S100A6 stimulates proliferation and migration of colorectal carcinoma cells through activation of the MAPK pathways.

The S100A6 protein, a member of the S100 protein family, is overexpressed in many tumors including colorectal carcinoma (CRC). Although recent studies showed that the elevated expression of S100A6 was associated with the stage and lymphatic permeation of CRC, little is known about whether and how S100A6 contributes to CRC development. Here we investigated the S100A6 expression in CRC tissues and cell lines, and explored the molecular mechanisms underlying the role of S100A6 in CRC development by examining cell proliferation and migration in vitro, and tumorigenicity in nude mice. The results show that S100A6 expression was markedly increased in CRC tissues and cell lines compared to normal colon tissues and a normal colon mucosal epithelial cell line, respectively. Recombinant adenovirus-mediated overexpression of S100A6 or treatment with recombinant S100A6 protein in HCT116, a CRC cell line with relative low S100A6 expression, resulted in enhanced cell proliferation and migration, and the mitogen-activated protein kinase (MAPK) activation in vitro, and tumor growth in vivo. Conversely, RNAi-mediated knockdown of S100A6 in LoVo, a CRC cell line with relative high S100A6 expression, resulted in reduced cell proliferation, migration and MAPK activity. S100A6-induced proliferation was partially attenuated by an ERK inhibitor while migration was suppressed by a p38 inhibitor. Taken together, our results suggest that the cellular effects of S100A6 are mediated by the ERK and p38 MAPK pathways, and modulation of these pathways may be employed for CRC prevention and therapy.