CD82 Correlates With S100 Proteins in Head and Neck Cancer

Objectives: Tetraspanin CD82 and S100 proteins are potential biomarkers in squamous cell carcinoma and many epithelial cancers. Data from our lab demonstrated that knocking out CD82 downregulated S100 proteins and inhibited cell migration. This study aimed to test if CD82 correlates with and regulates S100 proteins expression levels in head and neck cancer (HNC).
Methods: CAL 27 (ATCC CRL-2095), SCC-25 (ATCC CRL-1628), FaDu (ATCC HTB-43) and Detroit 562 (ATCC CCL-138) head and neck cancer cell lines were culture and Formalin-Fixed Paraffin-Embedded (FFPE) human HNC tissues. Human Gingival Epithelial cell (S-G) was used as a control. We used quantitative real time polymerase chain reaction, western blotting, imunohistochemistry, and enzyme-linked immunoassay to test the expression levels of CD82 and S100 proteins. Student’s T-test and ANOVA with post-hoc analyses were performed using Excel (Microsoft) and SigmaPlot 12.5 software (Systat). P< 0.001 was considered significant.
Results: The expression levels of CD82, S100A7, S100A7A, S100A6, S100A8, and S100A9 are upregulated in CAL 27, and similar in SCC-25, FaDu and Detroit 562 cells when compared to S-G cells. In the two poorly differentiated oral squamous cell carcinoma tissue, we find low or no expression of CD82 and S100A7. In well differentiated tissue, CD82 and S100 A7 were highly expressed and overlapped at the parabasal cells cells. Meanwhile, in tumoral islands, the highest expression of CD82 is in less differentiated cells while S100A7 is in more differentiated cells.
Conclusions: CD82 expression correlates with and may regulate S100 proteins expression in HNC cells and tissue. This association between CD82 and S100 family proteins in poorly differentiated HNC could be a novel mechanism through which CD82 regulates migration and metastasis. The combination of CD82 and S100A7 could be a potential biomarker for a distinct subtype of poorly differentiated HNC.