Objective SET8 is a member of the SET domain-containing family and the only known lysine methyltransferase(KMT)that monomethylates lysine 20 of histone H4(H4 K20 me1).SET8 has been implicated in many essential cellula...Objective SET8 is a member of the SET domain-containing family and the only known lysine methyltransferase(KMT)that monomethylates lysine 20 of histone H4(H4 K20 me1).SET8 has been implicated in many essential cellular processes,including cell cycle regulation,DNA replication,DNA damage response,and carcinogenesis.There is no conclusive evidence,however,regarding the effect of SET8 on radiotherapy.In the current study we determined the efficacy of SET8 inhibition on radiotherapy of tumors and the underlying mechanism.Methods First,we explored the radiotherapy benefit of the SET8 expression signature by analyzing clinical data.Then,we measured a series of biological endpoints,including the xenograft tumor growth in mice and apoptosis,frequency of micronuclei,and foci of 53 BP1 andγ-H2 AX in cells to detect the SET8 effects on radiosensitivity.RNA sequencing and subsequent experiments were exploited to verify the mechanism underlying the SET8 effects on radiotherapy.Results Low expression of SET8 predicted a better benefit to radiotherapy in lung adenocarcinoma(LUAD)and invasive breast carcinoma(BRCA)patients.Furthermore,genetic deletion of SET8 significantly enhanced radiation treatment efficacy in a murine tumor model,and A549 and MCF7 cells;SET8 overexpression decreased the radiosensitivity.SET8 inhibition induced more apoptosis,the frequency of micronuclei,and blocked the kinetics process of DNA damage repair as 53 BP1 andγ-H2 AX foci remained in cells.Moreover,RNF8 was positively correlated with the SET8 impact on DNA damage repair.Conclusion Our results demonstrated that SET8 inhibition enhanced radiosensitivity by suppressing DNA damage repair,thus suggesting that SET8 potentiated radiotherapy of carcinomas.As new inhibitors of SET8 are synthesized and tested in preclinical and clinical settings,combining SET8 inhibitors with radiation warrants consideration for precise radiotherapy.展开更多
目的细胞增殖是影响肾细胞癌进展的重要因素,本研究旨在探讨组蛋白赖氨酸甲基转移酶SET8在调节肾透明细胞癌786-O细胞增殖中的作用。方法将体外培养肾透明细胞癌786-O细胞随机分为空白对照组、空质粒组和SET8-shRNA组3组。采用四甲基偶...目的细胞增殖是影响肾细胞癌进展的重要因素,本研究旨在探讨组蛋白赖氨酸甲基转移酶SET8在调节肾透明细胞癌786-O细胞增殖中的作用。方法将体外培养肾透明细胞癌786-O细胞随机分为空白对照组、空质粒组和SET8-shRNA组3组。采用四甲基偶氮唑蓝(MTT)法检测3组细胞的增殖能力;RT-PCR和蛋白质印迹法检测3组细胞Survivin和Caspase-3的表达水平,分析干扰SET8对肾透明细胞癌786-O细胞增殖及相关基因和蛋白表达的影响。结果 shRNA-SET8可成功抑制786-O细胞中SET8蛋白的表达。MTT检测结果显示,0、12、24、36和48 h SET8-shRNA组增殖抑制率分别为(10.97±2.68)%、(20.38±7.12)%、(25.03±7.60)%、(30.35±1.97)%和(31.33±1.04)%,SET8-shRNA组786-O细胞的增殖能力较空白对照组和空质粒组明显降低,P<0.05。RT-PCR和蛋白质印迹法结果显示,SET8-shRNA组Survivin mRNA相对表达量为0.257±0.024,较空白对照组(1.046±0.041)和空质粒组(0.994±0.018)明显下降(P<0.05),其蛋白的相对表达量为0.834±0.072,较空白对照组(0.951±0.047)和空质粒组(1.203±0.092)明显下降,P<0.05;而Caspase-3mRNA的相对表达量为0.921±0.072,较空白对照组(0.421±0.022)和空质粒组(0.439±0.007)明显上升(P<0.05),蛋白的相对表达量为1.188±0.022,较空白对照组(0.541±0.060)和空质粒组(0.617±0.028)明显上升,P<0.05。结论干扰SET8可以有效抑制肾透明细胞癌786-O细胞SET8蛋白表达,从而抑制Survivin和上调Caspase-3的表达而抑制肾透明细胞癌786-O细胞增殖能力。展开更多
