Regulation of human deoxycytidine kinase expression

Mitchell, Beverly S.; Song, James J.; Johnson, Earnest E.; Chen, Everett; Dayton, Jennifer S.

doi:10.1016/0065-2571(93)90009-3

Cited by 18 publications

(5 citation statements)

References 15 publications

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“…[16][17][18] Human dCK functions as a homodimer of 60 kDa, consisting of two identical 30.5 kDa subunits. 17 dCK is expressed in a constitutive manner throughout the cell cycle, 2 19 20 and is expressed predominantly in lymphoid tissues, indicating cell type specific regulation.…”

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confidence: 99%

Immunocytochemical detection of deoxycytidine kinase in haematological malignancies and solid tumours

Hubeek

Peters²,

Broekhuizen³

et al. 2005

J Clin Pathol

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Background:Deoxycytidine kinase (dCK) is responsible for the activation of several clinically important deoxynucleoside analogues used for the treatment of haematological and solid malignancies.Aim:To measure dCK expression in tumour cells from different origins.Method:A rabbit antihuman dCK antibody was used for the immunocytochemical detection of dCK expression in three leukaemic cell lines (HL60, U937, and CCRF-CEM) and 97 patient samples (paediatric acute myeloid leukaemia (AML) and lymphoid leukaemia (ALL), retinoblastoma, paediatric brain tumours, and adult non-small cell lung cancer (NSCLC)).Results:CCRF-CEM, U937, and HL60 cells stained positively for dCK and the degree of expression correlated with dCK activity. dCK expression varied between tumour types and between individual patients within one tumour type. dCK was located predominantly in the cytoplasm. The staining intensity was scored as negative (0), low (1+), intermediate (2+), or high (3+). Expression of dCK was high in AML blasts. In contrast, brain tumour samples expressed low amounts of dCK. dCK staining ranged from low (1+) to high (3+) in ALL blasts, retinoblastoma, and NSCLC tissue samples. Staining was consistent (interobserver variability, 88%; κ = 0.83) and specific. Western blotting detected the dCK protein appropriately at 30 kDa, without additional bands.Conclusions:Immunocytochemistry is an effective and reliable method for determining the expression of dCK in patient samples and requires little tumour material. This method enables large scale screening of dCK expression in tumour samples.

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confidence: 99%

Immunocytochemical detection of deoxycytidine kinase in haematological malignancies and solid tumours

Hubeek

Peters²,

Broekhuizen³

et al. 2005

J Clin Pathol

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“…For example, thymidine kinase, the enzyme involved in ZDV phosphorylation, shows extremely low activity in quiescent lymphocytes and monocyte/macrophages but high activity in stimulated lymphocytes (5,12,13). Conversely, deoxycytidine kinase, the enzyme responsible for the initial phosphorylation of 3TC, shows relatively small changes during the different stages of the cell cycle (5,8,11). Consequently, the extent to which each drug is converted to its active triphosphate varies, and the concentration of the latter, rather than the parent drug, may need to be determined to establish a relationship between the dosage and therapeutic efficacy.…”

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confidence: 99%

Development of a New Cartridge Radioimmunoassay for Determination of Intracellular Levels of Lamivudine Triphosphate in the Peripheral Blood Mononuclear Cells of Human Immunodeficiency Virus-Infected Patients

Robbins

Tran

Pinkerton

et al. 1998

Antimicrob Agents Chemother

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A new sensitive method for the measurement of lamivudine triphosphate (3TC-TP), the active intracellular metabolite of lamivudine in human cells in vivo, has been established. The procedure involves rapid separation of 3TC-TP by using Sep-Pak cartridges, dephosphorylation to 3TC by using acid phosphatase, and measurement by radioimmunoassay using a newly developed anti-3TC serum. The radioimmunoassay had errors of less than 21% and a cross-reactivity of less than 0.016% with a wide variety of other nucleoside analogs. The limit of quantitation of the assay for intracellular 3TC-TP was 0.195 ng/ml (0.212 pmol/106 cells), and a cell sample of only 4 million cells was ample for the assay. This procedure, combined with our previously developed method for measuring zidovudine (ZDV) metabolite levels, proved capable of measuring 3TC-TP, ZDV monophosphate (ZDV-MP) and ZDV triphosphate (ZDV-TP) in human immunodeficiency virus (HIV)-infected subjects treated with combination 3TC and ZDV therapy. In seven subjects, intracellular 3TC-TP levels ranged from 2.21 to 7.29 pmol/106 cells, while intracellular ZDV-MP and ZDV-TP levels ranged from <0.01 to 1.76 and 0.01 to 0.07 pmol/106 cells, respectively. Concentrations of 3TC in plasma determined in these subjects ranged from 0.34 to 9.40 μM, which was about fivefold higher than ZDV levels in plasma of 0.04 to 1.4 μM. This is the first study to determine the intracellular levels of the active metabolites in HIV-infected subjects treated with this combination. These methods should prove very useful for in vivo pharmacodynamic studies of combination therapy.

