alpha-TEA inhibits survival and enhances death pathways in cisplatin sensitive and resistant human ovarian cancer cells

Apoptosis. 2006 Oct;11(10):1813-23. doi: 10.1007/s10495-006-9234-5.

Abstract

RRR-alpha-tocopherol ether linked acetic acid analog (alpha-TEA), is a potential chemotherapeutic agent for ovarian cancer. Pro-death and pro-life signaling pathways were studied to understand the anti-cancer actions of alpha-TEA on cisplatin-sensitive (A2780S) and -resistant (A2780/cp70R) human ovarian cancer cells. Both cell lines were refractory to Fas; whereas, alpha-TEA sensitized them to Fas signaling. alpha-TEA increased levels of Fas message, protein and membrane-associated Fas. Neutralizing antibodies to Fas or Fas L partially blocked alpha-TEA-induced apoptosis. alpha-TEA induced prolonged activation of c-Jun N-terminal kinase (JNK) and its substrate c-Jun; Bax conformational change; and cleavage of Bid and caspases-8, -9 and -3. Chemical inhibitors of JNK, and caspases blocked alpha-TEA-induced apoptosis. alpha-TEA decreased phosphorylation of protein kinase B (Akt/PKB) and extracellular signal-regulated kinase (ERK1/2), as well as cellular FLICE-like inhibitory protein (c-FLIP) and Survivin protein levels. Knockdown of Akt and ERK activity using phosphoinositide- 3-kinase (PI3K) and mitogen-activated protein kinase kinase (MKK1) inhibitors enhanced alpha-TEA-induced apoptosis. Over-expression of constitutively active Akt2 and MKK1 blocked alpha-TEA-induced apoptosis. Collectively, data show alpha-TEA to be a potent apoptotic inducer of both cisplatin-sensitive and -resistant human ovarian cancer cells via activating death receptor Fas signaling and suppressing anti-apoptotic AKT and ERK targets.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenocarcinoma / drug therapy
  • Apoptosis / drug effects*
  • CASP8 and FADD-Like Apoptosis Regulating Protein / metabolism
  • Caspase 8 / metabolism
  • Cell Survival / drug effects
  • Cisplatin / pharmacology*
  • Down-Regulation / drug effects
  • Drug Resistance, Neoplasm / drug effects*
  • Enzyme Activation / drug effects
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Female
  • Humans
  • Inhibitor of Apoptosis Proteins
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • JNK Mitogen-Activated Protein Kinases / physiology
  • Microtubule-Associated Proteins / metabolism
  • Mitochondria / drug effects
  • Neoplasm Proteins / metabolism
  • Oncogene Protein v-akt / metabolism
  • Ovarian Neoplasms / drug therapy
  • Proto-Oncogene Proteins c-jun / metabolism
  • Proto-Oncogene Proteins c-jun / physiology
  • Signal Transduction / drug effects
  • Survivin
  • Tocopherols
  • Tumor Cells, Cultured
  • Vitamin E / analogs & derivatives*
  • Vitamin E / pharmacology
  • Vitamin E / therapeutic use
  • fas Receptor / metabolism

Substances

  • BIRC5 protein, human
  • CASP8 and FADD-Like Apoptosis Regulating Protein
  • FAS protein, human
  • Inhibitor of Apoptosis Proteins
  • Microtubule-Associated Proteins
  • Neoplasm Proteins
  • Proto-Oncogene Proteins c-jun
  • Survivin
  • fas Receptor
  • Vitamin E
  • Oncogene Protein v-akt
  • Extracellular Signal-Regulated MAP Kinases
  • JNK Mitogen-Activated Protein Kinases
  • CASP8 protein, human
  • Caspase 8
  • 2,5,7,8-tetramethyl-2R-(4R,8R,12-trimethyltridecyl)chroman-6-yloxy acetic acid
  • Cisplatin
  • Tocopherols