基金supported by the National Natural Science Foundation of China[U1432121,11635013,11705248]。
文摘Objective SET8 is a member of the SET domain-containing family and the only known lysine methyltransferase(KMT)that monomethylates lysine 20 of histone H4(H4 K20 me1).SET8 has been implicated in many essential cellular processes,including cell cycle regulation,DNA replication,DNA damage response,and carcinogenesis.There is no conclusive evidence,however,regarding the effect of SET8 on radiotherapy.In the current study we determined the efficacy of SET8 inhibition on radiotherapy of tumors and the underlying mechanism.Methods First,we explored the radiotherapy benefit of the SET8 expression signature by analyzing clinical data.Then,we measured a series of biological endpoints,including the xenograft tumor growth in mice and apoptosis,frequency of micronuclei,and foci of 53 BP1 andγ-H2 AX in cells to detect the SET8 effects on radiosensitivity.RNA sequencing and subsequent experiments were exploited to verify the mechanism underlying the SET8 effects on radiotherapy.Results Low expression of SET8 predicted a better benefit to radiotherapy in lung adenocarcinoma(LUAD)and invasive breast carcinoma(BRCA)patients.Furthermore,genetic deletion of SET8 significantly enhanced radiation treatment efficacy in a murine tumor model,and A549 and MCF7 cells;SET8 overexpression decreased the radiosensitivity.SET8 inhibition induced more apoptosis,the frequency of micronuclei,and blocked the kinetics process of DNA damage repair as 53 BP1 andγ-H2 AX foci remained in cells.Moreover,RNF8 was positively correlated with the SET8 impact on DNA damage repair.Conclusion Our results demonstrated that SET8 inhibition enhanced radiosensitivity by suppressing DNA damage repair,thus suggesting that SET8 potentiated radiotherapy of carcinomas.As new inhibitors of SET8 are synthesized and tested in preclinical and clinical settings,combining SET8 inhibitors with radiation warrants consideration for precise radiotherapy.
文摘目的细胞增殖是影响肾细胞癌进展的重要因素,本研究旨在探讨组蛋白赖氨酸甲基转移酶SET8在调节肾透明细胞癌786-O细胞增殖中的作用。方法将体外培养肾透明细胞癌786-O细胞随机分为空白对照组、空质粒组和SET8-shRNA组3组。采用四甲基偶氮唑蓝(MTT)法检测3组细胞的增殖能力;RT-PCR和蛋白质印迹法检测3组细胞Survivin和Caspase-3的表达水平,分析干扰SET8对肾透明细胞癌786-O细胞增殖及相关基因和蛋白表达的影响。结果 shRNA-SET8可成功抑制786-O细胞中SET8蛋白的表达。MTT检测结果显示,0、12、24、36和48 h SET8-shRNA组增殖抑制率分别为(10.97±2.68)%、(20.38±7.12)%、(25.03±7.60)%、(30.35±1.97)%和(31.33±1.04)%,SET8-shRNA组786-O细胞的增殖能力较空白对照组和空质粒组明显降低,P<0.05。RT-PCR和蛋白质印迹法结果显示,SET8-shRNA组Survivin mRNA相对表达量为0.257±0.024,较空白对照组(1.046±0.041)和空质粒组(0.994±0.018)明显下降(P<0.05),其蛋白的相对表达量为0.834±0.072,较空白对照组(0.951±0.047)和空质粒组(1.203±0.092)明显下降,P<0.05;而Caspase-3mRNA的相对表达量为0.921±0.072,较空白对照组(0.421±0.022)和空质粒组(0.439±0.007)明显上升(P<0.05),蛋白的相对表达量为1.188±0.022,较空白对照组(0.541±0.060)和空质粒组(0.617±0.028)明显上升,P<0.05。结论干扰SET8可以有效抑制肾透明细胞癌786-O细胞SET8蛋白表达,从而抑制Survivin和上调Caspase-3的表达而抑制肾透明细胞癌786-O细胞增殖能力。
