SEPT6 drives hepatocellular carcinoma cell proliferation, migration and invasion via the Hippo/YAP signaling pathway

Int J Oncol. 2021 Jun;58(6):25. doi: 10.3892/ijo.2021.5205. Epub 2021 Apr 13.

Abstract

Septin 6 (SEPT6) is a member of the GTP‑binding protein family that is highly conserved in eukaryotes and regulates various biological functions, including filament dynamics, cytokinesis and cell migration. However, the functional importance of SEPT6 in hepatocellular carcinoma (HCC) is not completely understood. The present study aimed to investigate the expression levels and roles of SEPT6 in HCC, as well as the underlying mechanisms. The reverse transcription quantitative PCR, western blotting and immunohistochemistry staining results demonstrated that SEPT6 expression was significantly elevated in HCC tissues compared with corresponding adjacent non‑tumor tissues, which indicated that SEPT6 expression may serve as a marker of poor prognosis for HCC. By performing plasmid transfection and G418 treatment, stable SEPT6‑knockdown and SEPT6‑overexpression cell lines were established. The Cell Counting Kit‑8, flow cytometry and Transwell assay results demonstrated that SEPT6 overexpression significantly increased HCC cell proliferation, cell cycle transition, migration and invasion compared with the Vector group, whereas SEPT6 knockdown displayed significant suppressive effects on HCC cell lines in vitro compared with the control group. Mechanistically, SEPT6 might facilitate F‑actin formation, which induced large tumor suppressor kinase 1 dephosphorylation, inhibited Hippo signaling, upregulated yes‑associated protein (YAP) expression and nuclear translocation, and upregulated cyclin D1 and matrix metallopeptidase 2 (MMP2) expression. Furthermore, YAP overexpression significantly reversed SEPT6 knockdown‑induced inhibitory effects on HCC, whereas YAP knockdown significantly inhibited the oncogenic effect of SEPT6 overexpression on HCC. Collectively, the present study demonstrated that SEPT6 may promote HCC progression by enhancing YAP activation, suggesting that targeting SEPT6 may serve as a novel therapeutic strategy for HCC.

Keywords: hepatocellular carcinoma, septin 6, proliferation, migration, invasion, Hippo/yes‑associated protein signaling pathway.

Publication types

  • Observational Study

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Adult
  • Aged
  • Carcinoma, Hepatocellular / genetics*
  • Carcinoma, Hepatocellular / pathology
  • Carcinoma, Hepatocellular / surgery
  • Cell Movement / genetics
  • Cell Proliferation
  • Female
  • Gene Expression Regulation, Neoplastic
  • Gene Knockdown Techniques
  • Hepatectomy
  • Hippo Signaling Pathway
  • Humans
  • Liver / pathology
  • Liver / surgery
  • Liver Neoplasms / genetics*
  • Liver Neoplasms / pathology
  • Liver Neoplasms / surgery
  • Male
  • Middle Aged
  • Neoplasm Invasiveness / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Septins / genetics
  • Septins / metabolism*
  • Signal Transduction / genetics
  • Transcription Factors / metabolism*
  • Up-Regulation
  • YAP-Signaling Proteins

Substances

  • Adaptor Proteins, Signal Transducing
  • Transcription Factors
  • YAP-Signaling Proteins
  • YAP1 protein, human
  • Protein Serine-Threonine Kinases
  • SEPTIN6 protein, human
  • Septins

Grants and funding

The present study was supported by the Deutsche Forschungsgemeinschaft (grant nos. DFG STE 1022/2-3 and DFG STE 1022/4-1), the National Natural Science Foundation of China (grant nos. 81272657 and 81572422) and the China Scholarship Council (grant nos. 201908080017 and 201606230249).