Delivery of NF-κB shRNA using carbamate-mannose modified PEI for eliminating cancer stem cells

The presence of cancer stem cells (CSCs) is one of the main reasons that cause cancer relapse and metastasis. In this study, NF-κB shRNA was delivered to target CSCs using carbamate-mannose modified PEI (CMP) as a non-viral gene vector. The polymer was synthesized by blocking primary amine groups of branched PEI (10kDa) through nucleophilic addition between PEI and protected mannose-functionalized cyclic carbonate, followed by mannose deprotection. CMP/control shRNA nanocomplexes showed lower cytotoxicity and higher transfection efficiency in 4T1 murine breast cancer cells than unmodified PEI/control shRNA nanocomplexes. Importantly, CMP/NF-κB shRNA nanocomplexes (CMPN) were capable of inhibiting migration and invasion, decreasing mammosphere and colony formation and lowering ALDH⁺ CSC population. Furthermore, CMPN not only induced apoptosis and inhibited cell proliferation, but also sensitized the cells to the treatment with doxorubicin-loaded micellar nanoparticles. Therefore, CMPN may provide a promising approach for eliminating CSCs to prevent cancer relapse and metastasis.