Fisetin Inhibits Autophagy in HepG2 Cells via PI3K/Akt/mTOR and AMPK Pathway

Area of Science:

• * Molecular Biology
• * Cellular Biology
• * Pharmacology

Background:

• * Autophagy plays a complex role in hepatocellular carcinoma (HCC) development and progression.
• * The specific effects of fisetin, a natural flavonoid, on autophagy in HCC are not well understood.
• * Investigating fisetin's impact on autophagy could reveal novel therapeutic targets for HCC.

Purpose of the Study:

• * To elucidate the effect of fisetin on autophagy in hepatocellular carcinoma (HCC) cells.
• * To determine the underlying molecular mechanisms, including the involvement of PI3K/Akt/mTOR and AMPK signaling pathways.
• * To assess the potential of fisetin as a therapeutic agent against HCC by modulating autophagy.

Main Methods:

• * HepG2 cells were treated with varying concentrations of fisetin (25–100 µM) and autophagy modulators (rapamycin, chloroquine).
• * Autophagic flux, ATP levels, gene expression (qRT-PCR), and protein levels (Western blotting) of key autophagy and signaling markers were analyzed.
• * Flow cytometry was used to quantify autophagic flux formation via Cyto-ID staining.

Main Results:

• * Fisetin significantly decreased autophagic flux formation in HepG2 cells in a dose-dependent manner.
• * Gene expression analysis revealed altered mRNA levels of autophagy-related genes (mTOR, Atg5, Atg16L, LC3A, Atg7, Beclin1).
• * Western blotting indicated fisetin's modulation of autophagy markers (Atg7, Atg16L, Atg5) and activation of AMPK signaling (AMPKα, AMPKβ1/2, ACC) and PI3K/Akt/mTOR pathway components (Akt, mTOR).

Conclusions:

• * Fisetin inhibits autophagy in hepatocellular carcinoma cells.
• * The mechanism involves the activation of the PI3K/Akt/mTOR pathway and modulation of the AMPK signaling pathway.
• * Suppression of autophagy by fisetin presents a potential therapeutic strategy for treating HCC.