TABLE 4

Effect of siRNA-mediated gene silencing on the inhibitory effect of the carboxamide analogs toward vRNP activity

Data are the mean ± S.E.M. of three to five independent tests.

CompoundEC50a for Inhibition of Influenza vRNP Activity 
after siRNA-Mediated Gene Knockdownb for:IC50 for Inhibition 
of polIIc
HGPRTAPRTNAMPTADKNCCC
μM
T-70588 ± 17**8.0 ± 0.57.8 ± 1.912 ± 314 ± 411 ± 1>500
T-1105237 ± 35**31 ± 940 ± 1046 ± 740 ± 738 ± 4>500
Ribavirin5.5 ± 0.55.5 ± 0.05.0 ± 0.431 ± 104.7 ± 1.35.2 ± 1.0>500
Nucleozin1.6 ± 0.31.8 ± 0.22.0 ± 0.31.8 ± 0.31.9 ± 0.41.8 ± 0.143

  • ↵a EC50, 50% effective concentration producing 50% inhibition of influenza vRNP activity, estimated from the firefly reporter signal.

  • ↵b HEK293T cells were siRNA-transfected to silence the indicated genes (NC, negative control siRNA). After 48 hours, cells were transfected with the influenza vRNP-reconstituting plasmids and the firefly and Renilla reporter plasmids, and incubated with the test compounds. The luciferase activity was determined 24 hours later.

  • ↵c IC50, compound concentration causing 50% reduction of the polII-dependent Renilla luciferase signal.

  • ↵** P < 0.01 versus the EC50 value obtained in the non–siRNA-transfected control cells (CC) (two-tailed Student’s t test).