(A) Intracellular delivery of the siRNA-αCD22 Ab-SPIO NPs. The siRNA-αCD22 Ab-SPIO NPs are composed of A488-labelled control or MXD3 siRNAs, FITC-labelled αCD22 Abs, and A532-labelled SPIO NPs. The images were taken 4 hours after treatment with siRNA-αCD22 Ab-SPIO NPs. Untreated cells were shown as a control.
(B) MXD3 knockdown in the cells treated with the MXD3 siRNA-αCD22 Ab-SPIO NPs at 4 hours after treatment. Reh cells that were treated with the control siRNA-αCD22 Ab-SPIO NPs did not exhibit the same level of MXD3 knockdown and showed similar levels of expression to untreated cells. For each image, protein level was measured by MFI in each cell in the field and the average MFI is shown in the right lower corner of each MXD3 image.
(C) MXD3 protein knockdown quantified using MFI. The cells treated with MXD3 siRNA-αCD22 Ab-SPIO NPs showed decreased MXD3 protein expression compared with the cells treated with the control siRNA-αCD22 Ab-SPIO NPs or untreated cells. Each point represents the average MFI of all measured cells per treatment type, in 3 independent experiments. Untreated vs. MXD3 siRNA-αCD22 Ab-SPIO NPs (**) p = 0.00606, control vs. MXD3 siRNA-αCD22 Ab-SPIO NPs (**) p = 0.00814. The p-values are from the post-hoc Tukey studenized range test on a one-way ANOVA of log(MFI).
(D) Reduced cell growth in the cells treated with the MXD3 siRNA-αCD22 Ab-SPIO NPs. Data points indicate mean values of independent cell count in triplicates from 3 independent experiments. Live cell count was measured at 4, 8, 24, 48 and 72 h after a single treatment with the MXD3 or control siRNA-αCD22 Ab-SPIO NPs. Untreated cells were also used as a control. Error bars represent range (n=9 for each time point). The cells treated with the MXD3 siRNA-αCD22 Ab-SPIO NPs had significantly fewer live cells than either the untreated cells or the cells treated with the control siRNA-αCD22 Ab-SPIO NPs (p < 0.0001).
αCD22 Ab, anti-CD22 antibody; SPIO, superparamagnetic iron oxide; NP, nanoparticle; siRNA, small interfering RNA; MFI, mean fluorescence intensity.