CAF-1 promotes efficient PrimPol recruitment to nascent DNA for single-stranded DNA gap formation DOI Creative Commons

Joshua Straka,

Jude B. Khatib,

Lindsey M Pale

et al.

Nucleic Acids Research, Journal Year: 2024, Volume and Issue: 52(22), P. 13865 - 13880

Published: Nov. 18, 2024

Suppression of single-stranded DNA (ssDNA) gap accumulation at replication forks has emerged as a potential determinant chemosensitivity in homologous recombination (HR)-deficient tumors, ssDNA gaps are transformed into cytotoxic double-stranded breaks. We have previously shown that the histone chaperone CAF-1's nucleosome deposition function is vital to preventing degradation stalled correlating with HR-deficient cells' response genotoxic drugs. Here we report CAF-1-ASF1 pathway promotes both wild-type and breast cancer (BRCA)-deficient backgrounds. show this independent but instead may rely on its proper localization forks. Moreover, efficient nascent PrimPol, enzyme responsible for repriming upon stress, dependent CAF-1. As PrimPol been be generating byproduct function, role recruitment could directly impact formation. also chemoresistance observed cells when CAF-1 or ASF1A lost correlates suppression rather than protection Overall, work identifies an unexpected regulating generation.

Language: Английский

BRCA2 promotes genomic integrity and therapy resistance primarily through its role in homology-directed repair DOI Creative Commons
Pei Xin Lim,

Mahdia Zaman,

Weiran Feng

et al.

Molecular Cell, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 1, 2024

Language: Английский

Citations

31
EXO1 protects BRCA1-deficient cells against toxic DNA lesions DOI Creative Commons
Bert van de Kooij, Anne Schreuder, Raphael Pavani

et al.

Molecular Cell, Journal Year: 2024, Volume and Issue: 84(4), P. 659 - 674.e7

Published: Jan. 23, 2024

Inactivating mutations in the BRCA1 and BRCA2 genes impair DNA double-strand break (DSB) repair by homologous recombination (HR), leading to chromosomal instability cancer. Importantly, BRCA1/2 deficiency also causes therapeutically targetable vulnerabilities. Here, we identify dependency on end resection factor EXO1 as a key vulnerability of BRCA1-deficient cells. generates poly(ADP-ribose)-decorated lesions during S phase that associate with unresolved DSBs genomic but not wild-type or BRCA2-deficient Our data indicate BRCA1/EXO1 double-deficient cells accumulate due impaired single-strand annealing (SSA) top their HR defect. In contrast, retain SSA activity absence hence tolerate loss. Consistent EXO1-mediated SSA, find BRCA1-mutated tumors show elevated expression increased SSA-associated scars compared BRCA1-proficient tumors. Overall, our findings uncover promising therapeutic target for

Language: Английский

Citations

16
HMCES corrupts replication fork stability during base excision repair in homologous recombination–deficient cells DOI
María José Peña-Gómez,

Yaiza Rodríguez-Martín,

Marta del Rio Oliva

et al.

Science Advances, Journal Year: 2025, Volume and Issue: 11(13)

Published: March 26, 2025

Apurinic/apyrimidinic (AP) sites and single-strand breaks arising from base excision repair (BER) during the misincorporation of damaged nucleobases may hinder replication fork stability in homologous recombination–deficient (HRD) cells. At templated AP sites, cross-links between DNA 5-hydroxymethylcytosine binding, embryonic stem cell–specific (HMCES) regulate speed, avoiding cytotoxic double-strand breaks. While role HMCES at template strand is well studied, its effects on nascent are not. We provide evidence that HMCES–DNA-protein (DPCs) detrimental to BER-mediated removal 5-hydroxymethyl-2′-deoxycytidine (5hmdC)–derived 5-hydroxymethyl-2′-deoxyuridine forks. HRD cells have heightened HMCES-DPCs, which increase further upon 5hmdC exposure, suggesting binds both spontaneous 5hmdC-induced sites. depletion substantially suppresses 5hmdC-mediated defects, chromosomal aberrations, cell death This reveals HMCES-DPCs a source BER-initiated single-stranded gaps, indicates endogenous DPCs contribute genomic instability tumors.

