Apoptosis is induced in leishmanial cells by a novel protein kinase inhibitor withaferin A and is facilitated by apoptotic topoisomerase I–DNA complex

Sen, Nilkantha; Banerjee, Bhaswati; Das, Benu Brata; Ganguly, Anirban; Sen, Tanusree; Pramanik, Sumit Kumar; Mukhopadhyay, Sibabrata; Majumder, Hemanta K.

doi:10.1038/sj.cdd.4402002

Cited by 101 publications

(86 citation statements)

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“…This experiment provides direct and quantitative measurements of the cleavable complex formed in vitro. To understand whether the precipitated count is actually due to topoisomerase I-linked complexes, we performed immunoband depletion assay (12,18). Nuclear extracts were prepared from untreated and treated cells and subjected to SDS-PAGE.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, formation of cellular topoisomerase I-DNA cleavable complexes by these compounds do not result from their direct interaction with the topoisomerase I-DNA intermediates. Recently, Sen et al also reported conservation of the apoptotic topoisomerase I-DNA cleavable complex formation by a protein kinase inhibitor, withaferin A, in parasite Leishmania donovani (12). Thus, topoisomerase I-DNA cleavable complexes are implicated directly or indirectly in apoptosis, irrespective of the initiating mechanism or the agent.…”

Section: Introductionmentioning

confidence: 99%

“…formamidopyridine DNA glycosylase (Fpg; 1 mg/mL) was added and further incubated for 30 min at 25jC. DNA breaks were analyzed by alkaline comet assay with some modifications (12,21). Briefly 5,000 to 10,000 cells were mixed with 100 mL of 0.75% low-melting agarose and kept at 37jC.…”

Section: Methodsmentioning

confidence: 99%

“…DU145 cells were cultured in six-well plates with or without appropriate drugs. Nuclear extracts were prepared as described (12,19). Briefly, cells were suspended in hypotonic buffer [10 mmol/L Tris-HCl (pH 7.5), 0.1 mmol/L EDTA, 1 mmol/L phenylmethylsulfonyl fluoride, 1 mmol/L benzamidine hydrochloride, and 5 mmol/L DTT] and homogenized.…”

Section: Methodsmentioning

confidence: 99%

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Betulinic Acid, a Catalytic Inhibitor of Topoisomerase I, Inhibits Reactive Oxygen Species–Mediated Apoptotic Topoisomerase I–DNA Cleavable Complex Formation in Prostate Cancer Cells but Does Not Affect the Process of Cell Death

Ganguly¹,

Das

Roy³

et al. 2007

Cancer Research

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The ubiquitious enzyme topoisomerase I can be targeted by drugs which turn these enzymes into cellular poisons and subsequently induce cell death. Drugs like staurosporine, which do not target topoisomerase I directly, can also lead to stabilization of topoisomerase I-DNA cleavable complexes by an indirect process of reactive oxygen species (ROS) generation and subsequent oxidative DNA damage. In this study, we show that betulinic acid, a catalytic inhibitor of topoisomerases, inhibits the formation of apoptotic topoisomerase I-DNA cleavable complexes in prostate cancer cells induced by drugs like camptothecin, staurosporine, and etoposide. Although events like ROS generation, oxidative DNA damage, and DNA fragmentation were observed after betulinic acid treatment, there is no topoisomerase I-DNA cleavable complex formation, which is a key step in ROS-induced apoptotic processes. We have shown that betulinic acid interacts with cellular topoisomerase I and prohibits its interaction with the oxidatively damaged DNA. Using oligonucleotide containing 8-oxoguanosine modification, we have shown that betulinic acid inhibits its cleavage by topoisomerase I in vitro. Whereas silencing of topoisomerase I gene by small interfering RNA reduces cell death in the case of staurosporine and camptothecin, it cannot substantially reduce betulinic acidinduced cell death. Thus, our study provides evidence that betulinic acid inhibits formation of apoptotic topoisomerase I-DNA complexes and prevents the cellular topoisomerase I from directly participating in the apoptotic process. [Cancer Res 2007;67(24):11848-58]

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Betulinic Acid, a Catalytic Inhibitor of Topoisomerase I, Inhibits Reactive Oxygen Species–Mediated Apoptotic Topoisomerase I–DNA Cleavable Complex Formation in Prostate Cancer Cells but Does Not Affect the Process of Cell Death

Ganguly¹,

Das

Roy³

et al. 2007

Cancer Research

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“…Indeed, besides TRAIL and Fas ligand (present study), Top1cc also form in apoptotic human cells in response to arsenic trioxide (15), staurosporine (16), tubulin and Top2 inhibitors (17, 18), TNF␣ (17), and UV-C radiation (19). Apoptotic Top1cc have also been reported in the parasite Leishmania donovani (42).…”

