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Updated: Aug 15, 2025
A Macrophage-Tumor Spheroid Co-Invasion Assay
Published on: January 24, 2025
Tumor-associated macrophages mediate gastrointestinal stromal tumor cell metastasis through CXCL2/CXCR2
Hongke Cai1, Yi Chen1, Xi Chen2
1Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
Background:
Tumor-associated macrophages (TAMs) are linked with the progression and poor prognosis of multifarious solid tumors, but the regulatory mechanisms involved in gastrointestinal stromal tumors (GIST) remain indistinct. This study intended to delve into the job of TAM-derived chemokines in promoting metastasis in GIST microenvironment.
Methods:
Expression levels of M2-TAM markers and CXCL2 in primary and metastatic tissues of GIST were analyzed by bioinformatics methods, and we analyzed the correlation between CXCL2 and M2-TAM markers. Immunofluorescence was applied to assay CXCL2 and M2-TAM marker protein (CD68 and CD206) expression in tumor tissues. Serum CXCL2 concentration in metastatic and non-metastatic patients was assayed by ELISA. The differentiation of THP-1 cells was tested by flow cytometry. Cell function test was utilized to analyze the viability, invasion and migration of GIST cells. Western blot was used to examine the expression of epithelial-mesenchymal transition (EMT)-related proteins. The mouse liver metastasis model was established, and the effects of CXCL2 and EMT-related genes on metastasis were confirmed by hematoxylin-eosin staining and immunohistochemistry experiments.
Results:
Bioinformatics analysis ascertained that M2-TAM marker proteins and chemokine CXCL2 were highly expressed in GIST metastatic tissues, and CXCL2 and TAM were co-located in tumor tissues. Results of in vitro cell function experiments displayed that CXCL2 secreted by M2-TAM promoted the invasion, migration and EMT of GIST tumor cells, and the anti-CXCL2 antibody could block the metastasis promoting effect of CXCL2. Additionally, the silencing of CXCR2 in GIST cells inhibited the metastasis promoting effect of CXCL2. Animal studies further confirmed that CXCL2 promoted liver metastasis of GIST in vivo.
Conclusion:
This study preliminarily revealed the mechanism of M2-TAM promoting tumor metastasis by secreting CXCL2 in GIST tumor microenvironment, and proffered theoretical reference for the development of immunotherapy strategies targeting M2-TAM.
Insights
Tumor-associated macrophages (TAMs) secrete CXCL2, a chemokine that promotes gastrointestinal stromal tumor (GIST) metastasis. Targeting this CXCL2-TAM interaction may offer new immunotherapy strategies for GIST.
Area of Science:
- Oncology
- Immunology
- Gastroenterology
Background:
- Tumor-associated macrophages (TAMs) are implicated in solid tumor progression, but their role in gastrointestinal stromal tumors (GIST) is not fully understood.
- The specific mechanisms by which TAMs influence GIST metastasis require further elucidation.
Purpose of the Study:
- To investigate the role of TAM-derived chemokines in promoting metastasis within the GIST microenvironment.
- To explore the potential of targeting TAMs and their secreted factors for GIST immunotherapy.
Main Methods:
- Bioinformatic analysis of M2-TAM markers and CXCL2 expression in GIST tissues.
- Immunofluorescence, ELISA, and flow cytometry to assess protein and cell marker expression.
- In vitro cell function assays (viability, invasion, migration) and Western blot for EMT markers.
- Establishment of a mouse liver metastasis model to confirm in vivo effects.
Main Results:
- High expression of M2-TAM markers and CXCL2 was observed in metastatic GIST tissues, with co-localization of CXCL2 and TAM.
- CXCL2 secreted by M2-TAMs promoted GIST cell invasion, migration, and epithelial-mesenchymal transition (EMT).
- Blocking CXCL2 or silencing its receptor CXCR2 inhibited GIST metastasis in vitro and in vivo.
Conclusions:
- This study reveals that M2-TAMs promote GIST metastasis by secreting CXCL2, highlighting a novel mechanism in the tumor microenvironment.
- The findings provide a theoretical basis for developing targeted immunotherapies against M2-TAMs in GIST treatment.
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