Language: Английский

Citations

1
EXO1 and DNA2-mediated ssDNA gap expansion is essential for ATR activation and to maintain viability in BRCA1-deficient cells DOI Creative Commons
Néstor García‐Rodríguez,

Iria Domínguez-García,

María del Carmen Domínguez-Pérez

et al.

Nucleic Acids Research, Journal Year: 2024, Volume and Issue: 52(11), P. 6376 - 6391

Published: May 9, 2024

DNA replication faces challenges from lesions originated endogenous or exogenous sources of stress, leading to the accumulation single-stranded (ssDNA) that triggers activation ATR checkpoint response. To complete genome in presence damaged DNA, cells employ damage tolerance mechanisms operate not only at stalled forks but also ssDNA gaps by repriming synthesis downstream lesions. Here, we demonstrate human accumulate post-replicative following replicative stress induction. These gaps, initiated PrimPol and expanded long-range resection factors EXO1 DNA2, constitute principal origin signal responsible for upon contrast forks. Strikingly, loss DNA2 results synthetic lethality when combined with BRCA1 deficiency, BRCA2. This phenomenon aligns observation alone contributes expansion gaps. Remarkably, BRCA1-deficient become addicted overexpression EXO1, BLM. dependence on unveils a new vulnerability BRCA1-mutant tumors, shedding light potential therapeutic targets these cancers.

Language: Английский

Citations

8
(Single-stranded DNA) gaps in understanding BRCAness DOI Creative Commons
Anne Schreuder,

Tiemen J. Wendel,

Carlo G.V. Dorresteijn

et al.

Trends in Genetics, Journal Year: 2024, Volume and Issue: 40(9), P. 757 - 771

Published: May 23, 2024

The tumour-suppressive roles of BRCA1 and 2 have been attributed to three seemingly distinct functions - homologous recombination, replication fork protection, single-stranded (ss)DNA gap suppression their relative importance is under debate. In this review, we examine the origin resolution ssDNA gaps discuss recent advances in understanding role BRCA1/2 suppression. There are ample data showing that accumulation BRCA1/2-deficient cells linked genomic instability chemosensitivity. However, it remains unclear whether there a causative function cannot unambiguously be dissected from other functions. We therefore conclude closely intertwined not mutually exclusive.

Language: Английский

Citations

6
Phosphorylation-dependent WRN-RPA interaction promotes recovery of stalled forks at secondary DNA structure DOI Creative Commons
Alessandro Noto, Pasquale Valenzisi,

Flavia Di Feo

et al.

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Jan. 27, 2025

Language: Английский

Citations

0
Translesion-synthesis-mediated bypass of DNA lesions occurs predominantly behind replication forks restarted by PrimPol DOI Creative Commons
Ashna Dhoonmoon,

John T. Ambrose,

Saurabh Garg

et al.

Cell Reports, Journal Year: 2025, Volume and Issue: 44(3), P. 115360 - 115360

Published: Feb. 26, 2025

Language: Английский

Citations

0
Targeting Replication Fork Processing Synergizes with PARP Inhibition to Potentiate Lethality in Homologous Recombination Proficient Ovarian Cancers DOI Creative Commons
Ganesh Pai Bellare, Kshama Kundu,

Papiya Dey

et al.

