Junction plakoglobin, a potential prognostic marker of oral squamous cell carcinoma, promotes proliferation, migration and invasion

Background Junction plakoglobin (JUP) is an important cell-cell junction protein. Recently, its deregulation has been correlated with the initiation and progression of various malignancies. Our aim was to investigate the expression of JUP in oral squamous cell carcinoma (OSCC) and its correlation with prognosis and to further study the effects of JUP on the proliferation, apoptosis, migration and invasion of OSCC cells. Methods We detected JUP expression in 273 OSCC specimens using immunohistochemistry. We assessed the correlation of JUP expression with clinicopathologic parameters and patient survival by Cox regression. Then, expression levels of JUP in normal oral keratinocytes (NOKs) and OSCC cell lines were detected by Western blotting and quantitative real-time PCR (qPCR). Next, we used HSC3 cells to study the effect of JUP on tumor cell proliferation, apoptosis, migration, and invasion by using cell counting kit-8, flow cytometry, and transwell assays, respectively. Results Cox regression showed that high expression of JUP was related to the poor prognosis of OSCC patients. Western blotting and qPCR assays showed that the expression level of JUP in OSCC cell lines was higher than that in NOKs. Overexpression of JUP promoted the proliferation, metastasis, and invasion of HSC3 cells and inhibited apoptosis, while the opposite was observed after JUP knockdown. Conclusion This study initially revealed that JUP was overexpressed in OSCC, and that JUP promoted the proliferation, migration, and invasion of OSCC cells and inhibited apoptosis. Moreover, high expression of JUP could be used as a potential prognostic marker of OSCC.