Conjugation of folate via gelonin carbohydrate residues retains ribosomal-inactivating properties of the toxin and permits targeting to folate receptor positive cells.

2.50
Hdl Handle:
http://hdl.handle.net/10541/85566
Title:
Conjugation of folate via gelonin carbohydrate residues retains ribosomal-inactivating properties of the toxin and permits targeting to folate receptor positive cells.
Authors:
Atkinson, Sarah F; Bettinger, Thierry; Seymour, Leonard W; Behr, Jean-Paul; Ward, Christopher M
Abstract:
Conjugation of folate to proteins permits receptor-mediated endocytosis via the folate receptor (FR) and delivery of the conjugate into the cytoplasm of cells. Since many cancers up-regulate the FR it has enabled the targeting of toxins to tumor cells resulting in specific cell death. However, current conjugation methods rely on chemistries that can affect certain catalytic subunits, such as the A-chain of the plant toxin gelonin. As a result many folate-targeted toxins are a compromise between receptor/ligand interaction and toxin activity. We describe the first example of folate conjugated to a protein via carbohydrate residues, using a novel SH-folate intermediate. The folate-gelonin conjugate retains over 99% of toxin activity in a cell-free translational assay compared with unmodified gelonin and is able to bind the FR at the same affinity as free folic acid (10(-10) m). Additionally, the conjugate exhibits prolonged inhibition of protein synthesis in FR positive cell lines in vitro. Folate linked to gelonin via amino conjugation exhibits the same affinity for FR as free folic acid but the toxin is 225-fold less active in a cell-free translational assay. The effect of different conjugation methods on toxin activity and the implications for folate targeting of other glycoproteins are discussed.
Affiliation:
CRC Institute for Cancer Studies, University of Birmingham, Birmingham, B15 2TA United Kingdom.
Citation:
Conjugation of folate via gelonin carbohydrate residues retains ribosomal-inactivating properties of the toxin and permits targeting to folate receptor positive cells. 2001, 276 (30):27930-5 J. Biol. Chem.
Journal:
The Journal of Biological Chemistry
Issue Date:
27-Jul-2001
URI:
http://hdl.handle.net/10541/85566
DOI:
10.1074/jbc.M102825200
PubMed ID:
11359781
Type:
Article
Language:
en
ISSN:
0021-9258
Appears in Collections:
All Paterson Institute for Cancer Research

Full metadata record

DC FieldValue Language
dc.contributor.authorAtkinson, Sarah Fen
dc.contributor.authorBettinger, Thierryen
dc.contributor.authorSeymour, Leonard Wen
dc.contributor.authorBehr, Jean-Paulen
dc.contributor.authorWard, Christopher Men
dc.date.accessioned2009-11-06T15:01:25Z-
dc.date.available2009-11-06T15:01:25Z-
dc.date.issued2001-07-27-
dc.identifier.citationConjugation of folate via gelonin carbohydrate residues retains ribosomal-inactivating properties of the toxin and permits targeting to folate receptor positive cells. 2001, 276 (30):27930-5 J. Biol. Chem.en
dc.identifier.issn0021-9258-
dc.identifier.pmid11359781-
dc.identifier.doi10.1074/jbc.M102825200-
dc.identifier.urihttp://hdl.handle.net/10541/85566-
dc.description.abstractConjugation of folate to proteins permits receptor-mediated endocytosis via the folate receptor (FR) and delivery of the conjugate into the cytoplasm of cells. Since many cancers up-regulate the FR it has enabled the targeting of toxins to tumor cells resulting in specific cell death. However, current conjugation methods rely on chemistries that can affect certain catalytic subunits, such as the A-chain of the plant toxin gelonin. As a result many folate-targeted toxins are a compromise between receptor/ligand interaction and toxin activity. We describe the first example of folate conjugated to a protein via carbohydrate residues, using a novel SH-folate intermediate. The folate-gelonin conjugate retains over 99% of toxin activity in a cell-free translational assay compared with unmodified gelonin and is able to bind the FR at the same affinity as free folic acid (10(-10) m). Additionally, the conjugate exhibits prolonged inhibition of protein synthesis in FR positive cell lines in vitro. Folate linked to gelonin via amino conjugation exhibits the same affinity for FR as free folic acid but the toxin is 225-fold less active in a cell-free translational assay. The effect of different conjugation methods on toxin activity and the implications for folate targeting of other glycoproteins are discussed.en
dc.language.isoenen
dc.subject.meshBinding, Competitive-
dc.subject.meshCarrier Proteins-
dc.subject.meshCell Line-
dc.subject.meshCell-Free System-
dc.subject.meshDose-Response Relationship, Drug-
dc.subject.meshFolic Acid-
dc.subject.meshHela Cells-
dc.subject.meshHumans-
dc.subject.meshInhibitory Concentration 50-
dc.subject.meshLigands-
dc.subject.meshModels, Chemical-
dc.subject.meshPlant Proteins-
dc.subject.meshProtein Binding-
dc.subject.meshProtein Biosynthesis-
dc.subject.meshProtein Synthesis Inhibitors-
dc.subject.meshReceptors, Cell Surface-
dc.subject.meshRibosome Inactivating Proteins, Type 1-
dc.subject.meshRibosomes-
dc.subject.meshSulfides-
dc.subject.meshTime Factors-
dc.titleConjugation of folate via gelonin carbohydrate residues retains ribosomal-inactivating properties of the toxin and permits targeting to folate receptor positive cells.en
dc.typeArticleen
dc.contributor.departmentCRC Institute for Cancer Studies, University of Birmingham, Birmingham, B15 2TA United Kingdom.en
dc.identifier.journalThe Journal of Biological Chemistryen
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