| Summary: | 碩士 === 國立成功大學 === 藥理學研究所 === 98 === ABSTRACT
Aim: GAS7 is a member of growth-arrest-specific (GAS) gene family. Our previous study identified the chromosome 17p13.1, which harbors the GAS7 gene, as a high deletion region in lung cancer patients. In addition, the frequencies of low GAS7 mRNA and protein expression were 45.1% and 57.3%, respectively. Therefore, the present study aims to investigate the function of GAS7 gene and to study what the molecular mechanism of GAS7 alteration is in lung tumorigenesis.
Materials and Methods: We overexpressed GAS7C in lung cancer cells lines to evaluate the changes of cell cycle distribution and cell migration ability by FACS, wound healing assay, transwell-migration assay, and invasion assay. In addition, tail-vein experimental metastasis assay using GAS7C overexpression cells was examined in animal model. Results: The results indicated that GAS7C overexpression did not alter the cell cycle distribution, but decreased the lung cancer cells migration and invasion abilities both in vitro and in vivo. Immunoprecipitation-Western blotting was performed to further identify GAS7 association proteins. The results showed that GAS7C interacted with N-WASP, which is a key regulator in actin dynamic via fibronectin-integrin-FAK pathway. In addition, GAS7C interacted with β-catenin and ubiquitin-degradation pathway proteins such as hnRNP-U. Overexpression of GAS7C increased β-catenin ubiquitination level, thus decreased the β-catenin protein level. Collectively, these data suggested that GAS7C overexpression decreases the lung cancer cells migration may partly through its association proteins via fibronectin/integrin/FAK/N-WASP/actin dynamic pathway and hnRNP-U/β-TrCP/β-catenin ubiquitin-degradation pathway.
Conclusion: This is the first study to investigate the function of GAS7 gene and its alteration mechanisms in lung tumorigenesis. We demonstrated that GAS7C overexpression decreases lung cancer cells migration ability both in vivo and in vitro which may reduce the fibronectin-integrin-FAK pathway protein expression and increase protein complex formation of β-TrCP/β-catenin. This study provides new evidence that GAS7C may be used as a prediction biomarker or the target for gene therapy of lung cancer.
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