The novel phloroglucinol derivative BFP induces apoptosis of glioma cancer through reactive oxygen species and endoplasmic reticulum stress pathways

Phytomedicine. 2012 Sep 15;19(12):1093-100. doi: 10.1016/j.phymed.2012.06.010. Epub 2012 Jul 21.

Abstract

Prenyl-phloroglucinol derivatives from hop plants have been shown to have anticancer activities. This study is the first to investigate the anticancer effects of the new phloroglucinol derivative (2,4-bis(4-fluorophenylacetyl)phloroglucinol; BFP). BFP induced cell death and anti-proliferation in three glioma, U251, U87 and C6 cells, but not in primary human astrocytes. BFP-induced concentration-dependently cell death in glioma cells was determined by MTT and SRB assay. Moreover, BFP-induced apoptotic cell death in glioma cells was measured by Hochest 33258 staining and fluorescence-activated cell sorter (FACS) of propidine iodine (PI) analysis. Treatment of U251 human glioma cells with BFP was also found to induce reactive oxygen species (ROS) generation, which was detected by a fluorescence dye used FACS analysis. Treatment of BFP also increased a number of signature endoplasmic reticulum (ER) stress markers glucose-regulated protein (GRP)-78, GRP-94, IRE1, phosphorylation of eukaryotic initiation factor-2α (eIF-2α) and up-regulation of CAAT/enhancer-binding protein homologous protein (CHOP). Moreover, treatment of BFP also increased the down-stream caspase activation, such as pro-caspase-7 and pro-caspase-12 degradation, suggesting the induction of ER stress. Furthermore, BFP also induced caspase-9 and caspase-3 activation as well as up-regulation of cleaved PARP expression. Treatment of antioxidants, or pre-transfection of cells with GRP78 or CHOP siRNA reduced BFP-mediated apoptotic-related protein expression. Taken together, the present study provides evidences to support that ROS generation, GRP78 and CHOP activation are mediating the BFP-induced human glioma cell apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents, Phytogenic / pharmacology
  • Antineoplastic Agents, Phytogenic / therapeutic use*
  • Apoptosis / drug effects*
  • Benzoin / analogs & derivatives*
  • Benzoin / isolation & purification
  • Benzoin / pharmacology
  • Benzoin / therapeutic use
  • Biomarkers / metabolism
  • Caspases / metabolism
  • Cell Line, Tumor
  • Dose-Response Relationship, Drug
  • Endoplasmic Reticulum Chaperone BiP
  • Endoplasmic Reticulum Stress / drug effects*
  • Glioma / drug therapy*
  • Glioma / metabolism
  • Heat-Shock Proteins / metabolism
  • Humans
  • Humulus / chemistry*
  • Phloroglucinol / analogs & derivatives*
  • Phloroglucinol / isolation & purification
  • Phloroglucinol / pharmacology
  • Phloroglucinol / therapeutic use*
  • Phytotherapy
  • Plant Extracts / pharmacology
  • Plant Extracts / therapeutic use
  • Reactive Oxygen Species / metabolism*
  • Transcription Factor CHOP / metabolism

Substances

  • 2,4-bis(4-fluorophenylacetyl)phloroglucinol
  • Antineoplastic Agents, Phytogenic
  • Biomarkers
  • Endoplasmic Reticulum Chaperone BiP
  • HSPA5 protein, human
  • Heat-Shock Proteins
  • Plant Extracts
  • Reactive Oxygen Species
  • Transcription Factor CHOP
  • Phloroglucinol
  • Caspases
  • Benzoin