Molecular requirements of imino sugars for the selective control of N-linked glycosylation and glycosphingolipid biosynthesis

Butters, Terry D.; Broek, L. A. G. M. Van Den; Fleet, George W. J.; Krülle, Thomas M.; Wormald, Mark R.; Dwek, Raymond A.; Platt, Frances M.

doi:10.1016/s0957-4166(99)00468-1

Cited by 140 publications

(121 citation statements)

References 45 publications

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“…Alkylation of DNJ is not required to inhibit ␣-glucosidases, as DNJ presumably acts as a transition-state mimetic (28). DNJ alkylation is required for glucosyl transferase inhibition, with increasing chain length modestly increasing potency (29). The proposed mechanism of inhibition is through ceramide mimicry.…”

Section: Dnj Analogs Inhibit Enzymes That Make and Break Glucosyl Bondsmentioning

confidence: 99%

“…The ␤-Glu IC 50 value of NB-DNJ as determined in WT fibroblast lysates was Ϸ300 M, hence the small molecule concentration in tissue culture may simply have been too low to observe chaperone activity. Both N- (7-oxadecyl)deoxynojirimycin and N-(n-octyl)-deoxynojirimycin increased ␤-Glu activity over a wide range of concentrations, resulting in no inhibition through 100 M. Decreasing compound lipophilicity with oxygen-substituted alkyl chains [N-(7-oxadecyl)deoxynojirimycin] has been shown to decrease toxicity (29). N-(n-octyl)deoxynojirimycin was well tolerated by the cells after 9 days of exposure at concentrations as high as 100 M.…”

Section: Dnj Analogs Inhibit Enzymes That Make and Break Glucosyl Bondsmentioning

confidence: 99%

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Chemical chaperones increase the cellular activity of N370S β-glucosidase: A therapeutic strategy for Gaucher disease

Sawkar

Cheng

Beutler

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

481

455

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Gaucher disease is a lysosomal storage disorder caused by deficient lysosomal ␤-glucosidase (␤-Glu) activity. A marked decrease in enzyme activity results in progressive accumulation of the substrate (glucosylceramide) in macrophages, leading to hepatosplenomegaly, anemia, skeletal lesions, and sometimes CNS involvement. Enzyme replacement therapy for Gaucher disease is costly and relatively ineffective for CNS involvement. Chemical chaperones have been shown to stabilize various proteins against misfolding, increasing proper trafficking from the endoplasmic reticulum. We report herein that the addition of subinhibitory concentrations (10 M) of N-(n-nonyl)deoxynojirimycin (NN-DNJ) to a fibroblast culture medium for 9 days leads to a 2-fold increase in the activity of N370S ␤-Glu, the most common mutation causing Gaucher disease. Moreover, the increased activity persists for at least 6 days after the withdrawal of the putative chaperone. The NN-DNJ chaperone also increases WT ␤-Glu activity, but not that of L444P, a less prevalent Gaucher disease variant. Incubation of isolated soluble WT enzyme with NN-DNJ reveals that ␤-Glu is stabilized against heat denaturation in a dose-dependent fashion. We propose that NN-DNJ chaperones ␤-Glu folding at neutral pH, thus allowing the stabilized enzyme to transit from the endoplasmic reticulum to the Golgi, enabling proper trafficking to the lysosome. Clinical data suggest that a modest increase in ␤-Glu activity may be sufficient to achieve a therapeutic effect.

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Section: Dnj Analogs Inhibit Enzymes That Make and Break Glucosyl Bondsmentioning

confidence: 99%

Section: Dnj Analogs Inhibit Enzymes That Make and Break Glucosyl Bondsmentioning

confidence: 99%

Chemical chaperones increase the cellular activity of N370S β-glucosidase: A therapeutic strategy for Gaucher disease

Sawkar

Cheng

Beutler

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

481

455

View full text Add to dashboard Cite

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“…Both glycosidic bonds specifically cleaved by α-GluII have α(1,3) linkages, unlike the α(1,4)-maltoselike or α(1,6) bonds hydrolyzed by intestinal GH31 α-glucosidases. However, iminosugars, which are glucose mimetics and inhibit α-GluII, also target intestinal α-glucosidases and the ceramidespecific glucosyltransferase involved in glycosphingolipid biosynthesis (20). Toward an understanding of the molecular basis of iminosugar binding to their targets, and the development of better inhibitors of α-GluII, we have successfully established and describe here the first, to our knowledge, expression system capable of producing milligram quantities of an intact recombinant mammalian α-GluII heterodimer.…”

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confidence: 99%

Structures of mammalian ER α-glucosidase II capture the binding modes of broad-spectrum iminosugar antivirals

