RRR-alpha-tocopheryl succinate inhibits EL4 thymic lymphoma cell growth by inducing apoptosis and DNA synthesis arrest

Nutr Cancer. 1997;27(1):92-101. doi: 10.1080/01635589709514508.

Abstract

RRR-alpha-tocopheryl succinate (vitamin E succinate, VES) treatment of murine EL4 T lymphoma cells induced the cells to undergo apoptosis. After 48 hours of VES treatment at 20 micrograms/ml, 95% of cells were apoptotic. Evidence for the induction of apoptosis by VES treatments is based on staining of DNA for detection of chromatin condensation/fragmentation, two-color flow-cytometric analyses of DNA content, and end-labeled DNA and electrophoretic analyses for detection of DNA ladder formation. VES-treated EL4 cells were blocked in the G1 cell cycle phase; however, apoptotic cells came from all cell cycle phases. Analyses of mRNA expression of genes involved in apoptosis revealed decreased c-myc and increased bcl-2, c-fos, and c-jun mRNAs within three to six hours after treatment. Western analyses showed increased c-Jun, c-Fos, and Bcl-2 protein levels. Electrophoretic mobility shift assays showed increased AP-1 binding at 6, 12, and 24 hours after treatment and decreased c-Myc binding after 12 and 24 hours of VES treatment. Treatments of EL4 cells with VES+RRR-alpha-to-copherol reduced apoptosis without effecting DNA synthesis arrest. Treatments of EL4 cells with VES+rac-6-hydroxyl-2, 5,7,8-tetramethyl-chroman-2-carboxylic acid, butylated hydroxytoluene, or butylated hydroxyanisole had no effect on apoptosis or DNA synthesis arrest caused by VES treatments. Analyses of bcl-2, c-myc, c-jun, and c-fos mRNA levels in cells receiving VES + RRR-alpha-tocopherol treatments showed no change from cells receiving VES treatments alone, implying that these changes are correlated with VES treatments but are not causal for apoptosis. However, treatments with VES + RRR-alpha-tocopherol decreased AP-1 binding to consensus DNA oligomer, suggesting AP-1 involvement in apoptosis induced by VES treatments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Base Sequence
  • Blotting, Northern
  • Blotting, Western
  • Cell Cycle
  • DNA, Neoplasm / analysis
  • DNA, Neoplasm / biosynthesis*
  • DNA, Neoplasm / genetics
  • Flow Cytometry / methods
  • Gene Expression Regulation, Neoplastic
  • Lymphoma / chemistry
  • Lymphoma / metabolism*
  • Lymphoma / pathology*
  • Mice
  • Mice, Inbred C57BL
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Proto-Oncogene Proteins c-fos / genetics
  • Proto-Oncogene Proteins c-fos / metabolism
  • Proto-Oncogene Proteins c-jun / genetics
  • Proto-Oncogene Proteins c-jun / metabolism
  • Proto-Oncogene Proteins c-myc / genetics
  • Proto-Oncogene Proteins c-myc / metabolism
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Thymidine / metabolism
  • Thymus Neoplasms / chemistry
  • Thymus Neoplasms / metabolism*
  • Thymus Neoplasms / pathology*
  • Tocopherols
  • Transcription Factor AP-1 / genetics
  • Transcription Factor AP-1 / metabolism
  • Tumor Cells, Cultured
  • Vitamin E / analogs & derivatives*
  • Vitamin E / pharmacology

Substances

  • DNA, Neoplasm
  • Proto-Oncogene Proteins c-bcl-2
  • Proto-Oncogene Proteins c-fos
  • Proto-Oncogene Proteins c-jun
  • Proto-Oncogene Proteins c-myc
  • RNA, Messenger
  • Transcription Factor AP-1
  • Vitamin E
  • Tocopherols
  • Thymidine