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Gradient Irradiation Enhances Cell Killing Efficiency via Bystander Effects in MCF‐7 cells
Author(s) -
Zuo Li,
Zhou Tingyang
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.809.5
Subject(s) - bystander effect , apoptosis , mcf 7 , irradiation , viability assay , programmed cell death , andrology , cell , cell survival , cancer research , biology , chemistry , cancer , cancer cell , medicine , immunology , biochemistry , human breast , physics , nuclear physics
In recent years, a large body of evidence has shown that irradiated cells can produce signaling factors to reduce the survival of neighboring less‐ or non‐irradiated cells, termed as bystander effects. Bystander effects may play an important role in non‐uniform irradiation through the enhancement of cell killing efficacy at the under‐dosed regions. In this study, we tested the hypothesis that a gradient dose design may achieve better tumor suppression compared to uniform‐dose distribution in breast cancer cells (MCF‐7). Cells were divided into three groups receiving 8‐2 Gy (gradient irradiation, GI), 5 Gy (uniform irradiation, UI) or 0 Gy (control), respectively, followed by viability and apoptosis assays at 2, 24, and 48h after irradiation. Data were analyzed using one‐way ANOVA in SPSS. P < 0.05 was considered statistically different. Our results show that both GI and UI caused significant reduction of cell survival and increased apoptosis at 2, 24 and 48h as compared to control ( p < 0.05). Although at 2h the lower‐dose irradiated cells under GI showed higher viability and lower apoptosis than those of the cells receiving higher doses, the survival difference across the various regions of GI completely diminished at 24h and 48h. More cell death and apoptosis were observed in different areas of GI field as compared to those of the UI at 24 and 48h after irradiation ( p < 0.05). This study highlights a superior therapeutic effect of GI over UI due to the bystander signaling. Support or Funding Information American Physiological Society (APS) 2016 S&R Foundation Ryuji Ueno Award