Section: Discussionmentioning

confidence: 98%

Topoisomerase I Requirement for Death Receptor-induced Apoptotic Nuclear Fission

Sordet

Goldman

Redon

et al. 2008

Journal of Biological Chemistry

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Topoisomerase I (Top1) is known to relax DNA supercoiling generated by transcription, replication, and chromatin remodeling. However, it can be trapped on DNA as cleavage complexes (Top1cc) by oxidative and carcinogenic DNA lesions, base damage, and camptothecin treatment. We show here that Top1 is also functionally involved in death receptor-induced programmed cell death. In cells exposed to TRAIL or Fas ligand, Top1cc form at the onset of apoptosis. Those apoptotic Top1cc are prevented by caspase inhibition and Bax inactivation, indicating that both caspases and the mitochondrial death pathway are required for their formation. Accordingly, direct activation of the mitochondrial pathway by BH3 mimetic molecules induces apoptotic Top1cc. We also show that TRAIL-induced apoptotic Top1cc are preferentially formed by caspase-3-cleaved Top1 at sites of oxidative DNA lesions with an average of one apoptotic Top1cc/100 kbp. Examination of Top1 knockdown cells treated with TRAIL revealed similar DNA fragmentation but a marked decrease in apoptotic nuclear fission with reduced formation of nuclear bodies. Thus, we propose that Top1 contributes to the full apoptotic responses induced by TRAIL.Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) 2 is a promising therapeutic agent because it induces apoptosis in a wide variety of cancer cells without affecting normal tissues (1, 2). TRAIL belongs to the TNF family of cytokines, including TNF␣ and Fas ligand, which induce apoptosis by binding to their cognate plasma membrane receptors (3). The binding of TRAIL to the DR4 or DR5 receptors and the binding of Fas ligand to Fas receptor cause the intracellular death domains of those receptors to trimerize, which leads to the recruitment of FADD and the activation of caspase-8. Caspase-8 then cleaves and thereby activates caspase-3 either directly (type I cells) or/and indirectly (type II cells) (4) by activating the mitochondrial death pathway through the cleavage of Bid (5). Cleaved Bid binds to and activates the pro-apoptotic Bcl-2 relatives Bax and Bak proteins, causing the release of mitochondrial cytochrome c and the activation of caspase-9 and caspase-3 (6). Activated caspase-3 (and other downstream caspases) cleaves a broad array of intracellular targets including DNA topoisomerase I (Top1) (7). It is also required to induce the controlled rearrangement and degradation of nuclear structures with chromatin condensation, DNA fragmentation, nuclear fission, and release of apoptotic nuclear bodies in the extracellular space (8). TRAIL-induced apoptosis also involves an accumulation of intracellular reactive oxygen species (ROS) (9).Top1 removes DNA superhelical tensions generated during transcription, replication, and chromatin remodeling (10) and is essential in higher eukaryotes (11). It relaxes DNA by forming transient DNA single-strand breaks that are produced as Top1 forms a covalent bond between its active site tyrosine (Tyr 723 ) and a 3Ј-DNA phosphate. These Top1 cleavage complexes (Top1cc) allow con...

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Kinetoplastid AGC Kinases

Bachmaier

Boshart

2013

Protein Phosphorylation in Parasites

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Genes encoding protein kinases homologous to the AGC (PKA-PKG-PKC-like) group are relatively under-represented in trypanosomatid genomes, and most of them cannot be assigned to one of the subfamilies conserved in higher organisms, as illustrated by the zinc finger kinase ZFK, a kinase with unique and kinetoplastid-specific domain architecture outside the catalytic core. Second messenger-regulated kinases are apparently absent, like the PKC and PKG subfamilies, or have controversial ligand-binding properties, like PKA. Hence, the AGC group is very unconventional in kinetoplastids. Only the nuclear DBF2-related (NDR) kinases PK50 and PK53 are currently being prioritized for drug development. In this chapter the currently available knowledge on AGC kinases is reviewed, and the suggestion made that further investigations of this group of kinases will most likely deliver parasite-specific kinase drug targets.

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Apoptosis is induced in leishmanial cells by a novel protein kinase inhibitor withaferin A and is facilitated by apoptotic topoisomerase I–DNA complex

Cited by 101 publications

References 30 publications

Betulinic Acid, a Catalytic Inhibitor of Topoisomerase I, Inhibits Reactive Oxygen Species–Mediated Apoptotic Topoisomerase I–DNA Cleavable Complex Formation in Prostate Cancer Cells but Does Not Affect the Process of Cell Death

Betulinic Acid, a Catalytic Inhibitor of Topoisomerase I, Inhibits Reactive Oxygen Species–Mediated Apoptotic Topoisomerase I–DNA Cleavable Complex Formation in Prostate Cancer Cells but Does Not Affect the Process of Cell Death

Topoisomerase I Requirement for Death Receptor-induced Apoptotic Nuclear Fission

Kinetoplastid AGC Kinases

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