Cell clustering mediated by the adhesion protein PVRL4 is necessary for ?6?4 integrin-promoted ferroptosis resistance in matrix-detached cells.

ABSTRACT: Ferroptosis is an iron-dependent form of programmed cell death characterized by the accumulation of lipid-targeting reactive oxygen species that kill cells by damaging their plasma membrane. The lipid repair enzyme GSH peroxidase 4 (GPX4) protects against this oxidative damage and enables cells to resist ferroptosis. Recent work has revealed that matrix-detached carcinoma cells can be susceptible to ferroptosis and that they can evade this fate through the signaling properties of the ?6?4 integrin, which sustains GPX4 expression. Although these findings on ferroptosis are provocative, they differ from those in previous studies indicating that matrix-detached cells are prone to apoptosis via a process referred to as anoikis. In an effort to reconcile these discrepant findings, here we observed that matrix-detached epithelial and carcinoma cells cluster spontaneously via a mechanism that involves the cell adhesion protein PVRL4 (also known as Nectin-4). We found that this clustering process allows these cells to survive by stimulating a PVRL4/?6?4/Src signaling axis that sustains GPX4 expression and buffers against lipid peroxidation. In the absence of ?6?4, PVRL4-mediated clustering induced an increase in lipid peroxidation that was sufficient for triggering ferroptosis. When the clustering was inhibited, single cells did not exhibit a significant increase in lipid peroxidation in the absence of ?6?4, and they were more susceptible to apoptosis than to ferroptosis. These results indicate that ferroptosis induction depends on cell clustering in matrix-detached cells that lack ?6?4 and imply that the fate of matrix-detached cells can be determined by the state of their cell-cell interactions.

SUBMITTER: Brown CW 

PROVIDER: S-EPMC6102132 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature