Lung cancer is associated with very poor prognosis and considered one of the leading causes of death worldwide. Here, we present highly potent and selective bio-hybrid RNAi-peptide nanoparticles that can induce specific and long-lasting gene therapy in inflammatory tumour associated macrophages (TAMs), via an immune modulation of the tumour milieu combined with tumour suppressor effects. Our data prove that passive gene silencing can be achieved in cancer cells using regular RNAi NPs. When combined with M2 peptide-based targeted immunotherapy that immuno-modulates TAMs cell-population, a synergistic effect and long-lived tumour eradication can be observed along with increased mice survival. Treatment with low doses of siRNA (ED50 0.0025-0.01 mg/kg) in a multi and long-term dosing system substantially reduced the recruitment of inflammatory TAMs in lung tumour tissue, reduced tumour size (∼95%) and increased animal survival (∼75%) in mice. Our results suggest that it is likely that the combination of silencing important genes in tumour cells and in their supporting immune cells in the tumour microenvironment, such as TAMs, will greatly improve cancer clinical outcomes.
Keywords: RNAi; lung cancer; nanoparticles; tumour targeting; tumour-associated macrophages.