title: Dietary fish oil deactivates a growth-promoting signaling pathway in hepatoma 7288CTC in Buffalo rats.
abstract: Dietary fish oil decreases growth of solid tumors in rodents. Mechanisms for this effect are not well defined. In rat hepatoma 7288CTC, short-term (1-2 h) treatment with eicosapentaenoic acid during perfusion in situ reduced fatty acid uptake and [(3)H]thymidine incorporation. To determine if dietary fish oil had this effect in vivo, 48 male Buffalo rats were implanted with tissue-isolated hepatoma 7288CTC and were divided into three groups: Diet I (8% olive oil/2% corn oil), Diet II (6% olive oil/2% corn oil/2% fish oil), or Diet III (3% olive oil/3% corn oil/4% fish oil). When tumors weighed 4 to 6 g rats were anesthetized and tumor fatty acid uptake and 13-hydroxyoctadecadienoic acid release were measured in vivo by arterial minus venous differences. Tumors were analyzed for cyclic adenosine monophosphate (cAMP), DNA content, and [(3)H]thymidine incorporation. Fish oil feeding significantly (P < 0.05) reduced tumor growth, cAMP content, fatty acid uptake, 13-hydroxyoctadecadienoic acid formation, DNA content, and [(3)H]thymidine incorporation. Addition of either pertussis toxin or 8-bromoadenosine-cAMP to the arterial blood reversed the inhibitions in tumors in rats fed diet II. These results provide in vivo evidence that dietary fish oil suppressed a specific linoleic acid-dependent, inhibitory G protein-coupled, growth-promoting signaling pathway in rat hepatoma 7288CTC.
authors.affiliation: Bassett Research Institute, Cooperstown, NY 13326, USA.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Smith
authors.forename: Erin M
authors.initials: EM
authors.lastname: Dauchy
authors.forename: Robert T
authors.initials: RT
authors.lastname: Dauchy
authors.forename: Leonard A
authors.initials: LA
authors.lastname: Sauer
authors.forename: David E
authors.initials: DE
authors.lastname: Blask
authors.forename: Leslie K
authors.initials: LK
authors.lastname: Davidson
authors.forename: Jean A
authors.initials: JA
authors.lastname: Krause
authors.forename: Darin T
authors.initials: DT
authors.lastname: Lynch
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects*; D000242:Cyclic AMP / Q000378:metabolism; D004273:DNA, Neoplasm / Q000378:metabolism*; D004042:Dietary Fats, Unsaturated / Q000378:metabolism / Q000494:pharmacology*; D005395:Fish Oils; D008041:Linoleic Acids / Q000378:metabolism; D008114:Liver Neoplasms, Experimental / Q000098:blood supply / Q000473:pathology*; D008297:Male; D011897:Random Allocation; D051381:Rats; D011915:Rats, Inbred BUF; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D004273:DNA, Neoplasm; D004042:Dietary Fats, Unsaturated; D005395:Fish Oils; D008041:Linoleic Acids; C024348:13-hydroxy-9,11-octadecadienoic acid; D000242:Cyclic AMP