Evaluation of a UCMK/dCK fusion enzyme for gemcitabine-mediated cytotoxicity
- School of Molecular Biosciences, College of Veterinary Medicine, P.O. Box 647520, Washington State University, Pullman, WA 99164-7520 (United States)
Highlights: Black-Right-Pointing-Pointer Goal was to enhance dFdC cytotoxicity by the creation of a UCMK/dCK fusion enzyme. Black-Right-Pointing-Pointer The UCMK/dCK fusion enzyme possesses both native activities. Black-Right-Pointing-Pointer The fusion renders cells equally sensitive to dFdC relative to dCK expression alone. Black-Right-Pointing-Pointer Dual activities of fusion not sufficient to augment cell dFdC sensitivity in vitro. Black-Right-Pointing-Pointer Data may warrant the implementation of UCMK mutagenesis studies. -- Abstract: While gemcitabine (2 Prime -2 Prime -difluoro-2 Prime -deoxycytidine, dFdC) displays wide-ranging antineoplastic activity as a single agent, variable response rates and poor intracellular metabolism often limit its clinical efficacy. In an effort to enhance dFdC cytotoxicity and help normalize response rates, we created a bifunctional fusion enzyme that combines the enzymatic activities of deoxycytidine kinase (dCK) and uridine/cytidine monophosphate kinase (UCMK) in a single polypeptide. Our goal was to evaluate whether the created fusion could induce beneficial, functional changes toward dFdC, expedite dFdC conversion to its active antimetabolites and consequently amplify cell dFdC sensitivity. While kinetic analyses revealed the UCMK/dCK fusion enzyme to possess both native activities, the fusion rendered cells sensitive to the cytotoxic effects of dFdC at the same level as dCK expression alone. These results suggest that increased wild-type UCMK expression does not provide a significant enhancement in dFdC-mediated cytotoxicity and may warrant the implementation of studies aimed at engineering UCMK variants with improved activity toward gemcitabine monophosphate.
- OSTI ID:
- 22207601
- Journal Information:
- Biochemical and Biophysical Research Communications, Vol. 416, Issue 1-2; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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