Preliminary Study On The Function Of Stat3 In Liver Cancer Cells

Hepatocellular carcinoma(HCC) is the major primary malignant tumor in the human liver, but the molecular changes leading to liver cell transformation remain largely unknown. Cytokines evoke a series of signal pathways through binding to their receptors. And they also activate the expression of some down-stream genes. Consequently, some biological functional effects appear. Many researches reveal that there are relations between cancers and aberrant activation or inactivation of signal pathways in cells.STAT(Signal transducer and activator of transcription)proteins transduce signals for varieties of cytokines. They play important roles in cell growth, living, proliferation, differentiation,anti-apoptotic and transformation. Constitutively activated STAT3 is found in many cancers,including melanoma, breast cancer, head and neck cancer, implying the critical role of STAT3 in tumorgenesis.To understand the effects of STAT3, we studied the aberrant activation of STAT3 in BEL-7402 cell line and the influence on the migration of cells, some relations between STAT3 and β -Catenin , also the influence of STAT3 RNA interference, so as to try to search the way to treat the HCC.We successfully constructed the fusion genes of STAT3 (wild type/mutant) and GFP to study the function of constitutively activated STAT3 in BEL-7402 cell. By measuring the migration of the cells labeledby GFP-STAT3(WT/CYF), we proved that overexpression of STAT3(WT) could augment the migration of BEL-7402 cells, while STAT3(CYF) could decrease the migration.We demonstrated that endogenous P-catenin couldcoimmunoprecipitate with endogenous STAT3 in HepG2 cell line, and the immunoprecipitation was down-regulated with the increase of cell density. So, there would be certain crosstalk between STAT3 pathway and WNT pathway. But no synergized activation of the two pathways was detected.At the same time, we constructed the recombinant Adenovirus-AdEasy-Hl-STAT3i which could constitutively express short double-stranded polynucleotides for STAT3 RNA interference. The efficiency was detected via Western Blotting. As the aim of the experiments, we tried to find new gene therapy methods for liver cancer by gene knock-out.