In a preliminary cDNA microarray data-mining, stathmin (STMN1) was identified to be up-regulated in the Hepatocellular carcinomas (HCC). A further screening on HCC cell lines and some tissue specimens at both the mRNA and protein levels, STMN1 was confirmed to be a HCC tumor marker. However, the underlying mechanism that regulates STMN1 up-regulation in HCC is still unknown. The objective of this study was to identify the potential factors that up-regulate STMN1 mRNA and protein levels in HCC. Three HCC cell lines (SK-Hep1, Hep-3B and Hep-G2) and fifty-eight specimens (liver tumor and adjacent nontumor tissues in the same patient) were obtained. Quantitative real-time polymerase chain reaction and western blotting identified up-regulations of STMN1 at both mRNAs and proteins levels in three HCC cell lines and 58 specimens. Immunofluorescence assays further detected its cytoplasmical subcellular localization. Among tumor specimens, the STMN1 protein was significantly correlated with its mRNA expression level (In HCC; N=35; r=0.843; p<0.05; In Metastasis; N=11; r=0.947; p<0.05). In 46 tissue specimens (HCC=35; Metastasis=11), the expression level of E2F1 transcription factor was found to be up-regulated significantly in tumor specimens (p<0.05) and parallel to the STMN1 protein (In HCC; N=35; r=0.556; p<0.05; In Metastasis; N=11; r=0.524; p<0.05). In synchronized SK-Hep1 and Hep-3B cells, it hypothesizes that STMN1 expression is, in part, under the control of E2F1 transcription factors. Moreover, comparative mapping and chromatin immunoprecipitation assay confirmed two E2F1 and three MYC binding sites (the E box) in the STMN1 proximal promoter region. STMN1 proteins were down regulated after the electroporation of shE2F1 in SK-Hep1 cells in 31~36%. In conclusion, the high level of STMN1 protein was resulted from STMN1 mRNA up-regulation and E2F1 might play an important role to transactivate STMN1 gene in HCC and liver metastasis.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0828107-113854 |
| Date | 28 August 2007 |
| Creators | Horng, Kuo-chan |
| Contributors | Hui-Chiu Chang, Yow-Ling Shiue, Wen-Chun Hung |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0828107-113854 |
| Rights | not_available, Copyright information available at source archive |
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