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. 2010 Sep 12;1(1):13.
doi: 10.1186/2041-9414-1-13.

Emerging role of radiation induced bystander effects: Cell communications and carcinogenesis

Rajamanickam Baskar  1
Affiliations

Emerging role of radiation induced bystander effects: Cell communications and carcinogenesis

Rajamanickam Baskar. Genome Integr. .

Abstract

Ionizing radiation is an invaluable diagnostic and treatment tool used in various clinical applications. On the other hand, radiation is a known cytotoxic with a potential DNA damaging and carcinogenic effects. However, the biological effects of low and high linear energy transfer (LET) radiations are considerably more complex than previously thought. In the past decade, evidence has mounted for a novel biological phenomenon termed as "bystander effect" (BE), wherein directly irradiated cells transmit damaging signals to non-irradiated cells thereby inducing a response similar to that of irradiated cells. BE can also be induced in various cells irrespective of the type of radiation, and the BE may be more damaging in the longer term than direct radiation exposure. BE is mediated either through gap-junctions or via soluble factors released by irradiated cells. DNA damage response mechanisms represent a vital line of defense against exogenous and endogenous damage caused by radiation and promote two distinct outcomes: survival and the maintenance of genomic stability. The latter is critical for cancer avoidance. Therefore, efforts to understand and modulate the bystander responses will provide new approaches to cancer therapy and prevention. This review overviews the emerging role of BE of low and high LET radiations on the genomic instability of bystander cells and its possible implications for carcinogenesis.

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Figures

Figure 1
Figure 1
Schematic representation of signals in the form of soluble factors released from irradiated cells to distanced non-irradiated (bystander) cells. Damage caused in bystander cells in the form of mutation may lead to cancer formation.
Figure 2
Figure 2
Schematic representation of signals released from the irradiated cells passes through gap junctions to nearby (adjacent) cells and soluble factors (proteins and hormones) to distanced cells/organs.
Figure 3
Figure 3
Schematic representation of procedures followed for medium transfer treatment techniques from irradiated to the non-irradiated (bystander) cells.
See this image and copyright information in PMC

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