Colony Formation Assay

TNBC cells were placed in six-well plates overnight and then transfected with indicated vectors, and then exposed to various doses of X irradiation (0 Gy, 2 Gy, 4 Gy, 6 Gy and 8 Gy). After irradiation for 24 h, the medium was changed with fresh medium and updated every 3 days. After 2 weeks, TNBC cells were carefully washed with pre-cold phosphate-buffered saline (PBS) and fixed with the paraformaldehyde (4%, 1mL) for 30 min at 4°C. Subsequently, the cells were washed with PBS and stained with 0.1% crystal violet for 1 h, and again washed with PBS until per well was clear. If a colony exceeded 50 cells, the colony was counted.