Ligand‐activated interaction of PPARδ with c‐Myc governs the tumorigenicity of breast cancer

다국어 초록 (Multilingual Abstract)

<P>Peroxisome proliferator‐activated receptor (PPAR) δ is a promising therapeutic target in metabolic and inflammatory disorders. However, its role in oncogenesis is controversial, and its therapeutic potential remains to be determined. In our study, we show that ligand‐activated PPARδ forms a complex with the proto‐oncogene product c‐Myc. The interaction of PPARδ with c‐Myc affected the transcriptional activity of c‐Myc and the expression of its target genes. The PPARδ‐dependent regulation of c‐Myc activity was associated with decreased tumorigenicity in breast cancer cells. Administration of the PPARδ ligand GW501516 inhibited tumor growth in xenograft model mice bearing MDA‐MB‐231 cells stably expressing wild‐type PPARδ, but not those expressing dominant‐negative PPARδ, by interfering with c‐Myc function through protein–protein interaction. Our results indicating that PPARδ forms an antitumorigenic complex with c‐Myc in the presence of ligand suggest a potential role of PPARδ in breast cancer development.</P>