Inhibition by ganciclovir of cell growth and DNA synthesis of cells biochemically transformed with herpesvirus genetic information

Clair, M H St; Lambe, Catherine U.; Furman, Phillip A.

doi:10.1128/aac.31.6.844

Cited by 84 publications

(26 citation statements)

References 26 publications

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“…Incorporation of these metabolites into elongating DNA blocks elongation leading to cell death. [2][3][4] The HSV1tk/GCV system has proved efficient for inducing the regression of transplanted tumors in various animal models, 5 as well as of carcinogen-induced tumors. 6 Based on these favourable results, several clinical gene therapy trials are in progress aimed at assessing safety and efficacy of this treatment for treating malignancies, and preliminary results have now been reported.…”

Section: Abstract: Nucleoside Analogs; Cancer; Fusion Proteinsmentioning

confidence: 99%

The equine herpes virus 4 thymidine kinase is a better suicide gene than the human herpes virus 1 thymidine kinase

et al. 1999

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The herpes simplex virus type 1 thymidine kinase suicide idine. Using various murine and human cell lines expressgene (HSV1tk) together with ganciclovir (GCV) have been ing these viral tk, we show that HSV1-and EHV4tk are successfully used for in vivo treatment of various experithe more efficient suicide genes for the different nucleoside mental tumors, and many clinical trials using this system analogs tested. Moreover, EHV4tk expressing murine and have been launched. With the aim to improve this therahuman cells were three-to 12-fold more sensitive to GCV peutic system, we compared the potential efficacy of differthan HSV1tk expressing cells. This was correlated with the ent herpes virus derived thymidine kinases (HSV1, varpresence of five-fold higher amounts of the toxic triphosicella-zoster virus, equine herpes virus type-4 and Epsteinphated-GCV in EHV4-versus HSV1tk expressing cells. Barr virus) as suicide genes in association with the nucleoAltogether, these experiments underline the potential side analogs acyclovir, ganciclovir and bromovinyldeoxyuradvantages of the EHV4tk as a suicide gene. Keywords: nucleoside analogs; cancer; fusion proteinsThe herpes simplex virus type 1 thymidine kinase gene (HSV1tk) is the most widely used suicide gene, both in experimental settings and clinical trials. 1 Expression of the HSV1tk gene renders tumor cells sensitive to antiviral agents like acyclovir (ACV), ganciclovir (GCV) and bromovinyl deoxyuridine (BVDU). These nucleoside analogs are efficiently converted to their monophosphate form by HSV1tk, and are then converted to triphosphate compounds by host cellular kinases. Incorporation of these metabolites into elongating DNA blocks elongation leading to cell death. [2][3][4] The HSV1tk/GCV system has proved efficient for inducing the regression of transplanted tumors in various animal models, 5 as well as of carcinogen-induced tumors. 6 Based on these favourable results, several clinical gene therapy trials are in progress aimed at assessing safety and efficacy of this treatment for treating malignancies, and preliminary results have now been reported. 7,8 Despite the effectiveness of the HSV1tk/GCV system for killing tumor cells, it remains important to try to improve it, with the aim to maximize therapeutic efficacy and/or to facilitate treatment modalities. We thus looked for new suicide gene/prodrug combinations. Biochemical and in vivo studies have demonstrated different substrate specificity of herpes tk towards antiviral and cytostatic Correspondence: D KlatzmannReceived 8 January 1999; accepted 11 May 1999 nucleoside analogs. [9][10][11] We thus compared tk from HSV1, varicella-zoster virus (VZV), equine herpes virus type-4 (EHV4) and Epstein-Barr virus (EBV) for their capacity to sensitize tumor cells to ACV, GCV and BVDU.We generated expression vectors with each of these tk genes fused in frame with the Sh Ble gene conferring resistance to zeocin. 12 This should facilitate the selection of transduced cells and the detection of the chimeric proteins by immun...

