| Summary: | 碩士 === 國立臺灣大學 === 生物科技研究所 === 107 === Esophageal cancer (EC) is the 7th most common cancer and ranks 6th of mortality worldwide among all the other cancer types. Currently, the most common therapeutic strategy is concurrent chemoradiotherapy (CCRT). However, the respond rate of CCRT remains below 40%, and the other 60% patients may fail to this treatment. Worse than that, some patients may trigger disease progression after CCRT treatment. In our previous study, the tumor samples from EC patients with and without recurrence were performed by microRNA sequencing. The results showed that miR-338-5p was significantly down-regulated in the EC patients with recurrence. Moreover, the further study had shown that overexpressed miR-338-5p inhibited cell proliferation, migration, colony formation and drug resistance of esophageal squamous cell carcinoma CE-81T. In this study, we focused on the underlying mechanisms of inhibiting migration ability by miR-338-5p. Metastatic cells will detach from extracellular matrix and migrate to the other organs to form secondary tumor. Anoikis resistance is a critical step and required during metastasis. Based on our previous study, we hypothesized that miR-338-5p may promote anoikis and lead to decreasing metastatic ability of CE-81T.
In this study, anoikis and soft agar assays were performed to examine the effects of miR-338-5p on anoikis resistance in the CE-81T. The result showed that overexpression of miR-338-5p could increase anoikis in the CE-81T. To understand which genes may be the target of miR-338-5p and involved in regulation of anoikis, HRP-3 was validated as a target gene of miR-338-5p and play an important role in anoikis resistance. To further understand the importance of miR-338-5p and HRP-3 in regulation of anoikis, we generated anoikis resistant enriched subline (CE-81TAR) from adherent CE-81T. We found that CE-81TAR had more capacity of anoikis resistance and anchorage-independent growth than CE-81T. Moreover, overexpression of miR-338-5p and knockdown of HRP-3 could decrease anoikis resistance and anchorage-independent growth in CE-81TAR. Finally, knockdown of HRP-3 was shown to inhibit cell proliferation of CE-81T and CE-81TAR. Taken together, we indicated that miR-338-5p promoted anoikis by targeting HRP-3 and led to decreasing of migration in ESCC CE-81T.
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