Reduced expression of TANGO in colon and hepatocellular carcinomas.

The TANGO gene was originally identified as a new family member of the MIA gene family. The gene codes for a 14-kDa protein of so far unknown function. Recently, we identified TANGO as a tumor suppressor in malignant melanoma. In this study we evaluated TANGO transcription in different colon and hepatocellular carcinoma cell lines and tissue samples, to analyze whether loss of TANGO expression is a more general process in tumor development. TANGO was down-regulated or lost in all hepatocellular and colon cell lines compared to primary human hepatocytes or normal colon epithelial cells, respectively, and in most of the tumor samples compared to non-tumorous tissue. These results were confirmed in situ by immunohistochemistry on paraffin-embedded sections of colon and hepatocellular tumors. Functional assays with exogenous TANGO treatment of colon and hepatoma cell lines revealed reduced motility and invasion capacity. Our studies present for the first time the down-regulation of TANGO in colon and hepatocellular carcinoma and provide the first indications for a tumor suppressor role of the TANGO gene in human colon and hepatocellular carcinoma. Thus, functional relevant loss of TANGO expression may contribute to general tumor development and progression, and may provide a new target for therapeutic strategies.