Access

Article

Nature Medicine 13, 1070 - 1077 (2007)
Published online: 2 September 2007 | doi:10.1038/nm1627

Death-receptor O-glycosylation controls tumor-cell sensitivity to the proapoptotic ligand Apo2L/TRAIL

Klaus W Wagner1,7,8, Elizabeth A Punnoose1,2,8, Thomas Januario1, David A Lawrence2, Robert M Pitti2, Kate Lancaster3, Dori Lee1, Melissa von Goetz1, Sharon Fong Yee4, Klara Totpal4, Ling Huw1, Viswanatham Katta3, Guy Cavet5, Sarah G Hymowitz6, Lukas Amler1 & Avi Ashkenazi2

Apo2L/TRAIL stimulates cancer cell death through the proapoptotic receptors DR4 and DR5, but the determinants of tumor susceptibility to this ligand are not fully defined. mRNA expression of the peptidyl O-glycosyltransferase GALNT14 correlated with Apo2L/TRAIL sensitivity in pancreatic carcinoma, non–small-cell lung carcinoma and melanoma cell lines, and up to 30% of samples from various human malignancies showed GALNT14 overexpression. RNA interference of GALNT14 reduced cellular Apo2L/TRAIL sensitivity, whereas overexpression increased responsiveness. Biochemical analysis of DR5 identified several ectodomain O-(N-acetyl galactosamine–galactose–sialic acid) structures. Sequence comparison predicted conserved extracellular DR4 and DR5 O-glycosylation sites; progressive mutation of the DR5 sites attenuated apoptotic signaling. O-glycosylation promoted ligand-stimulated clustering of DR4 and DR5, which mediated recruitment and activation of the apoptosis-initiating protease caspase-8. These results uncover a new link between death-receptor O-glycosylation and apoptotic signaling, providing potential predictive biomarkers for Apo2L/TRAIL-based cancer therapy.