Structure and Dynamics of Thioguanine-modified Duplex DNA

Somerville, Lilla; Krynetski, Eugene Y.; Krynetskaia, Natalia F.; Beger, Richard D.; Zhang, Weixing; Marhefka, Craig; Evans, William E.; Kriwacki, Richard W.

doi:10.1074/jbc.m204243200

Cited by 96 publications

(78 citation statements)

References 39 publications

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“…Therefore, changes in chromatin architecture or gene regulation patterns could be important determinants of antimetabolite therapy. Structural analysis of synthetic DNA showed that incorporation of nucleoside analogs into DNA does not introduce gross changes in DNA geometry (Sahasrabudhe et al, 1996;Somerville et al, 2003). Instead, drastic shifts in DNA dynamics occur; for example, incorporation of deoxythioguanosine makes DNA more flexible (Somerville et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

“…Several antimetabolite agents do not disrupt integrity of DNA and lead only to minute alterations in DNA geometry (Sahasrabudhe et al, 1996;Somerville et al, 2003). Instead, incorporation of these chemical moieties into DNA increases local flexibility of the double helix in the area surrounding the modification, and changes the DNA-protein interactions (Krynetskaia et al, 2000;Somerville et al, 2003;Seibert et al, 2005).…”

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confidence: 99%

“…Instead, incorporation of these chemical moieties into DNA increases local flexibility of the double helix in the area surrounding the modification, and changes the DNA-protein interactions (Krynetskaia et al, 2000;Somerville et al, 2003;Seibert et al, 2005). Early evidence that chemotherapy-induced damage in DNA alters DNA-protein interactions in chromatin came from the work of Maybaum and Mandel (1983), who described unilateral chromatid damage in cells treated with thiopurine.…”

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confidence: 99%

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High Mobility Group Protein B1 Is an Activator of Apoptotic Response to Antimetabolite Drugs

Krynetskaia

Xie²,

Vučetić³

et al. 2007

Mol Pharmacol

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We explored the role of a chromatin-associated nuclear protein high mobility group protein B1 (HMGB1) in apoptotic response to widely used anticancer drugs. A murine fibroblast model system generated from Hmgb1 ϩ/ϩ and Hmgb1 Ϫ/Ϫ mice was used to assess the role of HMGB1 protein in cellular response to anticancer nucleoside analogs and precursors, which act without destroying the integrity of DNA. Chemosensitivity experiments with 5-fluorouracil, cytosine arabinoside (araC), and mercaptopurine (MP) demonstrated that Hmgb1 Ϫ/Ϫ mouse embryonic fibroblasts (MEFs) were 3 to 10 times more resistant to these drugs compared with Hmgb1 ϩ/ϩ MEFs. Hmgb1-deficient cells showed compromised cell cycle arrest and reduced caspase activation after treatment with MP and araC. Phosphorylation of p53 at Ser12 (corresponding to Ser9 in human p53) and Ser18 (corresponding to Ser15 in human p53), as well as phosphorylation of H2AX after drug treatment, was reduced in Hmgb1-deficient cells. trans-Activation experiments demonstrated diminished activation of proapoptotic promoters Bax, Puma, and Noxa in Hmgb1-deficient cells after treatment with MP or araC, consistent with reduced transcriptional activity of p53. We have demonstrated for the first time that Hmgb1 is an essential activator of cellular response to genotoxic stress caused by chemotherapeutic agents (thiopurines, cytarabine, and 5-fluorouracil), which acts at early steps of antimetaboliteinduced stress by stimulating phosphorylation of two DNA damage markers, p53 and H2AX. This finding makes HMGB1 a potential target for modulating activity of chemotherapeutic antimetabolites. Identification of proteins sensitive to DNA lesions that occur without the loss of DNA integrity provides new insights into the determinants of drug sensitivity in cancer cells.High mobility group protein B1 (HMGB1) is a versatile protein with intranuclear and extracellular functions. In the nucleus, it bends and plasticizes DNA; outside the cell, it acts as a cytokine mediator of inflammation. Despite its small size and a simple domain structure, HMGB1 facilitates numerous intranuclear processes, including transcription, replication, V(D)J recombination, and transposition (Hock et al., 2007). This versatility is achieved through the ability of HMGB1 to get involved in direct physical contacts with two distinct groups of macromolecules: HMGB1 reveals affinity with DNA cruciforms and bent, kinked, or chemically modified DNA; on the other hand, it interacts with a number of proteins, including p53, steroid hormone receptors, general and specific transcription factors, nuclear factor-B, DNA protein kinase (DNA-PK), etc. (Bianchi and Agresti, 2005). These two distinct groups of binding substrates suggest that HMGB1 may provide a molecular link between distorted DNA, and proteins involved in DNA metabolism or genotoxic stress response. Therefore, HMGB1 is a potential modulator of anticancer therapy targeted against DNA.Induction of apoptotic death in cancer cells via genotoxic stress by irradiation o...

