The αE-catenin gene (CTNNA1) acts as an invasion-suppressor gene in human colon cancer cells

Abstract

The acquisition of invasiveness is a crucial step in the malignant progression of cancer. In cancers of the colon and of other organs the E-cadherin/catenin complex, which is implicated in homotypic cell-cell adhesion as well as in signal transduction, serves as a powerful inhibitor of invasion. We show here that one allele of the αE-catenin (CTNNA1) gene is mutated in the human colon cancer cell family HCT-8, which is identical to HCT-15, DLD-1 and HRT-18. Genetic instability, due to mutations in the HMSH6 (also called GTBP) mismatch repair gene, results in the spontaneous occurrence of invasive variants, all carrying either a mutation or exon skipping in the second αE-catenin allele. The αE-catenin gene is therefore, an invasion-suppressor gene in accordance with the two-hit model of Knudsen for tumour-suppressor genes.