Advances in ex vivo mRNA-based gene transfer for cell-based cancer immunotherapy

Electroporation of messenger RNA (mRNA) is an ex vivo non-integrating gene transfer technique used in immune-cell-based trials for cancer to transiently supply immune cells with multiple proteins. This technique has been used to engineer dendritic cells and B cells with tumor-associated antigens to boost the immune system of cancer patients and to redirect the anti-tumor activity of T cells and natural killer cells with immune receptors. Although gene delivery via mRNA electroporation results only in transient expression of the protein of interest, many investigators and clinicians consider it as a feasible, flexible, and safe technique, compared with stable expression methods using viral vectors. In this review, we discuss the efficacy of mRNA electroporation for gene transfer and assess the strengths and limitations of this technique for redirecting and boosting immune responses against various tumor antigens in cancer immunotherapy.