Fig. 4: Inhibition of UBE2F sensitizes lung cancer cells to platinum.

A Establishment of UBE2F KO A549 stable cells. A549 cells with stable UBE2F knockout were generated by retrovirus infection, and the UBE2F protein levels were determined by western blot. B UBE2F protects lung cancer cells from platinum-induced growth inhibition. A549 WT and UBE2F KO cells were seeded in 6-well plates at a density of 50,000 cells/well, followed by treatment of low concentration of platinum as indicated for 7 days, and the remaining living cells were trypsinized and counted by Nexcelom. C UBE2F protects lung cancer cells from platinum-induced cell death. A549 WT and UBE2F KO cells were seeded in 6-well plates at a density of 500,000 cells/well, followed by treatment of high concentration of platinum as indicated for 48 h and the remaining living cells were trypsinized and counted by Nexcelom. D, E UBE2F deficiency leads to lung cancer cells more sensitive to platinum. A549 WT and UBE2F KO cells were seeded in 6-well plates at a density of 500,000 cells/well, followed by treatment of platinum as indicated for 48 h. The expression levels of PARP and NOXA were determined by western blot. F, G NOXA has an essential role in UBE2F-mediated apoptotic resistance to platinum. A549 WT and UBE2F KO cells were transfected with siRNA targeting NOXA. Cells were seeded in 6-well plates at a density of 500,000 cells/well, followed by treatment of high concentration of platinum as indicated for 48 h and the remaining living cells were trypsinized and counted by Nexcelom. The expression levels of NOXA were determined by western blot. Shown are average values with standard deviation (s.d.). ^*P < 0.05, ^**P < 0.001, and ^***P < 0.001 for the indicated comparison. n.s. not significant.