title: E-cadherin destabilization accounts for the pathogenicity of missense mutations in hereditary diffuse gastric cancer.
abstract: E-cadherin is critical for the maintenance of tissue architecture due to its role in cell-cell adhesion. E-cadherin mutations are the genetic cause of Hereditary Diffuse Gastric Cancer (HDGC) and missense mutations represent a clinical burden, due to the uncertainty of their pathogenic role. In vitro and in vivo, most mutations lead to loss-of-function, although the causal factor is unknown for the majority. We hypothesized that destabilization could account for the pathogenicity of E-cadherin missense mutations in HDGC, and tested our hypothesis using in silico and in vitro tools. FoldX algorithm was used to calculate the impact of each mutation in E-cadherin native-state stability, and the analysis was complemented with evolutionary conservation, by SIFT. Interestingly, HDGC patients harbouring germline E-cadherin destabilizing mutants present a younger age at diagnosis or death, suggesting that the loss of native-state stability of E-cadherin accounts for the disease phenotype. To elucidate the biological relevance of E-cadherin destabilization in HDGC, we investigated a group of newly identified HDGC-associated mutations (E185V, S232C and L583R), of which L583R is predicted to be destabilizing. We show that this mutation is not functional in vitro, exhibits shorter half-life and is unable to mature, due to premature proteasome-dependent degradation, a phenotype reverted by stabilization with the artificial mutation L583I (structurally tolerated). Herein we report E-cadherin structural models suitable to predict the impact of the majority of cancer-associated missense mutations and we show that E-cadherin destabilization leads to loss-of-function in vitro and increased pathogenicity in vivo.
authors.affiliation: IPATIMUP-Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal. jcorreia@ipatimup.pt
authors.forename: Joana
authors.initials: J
authors.lastname: Simões-Correia
authors.forename: Joana
authors.initials: J
authors.lastname: Figueiredo
authors.forename: Rui
authors.initials: R
authors.lastname: Lopes
authors.forename: François
authors.initials: F
authors.lastname: Stricher
authors.forename: Carla
authors.initials: C
authors.lastname: Oliveira
authors.forename: Luis
authors.initials: L
authors.lastname: Serrano
authors.forename: Raquel
authors.initials: R
authors.lastname: Seruca
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: D015820:Cadherins