Micelleplexes as nucleic acid delivery systems for cancer-targeted therapies

Cancer remains one of the leading causes of death worldwide despite significant therapeutic advancements and improved detection methods. Nucleic acid (NA) therapeutics are receiving increasing attention for cancer management and cure. Indeed, ribonucleic acid (RNA) oligonucleotides (such as small interfering RNA (siRNA) and micro RNA (miRNA)), messenger RNA (mRNA) and deoxyribonucleic acid (DNA) (such as plasmidic DNA (pDNA) and minicircle DNA (mcDNA)), have demonstrated potential as novel therapeutic agents. The imposing prospects of NA-based therapeutics reside in their ability to act as key-players mediating cellular pathways and bestowing potent gene silencing properties, as in the case of RNA interference (RNAi) agents, or by promoting the expression of specific required proteins for disease management (pDNA, mcDNA and mRNA, for instance). However, efficient NA therapeutics delivery is seriously hampered by NA physicochemical features, low in vivo serum stability and compromised cellular internalization, which swiftly reduce their biological activities. Recently, nano-based systems emerged as suitable vehicles for NA delivery. This review covers NA-carrying micelleplexes as robust and multifunctional polymer-based NA delivery systems, as well as the specific in vivo challenges for successful NA delivery to cancer cells and their prospects to become clinical reality, followed by a critical analysis of the major in vivo micelleplex-based cancer-targeted strategies accomplished till the present day.