Academic Journal
View in EDS

CRISPR Screening Identifies SMARCAL1 and MRN as Modulators of WRN Dependency in MSI-H Colorectal Cancer.

Bibliographic Details
Title: CRISPR Screening Identifies SMARCAL1 and MRN as Modulators of WRN Dependency in MSI-H Colorectal Cancer.
Authors: Ma T; Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas., Wu J; Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas., Li S; Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas., Chen J; Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Source: Cancer research [Cancer Res] 2026 Oct 15; Vol. 86 (20), pp. 5271-5286.
Publication Type: Journal Article
Language: English
Journal Info: Publisher: American Association for Cancer Research Country of Publication: United States NLM ID: 2984705R Publication Model: Print Cited Medium: Internet ISSN: 1538-7445 (Electronic) Linking ISSN: 00085472 NLM ISO Abbreviation: Cancer Res Subsets: MEDLINE
Imprint Name(s): Publication: Baltimore, Md. : American Association for Cancer Research
Original Publication: Chicago [etc.]
MeSH Terms: Werner Syndrome Helicase*/genetics , Werner Syndrome Helicase*/metabolism , Werner Syndrome Helicase*/antagonists & inhibitors , Colorectal Neoplasms*/genetics , Colorectal Neoplasms*/metabolism , Colorectal Neoplasms*/pathology , DNA Helicases*/genetics , DNA Helicases*/metabolism , MRE11 Homologue Protein*/metabolism , MRE11 Homologue Protein*/genetics , Cell Cycle Proteins*/metabolism , Cell Cycle Proteins*/genetics , Nuclear Proteins*/metabolism , Nuclear Proteins*/genetics , DNA Repair Enzymes*/metabolism , DNA Repair Enzymes*/genetics , Microsatellite Instability*, DNA-Binding Proteins/metabolism ; DNA-Binding Proteins/genetics ; Humans ; Cell Line, Tumor ; CRISPR-Cas Systems ; Acid Anhydride Hydrolases
Abstract: Microsatellite instability-high (MSI-H) colorectal cancer cells depend on the Werner syndrome helicase (WRN) to resolve cruciform DNA structures that arise from expanded TA-dinucleotide repeats. Loss of WRN induces replication stress and double-strand breaks, a vulnerability that can be recapitulated with the selective WRN inhibitor (WRNi) HRO761 in MSI-H cancer cells. To uncover the mechanisms governing sensitivity to WRN inhibition, we conducted genome-wide CRISPR/Cas9 screens in colorectal cancer cell lines treated with or without HRO761. These screens identified SMARCAL1 as a key modulator of WRN dependency. Depletion of SMARCAL1 rendered cells resistant to WRN inhibition, and rescue of this effect required the ATPase/translocase activity of SMARCAL1. Mechanistically, SMARCAL1 antagonized WRN and supported cruciform DNA structures, thereby enhancing cellular reliance on WRN. In addition, the MRE11-RAD50-NBS1 (MRN) complex, rather than MUS81 or ERCC1/XPF, was the principal mediator of cruciform DNA processing following WRN inhibition. Acute disruption of the MRN complex conferred profound resistance to WRN inhibition, whereas ataxia-telangiectasia mutated (ATM) deficiency produced a more modest resistant phenotype. Further genetic and pharmacologic epistasis analyses demonstrated that the MRN complex regulates WRNi sensitivity through both ATM-dependent signaling and MRE11 nuclease-dependent functions. Importantly, the key resistance mechanisms identified in this study were independently validated using a structurally distinct clinical-stage WRNi, VVD-214. Collectively, these findings identify the SMARCAL1-MRN-ATM axis as a critical regulator of WRN dependency and provide mechanistic insights into resistance to WRN-targeted therapy.
Significance: SMARCAL1 and the MRN-ATM pathway determine sensitivity to WRN inhibition in microsatellite instability-high colorectal cancer, revealing key mechanisms of WRN dependency and potential drivers of resistance to WRN inhibitors.
(©2026 The Authors; Published by the American Association for Cancer Research.)
