The find more effects of paclitaxel on dCK protein were measured by Western immunoblot analysis (Figure 3). The protein expression decreased by 24 to 56% in all cell lines, but the decrease was only statistically significantly lower

in paclitaxel-treated H460 cells compared to vehicle-control treated cells (P < 0.05). Figure 3 dCK and CDA protein expression in non-small cell lung cancer cell lines. (a) A representative Western immunoblot of crude cellular AZD5582 extracts from H460 (lane 1,2), H520 (lane 3,4), H838 (lane 5,6) and AG6000 (A2780 variant without dCK, lane 7). The odd lanes were treated with vehicle-control and the even lanes were treated with paclitaxel at the observed IC50 value for 24 hours. (b) The mean (± standard deviation) relative protein levels of dCK to β-actin

after exposure to paclitaxel at the observed IC-50 PI3K Inhibitor Library value for 24 hours compared to vehicle-control (set to the value of 1) from three independent experiments. (c) A representative Western immunoblot of crude cellular extracts from H460 (lane 1,2), H520 (lane 3,4), and H838 (lane 5,6). The odd lanes were treated with vehicle-control and the even lanes were treated with paclitaxel at the observed IC50 values for 24 hours. (d) The mean (± standard deviation) relative protein levels of CDA to β-actin treated with paclitaxel at the observed IC-50 value for 24 hours compared to relative protein levels of CDA to β-actin treated with vehicle-control (set to the value of 1) from three independent experiments. The enzyme specific activities of dCK are summarized in Table 3. The cells were exposed to vehicle-control or paclitaxel at the observed IC-50 value determined in the specific cell line. Basal dCK activity was highest in H838 cells and lowest in H460 cells. The mean activity increased 10 to 50% in all of the cell lines, but the increase in activity was only statistically significantly higher in H460 and H520 cells treated with paclitaxel compared to vehicle-control (P < 0.05). Table 3 Effects of paclitaxel on deoxycytdine kinase and cytidine deaminase activity

in solid tumor cell lines Exposure/Cell line H460 H520 H838 Control BCKDHB %G0 + G1 66 ± 1.2 62 ± 2.1 80 ± 7.5 %G2 + M 8.0 ± 1.4 13.2 ± 1.0 4.8 ± 2.4 %S 26 ± 1.7 25 ± 1.3 15 ± 5.1 % Apoptosis 7.5 ± 1.7 3.2 ± 0.6 9.7 ± 7.2 PAC 24 h > GEM 24 h %G0 + G1 17 ± 11 36 ± 6.4 23 ± 6.0 %G2 + M 25 ± 7.8 44 ± 6.4a 15 ± 4.7 %S 58 ± 3.2 20 ± 2.3 41 ± 1.0 % Apoptosis 8.6 ± 5.1 2.1 ± 1.4 4.6 ± 1.0 GEM 24 h > PAC 24 h %G0 + G1 13 ± 6.0 62 ± 4.9a 23 ± 10.3 %G2 + M 30 ± 1.7 9.7 ± 1.6 9.8 ± 8.0 %S 56 ± 7.7 28.8 ± 3.5 43 ± 1.6 % Apoptosis 7.0 ± 4.9 3.4 ± 2.2 0.87 ± 0.05a Mean (± standard deviation) percentage of cells in each phase of the cell cycle after exposure to vehicle control or sequential paclitaxel → gemcitabine or gemcitabine → paclitaxel at 24 hours intervals.