Doxorubicin-incorporated nanoparticles enhance siRNA delivery and target-specific knock-down in cancer cells. (a) A decrease in relative mRNA expression of XIAP, PARP, VEGF, and EGFR in H292 cells following a 24 h treatment with corresponding nanoparticles. Bars represent means ± s.e.m. (n = 3 independent experiments, *p < 0.05 compared to NP-siCTRL-Dy550 treated cells using Student’s t test). (b) H292 cells treated for 24 h with the un-assembled components of NP-DOX-siXIAP-Dy550 (calcium phosphate (CaP), DOX, and/or siXIAP) do not decrease relative XIAP mRNA levels compared to untreated cells. Bars represent means ± s.e.m. (n = 3). (c–j) 48 h treatment with NP-DOX-siRNA-Dy550 nanoparticles targeting XIAP (c, g), PARP1 (d, h), VEGF (e, i) or EGFR (f, j) results in significant knock-down of specific target proteins (c–f) and decreased cell viabilities (gej) in a panel of cancer cells. Bars represent means ± s.e.m. (n = 3 independent experiments, *p < 0.05 for NP-DOX-siRNA-Dy550 compared to NP-siCTRL-Dy550, NP-DOX-Dy550, or NP-siRNA-Dy550 using Student’s t test).