Disconnecting the Yin and Yang Relation of Epidermal Growth Factor Receptor (EGFR)-Mediated Delivery: A Fully Synthetic, EGFR-Targeted Gene Transfer System Avoiding Receptor Activation

Abstract

The epidermal growth factor receptor (EGFR) is upregulated within a high percentage of solid tumors and hence is an attractive target for tumor-targeted therapies including gene therapy. The natural EGFR ligand epidermal growth factor (EGF) has been used for this purpose, despite the risk of mitogenic effects due to EGFR activation. We have developed a fully synthetic, EGFR-targeted gene delivery system based on PEGylated linear polyethylenimine (LPEI), allowing evaluation of different EGFR-binding peptides in terms of transfection efficiency and EGFR activation. Peptide sequences directly derived from the human EGF molecule enhanced transfection efficiency with concomitant EGFR activation. Only the EGFR-binding peptide GE11, which has been identified by phage display technique, showed specific enhancement of transfection on EGFR-overexpressing tumor cells including glioblastoma and hepatoma, but without EGFR activation. EGFR targeting led to high levels of cell association of fluorescently labeled polyplexes after only 30 min of incubation. EGF pretreatment of cells induced enhanced cellular internalization of all polyplex types tested, pointing at generally enhanced macropinocytosis. EGF polyplexes diminished cell surface expression of EGFR for up to 4 hr, whereas GE11 polyplexes did not. In a clinically relevant orthotopic prostate cancer model, intratumorally injected GE11 polyplexes were superior in inducing transgene expression when compared with untargeted polyplexes.

PolyIC GE11 polyplex inhibits EGFR‐overexpressing tumors

“…These results confirm that GE11, as a free ligand, exhibits negligible affinity to the EGFR. Previous reports however, have demonstrated binding of GE11- and EGF-linked targeted liposomes to EGFR-expressing cells in vitro (15), as well as effective and specific gene delivery into EGFR expressing cells, both in vitro and in vivo , using PPGE11 (9,10,16). These results prompted us to further investigate the potencies of tethered GE11 and EGF in inhibiting the binding of [ 125 I]-EGF, when tethered to PEI-PEG.…”

“…Conjugation of GE11 to polyethyleneimine-polyethyleneglycol (PEI-PEG-GE11, PPGE11) enabled the targeting of EGFR over-expressing tumors in vitro and in vivo (9,10). We have recently shown that local and systemic application of EGFR-targeted poly Inosine/Cytosine (PolyIC) by PEI-PEG-EGF (PP-EGF) eradicates several pre-established EGFR-over-expressing tumor models (2,3).…”

Systemically Injected Exosomes Targeted to EGFR Deliver Antitumor MicroRNA to Breast Cancer Cells

“…10 Additionally, GE11-conjugated polyethylenimine vectors and polyethylene glycol-conjugated liposomes have been shown to be less mitogenic, and can efficiently transfect genes into cells expressing high levels of EGFR or tumor xenografts. [10][11][12][13] These studies indicated that the GE11 peptide is likely superior to EGF for clinically targeting EGFR-expressing tumors.…”

Biodistribution and Pharmacokinetics of Mad2 siRNA-loaded EGFR-Targeted Chitosan Nanoparticles in Cisplatin Sensitive and Resistant Lung Cancer Models

“…Due to their high overexpression, they have been extensively used as cancer cell selective targeting receptor. We have previously used a synthetic 12 amino acids peptide that has demonstrated efficient targeting of EGFR receptor and its targeting capability has been successfully validated in vitro as well as in vivo in various EGFR-overexpressing tumor cells such as A549 [38][39][40][41][42][43]. Most importantly, this peptide is capable of inducing nanoparticles cellular uptake without activating EGFR signaling pathway and therefore was included as targeting ligand in our formulation approach [44].…”