Micro-irradiation tools to visualize base excision repair and single-strand break repair

XRCC1 is an essential protein required for the maintenance of genomic stability through its implication in DNA repair. The main function of XRCC1 is associated with its role in the single-strand break (SSB) and base excision repair (BER) pathways that share several enzymatic steps. We show here that the polymorphic XRCC1 variant R194W presents a defect in its interaction with the DNA glycosylase OGG1 after oxidative stress. While proficient for single-strand break repair (SSBR), this variant does not colocalize with OGG1, reflecting a defect in its involvement in BER. Consistent with a role of XRCC1 in the coordination of the BER pathway, induction of oxidative base damage in XRCC1-deficient cells complemented with the R194W variant results in increased genetic instability as revealed by the accumulation of micronuclei. These data identify a specific molecular role for the XRCC1-OGG1 interaction in BER and provide a model for the effects of the R194W variant identified in molecular cancer epidemiology studies.

Download Full-text

Distinct spatiotemporal patterns and PARP dependence of XRCC1 recruitment to single-strand break and base excision repair

Nucleic Acids Research ◽

10.1093/nar/gkt025 ◽

2013 ◽

Vol 41 (5) ◽

pp. 3115-3129 ◽

Cited By ~ 61

Author(s):

Anna Campalans ◽

Thierry Kortulewski ◽

Rachel Amouroux ◽

Hervé Menoni ◽

Wim Vermeulen ◽

...

Keyword(s):

Base Excision Repair ◽

Excision Repair ◽

Strand Break ◽

Single Strand ◽

Spatiotemporal Patterns ◽

Single Strand Break ◽

Base Excision

Download Full-text

XRCC1 protects transcription from toxic PARP1 activity during DNA base excision repair

Nature Cell Biology ◽

10.1038/s41556-021-00792-w ◽

2021 ◽

Author(s):

Marek Adamowicz ◽

Richard Hailstone ◽

Annie A. Demin ◽

Emilia Komulainen ◽

Hana Hanzlikova ◽

...

Keyword(s):

Base Excision Repair ◽

Neurological Disease ◽

Excision Repair ◽

Strand Break ◽

Single Strand ◽

Toxic Activity ◽

Single Strand Break ◽

Dna Base Excision Repair ◽

Dna Base ◽

Base Excision

AbstractGenetic defects in the repair of DNA single-strand breaks (SSBs) can result in neurological disease triggered by toxic activity of the single-strand-break sensor protein PARP1. However, the mechanism(s) by which this toxic PARP1 activity triggers cellular dysfunction are unclear. Here we show that human cells lacking XRCC1 fail to rapidly recover transcription following DNA base damage, a phenotype also observed in patient-derived fibroblasts with XRCC1 mutations and Xrcc1−/− mouse neurons. This defect is caused by excessive/aberrant PARP1 activity during DNA base excision repair, resulting from the loss of PARP1 regulation by XRCC1. We show that aberrant PARP1 activity suppresses transcriptional recovery during base excision repair by promoting excessive recruitment and activity of the ubiquitin protease USP3, which as a result reduces the level of monoubiquitinated histones important for normal transcriptional regulation. Importantly, inhibition and/or deletion of PARP1 or USP3 restores transcriptional recovery in XRCC1−/− cells, highlighting PARP1 and USP3 as possible therapeutic targets in neurological disease.

Download Full-text

Antileukemic Efficacy in Vitro of Talazoparib and APE1 Inhibitor III Combined with Decitabine in Myeloid Malignancies

Cancers ◽

10.3390/cancers11101493 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1493 ◽

Cited By ~ 3

Author(s):

Kohl ◽

Flach ◽

Naumann ◽

Brendel ◽

Kleiner ◽

...

Keyword(s):

Base Excision Repair ◽

Excision Repair ◽

Donor Cell ◽

Strand Break ◽

Low Doses ◽

Single Strand Break ◽

Single Strand Break Repair ◽

Myeloid Leukemias ◽

Base Excision

Malignant hematopoietic cells of myelodysplastic syndromes (MDS)/chronic myelomonocytic leukemias (CMML) and acute myeloid leukemias (AML) may be vulnerable to inhibition of poly(ADP ribose) polymerase 1/2 (PARP1/2) and apurinic/apyrimidinic endonuclease 1 (APE1). PARP1/2 and APE1 are critical enzymes involved in single-strand break repair and base excision repair, respectively. Here, we investigated the cytotoxic efficacy of talazoparib and APE1 inhibitor III, inhibitors of PARP1/2 and APE1, in primary CD34+ MDS/CMML cell samples (n = 8; 4 MDS and 4 CMML) and in primary CD34+ or CD34− AML cell samples (n = 18) in comparison to healthy CD34+ donor cell samples (n = 8). Strikingly, talazoparib and APE1 inhibitor III demonstrated critical antileukemic efficacy in selected MDS/CMML and AML cell samples. Low doses of talazoparib and APE1 inhibitor III further increased the cytotoxic efficacy of decitabine in MDS/CMML and AML cells. Moreover, low doses of APE1 inhibitor III increased the cytotoxic efficacy of talazoparib in MDS/CMML and AML cells. In summary, talazoparib and APE1 inhibitor III demonstrated substantial antileukemic efficacy as single agents, in combination with decitabine, and combined with each other. Hence, our findings support further investigation of these agents in sophisticated clinical trials.

Download Full-text