Hexyl-pentynoic acid serves as a novel radiosensitizer for breast cancer by inhibiting UCHL3-dependent Rad51 deubiquitination

查看全文 作　　者：Zuchao [1,2]Cai;David [3,4]Lim;Beidi [1]Jia;Guochao [1]Liu;Wenwen [1]Ding;Zhendong [1]Wang;Zhujun [1]Tian;Junxuan [1]Peng;Fengmei [1]Zhang;Chao [1]Dong;Zhihui [1]Feng 机构地区：[1]Department of Occupational Health and Occupational Medicine,School of Public Health,Cheeloo College of Medicine,Shandong University,Jinan 250012,China;[2]Stomatology Hospital,School of Stomatology,Zhejiang University School of Medicine,Zhejiang Provincial Clinical Research Center for Oral Diseases,Key Laboratory of Oral Biomedical Research of Zhejiang Province,Cancer Center of Zhejiang University,Hangzhou 310000,China;[3]Translational Health Research Institute,School of Health Sciences,Western Sydney University,Campbelltown,New South Wales,Australia;[4]College of Medicine and Public Health,Flinders University,Bedford Park,South Australia,Australia 出　　处：《Radiation Medicine and Protection》索引2023年第4卷第4期,共10页 基　　金：supported by grants from Zhejiang Provincial Natural Science Foundation of China(LQ23H14003);National Natural Science Foundation of China(81472800,82173460);Department of Science and Technology of Shandong Province(2019GSF108083);Zhejiang Provincial Postdoctoral Scientific Research Project Funding(ZJ2022076),China. 摘　　要：Objective:To investigate the effects and underlying mechanism of 2-hexyl-4-pentynoic acid(HPTA),a derivative of valproic acid(VPA),on radiotherapy in breast cancer.Methods:MCF7 cells and 7,12-dimethylbenz-[α]-anthracene(DMBA)-induced transformed human normal breast cells(MCF10A–DMBA cells)were irradiated with 8 Gy X-rays.For both cells there were four groups:control,valproic acid(VPA)/HPTA,IR,and VPA/HPTA+IR groups.MTT and clonogenic survival assays were performed to assess cell proliferation,and comet assay was performed to evaluate DNA damage.Protein expression ofγH2AX,53BP1,Rad51,and BRCA1 was examined via immunofluorescence and immunoblotting.Cycloheximide chase and ubiquitination experiments were conducted to determine Rad51 ubiquitination.In vivo experiments involved a rat model of DMBA-induced breast cancer,with four fractionated doses of 2 Gy.Tumor tissue pathological changes andγH2AX,Rad51,and UCHL3 expression levels were measured by hematoxylin-eosin staining,immunohistochemistry,and immunoblotting.Results:Compared with the IR group,15μmol/L HPTA reduced the cell proliferation ability of irradiated MCF7 cells(t=2.16,P<0.05).The VPA/HPTA+IR group exhibited significantly increased DNA double-strand breaks relative to those in the IR group(VPA+IR vs.IR,t=13.37,P<0.05;HPTA+IR vs.IR,t=8.48,P<0.05).Immunofluorescence and immunoblotting experiments demonstrated that the VPA/HPTA+IR group displayed signifi-cantly increased cell foci formation,γH2AX and 53BP1 protein expression levels compared to the IR group[(γH2AX:VPA+IR vs.IR,t=8.88,P<0.05;HPTA+IR vs.IR,t=8.90,P<0.05),(53BP1,VPA+IR vs.IR,t=5.73,P<0.05;HPTA+IR vs.IR,t=6.40,P<0.05)].Further,Rad51 expression was downregulated(VPA+IR vs.IR,t=3.12,P<0.05;HPTA+IR vs.IR,t=2.70,P<0.05),and Rad51 inhibition effectively counteracted HPTA-induced radiosensitization.Ubiquitination detection further verified that HPTA inhibits Rad51 expression via UCHL3-dependent Rad51 deubiquitination.In vivo study results showed that 20 mg/kg HPTA significantly enhanced the radiosensitivity of breast tumors in rats by inhibiting Rad51 expression.Conclusions:HPTA is a highly effective radiosensitizer that enhances the radiotherapeutic efficacy of breast cancer treatment through UCHL3-dependent deubiquitination of Rad51. 关 键 词：2-hexyl-4-pentynoic acid RADIOSENSITIZATION UCHL3 RAD51 Homologous recombination DEUBIQUITINATION