PALB2 deficiency may sensitize H3K27M-mutant pediatric HGG cells to BMN673/talazoparib

BackgroudPediatric high-grade glioma (pHGG) with the histone H3 Lys27Met substitution (H3K27M) is a devastating disease with a high mortality rate in children and adolescents (from birth to 19 years of age). No effective treatments have been developed for this tumor type. Thus, a better understandin...

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Main Authors: Xiaowen Guan, Xinke Xu, Xiaolan Mo, Houliang Deng
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-06-01
Series:Frontiers in Oncology
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Online Access:https://www.frontiersin.org/articles/10.3389/fonc.2025.1589396/full
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author Xiaowen Guan
Xinke Xu
Xiaolan Mo
Houliang Deng
author_facet Xiaowen Guan
Xinke Xu
Xiaolan Mo
Houliang Deng
author_sort Xiaowen Guan
collection DOAJ
description BackgroudPediatric high-grade glioma (pHGG) with the histone H3 Lys27Met substitution (H3K27M) is a devastating disease with a high mortality rate in children and adolescents (from birth to 19 years of age). No effective treatments have been developed for this tumor type. Thus, a better understanding of the underlying complex mechanisms and identify more potential drugs targeting H3K27M-mutant pHGG are urgently needed.MethodsIn the current study, we established pHGG cell models harboring H3K27M by transfecting two pHGG cell lines, SF188 and Res259, with the H3K27M mutant and H3 wild-type (WT) plasmids and then performed drugs screening. Then we employed an EJ5 reporter assay to measure nonhomologous end joining (NHEJ) activity. Western blotting was used to analyze DNA damage markers (γ-H2AX and PLK1), and cell cycle progression was assessed. Additionally, we utilized whole-exome sequencing and CRISPR/Cas9 genome editing to generate Res259 cell lines with stable deficiencies in ARID1A, P53, or PALB2, followed by viability assays to evaluate drug sensitivity. ResultsNotably, BMN673 (talazoparib) was identified as a synthetic lethal hit in the H3K27M-mutant SF188 cell model. However, BMN673 did not affect the constructed H3K27M-mutant Res259 cells. Moreover, we showed that the H3K27M mutation induced an aberrant increase in NHEJ activity. Furthermore, BMN673 treatment increased the protein levels of γ-H2AX and PLK1, induced cell cycle arrest, and promoted PARP1 trapping in H3K27M-mutant SF188 cells. In addition, the results of a series of viability assays revealed that the H3K27M mutation combined with PALB2 deficiency sensitized H3K27M-mutant Res259 cells to BMN673. However, deficiencies in ARID1A or P53 did not produce similar effects.ConclusionOverall, our results may provide some reference value for further study of the effects of BMN673 and PALB2 deficiency in the treatment of H3K27M-mutant pHGG.
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spelling doaj-art-5909b2bf40694e70849d283559b0a1ee2025-08-20T02:37:42ZengFrontiers Media S.A.Frontiers in Oncology2234-943X2025-06-011510.3389/fonc.2025.15893961589396PALB2 deficiency may sensitize H3K27M-mutant pediatric HGG cells to BMN673/talazoparibXiaowen Guan0Xinke Xu1Xiaolan Mo2Houliang Deng3School of Life Sciences, Zhengzhou University, Zhengzhou, Henan, ChinaDepartment of Neurosurgery, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, ChinaDepartment of Pharmacy, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, ChinaDepartment of Pharmacy, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, ChinaBackgroudPediatric high-grade glioma (pHGG) with the histone H3 Lys27Met substitution (H3K27M) is a devastating disease with a high mortality rate in children and adolescents (from birth to 19 years of age). No effective treatments have been developed for this tumor type. Thus, a better understanding of the underlying complex mechanisms and identify more potential drugs targeting H3K27M-mutant pHGG are urgently needed.MethodsIn the current study, we established pHGG cell models harboring H3K27M by transfecting two pHGG cell lines, SF188 and Res259, with the H3K27M mutant and H3 wild-type (WT) plasmids and then performed drugs screening. Then we employed an EJ5 reporter assay to measure nonhomologous end joining (NHEJ) activity. Western blotting was used to analyze DNA damage markers (γ-H2AX and PLK1), and cell cycle progression was assessed. Additionally, we utilized whole-exome sequencing and CRISPR/Cas9 genome editing to generate Res259 cell lines with stable deficiencies in ARID1A, P53, or PALB2, followed by viability assays to evaluate drug sensitivity. ResultsNotably, BMN673 (talazoparib) was identified as a synthetic lethal hit in the H3K27M-mutant SF188 cell model. However, BMN673 did not affect the constructed H3K27M-mutant Res259 cells. Moreover, we showed that the H3K27M mutation induced an aberrant increase in NHEJ activity. Furthermore, BMN673 treatment increased the protein levels of γ-H2AX and PLK1, induced cell cycle arrest, and promoted PARP1 trapping in H3K27M-mutant SF188 cells. In addition, the results of a series of viability assays revealed that the H3K27M mutation combined with PALB2 deficiency sensitized H3K27M-mutant Res259 cells to BMN673. However, deficiencies in ARID1A or P53 did not produce similar effects.ConclusionOverall, our results may provide some reference value for further study of the effects of BMN673 and PALB2 deficiency in the treatment of H3K27M-mutant pHGG.https://www.frontiersin.org/articles/10.3389/fonc.2025.1589396/fullH3K27M-mutant pHGGBMN673PARP1 trappingDNA repairPALB2
spellingShingle Xiaowen Guan
Xinke Xu
Xiaolan Mo
Houliang Deng
PALB2 deficiency may sensitize H3K27M-mutant pediatric HGG cells to BMN673/talazoparib
Frontiers in Oncology
H3K27M-mutant pHGG
BMN673
PARP1 trapping
DNA repair
PALB2
title PALB2 deficiency may sensitize H3K27M-mutant pediatric HGG cells to BMN673/talazoparib
title_full PALB2 deficiency may sensitize H3K27M-mutant pediatric HGG cells to BMN673/talazoparib
title_fullStr PALB2 deficiency may sensitize H3K27M-mutant pediatric HGG cells to BMN673/talazoparib
title_full_unstemmed PALB2 deficiency may sensitize H3K27M-mutant pediatric HGG cells to BMN673/talazoparib
title_short PALB2 deficiency may sensitize H3K27M-mutant pediatric HGG cells to BMN673/talazoparib
title_sort palb2 deficiency may sensitize h3k27m mutant pediatric hgg cells to bmn673 talazoparib
topic H3K27M-mutant pHGG
BMN673
PARP1 trapping
DNA repair
PALB2
url https://www.frontiersin.org/articles/10.3389/fonc.2025.1589396/full
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