FIGURE 1: Poly(A:U) 50 bp TL-412 increases mTNFα secretion by RAW264.7 wt cells, while Poly(A:U) 70 bp TL-432 and 90 bp TL-452 trigger biological responses in both RAW264.7 wt and NCI-H292 wt cells. (A, D) Activation of myeloid cells by TLR3-ligands was determined on RAW264.7 cells treated with the different molecules at 10 µg/mL for 24 hours. The concentration of mTNFα was measured by ELISA. (B, E, F) Activation of tumor cells by TLR3-ligands was determined on NCI-H292 cells treated with the different molecules at 50 µg/mL for 24 hours. Cell viability was measured with MTS assay and expressed as percentage of untreated cells (B, F). Apoptosis was measured with AnnexinV-Glo assay and expressed as fold increase of untreated cells (E). (A) Among 47 tested 50 bp dsRNAs, only the Poly(A:U) (TL-412) induces mTNFα secretion by RAW264.7 wt cells. (B) None of the tested 50 bp dsRNAs reduces cell viability in NCI-H292 wt. (C) Schematic representation of a subset of dsRNA ligands, showing their sizes and compositions. TL-413, made of a random sequence containing A-U nucleotides, is represented in square. (D) Increasing the size of Poly(A:U) from 50 to 70 or 90 bp does not increase mTNFα secretion by RAW264.7 wt cells. (E, F) Increasing the size of Poly(A:U) from 50 to 70 or 90 bp triggers apoptosis and reduces cell viability in NCI-H292 wt. Data are representative of one (B) or at least two (A) independent assays or are the means of three independent assays (D-F). Results are expressed as mean ± SD. Unpaired Student's t-test: * = p<0.05; ** = p<0.01; *** = p<0.001; ns: not significant. Unpaired Student's t-test values are compared to Mock condition unless otherwise stated.