Small molecule inhibitor of OGG1 blocks oxidative DNA damage repair at telomeres and potentiates Methotrexate anticancer effects

Abstract Background: The most common oxidative DNA lesion is 8-oxoguanine (8-oxoG) which is mainly recognized and excised by the glycosylase OGG1, initiating the Base Excision Repair (BER) pathway. Telomeres are particularly sensitive to oxidative stress which disrupts telomere homeostasis triggering genome instability. Methods: We used U2OS OGG1-GFP osteosarcoma cell line to study the role of OGG1 at the telomeres in response to oxidative stress. Next, we investigated the effects of inactivating pharmacologically the BER during oxidative stress (OS) conditions by using a specific small molecule inhibitor of OGG1 (TH5487) in different human cell lines. Results: We have found that during OS, TH5487 effectively blocks BER initiation at telomeres causing accumulation of oxidized bases at this region, correlating with other phenotypes such as telomere losses, micronuclei formation and mild proliferation defects. Besides, the antimetabolite Methotrexate synergizes with TH5487 through induction of intracellular ROS formation, which potentiates TH5487 mediated telomere and genome instability in different cell lines. Conclusions: Our findings demonstrate that OGG1 is required to protect telomeres from OS and present OGG1 inhibitors as a tool to induce oxidative DNA damage at telomeres, with the potential for developing new combination therapies for cancer treatment.

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Small molecule inhibitor of OGG1 blocks oxidative DNA damage repair at telomeres and potentiates methotrexate anticancer effects

Scientific Reports ◽

10.1038/s41598-021-82917-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Juan Miguel Baquero ◽

Carlos Benítez-Buelga ◽

Varshni Rajagopal ◽

Zhao Zhenjun ◽

Raúl Torres-Ruiz ◽

...

Keyword(s):

Dna Damage ◽

Oxidative Dna Damage ◽

Genome Instability ◽

Excision Repair ◽

Specific Inhibitor ◽

New Combination ◽

Dna Lesion ◽

Damage Repair ◽

Molecule Inhibitor ◽

Base Excision

AbstractThe most common oxidative DNA lesion is 8-oxoguanine which is mainly recognized and excised by the 8-oxoG DNA glycosylase 1 (OGG1), initiating the base excision repair (BER) pathway. Telomeres are particularly sensitive to oxidative stress (OS) which disrupts telomere homeostasis triggering genome instability. In the present study, we have investigated the effects of inactivating BER in OS conditions, by using a specific inhibitor of OGG1 (TH5487). We have found that in OS conditions, TH5487 blocks BER initiation at telomeres causing an accumulation of oxidized bases, that is correlated with telomere losses, micronuclei formation and mild proliferation defects. Moreover, the antimetabolite methotrexate synergizes with TH5487 through induction of intracellular reactive oxygen species (ROS) formation, which potentiates TH5487-mediated telomere and genome instability. Our findings demonstrate that OGG1 is required to protect telomeres from OS and present OGG1 inhibitors as a tool to induce oxidative DNA damage at telomeres, with the potential for developing new combination therapies for cancer treatment.

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A Small-Molecule Inhibitor of WEE1, AZD1775, Synergizes with Olaparib by Impairing Homologous Recombination and Enhancing DNA Damage and Apoptosis in Acute Leukemia

Molecular Cancer Therapeutics ◽

10.1158/1535-7163.mct-16-0660 ◽

2017 ◽

Vol 16 (10) ◽

pp. 2058-2068 ◽

Cited By ~ 31

Author(s):

Tamara B. Garcia ◽

Jonathan C. Snedeker ◽

Dmitry Baturin ◽

Lori Gardner ◽

Susan P. Fosmire ◽

...

Keyword(s):

Dna Damage ◽

Homologous Recombination ◽

Acute Leukemia ◽

Small Molecule ◽

Small Molecule Inhibitor ◽

Molecule Inhibitor

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Dynamic Compartmentalization of Base Excision Repair Proteins in Response to Nuclear and Mitochondrial Oxidative Stress

Molecular and Cellular Biology ◽

10.1128/mcb.01357-08 ◽

2008 ◽

Vol 29 (3) ◽

pp. 794-807 ◽

Cited By ~ 31

Author(s):

Lyra M. Griffiths ◽

Dan Swartzlander ◽

Kellen L. Meadows ◽

Keith D. Wilkinson ◽

Anita H. Corbett ◽

...

