We developed a modular multifunctional nonviral gene delivery system by targeting the overexpressed
cancer surface receptor α5β1
integrin and the upregulated transcriptional activity of the
cancer resistance mediating
transcription factor NF-κB, thereby introducing a new form of transcriptional targeting. NF-κB regulated
therapy can improve specificity of gene expression in
cancer tissue and also may offset NF-κB mediated
cancer resistance. We delivered a
luciferase gene under the control of an NF-κB responsive
element (pNF-κB-Luc) encapsulated in a PR_b
peptide functionalized stealth
liposome that specifically targets the α5β1
integrin and achieved increased gene expression in DLD-1
colorectal cancer cells compared to BJ-fibroblast healthy cells in vitro. The multitargeted system was also able to differentiate between
cancer cells and healthy cells better than either of the individually targeted systems. In addition, we constructed a novel
cancer therapeutic plasmid by cloning a highly potent
diphtheria toxin fragment A (DTA) expressing gene under the control of an NF-κB responsive
element (pNF-κB-DTA). A dose-dependent reduction of cellular
protein expression and increased cytotoxicity in
cancer cells was seen when transfected with PR_b functionalized stealth
liposomes encapsulating the condensed pNF-κB-DTA plasmid. Our therapeutic delivery system specifically eradicated close to 70% of a variety of
cancer cells while minimally affecting healthy cells in vitro. Furthermore, the modular nature of the nonviral design allows targeting novel pairs of extracellular receptors and upregulated
transcription factors for applications beyond cancer gene
therapy.