| Summary: | 碩士 === 國立中興大學 === 分子生物學研究所 === 106 === Lung cancer is the leading deceases of the cancer-related death worldwide. However, the prognosis for lung cancer patients is rather poor by lack of early marker detected. To investigate the mechanisms involved in tumorigenesis and metastasis would be necessary for patients’ therapy. In our group’s previous studies, it has been found that YWHAZ associates with TCF-4 and β-catenin in the nucleus, and YWHAZ-β-catenin-TCF-4 complex further promote EMT, cell invasion and migration in lung cancer. Also, previous studies reveal that YWHAZ-β-catenin-TCF-4 complex can regulate four candidate genes: ATF3, DMTF1, DUSP1 and PAK2.
PAK2, also known as p21-activated kinases 2, belongs to the PAKs family of serine/threonine kinases which can be activated by small G proteins: Rac and Cdc42. PAK2 is believed to promote tumorigenesis through regulatin cell proliferation, apoptosis and cytoskeleton remodeling. In order to investigate the upstream mechanism of PAK2, luciferase reporter and site-directed mutagenesis assay were used to check promoter activity. At first, PAK2 promoter region from -2077 to +59 was cloned. Then, three 5'' terminal deleted fragment promoters were constructed. Luciferase assay results demonstrated that there is an important regulation region in -2077/-1547 fragment, and core promoter region of PAK2 is located at -478 bp to +59 bp. Furthermore, two TCF-4 binding motif sites -1467 and -1985 were predicted by TRANSFAC analysis. Both mutation vectors of TCF-4 binding site showed significantly lower luciferase activity compared with the wild type, indicating PAK2 may be activated by TCF-4. While PAK2 promoter region co-expressed with β-catenin or YWHAZ were analyzed, it is interesting to note the results show PAK2 may not be regulated by β-catenin but by YWHAZ. To investigate the function of PAK2 in lung cancer progression, stable cell lines were established. Overexpressing PAK2 in CL1-0 cell enhances cell colony formation and migration. In conclusion, PAK2 promoted cell motility by regulated of YWHAZ-TCF-4 interaction in lung cancer.
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