| Summary: | 碩士 === 國立成功大學 === 口腔醫學研究所 === 95 === Galectin-1(Gal-1) is a β-galactoside-binding lectin and involved in multiple biological functions, such as cell adhesion, proliferation, migration, apoptosis, inflammation, tumor progression and metastasis. Our previous investigations have shown that Gal-1 was overexpressed in the tumor-associated stroma as well as the invasion front during early oral carcinogenesis and correlated with worse prognosis of oral cancer. In this study we used siRNA of Gal-1 to determine the function of intracellular Gal-1. We found that silencing Gal-1 stimulates proliferation, increases cell cycle S phase, inhibits cell migration, and decreases the expression of MMP-2 and MMP-9. The migration inhibition of silencing Gal-1 might be due to the inhibition of small GTPase cdc42 activity and cytoskeleton rearrangement and significant decrease in the length and number of filopodia. Next, using a tandem affinity purification (TAP) method to purify the protein complex of Gal-1 and subsequent mass spectrometry to identify the associated proteins. Disheveled-associated activator of morphogenesis 1 (Daam1) and Histone H4 proteins were first identified as Gal-1 associated proteins by such approaches. Co-immunoprecipitation and mammalian two-hybrid analysis did not demonstrate that Gal-1 interacted with histone H4 and Daam1. However, Gal-1 was strongly sub-cellular colocalized with Daam1, and the expression of Daam1 was significantly decreased while gal-1 was silencing. These results implied that Daam1 might have a role in Gal-1-regulated cell functions. To further clarify the interacting network of Gal-1 and Daam1 might help to gain insight into the Gal-1 functions in oral carcinogenesis.
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