Kaempferol inhibits non-homologous end joining repair via regulating Ku80 stability in glioma cancer

Meiyang Chen; Erdi Zhao; Minjing Li; Ming Xu; Shiyu Hao; Yingli Gao; Xingli Wu; Xiang Li; Yue Yu; Zhenhai Yu; Yancun Yin

doi:10.1016/j.phymed.2023.154876

Kaempferol inhibits non-homologous end joining repair via regulating Ku80 stability in glioma cancer

Phytomedicine. 2023 Jul 25:116:154876. doi: 10.1016/j.phymed.2023.154876. Epub 2023 May 12.

Authors

Meiyang Chen¹, Erdi Zhao¹, Minjing Li², Ming Xu¹, Shiyu Hao¹, Yingli Gao¹, Xingli Wu³, Xiang Li³, Yue Yu³, Zhenhai Yu⁴, Yancun Yin⁵

Affiliations

¹ Laboratory of Experimental Hematology, School of Basic Medical Sciences, Binzhou Medical University, No. 346 Guanhai Road, Yantai, Shandong 264003, China.
² Institute of Integrated Medicine, Binzhou Medical University, Yantai 264003, China.
³ The Second School of Clinical Medicine, Binzhou Medical University, Yantai 264003, China.
⁴ Department of Anatomy, School of Basic Medicine, Binzhou Medical University, Yantai 264003, China.
⁵ Laboratory of Experimental Hematology, School of Basic Medical Sciences, Binzhou Medical University, No. 346 Guanhai Road, Yantai, Shandong 264003, China. Electronic address: yinyc1985@126.com.

PMID: 37210962
DOI: 10.1016/j.phymed.2023.154876

Abstract

Background: Targeting DNA damage response and DNA repair proficiency of cancers is an important anticancer strategy. Kaempferol (Kae), a natural flavonoid, displays potent antitumor properties in some cancers. However, the precise underlying mechanism of Kae regulates DNA repair system are poorly understood.

Purpose: We aim to evaluate the efficacy of Kae in the treatment of human glioma as well as the molecular mechanism regarding DNA repair.

Study design: Effects of Kae on glioma cells were detected using CCK-8 and EdU labeling assays. The molecular mechanism of Kae on glioma was determined using RNAseq. The inhibition effects of Kae on DNA repair were verified using Immunoprecipitation, immunofluorescence, and pimEJ5-GFP report assays. For in vivo study, orthotopic xenograft models were established and treated with Kae or vehicle. Glioma development was monitored by bioluminescence imaging, Magnetic Resonance Imaging (MRI), and brain sections Hematoxylin/Eosin (HE) staining. Immunohistochemical (IHC) analysis was used to detect expression of Ku80, Ki67 and γH2AX in engrafted glioma tissue.

Results: We found that Kae remarkably inhibits viability of glioma cells and decreases its proliferation. Mechanistically, Kae regulates multiple functional pathways associated with cancer, including non-homologous end joining (NHEJ) repair. Further studies revealed that Kae inhibits release of Ku80 from the double-strand breaks (DSBs) sites via reducing ubiquitylation and degradation of Ku80. Therefore, Kae significantly suppresses NHEJ repair and induces accumulation of DSBs in glioma cells. Moreover, Kae displays a dramatic inhibition effects on glioma growth in an orthotopic transplantation model. These data demonstrate that Kae can induce deubiquitination of Ku80, suppress NHEJ repair and inhibit glioma growth.

Conclusion: Our findings indicate that inhibiting release of Ku80 from the DSBs by Kae may be a potential effective approach for glioma treatment.

Keywords: DNA repair; Glioma; Kaempferol; Ku80; Non-homologous end joining.

MeSH terms

DNA Breaks, Double-Stranded*
DNA End-Joining Repair
Glioma* / drug therapy
Humans
Kaempferols / pharmacology
Ku Autoantigen / genetics
Ku Autoantigen / metabolism

Substances

Ku Autoantigen
Kaempferols