Investigation of prunetrin induced G2/M cell cycle arrest and apoptosis via Akt/mTOR/MAPK pathways in hepatocellular carcinoma cells

Biomed Pharmacother. 2024 May:174:116483. doi: 10.1016/j.biopha.2024.116483. Epub 2024 Mar 28.

Abstract

Hepatocellular carcinoma (HCC) stands as a leading cause of mortality, and despite recent advancements in the overall survival rates, the prognosis remains dismal. Prunetin 4-O-glucoside (Prunetrin or PUR), an active compound derived from Prunus sp., was explored for its impact on HepG2 and Huh7 cells. The cytotoxicity assessment revealed a notable reduction in cell viability in both cell lines, while exhibiting non-toxicity towards HaCaT cells. Colony formation studies underscored PUR's inhibitory effect on cell proliferation, dose-dependently. Mechanistically, PUR downregulated cell cycle proteins (CDC25c, Cdk1/CDC2, and Cyclin B1), inducing G2/M phase arrest, corroborated by flow cytometry. Western blot analyses exhibited dose-dependent cleavages of PARP and caspase 3, indicative of apoptosis. Treatment with the apoptotic inhibitor z-vmd-fmk provided evidence of PUR-induced apoptosis. Annexin V and PI flow cytometry further affirmed apoptotic induction. Enhanced expression of cleaved-caspase 9 and the pro-apoptotic protein Bak, coupled with reduced anti-apoptotic Bcl-xL, and affirmed PUR's induction of intrinsic apoptosis. Additionally, PUR activated the MAPK pathway, evidenced by elevated phospho p38 and phospho ERK expressions in both cell lines. Notably, a concentration-dependent decrease in mTOR and Akt expressions indicated PUR's inhibition of the Akt/mTOR pathway in HepG2 and Huh7 cells. These findings illuminate PUR's multifaceted impact, revealing its potential as a promising therapeutic agent against HepG2 and Huh7 cells through modulation of cell cycle, apoptosis, and key signaling pathways.

Keywords: Apoptosis; Cell cycle arrest; Flavonoids; HepG2 cells; Hepatocellular carcinoma; Huh7 cells.

MeSH terms

  • Apoptosis* / drug effects
  • Carcinoma, Hepatocellular* / drug therapy
  • Carcinoma, Hepatocellular* / metabolism
  • Carcinoma, Hepatocellular* / pathology
  • Cell Cycle Checkpoints / drug effects
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • G2 Phase Cell Cycle Checkpoints* / drug effects
  • Hep G2 Cells
  • Humans
  • Isoflavones / pharmacology
  • Liver Neoplasms* / drug therapy
  • Liver Neoplasms* / metabolism
  • Liver Neoplasms* / pathology
  • MAP Kinase Signaling System / drug effects
  • Proto-Oncogene Proteins c-akt* / metabolism
  • Signal Transduction / drug effects
  • TOR Serine-Threonine Kinases / drug effects
  • TOR Serine-Threonine Kinases / metabolism

Substances

  • MTOR protein, human
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases
  • prunetin
  • Isoflavones