Keyword(s):

Oxidative Stress ◽

Dna Damage ◽

Dna Repair ◽

Base Excision Repair ◽

Oxidative Dna Damage ◽

Excision Repair ◽

Intracellular Localization ◽

Genotoxic Stress ◽

Mitochondrial Oxidative Stress ◽

Base Excision

ABSTRACT DNAs harbored in both nuclei and mitochondria of eukaryotic cells are subject to continuous oxidative damage resulting from normal metabolic activities or environmental insults. Oxidative DNA damage is primarily reversed by the base excision repair (BER) pathway, initiated by N-glycosylase apurinic/apyrimidinic (AP) lyase proteins. To execute an appropriate repair response, BER components must be distributed to accommodate levels of genotoxic stress that may vary considerably between nuclei and mitochondria, depending on the growth state and stress environment of the cell. Numerous examples exist where cells respond to signals, resulting in relocalization of proteins involved in key biological transactions. To address whether such dynamic localization contributes to efficient organelle-specific DNA repair, we determined the intracellular localization of the Saccharomyces cerevisiae N-glycosylase/AP lyases, Ntg1 and Ntg2, in response to nuclear and mitochondrial oxidative stress. Fluorescence microscopy revealed that Ntg1 is differentially localized to nuclei and mitochondria, likely in response to the oxidative DNA damage status of the organelle. Sumoylation is associated with targeting of Ntg1 to nuclei containing oxidative DNA damage. These studies demonstrate that trafficking of DNA repair proteins to organelles containing high levels of oxidative DNA damage may be a central point for regulating BER in response to oxidative stress.

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Small molecule inhibitor of TAK1 ameliorates rat cartilaginous endplate degeneration induced by oxidative stress in vitro and in vivo

Free Radical Biology and Medicine ◽

10.1016/j.freeradbiomed.2020.01.002 ◽

2020 ◽

Vol 148 ◽

pp. 140-150

Author(s):

Pan Tang ◽

Wen-Xiang Chen ◽

Hong-Liang Gao ◽

Jia-Yong Dai ◽

Yu Gu ◽

...

Keyword(s):

Oxidative Stress ◽

Small Molecule ◽

Small Molecule Inhibitor ◽

Molecule Inhibitor ◽

Cartilaginous Endplate

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A natural small molecule inhibitor corilagin blocks HCV replication and modulates oxidative stress to reduce liver damage

Antiviral Research ◽

10.1016/j.antiviral.2017.12.004 ◽

2018 ◽

Vol 150 ◽

pp. 47-59 ◽

Cited By ~ 9

Author(s):

B. Uma Reddy ◽

Ranajoy Mullick ◽

Anuj Kumar ◽

Geetika Sharma ◽

Paromita Bag ◽

...

Keyword(s):

Oxidative Stress ◽

Small Molecule ◽

Liver Damage ◽

Small Molecule Inhibitor ◽

Molecule Inhibitor

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70 A Selective Small Molecule Inhibitor of Mcl-1 Induces Bak Dependent Apoptosis in Cancer Cell Lines

European Journal of Cancer ◽

10.1016/s0959-8049(12)71868-3 ◽

2012 ◽

Vol 48 ◽

pp. 23

Author(s):

D.C. Phillips ◽

Y. Xiao ◽

M. Bruncko ◽

C. Park ◽

H. Zhang ◽

...

