McSorley T, Ort S, Monnerjahn C, Konrad M. A designed equine herpes thymidine kinase (EHV4 TK) variant improves ganciclovir-induced cell-killing.
Biochem Pharmacol 2014;
87:435-44. [PMID:
24316433 DOI:
10.1016/j.bcp.2013.11.011]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 10/31/2013] [Accepted: 11/19/2013] [Indexed: 11/22/2022]
Abstract
The limitations of the ganciclovir (GCV)/herpes simplex virus thymidine kinase (HSV1 TK: EC 2.7.1.21) system as a suicide gene therapy approach have been extensively studied over the years. In our study, we focused on improving the cytotoxic profile of the GCV/equine herpes virus-4 thymidine kinase (EHV4 TK: EC 2.7.1.21) system. Our approach involved the structure-guided mutagenesis of EHV4 TK in order to switch its ability to preferentially phosphorylate the natural substrate deoxythymidine (dT) to that of GCV. We performed steady-state kinetic analysis, genetic complementation in a thymidine kinase-deficient Escherichia coli strain, isothermal titration calorimetry, and analysis of GCV-induced cell killing through generation of HEK 293 stable cell-lines expressing EHV4 TK mutants and wild-type EHV4 TK. We found that the EHV4 TK S144H-GFP mutant preferentially phosphorylates GCV and confers increased GCV-induced cytotoxicity compared to wild-type EHV4 TK.
Collapse