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Arp2/3 Inhibition Synergizes With PARP Inhibitors by Impairing Homologous Recombination in Gastric Cancer Cells
Wenlong Li1,2, Xinyue Pei1,3, Yongpei Li1,3
1Laboratory of Protein Structure and Function, Institute of Medicine and Pharmacy, Qiqihar Medical University, 161006 Qiqihar, Heilongjiang, China.
Frontiers in Bioscience (Landmark Edition)
|July 30, 2026
Summary
Inhibiting Arp2/3 compromises homologous recombination (HR) repair, creating a synthetic lethal interaction with Poly(ADP-ribose) polymerase inhibitors (PARPi) in gastric cancer. This combination enhances treatment efficacy for HR-proficient tumors.
Area of Science:
- Molecular Biology
- Cancer Research
- Genetics
Background:
- Poly(ADP-ribose) polymerase inhibitors (PARPi) show limited efficacy in gastric cancer due to rare homologous recombination (HR) deficiency.
- The Arp2/3 complex is implicated in DNA double-strand break repair via HR.
- Investigating Arp2/3 inhibition to induce HR deficiency and synergize with PARPi in gastric cancer.
Purpose of the Study:
- To determine if pharmacological inhibition of Arp2/3 can create a functional HR-deficient state.
- To evaluate the synergistic effect of Arp2/3 inhibition with PARPi in gastric cancer cells.
- To assess the impact on DNA repair capacity, proliferation, and apoptosis.
Main Methods:
- Assessed HR repair efficiency using a DR-GFP reporter assay in HEK-293T cells with Arp2/3 inhibition (CK666, siRNA, CRISPR/Cas9).
- Treated HGC-27 and AGS gastric cancer cells with CK666 alone and in combination with olaparib or niraparib.
- Evaluated cell viability, synergy, DNA damage (γH2AX foci), and apoptosis (cleaved PARP).
Main Results:
- Arp2/3 inhibition significantly impaired HR repair efficiency (p < 0.01).
- CK666 synergized with olaparib and niraparib, reducing PARPi IC50 threefold and suppressing proliferation.
- Combination treatment markedly enhanced DNA damage (γH2AX foci) and apoptosis (cleaved PARP).
Conclusions:
- Arp2/3 inhibition compromises HR repair capacity, inducing synthetic lethality with PARP inhibition in gastric cancer.
- This combination strategy offers a promising approach to broaden PARPi utility in HR-proficient tumors.
- Potential for dose reduction of PARPi to mitigate associated toxicities.
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