Liposomal delivery of siRNA against p65/relA effectively inhibits NFκB activity and it also effectively inhibits growth of gemcitabine-sensitive pancreatic cancer cells but not gemcitabine-resistant pancreatic cancer cells in vivo. A, tumors were formed in nude mice with MPanc-96 cells stably expressing the NFκB reporter. The mice were treated with or without neutral liposomes bearing siRNAp65 and the effects on bioluminescence imaging indicated significant reduction. B, tumors were formed in nude mice with MPanc-96/BxPC-3 cells stably expressing a constitutively regulated luciferase for analysis of tumor formation. Bioluminescent imaging was done weekly to assess tumor growth. C, after 5 wk the weights of the pancreata including the primary tumors were quantified. Columns, mean for five animals; bars, SE. *, P < 0.05, versus control.