| Summary: | 碩士 === 國立臺灣大學 === 口腔生物科學研究所 === 104 === Purpose: We aim to examine the roles of tripartite motif-containing protein 72 (TRIM72) in OSCC progression, and to correlate it with patient clinical status and survival rate. Underlying mechanism is also investigated.
Experimental design: Oral cancer cell lines, including SAS, CA922, HSC3, Cal27, and TW2.6, were used as in vitro models to investigate cell phenotypes, such as invasion, migration, and proliferation by ectopic expressed-TRIM72 or silenced-TRIM72 (shTRIM72) plasmids transfection. Boyden chamber assay was performed to check migration and invasion abilities. Proliferation ability was identified by MTT assay. Mice were injected with shTRIM72 or vector control SAS cells to examine lymph node metastasis and survival rate. mRNA microarray of stable transfectants elucidated the downstream signaling. EGFR protein pulse-chase assay and ubiquitination WB-IP analysis are used in this study.
Results: Clinical data revealed that TRIM72 expression was related to OSCC patient TNM stage, lymph node metastasis, and survival rate (P < 0.05). Transiently transfected SAS and CA922 cells with shTRIM72 plasmids significantly reduced migration and invasion ability (P < 0.05), but did not alter proliferation ability, compared to vector control cells. Furthermore, we established shTRIM72-stable transfectants in SAS cells, and found that silenced-TRIM72 could significantly down-regulate migration and invasion (P < 0.05). In animal study, lymph node metastasis ability was blocked in orthotopic-injected shTRIM72-stable transfectants, and the survival rate was increased compared to vector control clone (P < 0.05). Additionally, we performed high-throughput mRNA microarray analysis and GSEA analysis to identify epidermal growth factor receptor (EGFR) a crucial downstream pathway. TRIM72-enhanced EGFR expression through inhibited ubiquitin-related degradation, which prolonged the half-life of EGFR. Transfected with EGFR expression plasmid could completely restore migration and invasion abilities in shTRIM72 stable transfectants (P < 0.05). Although TRIM72 recruits Ca2+ to repair membrane damage, it enhanced OSCC progression in a Ca2+-independent manner.
Conclusions: TRIM72 was a poor prognostic factor in OSCC patents clinically. TRIM72 enhanced invasion and migration ability in OSCC cells, and increased lymph node metastasis in vivo. TRIM72 promoted EGFR expression through inhibited ubiquitin-related degradation in post-translational regulation to cause OSCC progression.
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