Docosahexaenoic acid reduces sterol regulatory element binding protein-1 and fatty acid synthase expression and inhibits cell proliferation by inhibiting pAkt signaling in a human breast cancer MCF-7 cell line
Journal
BMC Cancer
Journal Volume
17
Journal Issue
1
Pages
890
Date Issued
2017
Author(s)
Abstract
Background: Fatty acid synthase (FASN), the major enzyme in de novo fatty acid synthesis, is highly expressed in breast cancer and its expression is reduced by polyunsaturated fatty acids (PUFAs) in liver. We previously found a positive association between rat mammary tumor levels of the n-6 PUFA arachidonic acid (AA) and tumor weight. We examined the roles of the major n-3 PUFA, docosahexaenoic acid (DHA, 22:6n-3), and the major n-6 PUFA, AA, in FASN expression in, and proliferation of, human breast cancer MCF-7 cells. Methods: The cells were treated for 48 h with BSA or 60 μM BSA-bound DHA, AA, or oleic acid (OA, 18:1n-9), then were incubated with or without estradiol or insulin. Western blot and 3H-thymidine incorporation assay were used to determine the role of DHA on FASN regulation and MCF-7 cell proliferation. Results: DHA, but neither AA nor OA, inhibits estradiol-induced and insulin-induced expression of the precursor of sterol regulatory element binding protein-1 (p-SREBP-1), its mature form (m-SREBP-1), and FASN. Estradiol or insulin stimulation increased the pAkt/Akt and pS6/S6 ratios, expression of p-SREBP-1, m-SREBP-1, and FASN, and cell proliferation, and these effects were decreased by DHA. The DHA-induced decrease in FASN expression resulted from reduced pAkt/Akt signaling and not pERK1/2/ERK1/2 signaling. In addition, DHA enhanced the inhibitory effect of LY294002 on pAkt signaling and expression of p-SREBP-1, m-SREBP-1, and FASN. However, addition of rapamycin, an inhibitor of the mTOR signaling pathways, 1 h before addition of estradiol or insulin increased the pAkt/Akt ratio and FASN expression, and this effect was inhibited by addition of DHA 48 h before rapamycin. Conclusion: We conclude that, in MCF-7 cells, DHA inhibits pAKT signaling and thus expression of p-SREBP-1, m-SREBP-1, and FASN and cell proliferation. ? 2017 The Author(s).
Subjects
Arachidonic acid; Breast cancer; Docosahexaenoic acid; Estrogen; Fatty acid synthase; Fatty acids; Insulin; MTOR; PAKT signaling; Proliferation
SDGs
Other Subjects
2 morpholino 8 phenylchromone; docosahexaenoic acid; estradiol; fatty acid synthase; insulin; mammalian target of rapamycin; mitogen activated protein kinase 1; mitogen activated protein kinase 3; oleic acid; protein S6; rapamycin; sterol regulatory element binding protein 1; thymidine; antidiabetic agent; arachidonic acid; docosahexaenoic acid; estrogen; FASN protein, human; fatty acid synthase; insulin; oleic acid; protein kinase B; SREBF1 protein, human; sterol regulatory element binding protein 1; Akt signaling; antineoplastic activity; Article; cell proliferation; cell stimulation; concentration response; controlled study; drug mechanism; drug potentiation; enzyme phosphorylation; human; human cell; MCF-7 cell line; protein expression; Western blotting; breast tumor; cell proliferation; drug effect; female; gene expression regulation; genetics; metabolism; pathology; phosphorylation; signal transduction; tumor cell culture; Arachidonic Acid; Breast Neoplasms; Cell Proliferation; Docosahexaenoic Acids; Estrogens; Fatty Acid Synthase, Type I; Female; Gene Expression Regulation, Neoplastic; Humans; Hypoglycemic Agents; Insulin; Oleic Acid; Phosphorylation; Proto-Oncogene Proteins c-akt; Signal Transduction; Sterol Regulatory Element Binding Protein 1; Tumor Cells, Cultured
Publisher
BioMed Central Ltd.
Type
journal article