Analysis And Research Of The Transcription Repressor ZHX2 In Hepatocellular Carcinoma

Hepatocellular carcinoma is the leading cause of cancer related death worldwide. The morbidity and mortality still rank the front position among all malignancies. Hepatic carcinoma is often diagnosed at an advanced stage wheneffective treatment is no longer possible. Even in early stage patients treated by surgery, the recurrence rate remains high. The tradition treatment strategies of liver cancer include surgery, radiotherapy, chemotherapy and comprehensive treatment. Simultaneously, the emerging molecular targeted therapy provides new choice of hepatocellular carcinoma treatment strategies. However, the significant improvement in the five year mortality rate is far from satisfaction.Thus, there is an urgent need to diacover new molecular diagnostic and therapeutic targets for liver cancer patients.Objective The Zinc-Finger and Homeoboxes 2 (ZHX2) gene is a member of a small gene family, it is wi idespread in the human body, and are expressed. in various tissues, the expression of a variety of diseases of the key genes have regulatory role. Consistent with these data, positive transcripts for the ZHX2 gene at a significantly lower level than in HCCs and liver cancer cell lines,identified ZHX2 as a new tumor suppressor gene in HCC. ZHX2 can binding NF-YA regulation of downstream gene, thereby inhibiting the development of liver cancer, suggesting ZHX2 may inhibit the expression of other genes. It is not clear which ZHX2 regulates gene expression in HCC. Therefore, liver transcription factor target genes regulated ZHX2 worthy of further study.Methods Firstly, The level of ZHX2 mRNA was detected by using RT-PCR in liver cancer cells HepG2, SMM7721, Bel7402 and normal liver cells L02.In our study, to identify genes regulated by ZHX2 at genome wide level, we performed ChIP upon hunman liver cancer HepG2 cells using ZHX2 specific antibodies. The obtained DNA samples were subjected to high-throughput sequencing and bioinformatics analysis. Lastly, The expression of ZHX2, PTEN and P53 in hepatocellular carcinoma tissues and adjacent normal tissues were by immunohistochemistry. We analyze the relationship between them and clinicpathological indicator.Result ZHX2 mRNA in the three kinds of hepatoma cell lines were expressed. To determine the binding sites, we obtained 3093 binding sites for ZHX2, and mainly located at chromosome 1, 2, 3, 5, 7. Analysis on ChIP-Seq datasets from HepG2 cell indicated that they mainly occurred within intergenic,intron, upstream and promoter. In the promoter region we performed gene ontology and KEGG pathway enrichment analysis. Gene ontology (GO) analysis suggested that ZHX2 regulated a set of genes involved in various biological processes, including biological regulation, metabolic process, and regulation of biological process and so on. In cellular component including blood microparticle and pericentric heterochromatin. In molecular function including GTPase activator activity, GTPase regulator activity and enzyme activator activity. The analysis of KEGG pathway showed that these differential expression genes were enriched 4 pathway including infection disease pathway and Phagosome pathway.The low expression of ZHX2 in HCC (P=0.042), and the expression of ZHX2 was positive correlation with AFP (P=0.041). The low expression of PTEN in HCC (P=0.000), and the expression of PTEN was positive correlation with histological grade (P=0.025) and AFP (P=0.028). The high expression of P53 in HCC (P=0.000), and the expression of P53 was positive correlation with histological grade (P=0.045). There is a positive relationship between the expression of ZHX2 and that of PTEN in HCC tissues (r=0.258, P=0.031).Conclusion It is the first comprehensive study to investigate ZHX2 transcription at genome wide level by ChIP-Seq. We found ZHX2 regulate many genes through in intergenic regions in HepG2 cells. Our data provided that ZHX2 regulated genes involved in many infectious diseases and devouradjustment.ZHX2, PTEN and P53 probably plays an important role in the origin and development of HCC. There is a positive relationship between the expression of ZHX2 and that of PTEN in HCC tissues, suggesting that may be a key index for reflecting the biological behavior of HCC.