Downregulation of GPX8 in hepatocellular carcinoma: impact on tumor stemness and migration

• Published in: Cellular oncology (Dordrecht) Vol. 47; no. 4; pp. 1391 - 1403
• Main Authors: Tao, Chen-Yang, Wu, Xiao-Ling, Song, Shu-Shu, Tang, Zheng, Zhou, Yu-Fu, Tian, Meng-Xin, Jiang, Xi-Fei, Fang, Yuan, Zhu, Gui-Qi, Huang, Run, Qu, Wei-Feng, Gao, Jun, Chu, Tian-Hao, Yang, Rui, Chen, Jia-Feng, Zhao, Qian-Fu, Ding, Zhen-Bin, Dai, Zhi, Zhou, Jian, Liu, Wei-Ren, Shi, Ying-Hong, Fan, Jia
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.08.2024; Springer Nature B.V
• Subjects: 1-Phosphatidylinositol 3-kinase; AKT protein; Animals; Antitumor activity; Biomedical and Life Sciences; Biomedicine; Cancer Research; Carcinoma, Hepatocellular - genetics; Carcinoma, Hepatocellular - metabolism; Carcinoma, Hepatocellular - pathology; Cell Line, Tumor; Cell migration; Cell Movement - genetics; Down-regulation; Down-Regulation - genetics; Endoplasmic reticulum; Female; Gene Expression Regulation, Neoplastic; Glutathione; Glutathione Peroxidase - genetics; Glutathione Peroxidase - metabolism; Heat shock proteins; Hepatocellular carcinoma; Hsc70 protein; Humans; Immunoprecipitation; Kinases; KLF4 protein; Kruppel-Like Factor 4; Liver cancer; Liver Neoplasms - genetics; Liver Neoplasms - metabolism; Liver Neoplasms - pathology; Male; Mass spectroscopy; Mice; Mice, Inbred BALB C; Mice, Nude; Middle Aged; Neoplastic Stem Cells - metabolism; Neoplastic Stem Cells - pathology; Oct-4 protein; Oncology; Pathology; Phosphorylation; Pluripotency; Protein arrays; Protein transport; Proteins; Proto-Oncogene Proteins c-akt - metabolism; Signal transduction; Signal Transduction - genetics; Therapeutic targets; Transcriptomes; Tumors; GPX8; Hepatocellular carcinoma; Hsc70; Migration; Tumor stemness
• DOI: 10.1007/s13402-024-00934-w
• ISSN: 2211-3428; 2211-3436

Purpose GPX8, which is found in the endoplasmic reticulum lumen, is a member of the Glutathione Peroxidases (GPXs) family. Its role in hepatocellular carcinoma (HCC) is unknown. Methods Immunohistochemical staining was used to detect the protein levels of GPX8 in HCC tissue microarrays. A short hairpin RNA lentivirus was used to knock down GPX8, and the main signaling pathways were investigated using transcriptome sequencing and a phosphorylated kinase array. The sphere formation assays, cloning-formation assays and cell migration assays were used to evaluate the stemness and migration ability of HCC cells. Identifying the GPX8-interacting proteins was accomplished through immunoprecipitation and protein mass spectrometry. Results The GPX8 protein levels were downregulated in HCC patients. Low expression of GPX8 protein was related to early recurrence and poor prognosis in HCC patients. GPX8 knockdown could enhance the stemness and migration ability of HCC cells. Consistently, Based on transcriptome analysis, multiple signaling pathways that include the PI3K-AKT and signaling pathways that regulate the pluripotency of stem cells, were activated after GPX8 knockdown. The downregulation of GPX8 could increase the expression of the tumor stemness markers KLF4, OCT4, and CD133. The in vivo downregulation of GPX8 could also promote the subcutaneous tumor-forming and migration ability of HCC cells. MK-2206, which is a small-molecule inhibitor of AKT, could reverse the tumor-promoting effects both in vivo and in vitro. We discovered that GPX8 and the 71-kDa heat shock cognate protein (Hsc70) have a direct interaction. The phosphorylation of AKT encouraged the translocation of Hsc70 into the nucleus and the expression of the PI3K p110 subunit, thereby increasing the downregulation of GPX8. Conclusion The findings from this study demonstrate the anticancer activity of GPX8 in HCC by inactivating the Hsc70/AKT pathway. The results suggest a possible therapeutic target for HCC.