ptdTomato-N1

To determine the effects of different radiation qualities on cell proliferation and biological depth dose distribution after heavy ion exposure, stable human cell lines expressing novel fluorescent proteins were established and characterized. Human embryonic kidney (HEK/293) cells were stably transfected with a plasmid encoding tdTomato under the control of a constitutively active cytomegalovirus (CMV) promoter (ptdTomato-N1). The stably transfected cell line was named HEK-ptdTomato-N1 8. The cytotoxicity biosensor was tested by exposure to ionizing radiation (X-rays and accelerated heavy ions). As biological endpoints, the researchers studied proliferation kinetics and cell density 100 hours after irradiation as reflected by constitutive expression of tdTomato. Both decreased in a dose-dependent manner after radiation exposure. Finally, this cell line was used to biologically weight heavy ions with different linear energy transfers (LETs) as spatially correlated radiative masses. The relative bioeffectiveness of accelerated heavy ions in reducing cell proliferation peaks at a LET of 91 keV/μm. The results of this study demonstrate that the HEK-ptdTomato-N1 reporter cell line can be used as a rapid and reliable biosensor system for detecting cytotoxic damage induced by ionizing radiation.

Figure 1. Schematic diagram of ptdTomato-N1 vector and tdTomato expression in HEK/293 cells after transfection with the vector. Plasmid ptdTomato-N1 (A) was stably transfected into human embryonic kidney cells (HEK-ptdTomato-N1). After stable transfection, single colonies were picked and the cells were propagated in tissue culture flasks. Photographs were taken with a microscope camera Mrc 5 attached to a fluorescence microscope (B: phase contrast, C: red fluorescence, filter combination 540/590). (Chishti A A, et al., 2015)

Figure 2. Growth kinetics of HEK-ptdTomato-N1 in comparison to non-transfected HEK/293. (Chishti A A, et al., 2015)