Effect of gold nanoparticles on cytochrome P450 gene expression in HEPG2 cell line

Abstract

Gold nanoparticles (AuNPs) have been recently used for many clinical applications including drug delivery, therapeutics and diagnostics. AuNPs were synthesized by using the chemical reduction method with different stabilizers, citrate and polyethyleneimine (PEI), the AuNPs were determined for their effect on human cytochrome P450 (CYP) mRNA induction, namely CYP1A1, CYP1A2, CYP2C9, CYP2E1 and CYP3A4, using real-time PCR technique. The average particle diameters of freshly prepared citrate- and PEI-stabilized AuNPs were 15.00 ± 2.77 and 5.02 ± 1.81 nm, respectively. The zeta potentials of citrate and PEI-stabilized AuNPs were -40.60 ± 1.22 and 8.10 ± 1.59 mV, in orderly. Citrate-stabilized AuNPs (AuCi) has shown to have no cytotoxicity on HepG2 cells at the maximum concentration of 90 µM whereas IC₅₀ of PEI-stablilized AuNPs (AuPEI) was found to be 37.58 ± 1.15 µM. The significance in induction effect (p≤0.05) of AuCi at 10 µM observed on CYP1A2 and CYP2C9 was 2.32 ± 0.35 and 1.65 ± 0.39 folds, consecutively. AuPEI at a concentration of 1 µM significantly induced (p≤0.05) CYP1A1 and CYP1A2 up to 1.68 ± 0.35 and 2.08 ± 0.56 folds, respectively. The mixtures of AuNPs and CYP inducers, α-naphthoflavone for CYP1A and rifampicin for CYP2C9 and CYP3A4, decreased the effect of inducers significantly (p≤0.05) on CYP1A1, CYP1A2, CYP2C9 and CYP3A4 for AuCi, and on CYP1A1, CYP2C9 and CYP3A4 for AuPEI. Noticeably, the mixture of AuPEI at 1 µM and the inducer had a synergistic induction on CYP1A2 (p≤0.05). The potential of CYP induction of AuNPs seemed to depend upon the size and charge of AuNPs. AuPEI was about 3 times smaller in size than AuCi and contained positive charges which could support the cellular penetration. Nevertheless, the mechanism of CYP induction by AuNPs are suggested for further study.