This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chapkin, R. S. Articles by Erickson, K. L. Search for Related Content PubMed PubMed Citation Articles by Chapkin, R. S. Articles by Erickson, K. L.

Linoleic Acid Metabolism in Metastatic and Nonmetastatic Murine Mammary Tumor Cells¹

Department of Human Anatomy, School of Medicine, University of California, Davis, California 95616

The mechanism(s) by which dietary linoleic acid (18:2n-6) enhances mammary tumor growth and metastasis is not known. Since arachidonic acid (20:4n-6)-derived prostaglandins (PG) may play a role in the metastatic dissemination of tumor cells, the ability of two murine mammary tumor cell lines, 4526 (metastasis positive) and line 168 (spontaneous metastasis negative), to convert 18:2n-6 into prostaglandins was examined. Cells were initially incubated with [¹⁴C]18:2n-6 and after 8–24 h the [¹⁴C]fatty acids were quantitated by high-performance liquid chromatography following transesterification. [¹⁴C]18:2n-6 was metabolized primarily to [¹⁴C]dihomogammalinolenic acid (20:3n-6) in line 4526 cells and [¹⁴C]20:4n-6 in line 168 cells. Examination of cellular fatty acid levels revealed a 20:3n-6/20:4n-6 ratio of 1.79 ± 0.36 and 0.20 ± 0.02 in line 4526 and 168 cells, respectively. These data are consistent with an inherently lower 5 desaturase activity in line 4526 relative to 168. To assess the metabolism of 18:2n-6 into eicosanoid products, the cell lines were prelabeled with [¹⁴C]18:2n-6 or 0–40 µM nonradiolabeled 18:2n-6 overnight and subsequently stimulated with calcium ionophore A23187 for 1 h. Total PGE production, as determined by radioimmunoassay, was greater in 168 relative to 4526 cells at all 18:2n-6 concentrations. ¹⁴C-prostaglandins detected by high-performance liquid chromatography and argentation thin-layer chromatography were: PGF₁ and PGE₁ (derived from 20:3n-6) and PGF₂ and PGE₂ (derived from 20:4n-6) from line 4526; PGE₁ and PGE₂ from line 168. PGE₁/PGE₂ ratios were 1.43 ± 0.07 and 0.23 ± 0.03 for 4526 and 168 lines, respectively. Neither cell line synthesized lipoxygenase products following [¹⁴C]18:2n-6 or [³H]20:4n-6 incubations under the conditions employed. Additional studies are warranted in order to define the biological properties of 1- and 2- series cyclooxygenase products as they relate to tumor cell metastasis.

¹ Supported by NIH Grant CA-47050 and a grant from the National Dairy Board (administered by the National Dairy Council). Portions of this study were presented at the joint meeting of the American Society for Biochemistry and Molecular Biology and the American Society for Cell Biology, January 1989, San Francisco, California, and the Federation of American Societies for Experimental Biology, March 1989, New Orleans, Louisiana.

² To whom requests for reprints should be addressed, at Molecular and Cell Biology Section, Department of Animal Science, Texas A&M University, College Station, TX 77843-2471.

Received 1/18/89. Revised 4/24/89. Accepted 5/26/89.

This article has been cited by other articles:

				V. Pala, V. Krogh, P. Muti, V. Chajes, E. Riboli, A. Micheli, M. Saadatian, S. Sieri, and F. Berrino Erythrocyte Membrane Fatty Acids and Subsequent Breast Cancer: a Prospective Italian Study J Natl Cancer Inst, July 18, 2001; 93(14): 1088 - 1095. [Abstract] [Full Text] [PDF]

				M. S. Nussbaum Total Parenteral Nutrition and Tumor Metastases M. H. TOROSIAN, ROBERT B. DONOWAY Surgery 109:597-601, 1991 JPEN J Parenter Enteral Nutr, January 1, 1992; 16(1): 86 - 87. [Abstract] [PDF]