Concurrent downregulation of IDO and BRCA2 did not sensitize A549 to 5FUdR.

A549 clonal cells transfected with either scrambled shRNA (NC-3) or anti-IDO shRNA (2–18) were transiently transfected with breast cancer type-2 susceptibility protein (BRCA2) siRNA, induced with IFNγ (25 ng/ml) for 24 h, and then treated with 5FUdR (40 nM) for 72 h, at which time live cells were enumerated. Simultaneous downregulation of IDO and BRCA2 did not sensitize A549 to the TS-targeting drug 5FUdR to a greater degree than the knockdown of either gene alone. Bars represent the means of 3 independent measurements of cells (with or without downregulation of IDO) after BRCA2 siRNA transfection + 5FUdR treatment (n = 3 for each measurement) ± SD. Bars were normalized to values obtained from clones treated with IFNγ but untreated with 5FUdR or siRNA; those cells were considered to proliferate at a 100% level after IFNγ treatment. *Significant difference, Student's t-test, p