References: EMBO J. 2023 Feb 1;42(3):e111998. (PMID: 36541070)
Nat Chem Biol. 2008 Feb;4(2):119-25. (PMID: 18176557)
Mol Cell Biol. 2004 Jul;24(13):5776-87. (PMID: 15199134)
iScience. 2019 Mar 29;13:488-497. (PMID: 30898619)
Nat Protoc. 2013 Nov;8(11):2281-2308. (PMID: 24157548)
Nature. 2019 May;569(7757):503-508. (PMID: 31068700)
DNA Repair (Amst). 2010 Mar 2;9(3):331-44. (PMID: 20075015)
Crit Rev Biochem Mol Biol. 2017 Dec;52(6):696-714. (PMID: 28954549)
STAR Protoc. 2021 Feb 05;2(1):100321. (PMID: 33598657)
Nat Commun. 2020 Sep 18;11(1):4687. (PMID: 32948771)
Clin Cancer Res. 2016 Feb 15;22(4):813-20. (PMID: 26880610)
Cell Rep. 2014 May 22;7(4):1048-55. (PMID: 24813886)
Nature. 2012 Mar 28;483(7391):603-7. (PMID: 22460905)
Mol Cell. 2024 Feb 15;84(4):640-658.e10. (PMID: 38266639)
Genes Dev. 2009 Oct 15;23(20):2415-25. (PMID: 19793862)
Nucleic Acids Res. 2014 May;42(9):5846-62. (PMID: 24692662)
Nucleic Acids Res. 2019 May 7;47(8):4124-4135. (PMID: 30783677)
FEBS Lett. 2020 Dec;594(24):4320-4337. (PMID: 32936932)
Nature. 2024 May;629(8011):435-442. (PMID: 38658751)
Trends Cancer. 2021 May;7(5):430-446. (PMID: 33203609)
Oncogene. 2019 Apr;38(14):2451-2463. (PMID: 30532030)
EMBO Rep. 2011 Jun;12(6):574-80. (PMID: 21525954)
Br J Cancer. 2008 Nov 18;99(10):1607-12. (PMID: 18941461)
Nat Commun. 2022 Jul 22;13(1):4240. (PMID: 35869071)
Cell. 1998 May 1;93(3):477-86. (PMID: 9590181)
Chromosoma. 2011 Apr;120(2):109-27. (PMID: 21369956)
FEBS Lett. 2010 Sep 10;584(17):3682-95. (PMID: 20655309)
Cancer Treat Rev. 1998 Oct;24(5):331-44. (PMID: 9861196)
Cancer Res. 2013 Jul 15;73(14):4362-71. (PMID: 23576554)
Elife. 2019 Mar 25;8:. (PMID: 30910006)
EMBO J. 2006 Oct 18;25(20):4921-32. (PMID: 17036055)
Mol Cell. 2023 Aug 3;83(15):2810-2828.e6. (PMID: 37541219)
BMC Mol Biol. 2011 Aug 05;12:33. (PMID: 21816114)
Genome Res. 2009 Feb;19(2):191-8. (PMID: 18997000)
Mol Cell. 2016 Dec 1;64(5):940-950. (PMID: 27889449)
Nature. 2019 Apr;568(7753):551-556. (PMID: 30971823)
Elife. 2022 Jan 25;11:. (PMID: 35076389)
Genes Dev. 2012 Jan 15;26(2):151-62. (PMID: 22279047)
Cancer Discov. 2024 Aug 2;14(8):1457-1475. (PMID: 38587317)
J Biol Chem. 2015 Feb 13;290(7):4110-7. (PMID: 25552480)
Annu Rev Biochem. 2015;84:711-38. (PMID: 25580527)
Nat Commun. 2015 Apr 16;6:6746. (PMID: 25879486)
Cell. 2008 Oct 3;135(1):97-109. (PMID: 18854158)
FEBS Lett. 2014 Aug 1;588(15):2446-56. (PMID: 24928444)
EMBO J. 2002 Apr 15;21(8):2045-53. (PMID: 11953324)
Cell. 2013 Sep 26;155(1):94-106. (PMID: 24074863)
