Lip-C6, Lip-PDMP and gemcitabine cooperatively induce apoptosis of PANC-1 cells. Apoptosis of PANC-1 cells was detected by TUNEL assay following 24 h treatments with: (A) saline control, (B) Lip-C6 (5 µM C6-ceramide), (C) 20 µM gemcitabine (Gem), (D) Lip-C6 (5 µM C6-ceramide) + 20 µM Gem, (E) Lip-Ghost (empty nanoliposome), (F) Lip-PDMP (5 µM PDMP), (G) Lip-C6/PDMP (5 µM C6-ceramide and 5 µM PDMP), and (H) Lip-C6/PDMP (5 µM C6-ceramide and 5 µM PDMP) + 20 µM Gem. (I) Apoptotic cells were quantified as a percent of the total cell number. One-way ANOVA: *p < 0.001 compared with control, Lip-Ghost, Lip-C6, Gem and Lip-PDMP, #p < 0.05 compared with Lip-C6 + Gem and Lip-C6/Lip-PDMP, n = 5.