Characterization of DAPK1 as a novel transcriptional target of BRMS1.
Breast cancer metastasis suppressor 1 (BRMS1) can specifically regulate tumor metastasis in many cancers. Our previous studies have demonstrated that BRMS1 can promote cell apoptosis through regulating osteopontin (OPN) expression in hepatocellular carcinoma (HCC) cells. However, the transcriptional targets of BRMS1 have not been thoroughly studied. In this study, death-associated protein kinase 1 (DAPK1), a tumor suppressor gene with multiple roles in regulating cell death, was identified as a potential transcriptional target of BRMS1 in the whole genome expression microarray. Quantitative real-time PCR and western blot analysis of HCC cells overexpressing BRMS1 further confirmed the transcriptional regulation relationship between BRMS1 and DAPK1. Moreover, DAPK1 expression was frequently decreased or even lost in HCC tissue samples by comparison with neighboring pathologically normal liver tissue, which was consistent with the decreased BRMS1 expression pattern. To unravel the molecular mechanism of BRMS1 in regulating DAPK1, a series of deletion mutants of DAPK1 promoter was subjected to luciferase assay. The luciferase units of -200 to -80 bp region, with two tandem putative NF-κB binding sites, were specifically enhanced by BRMS1 expression. Site-directed mutants of NF-κB binding sites blocked the transcriptional activation effect. In addition, the binding capability of BRMS1 and the putative NF-κB binding sites were demonstrated in the chromatin immunoprecipitation (ChIP) assay. In conclusion, our study characterized DAPK1 as a novel transcriptional target of BRMS1. Transcriptional activation of DAPK1 might be another important mechanism accounting for the metastasis suppressive activity of BRMS1.
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
Xiaojing
X
Qiao
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
Xi
X
Yang
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
Yiren
Y
Zhou
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
Xinyu
X
Mei
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
Jianming
J
Dou
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
Wenjuan
W
Xie
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
Guoqing
G
Li
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
Yekai
Y
Wang
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
Shouyi
S
Qiao
Endoscopy Center and Department of General Surgery, Zhongshan Hospital of Fudan University, Shanghai, 200032, P.R. China.
Jianwei
J
Hu
State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
Yanhua
Y
Wu
D017209:Apoptosis / Q000235:genetics; D001665:Binding Sites; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D064550:Death-Associated Protein Kinases / Q000096:biosynthesis / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D016328:NF-kappa B / Q000235:genetics; D009362:Neoplasm Metastasis; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics*; D017384:Sequence Deletion; D046888:Tissue Array Analysis; D015533:Transcriptional Activation / Q000235:genetics*
C410024:BRMS1 protein, human; D004268:DNA-Binding Proteins; D016328:NF-kappa B; D012097:Repressor Proteins; C579096:DAPK1 protein, human; D064550:Death-Associated Protein Kinases