Cell-based high-throughput compound screening reveals functional interaction between oncofetal HMGA2 and topoisomerase I

Peter, Sabrina; Yu, Haojie; Ivanyi‐Nagy, Roland; Dröge, Peter

doi:10.1093/nar/gkw759

Cited by 19 publications

(42 citation statements)

References 40 publications

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“…Furthermore, our recent biochemical assays had shown that at a moderate range of HMGA2:scDNA stoichiometries, SN38-induced TOP1cc formation was enhanced 2- to 3-fold. At high stoichiometries, however, HMGA2 negatively interfered with TOP1 supercoil relaxation and reduced TOP1cc formation (29). It is likely that this results from direct competition between HMGA2 and TOP1, as both proteins recognize plectonemic DNA segment crossings in scDNA (28, 44).…”

Section: Resultsmentioning

confidence: 99%

“…This form of supercoil scrunching, as well as the replication fork chaperone function, requires the presence of AT-hook DNA-binding domains of HMGA2 (27, 28). Furthermore, our recent unbiased high-throughput compound screen in combination with biochemical assays pointed at a functional interaction between HMGA2 and human TOP1 (29). We therefore hypothesized that HMGA2, in addition to or in conjunction with its proposed scaffold forming function at HU-induced stalled forks, may be a cancer/stem cell-specific modulator of dynamic changes in chromatin structure involving DNA supercoiling that contributes to replication fork stability during replication stress.…”

Section: Introductionmentioning

confidence: 99%

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The chromatin structuring protein HMGA2 influences human subtelomere stability and cancer chemosensitivity

Ahmed

Ramani

Rong

et al. 2019

Preprint

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4The transient build-up of DNA supercoiling during the translocation of replication forks 3 5 threatens genome stability and is controlled by DNA topoisomerases (TOPs). This crucial 3 6 process has been exploited with TOP poisons for cancer chemotherapy. However, 3 7 pinpointing cellular determinants of the best clinical response to TOP poisons still remains 3 8 enigmatic. Here, we present an integrated approach and demonstrate that endogenous and 3 9 exogenous expression of the oncofetal high-mobility group AT-hook 2 (HMGA2) protein 4 0 exhibited broad protection against the formation of hydroxyurea-induced DNA breaks in 4 1 various cancer cells, thus corroborating our previously proposed model in which HMGA2 4 2 functions as a replication fork chaperone that forms a protective DNA scaffold at or close to 4 3 stalled replication forks. We now further demonstrate that high levels of HMGA2 also 4 4 protected cancer cells against DNA breaks triggered by the clinically important TOP1 poison 4 5 irinotecan. This protection is most likely due to the recently identified DNA supercoil 4 6 constraining function of HMGA2 in combination with exclusion of TOP1 from binding to 4 7 supercoiled substrate DNA. In contrast, low to moderate HMGA2 protein levels surprisingly 4 8 potentiated the formation of irinotecan-induced genotoxic covalent TOP1-DNA cleavage 4 9 8 1

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The chromatin structuring protein HMGA2 influences human subtelomere stability and cancer chemosensitivity

Ahmed

Ramani

Rong

et al. 2019

Preprint

Self Cite

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“…Our recent studies showed that HMGA2 formed unique higher order complexes with scDNA in vitro and that within these ternary complexes, HMGA2 juxtaposes DNA segments into closer proximity to each other (Peter et al , ; Zhao et al , ). These results, in conjunction with the observed protective effect of HMGA2 against the catalytic inhibitor Merb, led us to investigate whether HMGA2 could catalytically activate TOP2A leading to more efficient supercoil relaxation.…”

Section: Resultsmentioning

confidence: 99%

“…Indicated amounts of Etop (Sigma) diluted in DMSO were incubated with 100 ng of supercoiled Renilla reporter plasmid (Peter et al , ) in a buffer containing 10 m m Tris/HCl, pH 7.9, 50 m m KCl, 50 m m NaCl, 5 m m MgCl 2 , 0.1 m m EDTA, 1 m m ATP, 15 µg·mL −1 BSA. The DNA supercoil relaxation reactions were initiated by adding 4.5 U of human recombinant TOP2A (Affymetrix, Santa Clara, CA, USA) to each sample.…”

Section: Methodsmentioning

confidence: 99%

Oncofetal HMGA2 attenuates genotoxic damage induced by topoisomerase II target compounds through the regulation of local DNA topology