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Section: Abstract: Nucleoside Analogs; Cancer; Fusion Proteinsmentioning

confidence: 99%

The equine herpes virus 4 thymidine kinase is a better suicide gene than the human herpes virus 1 thymidine kinase

et al. 1999

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“…1,2 In this approach, the suicide gene encodes an enzyme (ie herpes simplex thymidine kinase (HSVtk) or cytosine deaminase) that is capable of converting a systemically delivered pro-drug (ie ganciclovir, 5-fluorocytosine) into a toxic metabolite that induces cell death. [3][4][5][6][7] A variety of vectors has been used to deliver suicide genes; however, the use of recombinant adenoviruses has probably stimulated the most research interest in the past decade. This is due to the ability of adenoviruses to infect a wide variety of dividing and non-dividing cells, their large packaging capacity (approximately 7.5 kb), and their ability to be propagated to produce high titers for use in clinical trials.…”

Section: Introductionmentioning

confidence: 99%

Use of protamine to augment adenovirus-mediated cancer gene therapy

Lanuti¹,

Kouri

Force³

et al. 1999

Gene Ther

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“…Cellular enzymes then phosphorylate the prodrug to the active nucleoside triphosphate. The viral DNA polymerase incorporates the metabolites preferentially into the elongating viral DNA, resulting in DNA-chain termination [4,5]. Recently, the herpesviral TK, such as those of HSV (herpes simplex virus), VZV (Varicella Zoster virus), equine herpes virus 4 and EBV (Epstein-Barr virus) [6][7][8][9] also have been found to be useful suicide genes in gene therapy.…”

Section: Introductionmentioning

confidence: 99%

Identification and characterization of the conserved nucleoside-binding sites in the Epstein-Barr virus thymidine kinase

Chen

Chang

et al. 2004

Biochemical Journal

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Thymidine kinase (TK), encoded by EBV (Epstein-Barr virus), is an attractive target for antiviral therapy and provides a novel approach to the treatment of EBV-associated malignancies. Despite the extensive use of nucleoside analogues for the treatment of viral infections and cancer, the structure-function relationship of EBV TK has been addressed rarely. In the absence of any structural information, we sought to identify and elucidate the functional roles of amino acids in the nucleoside-binding site using site-directed mutagenesis. Through alignment with other human herpesviral TK protein sequences, we predicted that certain conserved regions comprise the nucleoside-binding site of EBV TK and, through site-directed mutagenesis, showed significant changes in activity and binding affinity for thymidine of site 3 (-DRH-) and 4 (-VFP-) mutants. For site 3, only mutants D392E (Asp 392 → Glu) and R393H retain activity, indicating that a negative charge is important for Asp 392 and a positive charge is required for Arg 393 . The increased binding affinities of these two mutants for 3 -deoxy-2 ,3 -didehydrothymidine suggest that the two residues are also important for substrate selection. Interestingly, the changed metal-ion usage pattern of D392E reveals that Asp 392 plays multiple roles in this region. His 394 cannot be compensated by other amino acids, also indicating a crucial role. In site 4, the F402Y mutant retains full activity; however, F402S retains only 60 % relative activity. Strikingly, when Phe 402 is substituted with serine residue, the original preferred pyrimidine substrates, such as 3 -azido-3 -deoxythymidine, iododeoxyuridine and β-L-5-iododioxolane uracil (L-form substrate), have decreased competitiveness with thymidine, suggesting that Phe 402 plays a crucial role in substrate specificity and that the aromatic ring is important for function.

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Inhibition by ganciclovir of cell growth and DNA synthesis of cells biochemically transformed with herpesvirus genetic information

Cited by 84 publications

References 26 publications

The equine herpes virus 4 thymidine kinase is a better suicide gene than the human herpes virus 1 thymidine kinase

The equine herpes virus 4 thymidine kinase is a better suicide gene than the human herpes virus 1 thymidine kinase

Use of protamine to augment adenovirus-mediated cancer gene therapy

Identification and characterization of the conserved nucleoside-binding sites in the Epstein-Barr virus thymidine kinase

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