Synergistic Antiproliferative Effects of All-Trans Retinoic Acid and Paclitaxel on Autosomal Dominant Polycystic Kidney Disease Epithelial Cells

Figure 5

Combination treatment with PAC and ATRA suppresses ERK signaling. Protein expression was examined by flow cytometry analysis and western blotting. WT 9-7 cells were treated with DMSO or 1 nM PAC and 10 nM ATRA for 72 h. Cells were then collected, and the expression of p-MEK (a), p-ERK (b), ERK1 (c), and ERK2 (d) was measured by flow cytometry. (e) Expression levels of these signaling molecules were confirmed by western blotting. (f) WT 9-7 cells were incubated with 20 μM MKP inhibitor (NSC95397) for 6 h and then treated with 1 nM PAC and 10 nM ATRA. After 72 h, the cells were collected and ERK expression was examined by western blotting. (g) Densitometric analysis of protein bands was performed by ImageJ software. The band density of each protein was normalized against that of actin. . (h) WT 9-7 cells were treated with DMSO or 1 nM PAC plus 10 nM ATRA in the presence of 10 μM nifedipine for 72 h. Cells were then collected, and p-ERK expression was examined by western blotting.

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