Ahmed

Dröge

2019

Molecular Oncology

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Rapidly dividing cells maintain chromatin supercoiling homeostasis via two specialized classes of enzymes, DNA topoisomerase type 1 and 2 (TOP1/2). Several important anticancer drugs perturb this homeostasis by targeting TOP1/2, thereby generating genotoxic DNA damage. Our recent studies indicated that the oncofetal chromatin structuring high‐mobility group AT‐hook 2 (HMGA2) protein plays an important role as a DNA replication fork chaperone in coping with DNA topological ramifications that occur during replication stress, both genomewide and at fragile sites such as subtelomeres. Intriguingly, a recent large‐scale clinical study identified HMGA2 expression as a sole predicting marker for relapse and poor clinical outcomes in 350 acute myeloid leukemia (AML) patients receiving combinatorial treatments that targeted TOP2 and replicative DNA synthesis. Here, we demonstrate that HMGA2 significantly enhanced the DNA supercoil relaxation activity of the drug target TOP2A and that this activator function is mechanistically linked to HMGA2's known ability to constrain DNA supercoils within highly compacted ternary complexes. Furthermore, we show that HMGA2 significantly reduced genotoxic DNA damage in each tested cancer cell model during treatment with the TOP2A poison etoposide or the catalytic TOP2A inhibitor merbarone. Taken together with the recent clinical data obtained with AML patients targeted with TOP2 poisons, our study suggests a novel mechanism of cancer chemoresistance toward combination therapies administering TOP2 poisons or inhibitors. We therefore strongly argue for the future implementation of trials of HMGA2 expression profiling to stratify patients before finalizing clinical treatment regimes.

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“…The Dov-induced decrease in BER factors (MPG, APE-1, FEN1, PARP1, XRCC1) is anticipated to attenuate single-strand BER functions and enhance the occurrence of lethal dsDNA breaks (Davidson et al, 2013;Woodhouse et al, 2008). Another way of Dov to initiate DNA damage may involve HMGA2, which has recently been shown to augment topoisomerase I activity in a ternary complex with DNA and antagonize the topoisomerase I poison irinotecan/SN-38 (Peter et al, 2016). Attenuated HMGA2 expression may negatively affect topoisomerase I functions in GB.…”

Section: Discussionmentioning

confidence: 99%

Dovitinib enhances temozolomide efficacy in glioblastoma cells

et al. 2017

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The multikinase inhibitor and FDA-approved drug dovitinib (Dov) crosses the blood–brain barrier and was recently used as single drug application in clinical trials for GB patients with recurrent disease. The Dov-mediated molecular mechanisms in GB cells are unknown. We used GB patient cells and cell lines to show that Dov downregulated the stem cell protein Lin28 and its target high-mobility group protein A2 (HMGA2). The Dov-induced reduction in pSTAT3Tyr705 phosphorylation demonstrated that Dov negatively affects the STAT3/LIN28/Let-7/HMGA2 regulatory axis in GB cells. Consistent with the known function of LIN28 and HMGA2 in GB self-renewal, Dov reduced GB tumor sphere formation. Dov treatment also caused the downregulation of key base excision repair factors and O6-methylguanine-DNA-methyltransferase (MGMT), which are known to have important roles in the repair of temozolomide (TMZ)-induced alkylating DNA damage. Combined Dov/TMZ treatment enhanced TMZ-induced DNA damage as quantified by nuclear γH2AX foci and comet assays, and increased GB cell apoptosis. Pretreatment of GB cells with Dov (‘Dov priming’) prior to TMZ treatment reduced GB cell viability independent of p53 status. Sequential treatment involving ‘Dov priming’ and alternating treatment cycles with TMZ and Dov substantially reduced long-term GB cell survival in MGMT+ patient GB cells. Our results may have immediate clinical implications to improve TMZ response in patients with LIN28+/ HMGA2+ GB, independent of their MGMT methylation status.

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Cell-based high-throughput compound screening reveals functional interaction between oncofetal HMGA2 and topoisomerase I

Cited by 19 publications

References 40 publications

The chromatin structuring protein HMGA2 influences human subtelomere stability and cancer chemosensitivity

The chromatin structuring protein HMGA2 influences human subtelomere stability and cancer chemosensitivity

Oncofetal HMGA2 attenuates genotoxic damage induced by topoisomerase II target compounds through the regulation of local DNA topology

Dovitinib enhances temozolomide efficacy in glioblastoma cells

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