Keyword(s):

Cell Lines ◽

Cancer Cell ◽

Small Molecule ◽

Cancer Cell Lines ◽

Small Molecule Inhibitor ◽

Molecule Inhibitor

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Characterization of DDRI-18 (3,3′-(1H,3′H-5,5′-bibenzo[d]imidazole-2,2′-diyl)dianiline), a novel small molecule inhibitor modulating the DNA damage response

British Journal of Pharmacology ◽

10.1111/j.1476-5381.2012.01977.x ◽

2012 ◽

Vol 167 (1) ◽

pp. 141-150 ◽

Cited By ~ 6

Author(s):

DW Jun ◽

YS Jeong ◽

HJ Kim ◽

K-C Jeong ◽

S Kim ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Small Molecule ◽

Small Molecule Inhibitor ◽

Molecule Inhibitor ◽

Damage Response

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The Tak-1 Inhibitor AZ-Tak1 Inhibits XIAP, Activates Caspase-9, and Induces Apoptosis in Mantle Cell Lymphoma.

Blood ◽

10.1182/blood.v114.22.1692.1692 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1692-1692 ◽

Cited By ~ 1

Author(s):

Daniela Buglio ◽

Sangeetha Palakurthi ◽

Katharine F. Byth ◽

Anas Younes

Keyword(s):

Mantle Cell Lymphoma ◽

Cell Lines ◽

Small Molecule ◽

Cell Lymphoma ◽

Small Molecule Inhibitor ◽

Caspase 9 ◽

Lymphoma Cells ◽

Molecule Inhibitor ◽

Mantle Cell ◽

Induced Apoptosis

Abstract Abstract 1692 Poster Board I-718 Transforming growth factor-b-activated kinase 1 (TAK1) is a key regulator of NF-kB activation. TAK1 can be activated by a variety of pro-inflammatory cytokines and T and B cell receptors. Recent experiments demonstrated that deletion of TAK1 results in inactivation of both JNK and NF-kB signaling resulting in massive apoptotic death of hematopoietic cells in mice. In this study, we examined the expression pattern of TAK1 and its role as a potential therapeutic target for lymphoma. First, we examined TAK1 expression in a panel of lymphoid cell lines by western blot, and found it to be highly expressed in mantle cell lymphoma cell lines (Mino, SP53, and Jeko-1). These lines expressed relatively low levels of the tumor suppressor protein A20. Mino and SP53 expressed high level of p-p38. Subsequently, we investigated the in vitro activity of the novel TAK1 small molecule inhibitor AZ-Tak1 in these cell lines. AZ-Tak1 is a potent and a relatively selective inhibitor of TAK1 kinase activity, with an IC50 of 0.009 mM. It also inhibits Jak2 but at a much higher concentration (IC50=0.18 mM). AZ-Tak1 treatment decreased the level of p38 and ERK in mantle cell lymphoma cells, and induced apoptosis in a dose and time dependent manner, with an IC50 of 0.1-0.5 mM. Using the annexin-V and PI staining and FACS analysis, After 48 hours of incubation, AZ-Tak1 (0.1 mM) induced apoptosis in 28%, 34% and 86% of Mino, SP53, and Jeko cells, respectively, which was increased to 32%, 42%, and 86% when 0.5 mM concentration was used. Similar activity was also observed when primary mantle cell lymphoma cells were examined. Using pathway-specific protein arrays focusing on apoptosis, kinases, and transcription factors, AZ-Tak1 (0.5 mM) altered the level of several proteins that regulate cell growth and survival, especially members of the inhibitors of apoptosis (IAP) family. Specifically, AZ-Tak1 decreased the level of SMAC/DIABOLO and cytochrome –C in the mitochondria, which was associated with a decrease in the level of the anti-apoptotic protein X-linked IAP (XIAP) and activation of the intrinsic apoptotic pathway as evident by activation of caspase 9, cleavage of caspase 3, and induction of apoptosis. Furthermore, and consistant with its ability to inhibit Jak2 activity, AZ-Tak1 reduced STAT2 and STAT6 levels. AZ-Tak1 demonstrated no significant effect on bcl-2 family members. Finally, co-treatment with HDAC inhibitors demonstrated synergistic effect with low concentrations of AZ-Tak1. Collectively, our data demonstrate that targeting TAK1 by the small molecule inhibitor AZ-Tak1 induces cell death in mantle cell lymphoma by activating the intrinsic apoptosis pathway, suggesting that targeting TAK1 may have a therapeutic value for the treatment of mantle cell lymphoma. Disclosures Palakurthi: Astra Zeneca: Employment. Byth:Astra Zeneca : Employment.

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