Advanced Science, Journal Year: 2025, Volume and Issue: unknown

Published: March 16, 2025

Abstract Synthetic lethality in homologous recombination (HR)‐deficient cancers caused by Poly (ADP‐ribose) polymerase inhibitors (PARPi) has been classically attributed to its role DNA repair. The mode of action PARPi and resistance thereof are now believed be predominantly replication associated. Therefore, effective combinatorial approaches targeting fork processing along with HR‐downregulation target HR‐proficient possibly PARPi‐resistant tumors warranted. Stilbenes a privileged class molecules, which include resveratrol, pterostilbene, piceatannol, etc , that modulate both processes RAD51‐expression. In this investigation, screening small library stilbenes, including in‐house synthesized trans ‐4,4′‐dihydroxystilbene (DHS) was discovered as potent natural agent, downregulates RAD51 expression HR repair (GFP‐reporter assay). DHS induces extensive synergistic cell death ovarian when combined talazoparib (PARPi). Mechanistically, elicits replication‐stress through severely impeding progress, speed, inducing fork‐asymmetry. This leads robust induction single stranded (ssDNA) gaps poly‐ADP‐ribosylation (PARylation) S‐phase cells, signifying issues related lagging (Okazaki) strand synthesis. PARPi, abrogates PARylation, potentiates induced ssDNA gaps, their conversion into lethal double breaks MRE11 action. Furthermore, the combination is highly mitigating tumor xenograft growth SCID mice exhibited good therapeutic‐index no/minimal tissue‐toxicity.

Language: Английский

Citations

0
The Yeast HMGB Protein Hmo1 Is a Multifaceted Regulator of DNA Damage Tolerance DOI Open Access
Jinlong Huo,

Anhui Wei,

Na Guo

et al.

International Journal of Molecular Sciences, Journal Year: 2025, Volume and Issue: 26(7), P. 3255 - 3255

Published: April 1, 2025

The Saccharomyces cerevisiae chromosomal architectural protein Hmo1 is categorized as an HMGB protein, it contains two motifs that bind DNA in a structure-specific manner. However, has basic C-terminal domain (CTD) promotes bending instead of acidic one found canonical protein. diverse functions genome maintenance and gene regulation. It implicated damage tolerance (DDT) enables replication to bypass lesions on the template. believed direct error-free template switching (TS) pathway DDT aid formation key TS intermediate sister chromatid junction (SCJ), but underlying mechanisms have yet be resolved. In this work, we used genetic molecular biology approaches further investigate role DDT. We extensive functional interactions with components integrity network cellular response genotoxin methyl methanesulfonate (MMS), implicating execution or regulation homology-directed repair, replication-coupled chromatin assembly, checkpoint. Notably, our data pointed for directing SCJ nuclease-mediated resolution helicase/topoisomerase mediated dissolution processing/removal. They also suggested modulates both recycling parental histones deposition newly synthesized nascent at fork ensure proper formation. evidence counteracts function histone H2A variant H2A.Z (Htz1 yeast) possibly due their opposing effects resection. showed negative supercoiling proxy structure MMS-induced checkpoint signaling, which independent CTD Hmo1. Moreover, obtained indicating whether contributes its dependent host's background. Taken together, findings demonstrated can contribute to, regulate, multiple processes via different mechanisms.

Language: Английский

Citations

0
Discovery and Characterization of Small Molecule Inhibitors Targeting Exonuclease 1 for Homologous Recombination-Deficient Cancer Therapy DOI Creative Commons
Yixing Wang, Jessica D. Hess, Chen Wang

et al.

ACS Chemical Biology, Journal Year: 2025, Volume and Issue: unknown

Published: May 16, 2025

Human exonuclease 1 (EXO1), a member of the structure-specific nuclease family, plays critical role in maintaining genome stability by processing DNA double-strand breaks (DSBs), nicks, and replication intermediates during repair. As its activity is essential for homologous recombination (HR) fork processing, EXO1 has emerged as compelling therapeutic target, especially cancers marked heightened damage stress. Through high-throughput screening 45,000 compounds, we identified seven distinct chemical scaffolds that demonstrated effective selective inhibition EXO1. Representative compounds from two most potent scaffolds, C200 F684, underwent comprehensive docking analysis subsequent site-directed mutagenesis studies to evaluate their binding mechanisms. Biochemical assays further validated activity. Tumor cell profiling experiments revealed these inhibitors exploit synthetic lethality BRCA1-deficient cells, emphasizing specificity potential targeting genetically HR-deficient (HRD) driven deleterious mutations HR genes like BRCA1/2. Mechanistically, suppressed end resection, stimulated accumulation breaks, triggered S-phase PARylation, effectively disrupting repair pathways are cancer survival. These findings establish promising candidates treatment HRD lay groundwork optimization development targeted therapeutics.

Language: Английский

Citations

0