Novel Lipogenic Enzyme ELOVL7 Involves in Prostate Cancer Growth through Saturated Fatty-acid and Steroid Metabolism

We identified a novel lipogenic gene, ELOVL7, as an over-expressed gene in prostate cancer (PC) cells and it is involved in elongation of long-chain fatty acids and can play some important roles in prostate carcinogenesis. To investigate into downstream pathways of ELOVL7, we performed the gene expression analysis by the genome-wide cDNA microarrays. The genome–wide gene expression patterns were compared between PC cells transfected with siELOVL7 and these with siCONTROL and between the ELOVL7-overexpressing in-vivo tumors in mice bread with high fat diet (HFD) and those with normal diet (ND). HFD treatment significantly promoted the growth of ELOVL7-overexpressed PC cells in vivo. As a result, we identified five genes (IER3, HDAC8, GDF15, UGT2B11, and S1PR3) whose expressions were down-regulated with 20% and more in ELOVL7 knockdown and also were up-regulated with 20% and more in the tumors in the mice bread with HFD. The genome–wide gene expression patterns were compared between PC cells transfected with siELOVL7 and these with siCONTROL and between the ELOVL7-overexpressing in-vivo tumors bread with high fat diet (HFD) and those with normal diet (ND). HFD treatment significantly promoted the growth of ELOVL7-overexpressed PC cells in vivo.　The competitive hybridization was performed three times for each comparison (siELOVL7-1, -2, and-3; HFD-1, -2, and -3).