Lymph node metastasis is the hallmark of
malignant neoplasms in patients of
oral cancer, accounting for the poor diagnosis and reduced 5-year survival rate. Here we sought to identify cell motility-associated
proteins of
oral cancer by proteomic approach. We compared the
proteomes of two
oral cancer cells, CAL-27 and SAS, with the highest and the lowest migration potential, respectively, amongst six different
oral cancer cell lines. Subsequent identification of differentially expressed
proteins by LC-MS/MS and Western analysis revealed that SERPINB1 (
serine protease inhibitor, clade B, member1) was highly expressed in CAL-27, the high-motility
oral cancer cells. Semi-quantitative and real-time PCR further confirmed differential expression of SERPINB1 in these two cell lines at
mRNA level. To verify the motility-promoting function of SERPINB1 in
oral cancer cells, we showed that endogenous expression of SERPINB1 correlated positively with cell migration. Moreover, ectopic expression of SERPINB1 in
oral cancer cells, SAS, Ca9-22, CAL-27 and HSC-3, increased cell migration by 25%, 52%, 90% and 100%, respectively. Finally, we found that the expression of SERPINB1 was significantly higher in 5 of 8 (62.5%)
oral cancer tissues compared with the matched adjacent normal tissues. Besides, immunohistochemical results indicated over-expression of SERPINB1 in clinicopathologically invasive
oral squamous cell carcinoma (OSCC) but not in normal oral mucosa (p<0.01). Together, our findings have provided a possible
biomarker for
oral cancer metastasis.