Fatty acid and phospholipid biosynthetic pathways are regulated throughout mammary epithelial cell differentiation and correlate to breast cancer survival

Authors and Affiliations:

M. Luísa Dória*¹, Ana S. Ribeiro*¹, Jun Wang², Cândida Z. Cotrim¹, Pedro Domingues¹, Cecilia Williams², M. Rosário Domingues¹ and Luisa A. Helguero¹

¹Mass Spectrometry Centre, Organic Chemistry and Natural Products Research Unit, Department of Chemistry, Universidade de Aveiro, Campus de Santiago, Aveiro, Portugal; and

²Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, Texas, USA

* contributed equally to the work

Abstract:

This work combined gene and protein expression, gas chromatography-flame ionization detector, and hydrophilic interaction liquid chromatography-tandem mass spectrometry to compare lipid metabolism changes in undifferentiated/proliferating vs. functionally differentiated mammary epithelial cells (MECs) and to study their correlation to breast cancer survival. Sixty-eight genes involved in lipid metabolism were changed in MEC differentiation. Differentiated cells showed induction of Elovl6 (2-fold), Scd1 (4-fold), and Fads2 (2-fold), which correlated with increased levels of C16:1 n−7 and C18:1 n−9 (1.5-fold), C20:3 n−6 (2.5-fold), and C20:4 n−6 (6-fold) fatty acids (FAs) and more phospholipids (PLs) containing these species. Further, increased expression (2- to 3-fold) of genes in phosphatidylethanolamine (PE) de novo biosynthesis resulted in a 20% PE increase. Proliferating/undifferentiated cells showed higher C16:0 (1.7-fold) and C18:2 n−6 (4.2-fold) levels and more PLs containing C16:0 FAs [PC(16:0/16:1), PG(16:0/18:2), PG(16:0/18:1), and SM(16:0/18:0)]. Kaplan-Meier analysis of data from 3455 patients with breast cancer disclosed a positive correlation for 59% of genes expressed in differentiated MECs with better survival. PE biosynthesis and FA oxidation correlated with better prognosis in patients with breast cancer, including the basal-like subtype. Therefore, genes involved in mammary gland FA and PL metabolism and their resulting molecular species reflect the cellular proliferative ability and differentiation state and deserve further studies as potential markers of breast cancer progression.

Journal: The FASEB Journal

Link: http://www.fasebj.org/content/early/2014/06/25/fj.14-249672.abstract

Picture caption: from the left to the right, Prof. Maria Rosário Domingues, master Maria Luísa Dória and Dra. Luísa Helguero.