Hsa_circ_0009092/miR-665/NLK signaling axis suppresses colorectal cancer progression via recruiting TAMs in the tumor microenvironment

J Exp Clin Cancer Res. 2023 Nov 27;42(1):319. doi: 10.1186/s13046-023-02887-8.

Abstract

Background: It has been demonstrated that circularRNA (circRNAs) plays a critical role in various cancers. While the potential molecular mechanism of circRNAs in the progression of colorectal cancer (CRC) remains uncertain.

Methods: Differentially expressed circRNAs were identified by RNA sequencing. RT-qPCR detected the expression of circ_0009092, miR-665, and NLK in CRC tissues and cells. Functions of circ_0009092 on tumor cell proliferation, migration, and invasion were investigated by a series of in vitro assays. The underlying mechanism of circ_0009092 was explored by bioinformatics analysis, RNA immunoprecipitation (RIP) and luciferase assays. A co-culture assay in vitro was performed to detect the affection of circ_0009092 on macrophage recruitment in the tumor microenvironment (TME). A xenograft mouse model was used to explore the effect of circ_0009092 on tumor growth.

Results: Circ_0009092 was downregulated in CRCand predicted a good prognosis. Overexpression of circ_0009092 reduced tumor cell EMT, proliferation, migration, and invasion in vitro and in vivo. Mechanistically, circ_0009092 elevated the NLK expression via sponging miR-665 and suppressed the Wnt/β-catenin signaling pathway. EIF4EA3 induced circ_0009092 expression in CRC cells. In addition, NLK regulates phosphorylation and O-GlcNAcylation of STAT3 by binding to STAT3, thereby inhibiting CCL2 expression, in which it inhibits macrophage recruitment in the tumor microenvironment (TME).

Conclusion: EIF4A3 suppressed circ_0009092 biogenesis, whichinhibits CRC progression by sponging miR-665 to downregulate NLK. Circ_0009092/miR-665/NLK suppressed tumor EMT, proliferation, migration, and invasion by acting on the Wnt/β-catenin signaling pathway. NLK directly interacted with STAT3 and decreased the CCL2 expression, inhibiting the recruitment of tumor-associated macrophages (TAMs) in the TME. Our study provided novel insights into the roles of circ_0009092 as a novel promising prognostic and therapeutic target in CRC.

Keywords: CCL2; Colorectal cancer; NLK; TAMs; circ_0009092; miR-665.

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Cell Proliferation / genetics
  • Colorectal Neoplasms* / pathology
  • DEAD-box RNA Helicases / metabolism
  • Eukaryotic Initiation Factor-4A / metabolism
  • Humans
  • Mice
  • MicroRNAs* / genetics
  • MicroRNAs* / metabolism
  • Protein Serine-Threonine Kinases / metabolism
  • RNA, Circular / genetics
  • RNA, Circular / metabolism
  • Tumor Microenvironment / genetics
  • Tumor-Associated Macrophages / metabolism
  • Wnt Signaling Pathway

Substances

  • RNA, Circular
  • MicroRNAs
  • NLK protein, human
  • Protein Serine-Threonine Kinases
  • EIF4A3 protein, human
  • Eukaryotic Initiation Factor-4A
  • DEAD-box RNA Helicases
  • MIRN665 microRNA, human