A Lymph Node Metastatic Mouse Model Reveals Alterations of Metastasis-related Gene Expression in Metastatic Human Oral Carcinoma Sublines Selected from a Poorly Metastatic Parental Cell Line

Background: Greater than 40% of patients with squamous cell carcinoma (SCC) of the oral cavity have lymph node metastasis at the time of diagnosis and a 5-year survival rate of less than 50%. Changes in gene expression that regulate metastasis of SCC to lymph nodes have not been identified.

Methods: To study metastasis of oral SCC, highly metastatic oral SCC cell lines from a poorly metastatic oral SCC cell line were established by in vivo selection using a lymph node metastatic mouse model. The metastatic potential of the cells was studied using Matrigel invasion and cell surface protein adhesion assays. mRNA and protein encoded from metastasis-related genes in the metastatic derivatives and in their parental cells were examined using Northern blot analysis, immunoblotting, rapid analysis of gene expression, and a cDNA microarray technique.

Results: The in vivo selected metastatic cells showed much higher Matrigel invasion capability than the parental cells. They also showed alterations in their adhesion properties to three cell surface proteins. Comparison of metastatic and nonmetastatic cells revealed several significant alterations in the expression of metastasis-related genes, including up-regulation of the urokinase-type plasminogen activator receptor, integrin beta1, membrane type 1-matrix metalloproteinase, and down-regulation of protease-activated receptor-1.

Conclusions: To the authors' knowledge, the current study is the first to report on gene expression analysis using a lymph node metastatic mouse model of human oral SCC. The data suggest that certain alterations of metastasis-related gene expression favor invasion of oral SCC and that cell surface proteins may play major roles in the metastasis of oral SCC to the lymph nodes.