Abstract
Mismatch repair (MMR) deficiency has been linked to thiopurine resistance and hypermutation in relapsed acute lymphoblastic leukemia (ALL). However, the repair mechanism of thiopurine-induced DNA damage in the absence of MMR remains unclear. Here, we provide evidence that DNA polymerase β (POLB) of base excision repair (BER) pathway plays a critical role in the survival and thiopurine resistance of MMR-deficient ALL cells. In these aggressive resistant ALL cells, POLB depletion and its inhibitor oleanolic acid (OA) treatment result in synthetic lethality with MMR deficiency through increased cellular apurinic/apyrimidinic (AP) sites, DNA strand breaks and apoptosis. POLB depletion increases thiopurine sensitivities of resistant cells, and OA synergizes with thiopurine to kill these cells in ALL cell lines, patient-derived xenograft (PDX) cells and xenograft mouse models. Our findings suggest BER and POLB’s roles in the process of repairing thiopurine-induced DNA damage in MMR-deficient ALL cells, and implicate their potentials as therapeutic targets against aggressive ALL progression.
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Data availability
In this study, there were no new datasets generated but re-analysis of existing datasets included in previously published papers as described in Materials and methods. For further information, please contact the corresponding author.
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Acknowledgements
We thank Yu Liu (Shanghai Children’s Medical Center, School of Medicine, Shanghai Jiao Tong University) for helpful suggestions in clinical data re-analysis; Yan Xu, Yao Chen, Chun-Shuang Ma and Ming-Zhen Tian (Shanghai Children’s Medical Center, School of Medicine, Shanghai Jiao Tong University) for technical supports and helps. This work was sponsored by grants from National Key R&D Program of China (No. 2021YFA1100800 to B-BSZ), National Natural Science Foundation of China (No. 81970141 to B-BSZ; No. 82100179 to D-PY; No. 82000110 to CT; and No. 82070158 & No. 81870082 to C-WD), Shanghai Key Laboratory of Clinical Molecular Diagnostics for Pediatrics (No. 20DZ2260900 to B-BSZ), and Shanghai Sailing Program (No. 21YF1428100 to D-PY).
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J-YT, D-PY, CT and H-SF were major contributors to experiments and data analysis. J-YT, D-PY, CT, C-WD and B-BSZ were responsible for interpreting experimental data and writing the paper. H-YS, JL and JY contributed to related bioinformatics analysis. Y-NX, X-ML, FY, R-XX and FF provided reagents and contributed to several in vitro experiments. H-SF and C-WD made major contributions to in vivo experiments. F-LM, J-CH and HL gave helpful suggestions for paper writing. B-SL supplied clinical data of ALL patient samples.
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Teng, JY., Yang, DP., Tang, C. et al. Targeting DNA polymerase β elicits synthetic lethality with mismatch repair deficiency in acute lymphoblastic leukemia. Leukemia 37, 1204–1215 (2023). https://doi.org/10.1038/s41375-023-01902-3
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DOI: https://doi.org/10.1038/s41375-023-01902-3