in normal human fibroblasts and colon carcinoma cells

Marianne B. Sowa, Wilfried Goetz, Janet E. Baulch, Dinah N. Pyles, Jaroslaw Dziegielewski, Susannah Yovino, Andrew R. Snyder, Sonia M. De Toledo, Edouard I. Azzam, William F. Morgan

Research output: Contribution to journalArticlepeer-review

60 Scopus citations

Abstract

Purpose: To investigate radiation-induced bystander responses and to determine the role of gap junction intercellular communication and the radiation environment in propagating this response. Materials and methods: We used medium transfer and targeted irradiation to examine radiation-induced bystander effects in primary human fibroblast (AG01522) and human colon carcinoma (RKO36) cells. We examined the effect of variables such as gap junction intercellular communication, linear energy transfer (LET), and the role of the radiation environment in non-targeted responses. Endpoints included clonogenic survival, micronucleus formation and foci formation at histone 2AX over doses ranging from 10-100 cGy. Results: The results showed no evidence of a low-LET radiation-induced bystander response for the endpoints of clonogenic survival and induction of DNA damage. Nor did we see evidence of a high-LET, Fe ion radiation (1 GeV/n) induced bystander effect. However, direct comparison for 3.2 MeV α-particle exposures showed a statistically significant medium transfer bystander effect for this high-LET radiation. Conclusions: From our results, it is evident that there are many confounding factors influencing bystander responses as reported in the literature. Our observations reflect the inherent variability in biological systems and the difficulties in extrapolating from invitro models to radiation risks in humans.

Original languageEnglish (US)
Pages (from-to)102-113
Number of pages12
JournalInternational Journal of Radiation Biology
Volume86
Issue number2
DOIs
StatePublished - Feb 2010

All Science Journal Classification (ASJC) codes

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging

Keywords

  • Bystander effects
  • Human cells
  • Ionising radiation
  • Low-LET

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