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“…Thymidine kinase-1 is widely distributed and expressed in all of the proliferating neoplastic cells, but it is virtually absent in normal cells (33,34). Unlike thymidine kinase-1, 2Ј-deoxycytidine kinase does not seem to be strictly cell-cycle regulated, and it is expressed by a wide variety of cell types (35)(36)(37)(38). Various malignant tumors have been shown to have a 2-to 5-fold increase of 2Ј-deoxycytidine kinase levels compared with the corresponding normal tissues (38 -40).…”

Section: Introductionmentioning

confidence: 99%

Boron-Containing Nucleosides as Potential Delivery Agents for Neutron Capture Therapy of Brain Tumors

Barth¹,

Yang²,

Madhoun³

et al. 2004

Cancer Research

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The purpose of the present study was to evaluate both in vitro and in vivo a series of boron-containing nucleosides that potentially could be used as delivery agents for neutron capture therapy. The rationale for their synthesis was based on the fact that proliferating neoplastic cells have increased requirements for nucleic acid precursors, and, therefore, they should preferentially localize in the tumor. A series of 3-carboranlyalkyl thymidine analogs has been synthesized and a subset, designated N4, N5, and N7, and the corresponding 3-dihydroxypropyl derivatives, designated N4 -2OH, N5-2OH, and N7-2OH, have been selected for evaluation. Using these compounds as substrates for recombinant human thymidine kinase-1 and the mitochondrial isoenzyme thymidine kinase-2, the highest phosphorylation levels relative to thymidine were seen with N5 and the corresponding dihydroxypropyl analog N5-2OH. In contrast, N4, N4-OH, N7, and N7-OH had substantially lower phosphorylation levels. To compare compounds with high and low thymidine kinase-1 substrate activity, N5 and N7 and the corresponding dihydroxypropyl derivatives were selected for evaluation of their cellular toxicity, uptake and retention by the F98 rat glioma, human MRA melanoma, and murine L929 cell lines, all of which are thymidine kinase-1(؉), and a mutant L929 cell line that is thymidine kinase-1(؊). N5-2OH was the least toxic (IC 50 , 43-70 M), and N7 and N7-2OH were the most toxic (IC 50 , 18 -49 M). The highest boron uptake was seen with N7-2OH by the MRA 27 melanoma and L929 wild-type (wt) cell lines. The highest retention was seen with L929 (wt) cells, and this ranged from 29% for N5-2OH to 46% for N7. Based on the in vitro toxicity and uptake data, N5-2OH was selected for in vivo biodistribution studies either in rats bearing intracerebral implants of the F98 glioma or in mice bearing either s.c. or intracerebral implants of L929 (wt) tumors. At 2.5 hours after convection-enhanced delivery, the boron values for the F98 glioma and normal brain were 16.2 ؎ 2.3 and 2.2 g/g, respectively, and the tumor to brain ratio was 8.5. Boron values at 4 hours after convection-enhanced delivery of N5-2OH to mice bearing intracerebral implants of L929 (wt) or L929 thymidine kinase-1(؊) tumors were 39.8 ؎ 10.8 and 12.4 ؎ 1.6 g/g, respectively, and the corresponding normal brain values were 4.4 and 1.6 g/g, thereby indicating that there was selective retention by the thymidine kinase-1(؉) tumors. Based on these favorable in vitro and in vivo data, neutron capture therapy studies will be initiated using N5-2OH in combination with two non-cell cycle dependent boron delivery agents, boronophenylalanine and sodium borocaptate.

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Regulation of human deoxycytidine kinase expression

Cited by 18 publications

References 15 publications

Immunocytochemical detection of deoxycytidine kinase in haematological malignancies and solid tumours

Immunocytochemical detection of deoxycytidine kinase in haematological malignancies and solid tumours

Development of a New Cartridge Radioimmunoassay for Determination of Intracellular Levels of Lamivudine Triphosphate in the Peripheral Blood Mononuclear Cells of Human Immunodeficiency Virus-Infected Patients

Boron-Containing Nucleosides as Potential Delivery Agents for Neutron Capture Therapy of Brain Tumors

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