Induction of cell cycle arrest and apoptosis by tomentosin in hepatocellular carcinoma HepG2 and Huh7 cells

Hum Exp Toxicol. 2021 Feb;40(2):231-244. doi: 10.1177/0960327120943935. Epub 2020 Aug 13.

Abstract

Tomentosin, a sesquiterpene lactone, is known to possess various biological activities. However, its anticarcinogenic activity against human hepatocellular carcinoma (HCC) cells has not been investigated in detail. Thus, this study aimed to elucidate the cytotoxic mechanism of tomentosin in human HCC cell lines HepG2 and Huh7. WST-1, cell counting, and colony formation assay results showed that treatment with tomentosin decreased the viability and suppressed the proliferation rate of HepG2 and Huh7 cells in a dose- and time-dependent manner. Cell cycle analysis revealed increased population of cells at the SubG1 and G2/M stage, and decreased population of cells at the G0/1 stage in HepG2 and Huh7 cells treated with tomentosin. Annexin V/propidium iodide double staining and TUNEL assay results showed increased apoptotic cell population and DNA fragmentation in HepG2 and Huh7 cells treated with tomentosin. Western blotting analysis results showed that tomentosin treatment significantly increased the expression level of Bax, Bim (short form), cleaved PARP1, FOXO3, p53, pSer15p53, pSer20p53, pSer46p53, p21, and p27, but decreased the expression of Bcl2, caspase3, caspase7, caspase9, cyclin-dependent kinase 2 (CDK2), CDK4, CDK6, cyclinB1, cyclinD1, cyclinD2, cyclinD3, and cyclinE in a dose-dependent manner. Taken together, this study revealed that tomentosin, which acted through cell cycle arrest and apoptosis, may be a useful therapeutic option against HCC.

Keywords: FOXO3; Tomentosin; apoptosis; cell cycle arrest; hepatocellular carcinoma; p53.

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Carcinoma, Hepatocellular / drug therapy*
  • Carcinoma, Hepatocellular / metabolism
  • Caspases / metabolism
  • Cell Cycle Checkpoints / drug effects
  • Cell Line, Tumor
  • Cyclin-Dependent Kinases / metabolism
  • Cyclins / metabolism
  • Forkhead Box Protein O3 / metabolism
  • Humans
  • Lactones / pharmacology*
  • Liver Neoplasms / drug therapy*
  • Liver Neoplasms / metabolism
  • Mitogen-Activated Protein Kinases / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Sesquiterpenes / pharmacology*
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • Antineoplastic Agents
  • Cyclins
  • FOXO3 protein, human
  • Forkhead Box Protein O3
  • Lactones
  • Sesquiterpenes
  • Tumor Suppressor Protein p53
  • tomentosin
  • Proto-Oncogene Proteins c-akt
  • Cyclin-Dependent Kinases
  • Mitogen-Activated Protein Kinases
  • Caspases