Conclusions
The present study revealed novel and important functions of TPD53 in the proliferation and invasion of low-malignant OSCC cells.
Methods
Temporal changes in the expression of TPD52 family members at the protein and mRNA levels in OSCC cells and normal human epidermal keratinocytes (NHEK) were examined.
Results
The mRNA expression of TPD53 increased in HSC-3 and HSC-4 cells in a time-dependent manner. Similar results for protein expression were observed. The effects of TPD53 on anchorage-dependent and anchorage-independent proliferation, cell cycle, invasion and migration, epithelial-mesenchymal transition (EMT), and matrix metalloproteinase (MMP) activities in HSC-3 and HSC-4 cells were assayed. Finally, using the HSC-3-xenograft-nude-mice model, these effects were examined in vivo. Overexpression of TPD53 increased cell viability and the percentage of cells in the S phase. Furthermore, overexpression of TPD53 increased cell invasion, migration, and MMP activities, regardless of its effect on EMT. Notably, these effects were more pronounced in HSC-3 than in HSC-4 cells. Overexpression of TPD53 enhanced tumor formation and growth in mouse xenografts, corroborating the results of in vitro experiments. Conclusions: The present study revealed novel and important functions of TPD53 in the proliferation and invasion of low-malignant OSCC cells.