Caputo

Alonzi

Marti

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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The biosynthesis of enveloped viruses depends heavily on the host cell endoplasmic reticulum (ER) glycoprotein quality control (QC) machinery. This dependency exceeds the dependency of host glycoproteins, offering a window for the targeting of ERQC for the development of broad-spectrum antivirals. We determined smallangle X-ray scattering (SAXS) and crystal structures of the main ERQC enzyme, ER α-glucosidase II (α-GluII; from mouse), alone and in complex with key ligands of its catalytic cycle and antiviral iminosugars, including two that are in clinical trials for the treatment of dengue fever. The SAXS data capture the enzyme's quaternary structure and suggest a conformational rearrangement is needed for the simultaneous binding of a monoglucosylated glycan to both subunits. The X-ray structures with key catalytic cycle intermediates highlight that an insertion between the +1 and +2 subsites contributes to the enzyme's activity and substrate specificity, and reveal that the presence of D-mannose at the +1 subsite renders the acid catalyst less efficient during the cleavage of the monoglucosylated substrate. The complexes with iminosugar antivirals suggest that inhibitors targeting a conserved ring of aromatic residues between the α-GluII +1 and +2 subsites would have increased potency and selectivity, thus providing a template for further rational drug design.broad-spectrum antiviral | ER α-glucosidase II | eukaryotic secretion | glycoprotein folding | iminosugar

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“…N-Alkylated iminosugars (29) were chosen because they are well tolerated and appear to have fewer side effects in cells than PDMP and its derivatives (25,26) Specifically, N-alkyldeoxygalactonojirimycin (N-alkyl-DGJ) compounds were selected because they are even more selective for GCS than N-alkyl-deoxynojirimycin (N-alkyl-DNJ) compounds which also inhibit ␣-glucosidases I and II, albeit with much lower potency (30,31).…”

mentioning

confidence: 99%

Inhibition of Glucosylceramide Synthase Does Not Reverse Drug Resistance in Cancer Cells

Norris-Cervetto

Callaghan

Platt

et al. 2004

Journal of Biological Chemistry

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The multidrug-resistant cancer cell lines NCI/AdR RES and MES-SA/DX-5 have higher glycolipid levels and higher P-glycoprotein expression than the chemosensitive cell lines MCF7-wt and MES-SA. Inhibiting glycolipid biosynthesis by blocking glucosylceramide synthase has been proposed to reverse drug resistance in MDR cells by causing an increased accumulation of proapoptotic ceramide during treatment of cells with cytotoxic drugs. We treated both multidrug-resistant cell lines with the glucosylceramide synthase inhibitors PDMP (D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol), C 9 DGJ (N-nonyl-deoxygalactonojirimycin) or C 4 DGJ (N-butyl-deoxygalactonojirimycin). PDMP achieved a significant reversal of drug resistance in agreement with previous reports. However, the Nalkylated iminosugars C 9 DGJ and C 4 DGJ, which are more selective glucosylceramide synthase inhibitors than PDMP, failed to cause any reversal of drug resistance despite depleting glycolipids to the same extent as PDMP. Our results suggest that (a) inhibition of glucosylceramide synthase does not reverse multidrug resistance and (b) the chemosensitization achieved by PDMP cannot be caused by inhibition of glucosylceramide synthase alone.A major limitation in chemotherapy for cancer is multidrug resistance (MDR), 1 an innate or acquired phenotype, which allows cancer cells to resist a broad spectrum of chemotherapeutic drugs. One of the most extensively studied and clinically relevant mechanisms of drug resistance is the overexpression by cancer cells of the transmembrane multidrug transporter P-glycoprotein (MDR1, ABCB1, EC 3.6.3.44) (1). However, a drug resistance phenotype comprises many, often interacting, mechanisms of resistance (2). These include increased DNA repair, altered target sensitivity, decreased apoptotic response and numerous aberrant signal transduction pathways. Elevated levels of glycolipids have been correlated with multidrug resistance in cancer (3, 4). Manipulation of glycolipid levels in some MDR cancer cells was able to reverse drug resistance (5-12). This led to the hypothesis that elevated glucosylceramide synthase (GCS, EC 2.4.1.80) activity is a novel form of multidrug resistance and that inhibition of GCS is a promising therapeutic strategy for combating multidrug resistance. The biochemical basis is that an elevated GCS activity prevents the accumulation of ceramide, which is thought to precede, and trigger, apoptosis in response to some cytotoxic drugs (13-16). Therefore, inhibition of GCS activity will promote the accumulation of pro-apoptotic ceramide and enhance cell death in response to cytotoxic agents (17-21).This hypothesis rests largely on three lines of evidence. The first is that multidrug resistance correlates with elevated glycolipid levels (4), which is unfortunately hindered by the small number of samples analyzed and the fact that variability of glycolipid levels in cancers remains unknown.Second, genetic manipulation of the GCS enzyme in MCF7 cells can affect their sensitivity to various cytot...

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Molecular requirements of imino sugars for the selective control of N-linked glycosylation and glycosphingolipid biosynthesis

Cited by 140 publications

References 45 publications

Chemical chaperones increase the cellular activity of N370S β-glucosidase: A therapeutic strategy for Gaucher disease

Chemical chaperones increase the cellular activity of N370S β-glucosidase: A therapeutic strategy for Gaucher disease

Structures of mammalian ER α-glucosidase II capture the binding modes of broad-spectrum iminosugar antivirals

Inhibition of Glucosylceramide Synthase Does Not Reverse Drug Resistance in Cancer Cells

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