The established dogma in radiation sciences that underlies radiation
protection and therapeutic applications is that radiation effects
require induction of DNA damage only in cells that are directly hit by
the radiation. However, extensive work during the last decade
demonstrates that DNA damage responses can be detected in cells that are
only bystanders. Such effects include cell killing and responses
associated with DNA and chromosome damage. Here, we developed a strategy
for investigating bystander effects on chromosomal integrity by
premature chromosome condensation using hybrid cell formation between
nontargeted human lymphocytes and targeted CHO cells or vice versa. We
reasoned that signaling molecules generated in the targeted component of
the hybrid will transfer to the nontargeted cell, inducing damage
detectable at the chromosomal level. The results indicate that bystander
cytogenetic effects between CHO and human lymphocytes cannot be detected
under the experimental conditions used. This may be due either to the
lack of communication of such responses between the components of the
hybrid or to their abrogation by the experimental manipulations. These
observations and the methodology developed should be useful in the
further development of protocols for investigating bystander responses
and for elucidating the underlying mechanisms. (C) 2010 by Radiation
Research Societ
