Molecular mechanism for the synergistic effect of volasertib and miR-34a. (A–E) miR-34a expression level determined by qPCR after treatment of HPDE, MIA PaCa-2, MIA PaCa-2R, Capan-1, and Capan-1R cell lines. (F) Western blotanalysis of Bcl-2, PLK1, and c-myc in MIA PaCa-2 and MIA PaCa-2R cell lines. (G, H) PLK1 and c-myc mRNA expression levels determined by qPCR. PBS was used as control (n = 3, *p < 0.05, **p < 0.01, and ***p < 0.001).