       Document 0747
 DOCN  M9620747
 TI    ET-18-OCH3 inhibits nuclear factor-kappa B activation by
       12-O-tetradecanoylphorbol-13-acetate but not by tumor necrosis
       factor-alpha or interleukin 1 alpha.
 DT    9602
 AU    Daniel LW; Civoli F; Rogers MA; Smitherman PK; Raju PA; Roederer M;
       Department of Biochemistry, Bowman Gray School of Medicine, Wake; Forest
       University, Winston-Salem, North Carolina 27157-1016, USA.
 SO    Cancer Res. 1995 Nov 1;55(21):4844-9. Unique Identifier : AIDSLINE
       MED/96046585
 AB    1-O-Octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) is a
       synthetic diether phospholipid that is competitive with
       phosphatidylserine binding to the regulatory domain of protein kinase C
       (PKC). Our previous studies indicate that the selective inhibition of
       tumor cell growth by ET-18-OCH3 may be due to altered signal
       transduction mechanisms, including the inhibition of PKC. To further
       define the mechanism of action of ET-18-OCH3, we have used it to study
       the role of PKC in regulation of the transcription factor NF-kappa B,
       which is activated by diverse stimuli. In the 293.27.2 human kidney cell
       line, as in hematopoietic cells of all lineages, NF-kappa B is
       stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA), tumor necrosis
       factor-alpha (TNF-alpha), and interleukin-1 alpha (IL-1 alpha). The
       response to either TNF-alpha or IL-1 alpha is synergistically enhanced
       by TPA. However, the regulatory mechanisms and signal transduction
       systems responsible for NF-kappa B activation in response to these
       different stimuli have not been determined in detail. We have used
       ET-18-OCH3 and auranofin, which inhibit PKC by different mechanisms, to
       assess the role of PKC in NF-kappa B activation. ET-18-OCH3 markedly
       inhibits TPA-induced NF-kappa B activation, as measured by HIV long
       terminal repeat-directed expression of beta-galactosidase. The IC50 for
       inhibition by ET-18-OCH3 is approximately 2 microM, a noncytotoxic
       concentration. Inhibition of TPA-induced NF-kappa B activation was
       dependent upon preincubation with ET-18-OCH3, and the drug was active at
       approximately 2 mol% of total cellular phospholipid. ET-18-OCH3 did not
       inhibit NF-kappa B activation by either TNF-alpha or IL-1 alpha,
       indicating that there are multiple distinct signal transduction pathways
       leading to activation of NF-kappa B. We have confirmed these results
       using auranofin, an antirheumatic drug that is a specific PKC inhibitor
       interacting with the catalytic domain. Like ET-18-OCH3, auranofin
       blocked NF-kappa B activation by TPA but not by TNF-alpha or IL-1 alpha.
       Also like the ether lipid, auranofin only partially blocked the synergy
       exhibited by TPA and TNF-alpha. To confirm the role of NF-kappa B in
       this response, we measured NF-kappa B by electrophoretic mobility shift
       assay. Both ET-18-OCH3 and auranofin inhibited cellular induction of the
       active NF-kappa B complex in response to TPA but not in response to
       TNF-alpha.(ABSTRACT TRUNCATED AT 400 WORDS)
 DE    Antineoplastic Agents/*PHARMACOLOGY  Auranofin/PHARMACOLOGY
       Carcinogens/*ANTAGONISTS & INHIB/*PHARMACOLOGY  Cell Line  Cell
       Survival/DRUG EFFECTS  Drug Interactions  Enzyme Inhibitors/PHARMACOLOGY
       Gene Expression/DRUG EFFECTS  Human  HIV/GENETICS
       Interleukin-1/*PHARMACOLOGY  Kidney/CYTOLOGY  NF-kappa B/*ANTAGONISTS &
       INHIB/*DRUG EFFECTS  Phospholipid Ethers/*PHARMACOLOGY  Protein Kinase
       C/ANTAGONISTS & INHIB/PHYSIOLOGY  Repetitive Sequences, Nucleic Acid
       Stimulation, Chemical  Support, Non-U.S. Gov't  Support, U.S. Gov't,
       P.H.S.  Tetradecanoylphorbol Acetate/*ANTAGONISTS & INHIB/*PHARMACOLOGY
       Transfection  Tumor Necrosis Factor/*PHARMACOLOGY  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

