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Published on: November 28, 2019
Endostatin gene therapy inhibits intratumoral macrophage M2 polarization
Karen Foguer1, Marina de Souza Braga1, Jean Pierre Schatzmann Peron2
1Nephrology Division, Federal University of Sao Paulo, Sao Paulo, Brazil; Biotechnology Department, IPEN-CNEN, Sao Paulo, Brazil.
Background:
Renal cell carcinoma (RCC) is a highly vascularized cancer resistant to chemotherapy and radiotherapy. RCC is frequently infiltrated with immune cells, with macrophages being the most abundant cell type. Alternatively activated M2 macrophages are known to contribute to tumor progression. Endostatin (ES) is a fragment of collagen XVIII that possesses antiangiogenic activity. In this study, we investigated the impact of ES gene therapy on the polarization of tumor-associated macrophages (TAMs) in lung metastases from tumor-bearing mice.
Methods:
BALB/c mice divided into three groups: Normal, Control and ES-treated. Tumor-bearing mice were treated with ES-transduced cells or control cells over ten days. At the end of the study, plasma was collected, and pulmonary macrophages were isolated and used for FACS or RT-PCR. ELISA tests were used to analyze plasma and cell culture supernatant cytokines.
Results:
ES treatment significantly reduced the levels of anti-inflammatory and pro-angiogenic cytokines, including IL4, IL-10, IL-13 and VEGF. Gene expression of M2 markers, such as IL-10, Arg-1, VEGF and YM-1, declined significantly. Flow cytometry showed a reduction in the number of M2 F4/80+CD36+CD206+CD209+ macrophages and in IL-10 secretion by these cells. Reduced levels of IL-10 were also found in the culture supernatants of the ES-treated group.
Conclusions:
Our research corroborates previous observations that ES has an important anti-tumoral role. However, aside from promoting interferon-ɤ secretion and an effective T cell response, we show here that this switch is extended to TAMs, complicating the maintenance of pro-tumorigenic M2 macrophages and thus favoring tumor elimination.
Insights
Endostatin gene therapy effectively targets M2 macrophages in renal cell carcinoma lung metastases. This approach reduces pro-tumorigenic cytokines and promotes tumor elimination by modulating the tumor microenvironment.
Area of Science:
- Oncology
- Immunology
- Gene Therapy
Background:
- Renal cell carcinoma (RCC) is a vascularized cancer resistant to conventional treatments.
- Tumor-associated macrophages (TAMs), particularly M2 macrophages, promote RCC progression.
- Endostatin (ES), an antiangiogenic collagen fragment, is investigated for its therapeutic potential.
Purpose of the Study:
- To investigate the impact of Endostatin (ES) gene therapy on tumor-associated macrophage (TAM) polarization in a murine model of renal cell carcinoma lung metastases.
- To assess the effect of ES gene therapy on M2 macrophage markers and associated cytokine profiles.
Main Methods:
- BALB/c mice bearing tumors were treated with ES-transduced cells or control cells.
- Pulmonary macrophages were isolated for flow cytometry (FACS) and gene expression analysis (RT-PCR).
- Plasma and cell culture supernatants were analyzed for cytokine levels using ELISA.
Main Results:
- ES treatment significantly reduced pro-angiogenic and anti-inflammatory cytokines (IL-4, IL-10, IL-13, VEGF).
- Gene expression of M2 markers (IL-10, Arg-1, VEGF, YM-1) and the number of M2 macrophages (F4/80+CD36+CD206+CD209+) decreased significantly.
- ES therapy reduced IL-10 secretion by macrophages.
Conclusions:
- Endostatin gene therapy demonstrates an anti-tumoral role by modulating TAMs.
- ES therapy shifts TAM polarization away from pro-tumorigenic M2 phenotypes.
- This macrophage polarization switch, alongside T cell response enhancement, favors tumor elimination in RCC.
