Abstract 5219: The LIM protein LIMD2 functions as an effector and biomarker for metastasis in multiple tumor types

The LIM domain is found in proteins from a wide variety of eukaryotic organisms. The LIM domain is organized as a tandem zinc-finger structure that functions as a modular protein-binding interface. LIM domain containing proteins have diverse cellular roles such as regulators of gene expression, cytoarchitecture, cell adhesion, cell motility, signal transduction, and biosensors. LIMD2 belongs to the LIM only family of LIM proteins and was identified as a biomarker for papillary thyroid carcinoma lymph node metastasis from molecular profiling of matched samples. However, the biological function of LIMD2 remains unknown. To identify whether LIMD2 is a biomarker for other cancers, highly specific LIMD2 polyclonal and monoclonal antibodies were developed and several cancer cell lines were tested for LIMD2 expression. These cancer cell lines were derived from breast cancer, melanoma, bladder cancer, and thyroid cancer. We found that the cancer cell lines derived from more aggressive tumors exhibited higher levels of LIMD2 protein expression. Furthermore, cells expressing higher levels of LIMD2 had increased migratory capabilities. Over-expression of LIMD2 protein in the less aggressive bladder cancer cell line (RT4) showed an increase in migration and colony formation ability. Conversely, knockdown of LIMD2 using siRNA decreased the migratory ability of the malignant melanoma cancer cell line and caused morphological changes in these cells. These data not only underscore the importance of LIMD2 as a key metastatic biomarker, but also suggest that LIMD2 may play a functional role in tumorgenicity. LIMD2 may also serve as a novel anti-metastatic target to improve the efficacy of conventional cancer therapeutics. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5219. doi:10.1158/1538-7445.AM2011-5219