EMBO J. 2003 Oct 15;22(20):5612-21. (PMID: 14532133)
Nat Chem Biol. 2018 May;14(5):431-441. (PMID: 29581585)
Cell. 2008 Oct 3;135(1):14-6. (PMID: 18854148)
DNA Repair (Amst). 2004 Aug-Sep;3(8-9):845-54. (PMID: 15279769)
EMBO Rep. 2003 Sep;4(9):844-9. (PMID: 12949583)
Mol Cell. 2024 Dec 5;84(23):4522-4537.e7. (PMID: 39510066)
Gastroenterology. 2010 Jun;138(6):2073-2087.e3. (PMID: 20420947)
G3 (Bethesda). 2017 Aug 07;7(8):2719-2727. (PMID: 28655737)
Biomolecules. 2015 Oct 23;5(4):2877-902. (PMID: 26512707)
J Biol Chem. 2004 Nov 12;279(46):47411-4. (PMID: 15326170)
Cell. 2008 Oct 3;135(1):85-96. (PMID: 18854157)
Nature. 2020 Oct;586(7828):292-298. (PMID: 32999459)
Commun Biol. 2026 Jan 28;9(1):. (PMID: 41606312)
Genome Med. 2019 Aug 22;11(1):52. (PMID: 31439014)
Mol Cell. 2008 Sep 26;31(6):800-12. (PMID: 18922464)
J Med Chem. 2025 Dec 25;68(24):25912-25938. (PMID: 40964743)
Mol Cancer. 2017 Jul 6;16(1):116. (PMID: 28683746)
Annu Rev Biochem. 2008;77:259-87. (PMID: 18518821)
Nat Commun. 2017 Dec 7;8(1):1982. (PMID: 29215009)
Molecules. 2018 Dec 05;23(12):. (PMID: 30563071)
Cell Rep. 2018 Jan 30;22(5):1200-1210. (PMID: 29386108)
Nat Rev Mol Cell Biol. 2011 Feb;12(2):90-103. (PMID: 21252998)
Nature. 2025 Apr;640(8060):1093-1102. (PMID: 40205037)
Nature. 2024 May;629(8011):443-449. (PMID: 38658754)
Nat Biotechnol. 2017 May;35(5):463-474. (PMID: 28319085)
Mol Cell. 2014 Jan 9;53(1):7-18. (PMID: 24316220)
Nat Med. 2016 Nov;22(11):1342-1350. (PMID: 27694933)
Nat Commun. 2022 Jun 13;13(1):3396. (PMID: 35697743)
DNA Repair (Amst). 2024 Sep;141:103731. (PMID: 39089193)
Trends Cell Biol. 2014 May;24(5):321-7. (PMID: 24361091)
Grant Information: CA274234 National Cancer Institute (NCI); CA275712 National Cancer Institute (NCI); CA278758 National Cancer Institute (NCI)
Substance Nomenclature: EC 3.6.4.12 (Werner Syndrome Helicase)
EC 2.7.7.- (SMARCAL1 protein, human)
EC 3.6.4.12 (WRN protein, human)
EC 3.6.4.- (DNA Helicases)
EC 3.1.- (MRE11 Homologue Protein)
0 (Cell Cycle Proteins)
0 (MRE11 protein, human)
0 (DNA-Binding Proteins)
0 (Nuclear Proteins)
EC 3.6.- (RAD50 protein, human)
EC 6.5.1.- (DNA Repair Enzymes)
0 (NBN protein, human)
EC 3.6.- (Acid Anhydride Hydrolases)
Entry Date(s): Date Created: 20260722 Date Completed: 20261015 Latest Revision: 20261017
Update Code: 20261017
PubMed Central ID: PMC13669725
DOI: 10.1158/0008-5472.CAN-26-1023
PMID: 42484294
Database: MEDLINE
Description
ISSN:1538-7445
DOI:10.1158/0008-5472.CAN-26-1023