A Novel Effect of the New Antileukemic Drug, 2-Chloro-2′-deoxyadenosine, in Human Lymphocytes

Sasvári-Székely, Mária; Piróth, Zs; Kazimierczuk, Zygmunt; Staub, Maria

doi:10.1006/bbrc.1994.2337

Cited by 14 publications

(6 citation statements)

References 11 publications

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“…This is the first time that a reduction in dCK activity is observed in lymphocytes after exposure to 2CdA; indeed, previous studies reported that the activity of dCK increased two to four times in human lymphocytes upon exposure to 2CdA, albeit after short-term incubations (i.e. 1-2 h) (Keszler et al 2004;Sasvari-Szekely et al 1994;Staub 2006). It could be speculated that the longer exposure to 2CdA, besides killing the majority of B cells that have higher dCK expression and/ or activity, could select a B-cell population that has lower levels of the active enzyme.…”

Section: Discussionsupporting

confidence: 57%

“…It could be suggested that the DNA damage caused by the accumulation of 2CdATP within the cell might trigger a failed attempt to produce new nucleotide precursors for DNA reparation, causing dCK overexpression. This theory has been already proposed to explain the increase in dCK activity in lymphocytes treated in vitro with 2CdA (Sasvari-Szekely et al 1994;Staub 2006). Moreover, in stimulated CD4 + T cells exposed to 2CdA we observed an upregulation in NT5C2 mRNA expression possibly suggesting a compensatory effect to mitigate the consequences of dCK overexpression.…”

Section: Discussionmentioning

confidence: 84%

“…2CdA has a chlorine substitution for hydrogen in its purine ring, which renders it resistant to adenosine deaminase (Beutler 1992), an enzyme regulating both extracellular and intracellular levels of nucleotides (Cekic and Linden 2016;Dong et al 2016;Yegutkin 2008). 2CdA undergoes sequential phosphorylation, the first step of which is catalysed by deoxycytidine kinase (dCK), to generate the active mononucleotide 2-chlorodeoxyadenosine 5'-triphosphate (2CdATP), which accumulates in the cytoplasm and incorporates into DNA, thereby blocking its synthesis (Leist and Weissert 2011;Sasvari-Szekely et al 1994) and leading to cell death. Phosphorolysis of 2CdATP by 5'-nucleotidases reverts its activation and thereby, its accumulation into the cell.…”

Section: Introductionmentioning

confidence: 99%

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Different Susceptibility of T and B Cells to Cladribine Depends On Their Levels of Deoxycytidine Kinase Activity Linked to Activation Status

Carlini¹,

Ivaldi²,

Gualandi

et al. 2021

J Neuroimmune Pharmacol

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Deoxycytidine kinase (dCK) and 5’ deoxynucleotidase (NT5C2) are involved in metabolism of cladribine (2CdA), the immunomodulatory drug for multiple sclerosis; by mediating phosphorylation (activation) or phosphorolysis (deactivation) of 2CdA, respectively, these enzymes promote or prevent its accumulation in the cell, which leads to cell death. In particular, lymphocytes which present with a high intracellular dCK/NT5C2 ratio are more sensitive to 2CdA than other immune cells. We aim at determining if the expression of these enzymes and/or their activity differ in specific progenitor and mature immune cells and are influenced by cellular activation and/or exposure to 2CdA. Flow cytometry analysis showed no difference in dCK/NT5C2 ratio in progenitor and mature immune cells. 2CdA induced apoptosis in stimulated T and B cells and unstimulated B cells. dCK expression was enhanced by 2CdA at mRNA and protein levels in activated T cells and mRNA level in activated B cells. dCK activity, measured through an in-house luminescence release enzyme assay was higher in activated T and B cells, and such an increase was abrogated in activated B cells, but not T cells, upon exposure to 2CdA. These results reveal an important relationship between dCK activity and the effect of 2CdA on B and T cells, according to their activation status. Further study is warranted to evaluate whether dCK activity could, in the future, be a suitable predictive biomarker of lymphocyte response to 2CdA. Graphical Abstract "Image missing"

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Section: Discussionsupporting

confidence: 57%

Section: Discussionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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Different Susceptibility of T and B Cells to Cladribine Depends On Their Levels of Deoxycytidine Kinase Activity Linked to Activation Status

Carlini¹,

Ivaldi²,

Gualandi

et al. 2021

J Neuroimmune Pharmacol

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“…We have previously characterized the apoptotic effects induced by the adenosine analogue 2CA on cells of the astroglial lineage (Abbracchio et al, 1995;Ceruti, Barbieri et al, 1997). The present study was undertaken with the aim of defining the actions of this analogue on PBMC, in comparison with another adenosine analogue, 2CdA (cladribine) which is already known to trigger apoptosis of lymphoid cells (Beutler, 1992;Bryson and Sorkin, 1993;Sasvari-Szekely et al, 1994;Wood, 1994). It is important to elucidate the mechanisms at the basis of the action of these compounds on immune cells, with particular reference to the possible role of extracellular P1 receptors.…”

