S100A6 is transcriptionally regulated by β-catenin and interacts with a novel target, lamin A/C, in colorectal cancer cells

Abstract

In this paper we document an increased expression of S100A6, a calcium binding protein of the S100 family, and its co-localization with β-catenin in colorectal cancer tissues and in metastatic, SW620, versus non-metastatic, SW480, human colorectal cancer cell lines. Moreover, we show up-regulation of the S100A6 protein level in non-metastatic SW480 cells due to overexpression of β-catenin as well as the activation of the S100A6 gene promoter upon cell transfection with β-catenin and the TCF-Lef1 transcription factor. Since we found a high level of S100A6 in metastatic SW620 cells we searched for its interacting partners in the protein extract prepared from these cells. Using several methods we found that S100A6 interacts with lamin A/C, a protein known to be implicated in colon carcinogenesis. Our results reveal a novel and important network of relations and interactions between proteins potentially involved in colorectal cancer development and progression.