Epigallocatechin gallate-capped gold nanoparticles enhanced the tumor suppressors let-7a and miR-34a in hepatocellular carcinoma cells.

Shady M Mostafa,Nabila Abd El Maksoud,Amira M Gamal-Eldeen,Abdelgawad A Fahmi

doi:10.1590/0001-3765202020200574

Shady M Mostafa, Nabila Abd El Maksoud + Show 2 more

Open Access

https://doi.org/10.1590/0001-3765202020200574

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Abstract

Epigallocatechin gallate (EGCG), major constituent of green tea, possesses antioxidant, antiviral, and anticancer activities. Gold nanoparticles (AuNPs) play an important role in drug delivery due to their stability, ease of surface functionalization, and unique optical properties. This study aimed to investigate the influence of EGCG-capped AuNPs on tumor suppressor miRNAs (miR-34a and let-7a) and their targeted cell death mediators in HepG2 cells, compared with celastrol. EGCG-AuNPs were prepared and characterized. antioxidant activity was estimated by DPPH scavenging assay; cytotoxicity was assessed by MTT assay; let-7a and miR-34a expression was analyzed by qPCR; and miRNAs targets (c-Myc and caspase-3) were assessed by ELISA and immunocytofluorescence, respectively. The average size of EGCG-AuNPs was 35 nm, with a λmax of ~535 nm. EGCG-AuNPs exerted cytotoxicity on HepG2 cells stronger than that of EGCG alone. EGCG-AuNPs and EGCG presented half-maximal radical scavenging concentrations (SC50) of 539 µg/ml and 45 µg/ml, respectively. The expression levels of let-7a and miR-34a were significantly elevated in HepG2 cells after EGCG-AuNP treatment for 72 h. c-Myc protein expression was reduced, whereas caspase-3 expression was increased following treatment with EGCG-AuNPs. In conclusion, Au-NPs are effective carrier for EGCG, and EGCG-AuNPs are promising anti-cancer agent.

Highlights

Hepatocellular carcinoma (HCC) comprises approximately 75% of all liver cancer diseases
The sizes of the prepared Epigallocatechin gallate (EGCG)-AuNPs were measured by Transmission electron microscopy (TEM), which revealed that the prepared nanoparticles were spherical in shape and that the particle size associated with the normal distribution with 35 nm in diameter, on average (Fig. 1b)
Accumulating evidence shows that EGCG inhibits growth and induces apoptosis in hepatocellular carcinoma cells and liver cancer cells (Du et al 2012)

Summary

Introduction

Hepatocellular carcinoma (HCC) comprises approximately 75% of all liver cancer diseases. Current treatments for HCC include surgical resection, transplantation, and chemical therapy (e.g., Sorafenib), which is associated with low disease stabilization, due to acquired resistance (Petrick & McGlynn 2019). Catechins are the major constituents in green tea, with epigallocatechin gallate (EGCG) accounting for 65% of total catechins. EGCG has gained attention due to its antioxidant (Hu et al 2006), antiviral, and antimicrobial (Al-Shaeli et al 2019) activities, and as an anti-tumor agent that can target tumor cells rather than normal cells (Al-Shaeli et al 2019, Zan et al 2019, Tauber et al 2020, Chen et al 2019). The structure-function relationship of EGCG, as an anti-cancer agent, has been documented by several studies.

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