Bioengineered miR-1291 prodrug sensitizes human pancreatic cancer cells to Gem-nP. Compared to the MSA control, a low dose of MSA/miR-1291 had minimal effects on AsPC-1 (A) and PANC-1 (C) cell proliferation, whereas it significantly (*P < 0.001; 2-way ANOVA with Bonferroni posttests) improved the sensitivity of AsPC-1 (B) and PANC-1 (D) cells to Gem-nP, which was also indicated by the estimated pharmacodynamics parameters (E). AsPC-1 and PANC-1 cells were treated with MSA/mir-1291 or MSA control alone (A, C) or in combination with various concentrations of Gem-nP (B, D; shown are total concentrations of Gem-nP at a fixed ratio of 8: 1) for 48 h, and cell viability was determined by CellTiter-Glo assay. Values are mean ± SD (N = 3). *P < 0.05; **P < 0.01, compared to corresponding MSA control treatment (1-way ANOVA).