Abstract 2921: Antitumorigenic effects by ERβ in three different human colorectal cancer cell lines

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC The estrogen receptor beta (ERβ) is the predominant ER in the human colonic epithelium. Levels of ERβ are reduced in colorectal cancer compared to normal colon tissue. In a previous study, we generated ERβ-expressing colon cancer cells and showed that ERβ inhibits proliferation as well as colon cancer xenograft growth, as a consequence of ERβ mediated inhibition of cell-cycle pathways. The present study was conducted to investigate genome wide changes by ERβ in three human colon cancer cell lines (SW480, HT29 and HCT116). They have very low or no levels of ERβ expression and were transduced with lentivirus containing an ERβ expression cassette. Microarray studies showed that ERβ regulated 623, 643 and 124 genes for SW480, HT29 and HCT116, respectively. Comparisons showed few genes in common for the three cell lines. However, over representation analysis showed that several themes, such as cell proliferation, cell communication and apoptosis were regulated in all of the cell lines. By comparing our results with those from a ChIP-on-Chip assay in breast cancer cells, we found that a considerable proportion of regulated genes had an ERβ binding site nearby or within the gene. Our preliminary conclusion is that ERβ appears to, at the gene expression level, have related anti-tumorigenic effects in different colon tumor cells, but different genes may be regulated in different cells types. Furthermore, the fact that several of the regulated genes possessed an ERβ DNA binding region nearby or within the gene indicates a direct regulation for many of these genes. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2921.