RNA-only multi-input microRNA classifier circuit differentiates between HeLa, HEK 293 and MCF7 cells.
(a) An L7Ae-based multi-input microRNA classifier specifically recognizes HeLa cells based on a unique microRNA profile (highly expressed miR21 and low levels of miR141, 142(3p) and 146a). (b) Differential expression of output protein EGFP in HeLa, HEK and MCF7 cells with transient pDNA transfection. EGFP expression from the classifier circuit results in 18-fold and 25-fold higher output in HeLa cells in comparison to HEK and MCF7 cells, respectively (HEK fluorescence was normalized to 1 and circuit-regulated EGFP fluorescence was normalized to mKate expressed constitutively from the same promoter, to account for different expression levels across cell types). (c–d) Specific induction of apoptosis in HeLa cells by expression of circuit-controlled hBax protein compared with constitutive hBax expression: Annexin V positive cells in pDNA (c) and modRNA (d) transfected cells. (e) Cell death assay in a mixed HEK/HeLa-EBFP2 culture with modRNA delivery. The graphs indicate percent of dead cells as measured with AADvanced staining, with HEK and HeLa cells distinguished by EBFP fluorescence. EGFP-only transfection was used as a control in all apoptotic/cell death assays.