Section: Discussionmentioning

confidence: 99%

Apoptosis by 2-chloro-2′-deoxy-adenosine and 2-chloro-adenosine in human peripheral blood mononuclear cells

Barbieri

Abbracchio

Salvioli

et al. 1998

Neurochemistry International

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Adenosine has profound effects on immune cells and has been implicated in the intrathymic apoptotic deletion of T-cells during development. In order to characterize adenosine effects on quiescent peripheral blood mononuclear cells (PBMC), we have evaluated the ability of the previously characterized adenosine receptor agonist 2-chloro-adenosine (2CA; Ceruti, Barbieri et al., 1997) and of the antineoplastic drug 2-chloro-2'-deoxy-adenosine (2CdA, cladribine) to trigger apoptosis of PBMC. Apoptosis was assessed by morphological changes, DNA fragmentation by agarose gel electrophoresis and appearance of hypodiploid DNA peak by flow cytometry. 2CA (10 microM) and 2CdA (1 microM) induced apoptosis in human PBMC, which are relatively insensitive to apoptosis. For both agents, the effect was concentration- and time-dependent, although 2CdA induced apoptosis more potently than 2CA. Evaluation of mitochondrial function in parallel samples using the mitochondrial membrane-potential-specific dye JC-1 showed that mitochondrial damage followed the same kinetics as apoptosis, hence an early damage of mitochondria is likely not responsible for adenosine-induced death of PBMC. The effect of 2CA was partially prevented by addition of dipyridamole (DP), a nucleoside transport inhibitor, hence some of the apoptotic effect of this nucleoside is, at least in part, due to intracellular action. Alternatively, DP did not affect 2CdA-induced apoptosis, suggesting that 2CdA may enter cells via a DP-insensitive transporter. 5-Iodotubercidin (5-Itu), a nucleoside kinase inhibitor, was also able to partially prevent the action of 2CA and was not able to affect 2CdA-induced apoptosis, suggesting a different role for phosphorylation in 2CA- vs 2CdA-induced apoptosis. To test the role of P1 receptors, agonists and antagonists selective at various P1 receptor subtypes were used. Data suggest that, for 2CA, apoptosis is partially sustained by activation of the A2A receptor subtype, whereas no role is exerted by P1 receptors in 2CdA-dependent apoptosis. Moreover, in these cells, apoptosis could also be triggered through intense activation of the A3 receptor via selective agonists such as 2-chloro-N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide (Cl-IB-MECA), but this mechanism plays no role in either 2CA- or 2CdA-induced apoptosis. On the whole, our results suggest that 2CA and 2CdA follow different pathways in inducing apoptosis of immune cells. Moreover, our data also suggest that there are at least three different ways by which adenosine derivatives may induce apoptosis of human PBMC: (i) through an A2A-like extracellular membrane receptor; (ii) through entry of nucleosides into cells and direct activation of intracellular events involved in the apoptotic process; or (iii) through activation of the A3 receptor.

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“…dCK is known to be under a feedback control by dCTP [6,12]. Inhibition of several enzymes, such as ribonucleotide reductase [13], dCMP deaminase [14] and adenosine deaminase [15] by intracellular metabolites of chemotherapeutic agents, e.g. Cladribine, might alter the deoxynucleotide pools, thus influencing the activity of dCK.…”

mentioning

confidence: 99%

Modulation of human deoxycytidine kinase activity as a response to cellular stress induced by NaF.

et al. 2001

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Deoxycytidine kinase (dCK) is one of the key enzymes of deoxynucleoside salvage supplying resting lymphocytes with DNA precursors for synthesis and repair. The level of dCK activity is especially important in chemotherapy with the use of deoxynucleoside analogues like arabinosyl cytosine (Citarabid, ara-C), or 2-chloro-deoxyadenosine (Cladribine, CdA). Previous results showed that Cladribine treatment of human lymphocytes increased several fold the activity of dCK without increasing the amount of dCK protein itself (Sasvári-Székely, et al., 1998, Biochem. Pharmacol. 56, 1175), and a possible post-translational modification was suggested. This theory was further investigated using NaF as an inhibitor of protein phosphatases. It was shown that NaF treatment of cells elevated dCK activity while inhibiting DNA synthesis. The possible mechanism of dCK activation/inactivation induced by exposure of cell cultures to different agents is discussed.

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A Novel Effect of the New Antileukemic Drug, 2-Chloro-2′-deoxyadenosine, in Human Lymphocytes

Cited by 14 publications

References 11 publications

Different Susceptibility of T and B Cells to Cladribine Depends On Their Levels of Deoxycytidine Kinase Activity Linked to Activation Status

Different Susceptibility of T and B Cells to Cladribine Depends On Their Levels of Deoxycytidine Kinase Activity Linked to Activation Status

Apoptosis by 2-chloro-2′-deoxy-adenosine and 2-chloro-adenosine in human peripheral blood mononuclear cells

Modulation of human deoxycytidine kinase activity as a response to cellular stress induced by NaF.

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