Abstract 2098: The receptor tyrosine kinase AXL is a target for the human miR-34a microRNA

Determining the protein targets of microRNAs (miRNAs) will be critical to understanding the role these non-coding RNAs play in regulating gene function and what impact they have in cancer biology. In this study, we show by a combination of microarray, Northern, and PCR-based analyses that the human miR-34a miRNA is significantly under-expressed in basal-like breast cancer cell lines exhibiting triple receptor negative characteristics, as compared to a non-tumorigenic mammary epithelial cell line control. Introduction of a synthetic mimic of hsa-miR-34a into MDA-MB-231 cells resulted in a substantial alteration in both the mRNA and protein levels of the receptor tyrosine kinase AXL, 48 hours post-transfection. Furthermore, the transfection of the hsa-miR-34a mimic decreased the migratory potential of these cells in a manner consistent with the function of AXL as a promoter of cell proliferation, invasion, and metastasis in a number of cancer cell types including breast cancer. This observed phenotypic effect supports the hypothesis that miR-34a functions as a tumor suppressor, with the direct translational repression of AXL representing just one of many possible targets that this miRNA regulates. 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 2098.