JNK promotes epithelial cells anoikis by transcriptional and post-translational regulation of BH3-only proteins

Developmental morphogenesis, tissue injury, and oncogenic transformation can cause the detachment of epithelial cells. These cells are eliminated by a specialized form of apoptosis (anoikis). While the processes that contribute to this form of cell death have been studied, the underlying mechanisms remain unclear. Here we tested the role of the cJUN NH2-terminal kinase (JNK) signaling pathway using murine models with compound JNK-deficiency in mammary and kidney epithelial cells. These studies demonstrated that JNK is required for efficient anoikis in vitro and in vivo. Moreover, JNK-promoted anoikis required pro-apoptotic members of the BCL2 family of proteins. We show that JNK acts through a BAK/BAX-dependent apoptotic pathway by increasing BIM expression and phosphorylating BMF leading to death of detached epithelial cells. Overall design: In order to understand the role of the JNK pathway in anoikis, Rosa-CreER (Control) and Jnk1flox/flox Jnk2-/- Rosa-CreER (Jnk1-/-Jnk2-/-) cells were grown as attached monoloayers or suspended for 4 hours. RNA was isolated from these cells and subjected to RNASeq to measure differential gene expression. Three separate samples from each condition were analyzed.

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Girnius N, Davis RJ