In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 35, No. 15_suppl ( 2017-05-20), p. e15739-e15739
Abstract:
e15739 Background: Hypoxia induced reprogramming of cell energy metabolism and changes in glycosylation are hallmarks of cancer promoting the induction of an invasive and treatment-resistant phenotype, triggering metastases at an early stage of tumor development. We examined the impact of hypoxia on O-GalNAc glycosylation in human HEK293, PDAC cell lines and clinical specimens. Methods: We profiled the expression of 88 glycosylation related genes by qPCR in HEK293 cells subjected to hypoxia either induced by 1% O 2 or 200 mm CoCl 2 identifying key O-GalNAc glycosyltransferases downregulated. Functional assays and glycoprotein analysis displayed a pronounced rate of O-GalNAc modified cytosolic proteins derived from hypoxia treated cells and PDAC specimens. Glycosidase assays could validate specificity of detection method used. Aberrant glycotype could be induced by HIF pathway activator ML 228 and inhibited using Echinomycin. PTK and STK analysis of cell lysates displayed correlation between phosphorylation and O-glycosylation in hypoxic samples. Results: Mechanistically we could show, that hypoxia induced decreased levels of C1GALT1C1 results in reduced T-Synthase activity with subsequent expression of truncated O-glycans (Tn antigen). Differential O-GalNAc glycosylation is inducible using HIF pathway activator ML228 under normoxia and the effect is reversed using 5 µM Echinomycin under hypoxia underscoring the role of HIF1a regulated transcription. Interestingly, the pattern of Tn antigen modified proteins derived from hypoxic samples differs significantly from engineered COSMC deficient cells, displaying O-GalNAc moieties in addition to O-GlcNAc in cytosolic protein fractions. Conclusions: Our findings point to a novel crosstalk of O-GalNAc and O-GlcNAcylation under hypoxia extending the knowledge base of differential O-GalNAc glycosylation in pancreatic cancer.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2017.35.15_suppl.e15739
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2017
detail.hit.zdb_id:
2005181-5
