To investigate the effects of glutathione peroxidase 7 (GPX7) on the proliferation and senescence of hepatocellular carcinoma (HCC) cells and its potential value as a therapeutic target.

Clinical and transcriptomic data from HCC patients in The Cancer Genome Atlas (TCGA) database were analyzed to evaluate the relationship between GPX7 expression and prognosis. Western blotting, qRT-PCR, CCK-8 assay, EdU staining, and SA-β-Gal staining were employed to compare the expression and function of GPX7 in HCC cell lines and normal liver cells. A stable GPX7-knockdown Hep3B cell line was established, and transcriptomic changes were analyzed using RNA-seq. The PI3K inhibitor LY294002 and its activator 740 Y-P were utilized to determine the role of GPX7 in regulating cell senescence via the PI3K-AKT pathway. An orthotopic xenograft model was constructed using 18 male nude mice (6 weeks old, 18~22 g) to observe tumor growth. Tumor and adjacent tissue samples from 56 HCC patients (obtained from the Eighth Medical Center of Chinese PLA General Hospital between January 2012 and December 2022) were analyzed to assess the relationship between GPX7 expression and clinicopathological features.

TCGA data analysis revealed that GPX7 was significantly highly expressed in HCC tumor tissues (P<0.01), and the patients with high GPX7 expression had obviously shorter overall survival (OS) (P=0.018). Western blotting and qRT-PCR showed that the expression level of GPX7 was notably higher in the HCC cell lines than the normal liver cells (P<0.01). After GPX7 knockdown, the CCK-8 absorbance values of HCC cells were significantly reduced (P<0.01), the proportion of EdU-positive cells was obviously decreased (P<0.01), and the proportion of SA-β-Gal positive cells was notably increased (P<0.01). RNA-seq analysis revealed that differentially expressed genes were significantly enriched in the PI3K-AKT signaling pathway (P<0.05). The PI3K inhibitor LY294002 significantly enhanced the GPX7 knockdown-induced cell senescence (P<0.01), while the activator 740 Y-P partially reversed this effect (P<0.05). In the xenograft model, GPX7 knockdown significantly inhibited tumor growth in nude mice (P<0.01), and the PI3K activator 740 Y-P partially reversed this effect (P<0.01). Clinical sample analysis displayed that high GPX7 expression was negatively correlated with tumor differentiation (P<0.05), and its high expression was associated with shortened OS (HR=2.61, 95%CI: 1.26~5.39, P=0.005).

GPX7 regulates cell proliferation and senescence through the PI3K-AKT pathway, and may serve as a potential therapeutic target for HCC treatment.