PTPH1 promotes tumor growth and metastasis in human glioma

Glioma is the most common form of brain tumor, accounting for over 50% of all primary tumors. Despite progress in the treatment of glioma, the prognosis is still poor. In this study, we examined protein-tyrosine phosphatase H1 (PTPH1) in human gliomas.

Cell growth potential was measured by CCK-8 assay and colony formation. Cell cycle distribution was measured by flow cytometry. Transwell assay was used to detect the motility of tumor cells. Real-time PCR and Western blot were used to measure the mRNA and protein expression of indicated genes. Xenograft model was established to measure the role of PTPH1 in vivo.

The expression of PTPH1 was significantly higher in the tumor tissues as compared with that in the adjacent normal tissues. Knockdown of PTPH1 significantly slowed cell proliferation and reduced colony formation abilities in glioma cell lines U87 and U251. Additionally, knockdown of PTPH1 caused cell cycle arrest in the S-phase. Furthermore, depletion of PTPH1 in glioma U87 cells significantly limited tumor growth in a xenograft model. Interestingly, knockdown of PTPH1 also decreased cell migration abilities in both U87 and U251 cells. Accordingly, matrix metalloproteinase 9 (MMP9) was also decreased upon knockdown of PTPH1 in both cell lines. Moreover, we found that phosphorylated MEK (p-MEK) and phosphorylated MAPK (p-MAPK) were both decreased, whereas the total levels of MEK and MAPK remained unchanged after depletion of PTPH1 in both cell lines.

Our data suggest that PTPH1 may be a novel biomarker that indicates the aggressiveness of gliomas. Targeting PTPH1 might be a promising strategy for the treatment of gliomas.