mRNA Vaccines and Drugs: a New Favorite for Cancer Immunotherapy

mRNA vaccines and drugs enter host cells through delivery vectors and produce target proteins using the protein synthesis mechanism of cells. mRNA and target proteins can induce the body to produce innate immunity and adaptive immunity, and the target protein itself can also play a corresponding role. Tumor cells are inhibited and cleared under the above immune effects and target proteins. This article reviews the immunogenicity of mRNA, that is, the specific mechanism of stimulating the body to produce an immune response. At the same time, the main types of cells transfected by mRNA vaccine were briefly introduced. (1) Muscle cells, epidermal cells, dendritic cells and macrophages at the injection site; (2) immune cells in peripheral lymphoid organs; (3) liver cells and spleen cells, etc. . Although transfected with a variety of cells, it is mainly enriched in immune cells and liver cells because immune cells express toll-like receptors and liver cells express low-density lipoprotein receptors. mRNA vaccines and drugs are mainly divided into non-replicating mRNA (nrmRNA), self-amplifying RNA (saRNA), trans-amplifying RNA (taRNA) and circular RNA (circRNA).This article reviews how these 4 types of vaccines and drugs work, and compares their advantages and disadvantages. Due to its inherent immunogenicity, instability, and low delivery efficiency in vivo, , mRNA vaccines and drugs have been unable to enter the clinic. This article describes in detail how to reformation and modify the 5'cap, 5'UTR, 3'UTR, ORF, 3'Poly(A) and some nucleotides of mRNA to eliminate its immunogenicity and instability. Due to the low efficiency of the delivery carrier, the researchers optimized it. This article briefly introduces the application of non- viral vectors and their targeting, specifically involving the mechanism of action of various types of delivery vectors and their advantages and disadvantages, and summarizes some of the current targeting vectors. Targeted carriers can improve the delivery efficiency of mRNA to specific tissues and prevent side effects of systemic exposure, such as liver injury. The specific methods of using mRNA vaccines and drugs to treat cancer are as follows: mRNA can be used to encode and transcribe tumor-associated antigens, tumor-specific antigens (TSAs), therapeutic antibodies, cytokines, tumor suppressors, oncolytic viruses, CRISPR-Cas9, CARs and TCRs, so as to play an anti-tumor role. In this paper, the specific mechanism of the above methods and the current research and development of corresponding mRNA vaccines and drugs are briefly reviewed. The successful development of the COVID-19 mRNA vaccine has brought mRNA technology to the attention of the world and brought new and effective means for the prevention and treatment of cancer. mRNA vaccines and drugs have the advantages of short development cycle, dual immune mechanism, safety, high efficiency and large-scale production. At the same time, there are also many areas that need further improvement, such as the development of ideal target TSAs, the in-depth development of saRNA, taRNA and circRNA, the development of targeted nano-delivery for different tissues and organs, the expansion of mRNA administration routes, and the development of mRNA that can be stably stored at room temperature or even high temperature. These problems need to be further studied and solved. In addition to cancer therapy, mRNA vaccines and drugs can also be used in the treatment of infectious diseases, genetic diseases, regenerative medicine and anti-aging. mRNA vaccines and drugs are a very promising platform, and we believe that they will benefit cancer patients in the near future.