SNAIL Induces EMT and Lung Metastasis of Tumours Secreting CXCL2 to Promote the Invasion of M2-Type Immunosuppressed Macrophages in Colorectal Cancer

Int J Biol Sci. 2022 Apr 11;18(7):2867-2881. doi: 10.7150/ijbs.66854. eCollection 2022.

Abstract

Background: There is increasing evidence that tumour-associated macrophages (TAMs) are critical in the formation of lung metastases. However, the molecular mechanisms of tumour interactions with TAMs via EMT are largely unknown. Methods: The mechanism of lung metastasis was studied in patient tissues. The mechanism of SNAIL regulation of the interaction between mesenchymal cells and M2 macrophages was elucidated using coculture of M2 macrophages and Transwell assays in vitro and in vivo in nude mice and NOD-SCID mice. Results: We demonstrated for the first time that SNAIL and CXCL2 were abnormally overexpressed in colorectal cancer, especially lung metastasis, and were associated with poor prognosis in colorectal cancer patients. We demonstrated that SNAIL promoted the secretion of CXCL2 by mesenchymal cells and induced the activation of M2 macrophages. We found that CXCL2 attracted M2-type macrophages to infiltrate and promote tumour metastasis. Conclusion: These findings suggest that SNAIL promotes epithelial tumour transformation, and that transformed mesenchymal cells secrete CXCL2, which promotes M2 macrophage infiltration and tumour cell metastasis. These findings elucidate the tumour-TAM interaction in the metastatic microenvironment, which is mediated by tumour-derived CXCL2 and affects lung metastasis. This study also provides a theoretical basis for the occurrence of secondary lung cancer.

Keywords: CXCL2; Colorectal Cancer; EMT; Lung Metastasis; Macrophages; SNAIL.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Cell Movement
  • Chemokine CXCL2
  • Colorectal Neoplasms* / genetics
  • Colorectal Neoplasms* / metabolism
  • Colorectal Neoplasms* / pathology
  • Epithelial-Mesenchymal Transition / genetics
  • Humans
  • Lung Neoplasms* / genetics
  • Lung Neoplasms* / metabolism
  • Lung Neoplasms* / secondary
  • Macrophages
  • Mice
  • Mice, Inbred NOD
  • Mice, Nude
  • Mice, SCID
  • Snail Family Transcription Factors* / genetics
  • Snail Family Transcription Factors* / metabolism
  • Tumor Microenvironment

Substances

  • CXCL2 protein, human
  • Chemokine CXCL2
  • SNAI1 protein, human
  • Snail Family Transcription Factors