Histone methyltransferase KMT2D mediated lipid metabolism via peroxisome proliferator-activated receptor gamma in prostate cancer

BACKGROUND: Prostate cancer (PCa) is the most common type of cancer in men. Destruction of or blocking lipid metabolism impairs the growth, proliferation, and survival of tumor cells. Recent studies on hepatic steatosis suggest that kinase tethers histone-lysine N-methyltransferase 2D (KMT2D) to peroxisome proliferator-activated receptor gamma (PPARγ), transactivating its target genes. Here, to determine a therapeutic approach that may interfere with PCa lipid metabolism, the interaction mechanism of KMT2D and PPARγ was verified in PCa. METHODS: Molecular techniques and bioinformatics analysis were used to explore the relationship between KMT2D and lipid metabolism pathways in PCa. Moreover, the changes of lipid droplets were detected by oil red O staining and BODIPY staining. Molecular techniques were used to investigate the effect of KMT2D on PPARγ signaling in PCa cells. Co-immunoprecipitation (Co-IP) and DNA pull-down verified the mechanism of interaction between KMT2D and PPARγ. RESULTS: KMT2D knockdown reduced the lipid droplet content in PC-3 and DU-145 cells and downregulated the expression of lipid metabolic genes. Low-dose rosiglitazone (ROSI) effectively activated the PPARγ pathway to promote lipid droplet synthesis and cell proliferation and migration. However, ROSI could not function effectively after KMT2D knockdown. Both co-IP and DNA pull-down analyses showed that KMT2D and PPARγ could be tethered to regulate the expression of PPARγ target genes. CONCLUSIONS: In PCa, KMT2D interacted with PPARγ, which directly participated in the regulation of lipid metabolism-related genes and affected lipid synthesis. Therefore, inhibiting the interaction between KMT2D and PPARγ is a potential therapeutic strategy.