Unsaturated Fatty Acids Stimulate Tumor Growth through Stabilization of β-Catenin

• Main Authors: Hyeonwoo Kim, Carlos Rodriguez-Navas, Rahul K. Kollipara, Payal Kapur, Ivan Pedrosa, James Brugarolas, Ralf Kittler, Jin Ye
• Format: Article
• Language: English
• Published: Elsevier 2015-10-01
• Series: Cell Reports
• Online Access: http://www.sciencedirect.com/science/article/pii/S2211124715010219

Some cancer cells exhibit elevated levels of free fatty acids (FAs) as well as high levels of β-catenin, a transcriptional co-activator that promotes their growth. Here, we link these two phenomena by showing that unsaturated FAs inhibit degradation of β-catenin. Unsaturated FAs bind to the UAS domain of Fas-associated factor 1 (FAF1), a protein known to bind β-catenin, accelerating its degradation. FA binding disrupts the FAF1/β-catenin complex, preventing proteasomal degradation of ubiquitinated β-catenin. This mechanism for stabilization of β-catenin differs from that of Wnt signaling, which blocks ubiquitination of β-catenin. In clear cell renal cell carcinoma (ccRCC) cells, unsaturated FAs stimulated cell proliferation through stabilization of β-catenin. In tissues from biopsies of human ccRCC, elevated levels of unsaturated FAs correlated with increased levels of β-catenin. Thus, targeting FAF1 may be an effective approach to treat cancers that exhibit elevated FAs and β-catenin.