Project title: In vitro studies of radiation induced bystander effects

Generally, radiation induced bystander effect (RIBE) can be defined as the phenomenon that the irradiated cells (by α particles, X- or γ-ray, heavy ions etc.) can release some signaling molecule(s), which is transferred via the medium or gap-junctions, so that the same cytotoxicity or genotoxicity can be observed in the non-irradiated cells, which are either close to the irradiated cells or shared the conditioned medium harvested from the irradiated cells. RIBE has challenged the conventional dogma of radiation protection, the guidelines for which are based on prediction of biological effects of low doses of radiation by extrapolating from known epidemiological datasets. Our current projects in RIBE include studies on (1) up-regulation of reactive oxygen species (ROS) by mitochondria-dependent bystander signaling, (2) protection of bystander cells by exogenous carbon monoxide, (3) induction of nitric oxide mediated DNA double strand breaks in proliferating bystander cells, and (4) rescue effect.


Chen, S., Zhao, Y., Zhao, G., Han, W., Bao, L., Yu, K.N., Wu, L., 2009. Up-regulation of ROS by mitochondria-dependent bystander signaling contributes to genotoxicity of bystander effects, Mutation Research, 666, 68-73.


Han, W., Chen, S., Yu, K.N., Wu, L., 2010. Nitric Oxide Mediated DNA Double Strand Breaks Induced in Proliferating Bystander Cells after Alpha-Particle Irradiation. Mutation Research, 684, 81-89.

Han, W., Wu, L., Chen, S., Yu, K.N., 2010. Exogenous Carbon Monoxide Protects the Bystander Chinese Hamster Ovary Cells in Mixed Co-Culture System after Alpha-Particle Irradiation. Carcinogenesis, 31, 275-280.

Chen, S., Zhao, Y., Han, W., Chiu, S.K., Zhu, L., Wu, L., Yu, K.N., 2010. Rescue effects in radiobiology: unirradiated bystander cells assist irradiated cells through intercellular signal feedback. Mutation Research, 706, 59-64. 

Han, W., Yu, K.N., Wu, L.J., Wu, Y.C., Wang, H.Z., 2011. Mechanism of Protection of Bystander Cells by Exogenous Carbon Monoxide: Impaired Response to Damage Signal of Radiation-Induced Bystander Effect. Mutation Research, 709-710, 1-6.

Supervisor: Prof Peter K N Yu (

Suitable for: M.Phil. or Ph.D.

A good degree in radiation biophysics or biology