(A). RT-PCR. Experiment was repeated three times with similar results.
(B) 1. Immunoblotting analysis of RRM1 in TC-1 and TC-1-GR cells. 2. Immunoblotting analysis of RRM1 in TC-1-GR cells transfected with RRM1-specific siRNA or control siRNA (Con). In A and B, β-Actin was used as an internal control.
(C). The IC50 values of didox in TC-1 and TC-1-GR cells. The cytotoxicity of didox was measured after 48 h of incubation. IC50 values were calculated from three different determinations.
(D). Cytotoxicity of gemcitabine in TC-1-GR cells transfected with RRM1-specific siRNA. Cytotoxicity of gemcitabine HCl at 1.6 μM and 35 μM was measured after 48 h of incubation. Con: cells transfected with negative control siRNA; siRNA: cells transfected with siRNA specific to RRM1. Data are presented as mean ± SD (n = 3) in C and D.