The role of polyethylenimine-functionalized gold nanoclusters carrying plasmid CMTM5 in impeding the malignant progression of prostate cancer cells by promoting EGFR endocytosis

Linjin Li, Chengpeng Li, Feilong Miao, Wu Chen, Xianghui Kong, Ruxian Ye,  Rui Feng

Abstract:

In this research, polyethylenimine-functionalized gold nanoclusters (PEI-AuNCs) were synthesized for the delivery of plasmid CMTM5 (pCMTM5) to prostate cancer (PCa) cells, with the objective of elucidating the mechanism underlying its anticancer efficacy. The PEI-AuNCs loaded with pCMTM5 (PEI-AuNCs@pCMTM5) tumor-targeting drug delivery system was established. Subsequently, both the obtained PEI-AuNCs and PEI-AuNCs@pCMTM5 underwent characterization through a transmission electron microscope (TEM) and dynamic light scattering (DLS). Employing RT-qPCR, western blot, flow cytometry, immunofluorescence, and co-immunoprecipitation (co-IP) assays, the consequences of CMTM5 overexpression on the expression of EGFR were investigated. Moreover, the influence of PEI-AuNCs@pCMTM5 on PC-3 cells was assessed through CCK-8, wound healing assay, and Transwell experiments. As a result, the PEI-AuNCs and PEI-AuNCs@pCMTM5 were presented as uniformly dispersed spherical with stable particle sizes and positive charges, showcasing favorable dispersion within the solution. In comparison to Lip2000, the PEI-AuNCs demonstrated superior transfection efficiency and lower cellular toxicity. Following the overexpression of CMTM5, the proliferative capacity of PC-3 cells was markedly suppressed, while both migratory and invasive abilities exhibited noteworthy reduction, with the efficacy of PEI-AuNCs@pCMTM5 consistently outperforming that of free pCMTM5. Subsequent mechanistic investigations unveiled that CMTM5 does not directly inhibit the synthesis of EGFR or facilitate its degradation, but rather influences the endocytic process of EGFR. In conclusion, the PEI-AuNCs nano-delivery system exhibits good biocompatibility and efficaciously conveys pCMTM5 to PCa cells. Crucially, pCMTM5 does not directly interact with EGFR, and CMTM5 governs the malignant progression of PC3 cells by promoting EGFR endocytosis.