4.1N is involved in a flotillin-1/β-catenin/Wnt pathway and suppresses cell proliferation and migration in non-small cell lung cancer cell lines

The membrane-cytoskeletal protein 4.1N has recently been proposed as a tumor suppressor in a number of cancers of epithelial origin, including non-small-cell lung cancer (NSCLC). However, the molecular mechanism associated with 4.1N tumor suppression remains has not been thoroughly characterized. In this study, 4.1N was shown to directly interact with the lipid raft marker flotillin-1 through its FERM and U2 domains in several different NSCLC cell lines using immunoprecipitation, co-immunoprecipitation and pull-down assays. Moreover, 4.1N silencing/overexpression experiments in paired 95C/95D cells that are of homologous origin but varying endogenous 4.1N expression (high expression in 95C cells, low expression in 95D cells) indicated that 4.1N is involved in the suppression of cell proliferation and migration through a flotillin-1/beta-catenin/Wnt pathway. Taken together, the findings of this study help to elucidate the novel tumor suppressor role of 4.1N in NSCLC.