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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High Mobility Group Protein B1 Is an Activator of Apoptotic Response to Antimetabolite Drugs

Krynetskaia

Xie²,

Vučetić³

et al. 2007

Mol Pharmacol

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“…Primarily, 2 0 -deoxy-6-thioguanosine-5 0 triphosphate (dG S TP) is incorporated into DNA, subsequently showing a characteristic delayed cytotoxic effect (Maybaum and Mandel, 1983). Recent studies have shown that the incorporation of dG s TP into duplex DNA results in subtle localised modification on DNA structure (Somerville et al, 2003). Moreover, chromatin structure alteration is most evident in the G2 phase of the cell cycle (Maybaum and Mandel, 1983).…”

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confidence: 99%

Mechanistic mathematical modelling of mercaptopurine effects on cell cycle of human acute lymphoblastic leukaemia cells

2005

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The antimetabolite mercaptopurine (MP) is widely used to treat childhood acute lymphoblastic leukaemia (ALL). To study the dynamics of MP on the cell cycle, we incubated human T-cell leukaemia cell lines (Molt-4 sensitive and resistant subline and P12 resistant) with 10 mM MP and measured total cell count, cell cycle distribution, percent viable, percent apoptotic, and percent dead cells serially over 72 h. We developed a mathematical model of the cell cycle dynamics after treatment with MP and used it to show that the Molt-4 sensitive controls had a significantly higher rate of cells entering apoptosis (2.7-fold, Po0.00001) relative to the resistant cell lines. Additionally, when treated with MP, the sensitive cell line showed a significant increase in the rate at which cells enter apoptosis compared to its controls (2.4-fold, Po0.00001). Of note, the resistant cell lines had a higher rate of antimetabolite incorporation into the DNA of viable cells (41.4-fold, Po0.01). Lastly, in contrast to the other cell lines, the Molt-4 resistant subline continued to cycle, though at a rate slower relative to its control, rather than proceed to apoptosis. This led to a larger S-phase block in the Molt-4 resistant cell line, but not a higher rate of cell death. Gene expression of apoptosis, cell cycle, and repair genes were consistent with mechanistic dynamics described by the model. The thiopurine antimetabolites mercaptopurine (MP) and thioguanine are analogues of the purine bases hypoxanthine and guanine and these medications are a major component of paediatric acute lymphoblastic leukaemia (ALL) treatment protocols worldwide. After cellular uptake, the first essential activation step is catalysed by hypoxanthine-guanine phosphoribosyl transferase (HPRT). Phosphoribosylation activates MP through the purine 'salvage pathway' via TIMP (6-thioinosine-5 0 -monophosphate), and TXMP (6-thioxanthosine-5 0 -monophosphate) to thioguanine nucleotides (TGNs) which are considered to be the main active metabolites (Relling et al, 1999). Thiopurine-S-methyltransferase (TPMT) catalyses S-methylation of MP and MP-metabolites, that is the main intracellular inactivating pathway in haematopoietic tissues. However, the most abundant S-methylated MP metabolite, S-methylthioinosine-5 0 -monophosphate ( me TIMP), inhibits phosphoribosyl pyrophosphate (PRPP)-amidotransferase, an essential enzyme in the de novo purine synthesis pathway (DNPS). The MP pathway is given in Figure 1A, illustrating the above-described enzymes.Thiopurine cytotoxicity is explained in part by inhibition of DNPS, which is essential for generating new purines for DNA and RNA synthesis. However, incorporation of TGNs into DNA and RNA is generally considered to be the principal mechanism of MP cytotoxicity. Primarily, 2 0 -deoxy-6-thioguanosine-5 0 triphosphate (dG S TP) is incorporated into DNA, subsequently showing a characteristic delayed cytotoxic effect (Maybaum and Mandel, 1983). Recent studies have shown that the incorporation of dG s TP into duplex DNA results in s...

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“…[1][2][3] Thioguanine, which is used in the therapy of acute leukemia, is believed to exert its cytotoxic therapeutic effect by being incorporated into DNA as deoxy-6-thioguanosine. [4,5] Because of their therapeutic relevance, these modified bases have also been the subject of theoretical studies. [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Watson-crick base pairs with thiocarbonyl groups: How sulfur changes the hydrogen bonds in DNA

2008

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Abstract:We have theoretically analyzed mimics of Watson-Crick AT and GC base pairs in which N-H•••O hydrogen bonds are replaced by N-H•••S, using the generalized gradient approximation (GGA) of density functional theory at BP86/TZ2P level. The general effect of the above substitutions is an elongation and a slight weakening of the hydrogen bonds that hold together the base pairs. However, the precise effects depend on how many, and in particular, on which hydrogen bonds AT and GC are substituted.. Another purpose of this work is to clarify the relative importance of electrostatic attraction versus orbital interaction in the hydrogen bonds involved in the mimics, using a quantitative bond energy decomposition scheme. At variance with widespread believe, the orbital interaction component in these hydrogen bonds is found to contribute more than 40% of the attractive interactions and is thus of the same order of magnitude as the electrostatic component, which provides the remaining attraction.© Versita Warsaw and Springer-Verlag Berlin Heidelberg.

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Structure and Dynamics of Thioguanine-modified Duplex DNA

Cited by 96 publications

References 39 publications

High Mobility Group Protein B1 Is an Activator of Apoptotic Response to Antimetabolite Drugs

High Mobility Group Protein B1 Is an Activator of Apoptotic Response to Antimetabolite Drugs

Mechanistic mathematical modelling of mercaptopurine effects on cell cycle of human acute lymphoblastic leukaemia cells

Watson-crick base pairs with thiocarbonyl groups: How sulfur changes the hydrogen bonds in DNA

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