Mechanism of Transcription Factor SP1 Regulates Expression of Tripartite Motif-containing Protein 7 in Hepatocellular Carcinoma / 中国生物化学与分子生物学报

ABSTRACT

Tripartite motif containing protein 7 (TRIM7), as a member of the E3 ubiquitin ligase TRIM family, plays an important regulatory role in immune regulation, metabolism and other physiological processes. The aberrant expression of TRIM7 is closely related to the development and progression of hepatocellular carcinoma (HCC) and it shows a complex regulatory role. However, the regulatory mechanism for the expression of TRIM7 in HCC remains unknown. In this study, multiple online databases were used to analyze the expression of TRIM7 in HCC and data indicated that TRIM7 expression was upregulated in HCC and correlated to poor prognosis. Subsequently, the transcription factor binding sites in the TRIM7 promoter region were analyzed using UCSC and JASPAR databases, and the results showed that TRIM7 promoter contains four SP1 binding sites. In this work, we demonstrated that SP1 could directly bind to its binding sites in TRIM7 promoter and positively regulate the transcriptional activity driven by the TRIM7 promoter using dual luciferase reporter experiments and the ChIP-PCR method. Moreover, our results also showed SP1 overexpression upregulated the expression of TRIM7 at both mRNA and protein levels (P<0. 01),and SP1 inhibitor, mithramycin A, could reverse the activated effect of SP1 on TRIM7 expression (P<0. 01). In conclusion, this study preliminarily reveals the regulatory mechanism of TRIM7 upregulation in HCC, which provides an important theoretical basis for further study of the gene function, early diagnosis and targeted therapy.