Prolonged confinement is a consequence of amoeboid cancer-cell invasion. In this issue of Developmental Cell, Zhang et al.1 show that sustained mechanical stress activates PIEZO1-STAT1-dependent MLKL expression, leading to MLKL-dependent membrane-lytic death in cells without detectable RIPK3 and canonical MLKL phosphorylation, broadening current models of necroptotic competence.
Senescent cells develop a persistent inflammatory signature with broad consequences for tissue function and disease. Martini et al.1 show that mitochondrial citrate metabolism drives inflammation through a pathway that acts independently of mitochondrial DNA-driven immune signaling yet cooperates with it to amplify the inflammatory response.
Ringham et al.1 identify CHL1+CXCL9+ cancer-associated fibroblasts at lung tumor margins that recruit suppressive CXCR3+ regulatory T cells, revealing how stromal chemokine gradients can promote immune evasion. Viewed alongside immune-stimulatory CCL19+ fibroblastic reticular cells, these findings suggest that immune-interacting fibroblasts are context-dependent organizers of tumor immunity.
The mesenchymal-amoeboid transition (MAT) enhances cancer cell migration and therapy resistance during dissemination through mechanically confined spaces. Using an in vitro MAT induction system combining physical confinement with a non-adhesive environment to mimic interstitial migration, we introduce “long-term MAT” (L-MAT) to describe cells sustaining MAT under prolonged pressure and show that L-MAT triggers receptor-interacting protein kinase 3 (RIPK3)-independent necroptosis. Mechanistically, the PIEZO1-STAT1 axis upregulates mixed lineage kinase domain-like pseudokinase (MLKL), whose membrane accumulation drives necroptosis in cells otherwise resistant to death-receptor signaling. Before membrane rupture, L-MAT cells show progressive migration restriction; MLKL-knockout cells bypass this checkpoint and persist as surviving clones. Spatial transcriptomics of patient tumors shows MLKL expression correlates with PIEZO1 activation and immunogenicity in less aggressive regions, while advanced malignant and metastatic clones show reduced MLKL. These findings establish MLKL as a conditional tumor checkpoint and identify the PIEZO1-STAT1-MLKL axis as a predictive biomarker and therapeutic target.
Several intracellular regulators of stress granules (SGs) have been identified but it remains unclear whether SGs are also coordinated by extracellular signals. In this issue of Developmental Cell, Li et al. identify an extracellular nitrate-responsive module that helps assemble the SG under acute stress and later promotes its autophagic degradation.1
