Linoleic Acid Metabolism in Metastatic and Nonmetastatic Murine Mammary Tumor Cells | Academic Article individual record
abstract

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. [4C]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 Δ5 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: PGF1α and PGE1 (derived from 20: 3n−6) and PGF2α and PGE2 (derived from 20: 4n−6) from line 4526; PGE1 and PGE2 from Une 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. © 1989, American Association for Cancer Research. All rights reserved.

author list (cited authors)
Chapkin, R. S., Hubbard, N. E., Buckman, D. K., & Erickson, K. L.
publication date
1989
published in
keywords
  • Arachidonic Acid
  • Prostaglandins
  • Mammary Neoplasms, Experimental
  • Linoleic Acids
  • Fatty Acids, Unsaturated
  • Mice
  • Arachidonic Acids
  • Prostaglandin-Endoperoxide Synthases
  • Tumor Cells, Cultured
  • Linoleic Acid
  • Animals
  • Female
  • Neoplasm Metastasis