JUNE 2003

Radiation induces gene expression in tumors

By: Paula Gould

CONTEXT: In vitro and in vivo experiments examined whether radiation can induce gene expression in cancerous tumors.

RESULTS: Dr. Heiko Alfke, an associate professor of radiology at the University of Marburg in Germany, used a CCD digital camera and an external light source to image flank tumors in anesthetized mice. The mice were injected four weeks earlier with melanoma cells (MeWo) expressing wild type green fluorescent protein. Tumors expressing the protein could all be viewed using the in vivo optical technique.

For the in vitro analysis, Alfke transiently transfected pancreatic carcinoma cells (BxPC3) with a known radiation-inducible vector coded for luciferase and a green fluorescent protein. The cells were imaged with a highly sensitive, cooled CCD digital camera in a light box. Results were presented at the 2003 European Congress of Radiology.

IMAGE: In the in vitro experiment, light emission associated with luciferase gene expression rose by a factor of 1.5 to 2 in images acquired 48 hours after the cells were exposed to a 6-Gy dose of radiation. (Provided by H. Alfke)

IMPLICATIONS: The research is leading to clinical trials in which injected reporter genes will be combined with therapeutic genes to monitor and control tumor response to radiotherapy.