Molecular mechanism of the uptake and toxicity of EGF-LipoAgNPs in EGFR-overexpressing cancer cells

Abstract

The surface of silver nanoparticles (AgNPs) is characterized by high reactivity resulting in prooxidative and cytotoxic properties. These effects are observed both in normal and in cancer cells, which overexpress the Epidermal Growth Factor Receptor (EGFR). In our previous paper, we have demonstrated that, with the use of liposomes labeled with the Epidermal Growth Factor (EGF), it is possible to direct the toxic effect of AgNPs in EGFR-overexpressing cells. Unfortunately, the mechanism of uptake and toxicity induction by such liposomes is still unknown. Therefore, the aim of this study was to determine the impact of EGF-LipoAgNPs on certain genes related to endocytosis and toxicity induction by such liposomes in human lung (A549) and tongue (SCC-15) cancer cells. The siRNA knock-out gene method was used in this study to determine the engagement of EGFR in this process. The confocal microscopy study revealed that the number of liposomes in the cytoplasm of the A549EGFR- and SCC-15EGFR- cells was lowered by 51.99 × 103 RFU and 138.50 × 103 RFU, respectively, proving the crucial role of EGFR in the liposome uptake. Moreover, the expression of the SHH and ATM genes was significantly increased, whereas the expression of the NRF2 gene was decreased after the treatment with EGF-LipoAgNPs and native AgNPs. Furthermore, the expression of the CLTC, AP2M1, CAV1, and SH3GLB1 genes indicated that the tested liposomes are uptaken via the clathrin-dependent pathway with engagement of the AP-2 complex and endophilin in this process. Summarizing, the created targeted delivery system of AgNPs causes an increase in the prooxidative and toxic effect of such NPs and has an impact on endocytosis regulatory genes, especially those related to the clathrin-mediated endocytosis.