Dose-dependent effect of dietary conjugated linoleic acid on the growth of rat hepatoma dRLh-84 cells in vivo.
In this study, the effect of varying doses of conjugated linoleic acid (CLA) on the growth of transplanted hepatoma dRLh-84 cells and the relationship between tumor growth and prostaglandin (PG) E2 production or cyclooxygenase (COX)-2 expression were examined. Donryu rats were fed an experimental diet containing 0, 0.1, 0.5, or 2 wt.% CLA for 3 wk, and then dRLh-84 cells were transplanted into the liver. Results show that dietary CLA (0.5 and 2 wt.%) significantly enhanced the growth of the transplanted hepatoma cells compared to the non-CLA diet group at 20 d after cell transplantation. Tumor weight at 10 d after transplantation was also significantly higher in the 2 wt.% CLA group than in non-CLA fed rats. Ten days after transplantation, the PGE2 level in the tumor tissue was shown to be depressed in a CLA dose-dependent manner. Cyclooxygenase-2 (COX-2) mRNA expression in the tumor also tended to be lower in the CLA group than in the non-CLA diet group 10 d after transplantation. Dietary CLA did not affect the tumor phospholipid arachidonic acid level, which is a substrate for PG synthesis. These results indicate that dietary CLA of at least 0.5 wt.% enhances the growth of transplanted dRLh-84 cells in vivo. It is believed that growth promotion of dRLh-84 cells in vivo by CLA cannot be clarified by the PG synthesis dependent mechanism.
Yamasaki
Masao
M
Laboratory of Food Chemistry, Division of Applied Biological Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
Ikeda
Atsushi
A
Hirao
Akira
A
Tanaka
Yoko
Y
Rikimaru
Tatsuya
T
Shimada
Mitsuo
M
Sugimachi
Keizo
K
Tachibana
Hirofumi
H
Yamada
Koji
K
D000818:Animals; D015139:Blotting, Southern; D001835:Body Weight / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D051546:Cyclooxygenase 2; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D015232:Dinoprostone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D019787:Linoleic Acid / Q000494:pharmacology*; D008099:Liver / Q000033:anatomy & histology / Q000187:drug effects; D008114:Liver Neoplasms, Experimental / Q000378:metabolism / Q000473:pathology*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010743:Phospholipids / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
D004042:Dietary Fats, Unsaturated; D007527:Isoenzymes; D010743:Phospholipids; D012333:RNA, Messenger; D019787:Linoleic Acid; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone