Differential DNA damage response to WRN inhibition identifies a targetable vulnerability in <i>ARID1A</i>-mutated cancers.

Kim, Jiwon; Oh, Jaeik; Jang, Dongjun; Shin, Seungjae; Lee, Soo-Jin; Lee, Sang Eun; Yang, Yoojin; Kim, Dohee et al. · Sci Adv · 2026

basic_science · Level V

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Abstract

<i>ARID1A</i> (AT-rich interaction domain 1A), a key subunit of the switch/sucrose non-fermentable (SWI/SNF) chromatin remodeling complex, is frequently mutated in cancers. However, effective clinical treatments for patients with this mutation are limited, highlighting a need for therapeutic strategies. Here, we identify Werner syndrome adenosine 5'-triphosphate-dependent helicase (WRN) as a critical vulnerability in <i>ARID1A</i>-mutated cancers. Upon genetic and pharmacological inhibition of WRN, <i>ARID1A</i>-mutated cells had defective checkpoint kinase 1 (Chk1)-mediated DNA damage signaling, resulting in compensatory checkpoint kinase 2 (Chk2) activation, leading to G<sub>1</sub> phase arrest and apoptosis, whereas <i>ARID1A</i>-proficient cells underwent Chk1-dependent G<sub>2</sub>-M arrest. Additional p21 inhibition in the context of WRN suppression promoted cell cycle reentry of G<sub>1</sub>-arrested <i>ARID1A</i>-mutated cells, resulting in enhanced cytotoxicity through mitotic catastrophe. The antitumor efficacy of WRN inhibition alone and in combination with p21 inhibition was validated using cell line-based xenograft and patient-derived xenograft mouse models. Our findings define WRN as a selective therapeutic target in <i>ARID1A</i>-mutated cancers and suggest a combinatorial strategy of WRN and p21 inhibition as a therapeutic approach.