Application of mRNA regulatory regions to improve tumor specificity of transgene expression

Efficiency and specificity are two key attributes of anti-cancer drugs including genetic therapeutic agents. We suggest a way to improve specificity of gene therapy drugs based on the ability of 3'-untranslated regions (UTR) of some mRNAs selectively stabilize transcripts only during cell division. The mRNAs of genes encoding DNA methyltransferase I (DNMT1) and topoisomerase IIα (TOP2A) are among such transcripts. When inserted into genetic constructs designed to produce therapeutic protein in tumor cells, such 3'-UTR would lead to diminished effect of therapeutic protein on normal cells, which are characterized by low or absent proliferative activity. However, when included in gene expression cassette, these 3'-UTR might result in decreased transgene expression, thus, overweighting the advantage of increased specificity of expression. We showed that DNMT1 and to the lesser extent TOP2A 3'-UTR do not alter significantly therapeutic transgene expression level in tumor cells, thus, confirming the functionality of the proposed approach.