kappa-Opioid Receptor Potentiates Apoptosis via a Phospholipase C Pathway in the CNE2 Human Epithelial Tumor Cell Line

Biochim Biophys Acta. 2000 Dec 11;1499(1-2):49-62. doi: 10.1016/s0167-4889(00)00107-5.

Abstract

The mechanism by which kappa-opioid receptor (kappaor) modulated apoptosis was investigated in CNE2 human epithelial tumor cells. Induction of these cells to undergo apoptosis with staurosporine was associated with a massive increase in intracellular cAMP level. The inhibition of the increase in cAMP partially inhibited apoptosis as evidenced by a reduction of PARP and caspase-3 cleavage. Accordingly, a low but significant level of apoptosis is induced in these cells by the elevation of cAMP through the addition of forskolin and isobutylmethylxanthine. The existence of a cAMP-dependent and a cAMP-independent apoptotic pathway is therefore suggested. Receptor binding studies, RT-PCR experiments and Western blot analysis demonstrated the presence of type 1 kappaor in the CNE2 cells. Stimulation of kappaor in these cells resulted in the production of inositol (1,4,5)-trisphosphate, reduction of cAMP level and a marked enhancement of staurosporine-induced apoptosis. The potentiation of apoptosis by kappaor was prevented by inhibition of phospholipase C but was slightly enhanced by the presence of the active cAMP analogues, 8-CPT-cAMP and dibutyryl-cAMP. These data demonstrate for the first time that the phospholipase C pathway activated by type 1 kappaor expressed by cancer cells is involved in the potentiation of apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer / pharmacology
  • Adenine / analogs & derivatives*
  • Adenine / pharmacology
  • Apoptosis*
  • Base Sequence
  • Benzomorphans / pharmacology
  • Cell Membrane / drug effects
  • Colforsin / pharmacology
  • Cyclic AMP / metabolism
  • Dideoxyadenosine / pharmacology
  • Drug Synergism
  • Epithelial Cells / physiology*
  • Estrenes / pharmacology
  • Humans
  • Molecular Sequence Data
  • Pyrrolidinones / pharmacology
  • Receptors, Opioid, kappa / drug effects
  • Receptors, Opioid, kappa / physiology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction
  • Staurosporine / antagonists & inhibitors
  • Staurosporine / pharmacology
  • Tumor Cells, Cultured
  • Type C Phospholipases / antagonists & inhibitors
  • Type C Phospholipases / physiology*

Substances

  • Benzomorphans
  • Estrenes
  • Pyrrolidinones
  • Receptors, Opioid, kappa
  • 1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione
  • 9-(tetrahydro-2-furyl)-adenine
  • Colforsin
  • Dideoxyadenosine
  • 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer
  • Cyclic AMP
  • Type C Phospholipases
  • Staurosporine
  • bremazocine
  • Adenine