Figure 4.

Simultaneous siRNA-mediated knockdown of BRCA2 and TS induces complementary lethality to cisplatin, melphalan, and both TS-targeting drugs. A549 cells were transfected with control, TS and/or BRCA2 siRNA and, at 24 hours after transfection, treated with (a) cisplatin (IC₂₅), (b) melphalan (IC₂₅), (c) 5-FUdR (IC₂₅), or (d) pemetrexed (IC₂₅). HeLa cells were treated under the same conditions and with (e–h) the same drugs. Effects on cell proliferation were determined by direct cell counting at 96 hours and calculated as a percentage of nondrug-treated, control siRNA-transfected cells.*Different from cells treated with control nontargeting siRNA and drug (Student's t-test, P < 0.05). **Different from cells treated with single siRNA and drug (Student's t-test, P < 0.05). Representative data from one of three independent experiments is shown (mean ± SD).