PSMD12 promotes glioma progression by upregulating the expression of Nrf2

BACKGROUND: Glioma is the most common and aggressive primary brain tumor in adults. Proteasome 26S subunit, non-ATPase 12 (PSMD12), an important subunit in the 26S proteasome, is known to be involved in the growth and apoptosis of breast cancer cells. However, its exact function and underlying molecular mechanisms in glioma remain unknown. METHODS: PSMD12 expression was detected in glioma tissue specimens by immunohistochemistry (IHC) and TCGA database. Overexpression and down-regulation of PSMD12 and Nrf2 were induced in glioma cell lines, and CCK-8 and Transwell assays were used to detect cell proliferation and invasion evaluation, respectively. Xenograft model was used to observe the effect of knockdown of PSMD12 on tumor growth. Immunohistochemical assays and TCGA database were conducted to reveal the relationships between PSMD12 expression and Nrf2. Finally, Western blot and related biological function experiments were used to explore the mechanism of PSMD12 regulating the glioma progression and Nrf2. RESULTS: We revealed that PSMD12 is upregulated in glioma, especially in high-grade glioma, by analyzing bioinformatics data and clinical specimens. PSMD12 upregulation was associated with poor prognosis in glioma patients. Knockdown of PSMD12 inhibited the growth of glioma cells in vitro and in vivo and decreased their invasion ability, whereas PSMD12 overexpression had the opposite effect. Mechanistic analysis revealed that PSMD12 increased the expression of nuclear factor E2-related factor 2 (Nrf2), which functions as a tumor promoter in the development of glioma. Similar to PSMD12, Nrf2, which exhibited a strong positive correlation with PSMD12, was abnormally elevated in glioma tissues and contributed to worse overall survival (OS). Nrf2 overexpression reversed the inhibitory effects induced by PSMD12 knockdown. Finally, PSMD12 enhanced the proliferation and invasion of glioma cells via Akt signaling-mediated Nrf2 expression. CONCLUSIONS: These results suggest that PSMD12 is considered to be a crucial regulator of the development and progression of glioma and may serve as a potential biomarker or therapeutic target for the treatment of glioma.