Phosphorylation of NHERF1 S279 and S301 differentially regulates breast cancer cell phenotype and metastatic organotropism.

Abstract Metastatic cancer cells are highly plastic for the expression of different tumor phenotype hallmarks and organotropism. This plasticity is highly regulated but the dynamics of the signaling processes orchestrating the shift from one cell phenotype and metastatic organ pattern to another are still largely unknown. The scaffolding protein NHERF1 has been shown to regulate the expression of different neoplastic phenotypes through its PDZ domains, which forms the mechanistic basis for metastatic organotropism. This reprogramming activity was postulated to be dependent on its differential phosphorylation patterns. Here, we show that NHERF1 phosphorylation on S279/S301 dictates several tumor phenotypes such as in vivo invasion, NHE1-mediated matrix digestion, growth and vasculogenic mimicry. Remarkably, injecting mice with cells having differential NHERF1 expression and phosphorylation drove a shift from the predominantly lung colonization (WT NHERF1) to predominately bone colonization (double S279A/S301A mutant), indicating that NHERF1 phosphorylation also acts as a signaling switch in metastatic organotropism. Graphical abstract Unlabelled Image Highlights • NHERF1 Ser279/S301 phosphorylation acts as a Bidirectional Signalling Switch (BSS). • NHERF1-mediated BSS determines NHE1-driven invadopodia ECM degradation and invasion. • NHERF1-mediated BSS determines the angiogenic secretome and vasculogenic mimicry. • NHERF1-mediated BSS determines anchorage-independent and 3D growth. • Epigenetic alterations determine tumor cell phenotype and organotrophic preference. [ABSTRACT FROM AUTHOR]