Altered glycosylation on the surfaces or secreted proteins of tumor cells is common in pancreatic cancer and is thought to promote cancer progression, but the factors leading to the changes in carbohydrate structures are incompletely understood. We hypothesized that pro-inflammatory conditions can lead to alterations in cancer-associated glycans on mucins produced by pancreatic-cancer cells. Using a novel antibody-glycan microarray method, we measured the effects of pro-inflammatory stimuli (oxidative stress and treatment with the cytokines IFNγ, IL-1α, and TNFα) on the expression and glycosylation of the mucins MUC1, MUC5AC, and MUC16 in multiple pancreatic cancer cell lines. Mucin glycosylation was significantly affected in specific cell lines, particularly in structures involving terminal galactose or N-acetylgalactosamine. In addition, the responses of the cell lines grouped according to the expression of cell-surface markers that are associated with tumorigenicity, as cell lines bearing minimal surface markers showed evidence of increased O-glycan extension and decreased presentation of terminal β1,4-linked galactose, opposite to cell lines bearing multiple markers. These results suggest mechanisms whereby inflammation might influence tumor behavior in a cell-type specific manner through modulating the presentation of cancer-associated glycans.
Transfer of membrane between endoplasmic reticulum and Golgi apparatus in situ is considered to occur via 60-nm transition vesicles derived from part-rough, partsmooth transition elements of the endoplasmic reticulum. A procedure is described for the isolation of a fraction enriched in these transition elements from rat liver. The isolated fraction generates small vesicles morphologically resembling transition vesicles when incubated with nucleoside triphosphate at 370C. In the cell-free system consisting of a donor fraction enriched in transition elements and an acceptor fraction consisting of intact Golgi apparatus immobilized on nitrocellulose strips, transfer in vitro of radiolabeled membranes was demonstrated. Nucleoside triphosphates were required for transfer, and transfer was facilitated by a cytosol fraction of Mr >10,000. In the presence of both nucleoside triphosphate and cytosol, radiolabeled proteins were transferred in a manner dependent upon both time and temperature. Transfer appeared to be both vectorial and specific in that, with Golgi apparatus (or endoplasmic reticulum) as both donor and acceptor, only negligible time and temperature-dependent transfer was observed. The test system described is expected to facilitate further investigation of the transfer process and to provide a convenient assay to guide transition vesicle isolation and characterization.Transfer of membrane materials from endoplasmic reticulum to Golgi apparatus long has been considered from morphological evidence to be mediated by transition vesicles that bleb off specialized, part-rough, part-smooth regions of the endoplasmic reticulum (1, 2). These vesicles, covered by a nap-like coat material not containing clathrin (3-5), are thought to coalesce to form new Golgi apparatus cisternae or to fuse with existing Golgi apparatus membranes to effect delivery to the Golgi apparatus of materials derived from the endoplasmic reticulum (6).Operation of the segment of the exocytotic pathway has been assumed largely from static images provided from electron microscopy. To demonstrate the phenomenon in vitro, we used a cell-free incubation mixture patterned after that described by Rothman and colleagues (7,8). With appropriately "primed" (complete incubation, 37°C) preparations of part-rough, part-smooth transitional regions of endoplasmic reticulum from rat liver, we observed the formation of small blebbing profiles similar to those associated with transition elements in situ (9). These vesicles were characterized by an electron-dense (but not clathrin-derived) coat material.In this paper, we report the reconstitution of membrane transfer in a cell-free environment using rat liver fractions. Radioactivity was transferred from transition elements metabolically labeled with [3H]leucine to Golgi apparatus immobilized on nitrocellulose strips. Transfer was time and temperature dependent and was enhanced by the presence of nucleoside triphosphate (plus a regenerating system) and a cytosol fraction of Mr >10,000.MATERIALS AND METHO...
Altered glycosylation on the surfaces or secreted proteins of tumor cells is common in pancreatic cancer and is thought to promote cancer progression, but the factors leading to the changes in carbohydrate structures are incompletely understood. We hypothesized that pro-inflammatory conditions can lead to alterations in cancer-associated glycans on mucins produced by pancreaticcancer cells. Using a novel antibody-glycan microarray method, we measured the effects of proinflammatory stimuli (oxidative stress and treatment with the cytokines IFNγ, IL-1α, and TNFα) on the expression and glycosylation of the mucins MUC1, MUC5AC, and MUC16 in multiple pancreatic cancer cell lines. Mucin glycosylation was significantly affected in specific cell lines, particularly in structures involving terminal galactose or N-acetylgalactosamine. In addition, the responses of the cell lines grouped according to the expression of cell-surface markers that are associated with tumorigenicity, as cell lines bearing minimal surface markers showed evidence of increased O-glycan extension and decreased presentation of terminal β1,4-linked galactose, opposite to cell lines bearing multiple markers. These results suggest mechanisms whereby inflammation might influence tumor behavior in a cell-type specific manner through modulating the presentation of cancer-associated glycans.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.