The human immortalized keratinocytes
HaCaT cells were obtained from China Center for Type Culture Collection (CCTCC, Wuhan, China). The human embryonic dermal fibroblasts
WS1 cells were obtained from American Type Culture Collection (ATCC, Manassas, VA, USA). Both cell lines were grown in
DMEM (high glucose, Sigma-Aldrich, St Louis, MO, USA) supplemented with 10% fetal bovine serum (
FBS, Wisent, St-Bruno, Quebec, Canada), 100 U/ml
streptomycin and 100 U/ml
penicillin (both from Beyotime Institute of Biotechnology, China) at 37
°C in a humidified atmosphere of 95% air and 5% CO
2.
To study the factors in irradiated
HaCaT cells that were involved in the bystander effect in unirradiated
WS1 cells, a transwell insert co-culture system was utilized. 1.2 × 10
5 HaCaT cells and 4 × 10
4 WS1 cells were seeded on coverslips in 6-well plates (with a growth area of 9.6 cm
2) and in companion Millicell
® transwell culture inserts (Millipore, MA, USA) (with a growth area of 5.7 cm
2), respectively. The insert had a porous membrane with a pore size of 0.4 μm to allow the passage of molecules but not cells. Immediately after HaCaT being irradiated, the inserts with
WS1 cells were put into the wells with
HaCaT cells for 24 h. HaCaT and
WS1 cells shared the same medium, but were separated from each other with a distance of 3 mm.
Yin X., Tian W., Wang L., Wang J., Zhang S., Cao J, & Yang H. (2015). Radiation quality-dependence of bystander effect in unirradiated fibroblasts is associated with TGF-β1-Smad2 pathway and miR-21 in irradiated keratinocytes. Scientific Reports, 5, 11373.