title: Effect of alginate microencapsulation on the catalytic efficiency and in vitro enzyme-prodrug therapeutic efficacy of cytosine deaminase and of recombinant E. coli expressing cytosine deaminase.
abstract: Cytosine deaminase (CD) catalyses the enzymatic conversion of the non-toxic prodrug 5-fluorocytosine (5-FC) to the potent chemotherapeutic form, 5-fluorouracil (5-FU). Intratumoral delivery of CD localises chemotherapy dose while reducing systemic toxicity. Encapsulation in biocompatible microcapsules immunoisolates CD and protects it from degradation. We report on the effect of alginate encapsulation on the catalytic and functional activity of isolated CD and recombinant E. coli engineered to express CD (E. coli(CD)). Alginate microcapsules containing either CD or Escherichia coli(CD) were prepared using ionotropic gelation. Conversion of 5-FC to 5-FU was quantitated in unencapsulated and encapsulated CD/E. coli(CD) using spectrophotometry, with a slower rate of conversion observed following encapsulation. Both encapsulated CD/5-FC and E. coli(CD)/5-FC resulted in cell kill and reduced proliferation of 9 L rat glioma cells, which was comparable to direct 5-FU treatment. Our results show that encapsulation preserves the therapeutic potential of CD and E. coli(CD) is equally effective for enzyme-prodrug therapy.
authors.affiliation: a Dartmouth College , Hanover , NH , USA ;
authors.forename: Michael G
authors.initials: MG
authors.lastname: Funaro
authors.affiliation: b Department of Radiology , Geisel School of Medicine at Dartmouth , Hanover , NH , USA ;
authors.forename: Krishnamurthy V
authors.initials: KV
authors.lastname: Nemani
authors.affiliation: c Division of Cancer Imaging Research , Johns Hopkins University ICMIC Program, Russell H. Morgan Department of Radiology and Radiological Science, the Johns Hopkins University School of Medicine , Baltimore , MD , USA ;
authors.forename: Zhihang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: c Division of Cancer Imaging Research , Johns Hopkins University ICMIC Program, Russell H. Morgan Department of Radiology and Radiological Science, the Johns Hopkins University School of Medicine , Baltimore , MD , USA ;
authors.forename: Zaver M
authors.initials: ZM
authors.lastname: Bhujwalla
authors.affiliation: d Thayer School of Engineering at Dartmouth , Hanover , NH , USA ;
authors.forename: Karl E
authors.initials: KE
authors.lastname: Griswold
authors.affiliation: b Department of Radiology , Geisel School of Medicine at Dartmouth , Hanover , NH , USA ;|d Thayer School of Engineering at Dartmouth , Hanover , NH , USA ;|e Department of Medicine , Geisel School of Medicine at Dartmouth , Hanover , NH , USA.
authors.forename: Barjor
authors.initials: B
authors.lastname: Gimi
mesh_terms: D000464:Alginates / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D045744:Cell Line, Tumor; D018914:Cells, Immobilized / Q000201:enzymology; D043525:Cytosine Deaminase; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology*; D005472:Fluorouracil / Q000737:chemistry / Q000494:pharmacology; D005910:Glioma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D020723:Glucuronic Acid / Q000737:chemistry / Q000494:pharmacology; D006603:Hexuronic Acids / Q000737:chemistry / Q000494:pharmacology; D011355:Prodrugs / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000464:Alginates; D004800:Enzymes, Immobilized; D006603:Hexuronic Acids; D011355:Prodrugs; D011994:Recombinant Proteins; D020723:Glucuronic Acid; D043525:Cytosine Deaminase; D005472:Fluorouracil
keywords: 5-fluorocytosine; 5-fluorouracil; Enzyme-prodrug therapy; alginate microcapsules; enzyme immobilisation