Abstract 1423: SatB2, targeted by miR31, is a modulator in cancer microenvironment

Abstract Cancer growth and metastasis involve an active interaction between primary tumor cells and the tumor's microenvironment, which consists of fibroblasts, vascular cells and inflammatory cells. Such interactions between the cancer and the cells within the microenvironment induce differential expression of genes that act to foster the growth, invasion and spread of tumor cells. This study utilizes pair-wise primary cultures of fibroblasts from normal and cancerous human endometrial tissues of the same patients to investigate the potential factors in the tumor microenvironment and their role in carcinogenesis. Both microRNA and mRNA profiling were performed on paired normal and cancer fibroblasts. SatB2 emerged as a promising candidate when its expression was shown to be significantly increased in fibroblasts surrounding the tumor tissues in all but one patients tested (n=8). Further investigation documented that SatB2 is a target for miR31, via 2 binding sites located within the SATB2 3’ UTR region. In concordance, miR31 is down-regulated in tumor fibroblasts, which further implicates the potential role of SatB2 in promoting a favorable environment for tumors. Ectopic expression of SATB2 in normal fibroblasts does not affect the growth rate of an endometrial cancer cell line (EC-1) in co-culture experiments; however, it did increase the motility of EC-1 cells towards these fibroblasts by multiple folds in both in vitro migration and invasion assays. A reduction of SATB2 expression in cancer activated fibroblasts (CAFs) by shRNA attenuated the migratory ability of EC-1 cells, further supporting the role of SatB2 in tumor aggression. Our observations also indicated that the conditioned media from CAFs were sufficient to induce the motility changes in the EC-1 cells. We believe the elucidation of SatB2 pathway(s) will assist in uncovering the intricate connections between tumors and their microenvironments, leading to new targets for treating tumor progression. 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 1423.