Overexpression of DUSP4 reverses the inductive effect of miR-429 overexpression on the expression of apoptosis-related proteins in resistant CRC cells treated with nintedanib. (A) Western blotting of apoptosis-related proteins in resistant CRC cells treated with nintedanib. The expression levels of apoptosis-related proteins, including (B) Bcl-2, (C) Bax, (D) cleaved caspase-3 and (E) caspase-3 in CRC cells were detected by western blotting. **P<0.01, ***P<0.001 vs. SW480; #P<0.05, ##P<0.01, ###P<0.001 vs. SW480-R; ∆∆P<0.01, ∆∆∆P<0.001 vs. SW480-R mimic NC; $P<0.05 vs. SW480-R miR-429 mimic + Oe-NC. CRC, colorectal cancer; miR-429, microRNA-429; DUSP4, dual specificity protein phosphatase 4; NC, negative control; Oe-DUSP4, DUSP4 overexpression plasmid; Oe-NC, NC overexpression plasmid; -R, resistant to nintedanib.