Expression of SPRR3 is associated with tumor cell proliferation and invasion in glioblastoma multiforme

Esophagin, also known as small proline-rich protein 3 (SPRR3), has been demonstrated to be important in the initiation and progression of numerous types of tumor, including colorectal and breast cancer. However, studies concerning the biological functions of SPRR3 in glioblastoma multiforme (GBM) are limited. Therefore, we aimed to identify the functions and molecular mechanisms underlying the role of SPRR3 in GBM. Hypomethylation of SPRR3 was observed and associated with a poor clinical outcome in GBM patients compared with healthy individuals by using gene methylation profiling. The present study was performed to investigate the expression status and effects of SPRR3 in GBM. The U251 cell line was used in the functional analyses. Cell growth was examined by MTT and colony formation assay. Cell invasion was measured using the Transwell invasion assay. The expression of SPRR3 in tissue samples was examined by immunohistochemistry. The results revealed that the overexpression of SPRR3 accelerates U251 cell proliferation and invasion. It was also observed that SPRR3 was markedly upregulated in 72.7% of GBM samples (24/33) compared with the normal tissue. These results suggest that an increased expression of SPRR3 is involved in tumorigenesis.