Lipids

, Volume 36, Issue 10, pp 1161–1168

Modulation of arachidonic acid distribution by conjugated linoleic acid isomers and linoleic acid in MCF-7 and SW480 cancer cells

Article

DOI: 10.1007/s11745-001-0827-0

Cite this article as:
Miller, A., Stanton, C. & Devery, R. Lipids (2001) 36: 1161. doi:10.1007/s11745-001-0827-0

Abstract

The relationship between growth and alterations in arachidonic acid (AA) metabolism in human breast (MCF-7) and colon (SW480) cancer cells was studied. Four different fatty acid preparations were evaluated: a mixture of conjugated linoleic acid (CLA) isomers (c9,t11, t10,c12,c11,t13, and minor amounts of other isomers), the pure c9,t11-CLA isomer, the pure t10,c12-CLA isomer, and linoleic acid (LA) (all at a lipid concentration of 16 μg/mL). 14C-AA uptake into the monoglyceride fraction of MCF-7 cells was significantly increased following 24 h incubation with the CLA mixture (P<0.05) and c9,t11-CLA (P<0.02). In contrast to the MCF-7 cells, 14C-AA uptake into the triglyceride fraction of the SW480 cells was increased while uptake into the phospholipids was reduced following treatment with the CLA mixture (P<0.02) and c9,t11-CLA (P<0.05). Distribution of 14C-AA among phospholipid classes was altered by CLA treatments in both cell lines. The c9,t11-CLA isomer decreased (P<0.05) uptake of 14C-AA into phosphatidylcholine while increasing (P<0.05) uptake into phosphatidylethanolamine in both cell lines. Both the CLA mixture and the t10,c12-CLA isomer increased (P<0.01) uptake of 14C-AA into phosphatidylserine in the SW480 cells but had no effect on this phospholipid in the MCF-7 cells. Release of 14C-AA derivatives was not altered by CLA treatments but was increased (P<0.05) by LA in the SW480 cell line. The CLA mixture of isomers and c9,t11-CLA isomer inhibited 14C-AA conversion to 14C-prostaglandin E2 (PGE2) by 20–30% (P<0.05) while increasing 14C-PGF by 17–44% relative to controls in both cell lines. LA significantly (P<0.05) increased 14C-PGD2 by 13–19% in both cell lines and increased 14C-PGE2 by 20% in the SW480 cell line only. LA significantly (P<0.05) increased 5-hydroperoxyeicosatetraenoate by 27% in the MCF-7 cell line. Lipid peroxidation, as determined by increased levels of 8-epi-prostaglandin F (8-epi-PGF), was observed following treatment with c9,t11-CLA isomer in both cell lines (P<0.02) and with t10,c12-CLA isomer in the MCF-7 cell line only (P<0.05). These data indicate that the growth-promoting effects of LA in the SW480 cell line may be associated with enhanced conversion of AA to PGE2 but that the growth-suppressing effects of CLA isomers in both cell lines may be due to changes in AA distribution among cellular lipids and an altered prostaglandin profile.

Abbreviations

AA

arachidonic acid

CLA

conjugated linoleic acid

5-HPETE

5-hydroperoxyeicosatetraenoate

IP3

inositol triphosphate

LA

linoleic acid

LTB4

leukotriene B4

MG

monoglyceride

PBS

phosphate-buffered saline

PC

phosphatidylcholine

PE

phosphatidylethanolamine

PG

prostaglandin

PGD2

prostaglandin D2

PGE2

prostaglandin E2

PGF

prostaglandin F

PI

phosphatidylinositol

PKC

protein kinase C

PL

phospholipid

PLA2

phospholipase A2

PLC

phospholipase C

PS

phosphatidylserine

TG

triglyceride

TLC

thin-layer chromatography

Copyright information

© AOCS Press 2001

Authors and Affiliations

  • Aine Miller
    • 2
  • Catherine Stanton
    • 1
  • Rosaleen Devery
    • 2
  1. 1.Teagasc, Dairy Products Research CentreFermoyIreland
  2. 2.School of BiotechnologyDublin City UniversityDublinIreland