Abstract 1461: mRNA therapeutics against cancers and infectious diseases

Abstract

Abstract In vitro transcribed (IVT) mRNA is forming a new basis of drug delivery as it can be synthetically engineered to express the desired protein in lesser time and be more specific than the other 2 types of antigens. Using DNA (coding for proto-oncogenes) for immunization poses a risk for host cell transformation into a malignant one and hence proto-oncogenes would express for a longer time. Therefore, mRNA was considered for cancer immunotherapy as it does not integrate into the host cell's genome, so no question of insertional mutagenesis arises. Our main aim is to develop a stable mRNA system working both in vitro and in vivo and then use this system to develop mRNA vaccines. The stability of IVT mRNA can be increased by changing the 3' and 5' UTRs, adding a 5'cap and 3' poly-A tail which could even increase their half-life to a few days. For creating a stable mRNA working system in vitro, EGFP-2A gene was cloned along with the AdsA (Staphylococcus aureusgene important for infection) in a vector backbone with TMV 3’UTR and 5’UTR. The mRNA created in vitro was with modified uridine and cap 1 structure and transfected to the mammalian cell lines. This transfection was further enhanced by using liposome created in the lab (using some cationic and helper lipids in different ratios) by film rehydration method. The expression of luciferase mRNA was then detected in mice by live imaging indicating that the mRNA system is stable in vivo. Further, to direct the mRNA encoded antigens to MHC1 and MHC2 pathways they were tagged with a htPA secretion tag and MHC1 targeting signal along with a 3XFLAG tag. We tried various mode of injections with AdsA mRNA to have a profile of ELISPOT with differently exposed mRNA (in vivo in mice). Now we are focussing on some neo antigens for tumor to be used as. Avaccine in the form of mRNA. Citation Format: Smriti Arya, Qiubin Lin, Nan Zhou, Jiandong Huang. mRNA therapeutics against cancers and infectious diseases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1461.