Abstract Exact targeting of specific mammalian cell types or diseased cells is one of the most urgently needed prerequisites for a new generation of potent pharmaceuticals. Different approaches have been pursued, failing mainly due to a lack of specific surface markers in most cases. Developing a completely novel RNA-based methodology, we can now ensure exact cell targeting and simultaneously combine this with selective expression of effector proteins, thereby functionalization of the target cell for therapy, diagnostics or cell steering. The specific combination of the molecular properties of antisense technology and mRNA therapy with functional RNA secondary structures allowed us to develop selectively expressed RNA molecules for medical applications. These so-called seRNAs remain inactive in non-target cells and are only activated by partial degradation to induce translation in preselected cell types of interest. Cell type specificity and type of functionalization are easily adaptable based on a simple modular system. In proof of concept in vitro and in vivo studies we used seRNAs as a highly selective platform technology for powerful glioblastoma cancer cell targeting and significantly reduce brain tumors of mice without detectable side effects with just a single treatment within days. Our data open up new potential avenues for the efficient treatment of various cancers and other human diseases.

Selectively expressed RNA molecules: a new dimension in functionalized cell targeting