The SIX2/PFN2 feedback loop promotes the stemness of gastric cancer cells

J Transl Med. 2024 Sep 10;22(1):832. doi: 10.1186/s12967-024-05618-5.

Abstract

Background: The roles of the transcriptional factor SIX2 have been identified in several tumors. However, its roles in gastric cancer (GC) progression have not yet been revealed. Our objective is to explore the impact and underlying mechanisms of SIX2 on the stemness of GC cells.

Methods: Lentivirus infection was employed to establish stable expression SIX2 or PFN2 in GC cells. Gain- and loss-of-function experiments were conducted to detect changes of stemness markers, flow cytometry profiles, tumor spheroid formation, and tumor-initiating ability. ChIP, RNA-sequencing, tissue microarray, and bioinformatics analysis were performed to reveal the correlation between SIX2 and PFN2. The mechanisms underlying the SIX2/PFN2 loop-mediated effects were elucidated through tissue microarray analysis, RNA stability assay, IP-MS, Co-Immunoprecipitation, and inhibition of the JNK signaling pathway.

Results: The stemness of GC cells was enhanced by SIX2. Mechanistically, SIX2 directly bound to PFN2's promoter and promoted PFN2 activity. PFN2, in turn, promoted the mRNA stability of SIX2 by recruiting RNA binding protein YBX-1, subsequently activating the downstream MAPK/JNK pathway.

Conclusion: This study unveils the roles of SIX2 in governing GC cell stemness, defining a novel SIX2/PFN2 regulatory loop responsible for this regulation. This suggests the potential of targeting the SIX2/PFN2 loop for GC treatment (Graphical Abstracts).

Keywords: Gastric cancer; MAPK/JNK pathways; PFN2; SIX2; Stemness.

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Feedback, Physiological*
  • Gene Expression Regulation, Neoplastic*
  • Homeodomain Proteins* / genetics
  • Homeodomain Proteins* / metabolism
  • Humans
  • MAP Kinase Signaling System
  • Neoplastic Stem Cells* / metabolism
  • Neoplastic Stem Cells* / pathology
  • Profilins* / genetics
  • Profilins* / metabolism
  • Promoter Regions, Genetic / genetics
  • Protein Binding
  • RNA Stability / genetics
  • Stomach Neoplasms* / genetics
  • Stomach Neoplasms* / metabolism
  • Stomach Neoplasms* / pathology

Substances

  • Profilins
  • Homeodomain Proteins