Figure 2.

Polyplex-mediated NIS gene transfer in vitro

Cell surface receptor expression of EGFR and TfR was measured by flow cytometry. A specific antibody monitored the expression levels of human EGFR and TfR on Hep3B, MCF-7, and U87 cells compared with isotype controls (A). ¹²⁵I cell transfection studies (n = 3 for each cell line) showed EGFR- and TfR-specific transfection efficiency of targeted polyplexes (GE11/NIS, TfRre/NIS) (B). Dual/NIS polyplexes showed transfection efficiency in Hep3B and U87 cells (B). Background radiation levels after control transfection with LUC-coding polyplexes (Dual/LUC) or the addition of NIS-specific inhibitor perchlorate proved NIS dependency of iodide uptake (B). Treatment with the dynamin inhibitor dynasore resulted in a dose-dependent inhibition of the transfection of MCF-7 and U87 cells using TfRre/NIS polyplexes demonstrating the TfR dependency of transfection with TfR-targeted polyplexes. Total inhibition was reached by the concentration of 40 μM on MCF-7 and 50 μM on U87 cells (∗p ≤ 0.05, ∗∗p ≤ 0.01). Cell viability of Hep3B, MCF-7, and U87 was not affected by polyplex treatment (C). Results are reported as mean ± SEM.