Fig. 3

In vitro performances of anti-HBV siRNAs. a–h On target and off-target activities of the unmodified (a–d) and chemically modified (e–h) anti-HBV siRNAs. psiCHECK™ dual-luciferase reporter system, an extremely sensitive activity evaluation system, was employed in this assay. The transfection concentrations were 100, 25, 6.25, 1.5625, 0.3906, 0.0977, 0.0244, 0.0061, 0.0015, 0.0004, 0.0001 nM, respectively. GS-CM or PS-CM mean the guide strand (GS) or passenger strand (PS) of the siRNA match with its targeting mRNA incomplete match (CM) manner. The guide strand is the desired gene silencing modulator, revealing siRNA’s on-target activity. GS-SM or PS-SM means the guide or passenger strand of siRNA works via seed-region-matching, a miRNA-like pathway. Hence, gene silencing mediated by PS-CM, GS-SM, or PS-SM represents siRNA’s off-target effect. i Serum stability of unmodified SR16-X2 and modified SR16-X2M2 (siHBV). j, k In vitro anti-HBV activity of SR16-X2M2. Virus RNA expression (j) and HBsAg level in culture medium (k) of HepG2.2.15 receiving lipo-transfection of SR16-X2M2 at 50, 25, and 12.5 nM, respectively