The Open Biochemistry Journal




ISSN: 1874-091X ― Volume 13, 2019

The Role of Herpes Simplex Virus-1 Thymidine Kinase Alanine 168 in Substrate Specificity



Candice L Willmon1, Django Sussman2, Margaret E Black*, 1
1 Department of Pharmaceutical Sciences, Washington State University, Pullman, WA
2 Fred Hutchinson Cancer Research Center, Seattle, WA, USA

Abstract

Herpes simplex virus type 1 (HSV) thymidine kinase (TK) has been widely used in suicide gene therapy for the treatment of cancer due to its broad substrate specificity and the inability of the endogenous human TK to phosphorylate guanosine analogs such as ganciclovir (GCV). The basis of suicide gene therapy is the introduction of a gene that encodes a prodrug-activating enzyme into tumor cells. After administration, the prodrug is selectively converted to a toxic drug by the suicide gene product thereby bringing about the eradication of the cancer cells. A major drawback to this therapy is the low activity the enzyme displays towards the prodrugs, requiring high prodrug doses that result in adverse side effects. Earlier studies revealed two HSV TK variants (SR39 and mutant 30) derived by random mutagenesis with enhanced activities towards GCV in vitro and in vivo. While these mutants contain multiple amino acid substitutions, molecular modeling suggests that substitutions at alanine 168 (A168) may be responsible for the observed increase in prodrug sensitivity. To evaluate this, site-directed mutagenesis was used to individually substitute A168 with phenylalanine or tyrosine to reflect the mutations found in SR39 and mutant 30, respectively. Additionally, kinetic parameters and the ability of these mutants to sensitize tumor cells to GCV in comparison to wild-type thymidine kinase were determined.

Keywords: Herpes Simplex Virus 1 Thymidine Kinase, ganciclovir, substrate specificity, gene therapy.


Article Information


Identifiers and Pagination:

Year: 2008
Volume: 2
First Page: 60
Last Page: 66
Publisher Id: TOBIOCJ-2-60
DOI: 10.2174/1874091X00802010060

Article History:

Received Date: 22/2/2008
Revision Received Date: 19/3/2008
Acceptance Date: 25/3/2008
Electronic publication date: 9/5/2008
Collection year: 2008

Article Metrics:

CrossRef Citations:
0

Total Statistics:

Full-Text HTML Views: 1234
Abstract HTML Views: 803
PDF Downloads: 256
Total Views/Downloads: 2293

Unique Statistics:

Full-Text HTML Views: 572
Abstract HTML Views: 398
PDF Downloads: 151
Total Views/Downloads: 1121
Geographical View

© Willmon et al.; Licensee Bentham Open.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.5/), which permits unrestrictive use, distribution, and reproduction in any medium, provided the original work is properly cited.


* Address correspondence to these authors at the Dept. of Pharmaceutical Sciences, P.O. Box 646534, Washington State University, Pullman, WA 99164-6534, USA; Tel: (509) 335-6265; Fax: (509) 335-5902; E-mail: blackm@mail.wsu.edu


Endorsements



"We have always had a fruitful cooperation and long-term experience of publishing with Bentham Open."

"A number of our original papers have appeared in its different journals, as the Bentham Open Publishers provides sufficient research in the field of science and technologies (belonging to the pharmaceutical, biotechnology, biomedical industries etc). The staff of the Bentham Open always treat our papers very seriously and gently during the rutile paper reviewing process, so far we always felt their kindness and highly cooperative support. Today, Bentham Open is providing a great support to science and research, giving opportunities of high standard publishing as well as promoting and enhancing selected papers around the world through communication and exchange of global scientific education."


Kholmirzo T. Kholmurodov
Leading Scientist
FLNP (Frank Laboratory of Neutron Physics) JINR (Joint Institute of Nuclear Research) Moscow region, Russia


Browse Contents



Webmaster Contact: info@benthamopen.net
Copyright © 2019 Bentham Open