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MDSCs mediate angiogenesis and predispose canine mammary tumor cells for metastasis via IL-28/IL-28RA (IFN-λ) signaling.

Mucha J, Majchrzak K, Taciak B, Hellmén E, Król M - PLoS ONE (2014)

Bottom Line: Particularly important was the detected increased activation of IL-28/IL-28RA (IFN-λ) signaling.The highest expression of IL-28 was observed in stage III/IV mammary tumor-bearing dogs.Thus, IL-28 may constitute an interesting target for further therapies.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences - WULS, Warsaw, Poland.

ABSTRACT

Background: Myeloid-derived suppressor cells (MDSCs) function in immunosuppression and tumor development by induction of angiogenesis in a STAT3-dependent manner. Knowledge of MDSC biology is mainly limited to mice studies, and more clinical investigations using spontaneous tumor models are required. Here we performed in vitro experiments and clinical data analysis obtained from canine patients.

Methods: Using microarrays we examined changes in gene expression in canine mammary cancer cells due to their co-culture with MDSCs. Further, using Real-time rt-PCR, Western blot, IHC, siRNA, angiogenesis assay and migration/invasion tests we examined a role of the most important signaling pathway.

Results: In dogs with mammary cancer, the number of circulating MDSCs increases with tumor clinical stage. Microarray analysis revealed that MDSCs had significantly altered molecular pathways in tumor cells in vitro. Particularly important was the detected increased activation of IL-28/IL-28RA (IFN-λ) signaling. The highest expression of IL-28 was observed in stage III/IV mammary tumor-bearing dogs. IL-28 secreted by MDSCs stimulates STAT3 in tumor cells, which results in increased expression of angiogenic factors and subsequent induction of angiogenesis by endothelial cells, epithelial-mesenchymal transition (EMT) and increased migration of tumor cells in vitro. Knockdown of IL-28RA decreased angiogenesis, tumor cell invasion and migration.

Conclusions: We showed for the first time that MDSCs secrete IL-28 (IFN-λ), which promotes angiogenesis, EMT, invasion and migration of tumor cells. Thus, IL-28 may constitute an interesting target for further therapies. Moreover, the similarity in circulating MDSC levels at various tumor clinical stages between canine and human patients indicates canines as a good model for clinical trials of drugs targeting MDSCs.

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Related in: MedlinePlus

Changes in cytokeratin and vimentin expression.Representative pictures showing changes in expression of cytokeratin (upper panel) and vimentin (bottom panel) in P114 canine mammary control cells (mock-transfected), cells treated with Il-28ra-specific siRNA and cells treated with IL-28. Values that differed significantly are marked as * (P<0.05) or *** (P<0.001).
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pone-0103249-g003: Changes in cytokeratin and vimentin expression.Representative pictures showing changes in expression of cytokeratin (upper panel) and vimentin (bottom panel) in P114 canine mammary control cells (mock-transfected), cells treated with Il-28ra-specific siRNA and cells treated with IL-28. Values that differed significantly are marked as * (P<0.05) or *** (P<0.001).

Mentions: Immunohistochemical analysis showed that canine mammary tumor cells undergo EMT due to treatment with IL-28. In control conditions, cytokeratin expression was very strong in all the examined cell lines (mean IOD = 750,000 a.U.), whereas vimentin expression was weak (IOD = 433,000 a.U.) (Fig. 3). We observed that because of IL-28 treatment, cytokeratin expression significantly decreased (mean IOD = 424,000 a.U., P<0.001) whereas vimentin expression significantly increased (mean IOD = 723,000 a.U., P<0.001) (Fig. 3). These differences were not as highly significant due to IL-28RA knockdown (P<0.05). However, the mean IOD of cytokeratin was 862,000 a.U., and vimentin 405,781 a.U. (Fig. 3).


MDSCs mediate angiogenesis and predispose canine mammary tumor cells for metastasis via IL-28/IL-28RA (IFN-λ) signaling.

Mucha J, Majchrzak K, Taciak B, Hellmén E, Król M - PLoS ONE (2014)

Changes in cytokeratin and vimentin expression.Representative pictures showing changes in expression of cytokeratin (upper panel) and vimentin (bottom panel) in P114 canine mammary control cells (mock-transfected), cells treated with Il-28ra-specific siRNA and cells treated with IL-28. Values that differed significantly are marked as * (P<0.05) or *** (P<0.001).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4116234&req=5

pone-0103249-g003: Changes in cytokeratin and vimentin expression.Representative pictures showing changes in expression of cytokeratin (upper panel) and vimentin (bottom panel) in P114 canine mammary control cells (mock-transfected), cells treated with Il-28ra-specific siRNA and cells treated with IL-28. Values that differed significantly are marked as * (P<0.05) or *** (P<0.001).
Mentions: Immunohistochemical analysis showed that canine mammary tumor cells undergo EMT due to treatment with IL-28. In control conditions, cytokeratin expression was very strong in all the examined cell lines (mean IOD = 750,000 a.U.), whereas vimentin expression was weak (IOD = 433,000 a.U.) (Fig. 3). We observed that because of IL-28 treatment, cytokeratin expression significantly decreased (mean IOD = 424,000 a.U., P<0.001) whereas vimentin expression significantly increased (mean IOD = 723,000 a.U., P<0.001) (Fig. 3). These differences were not as highly significant due to IL-28RA knockdown (P<0.05). However, the mean IOD of cytokeratin was 862,000 a.U., and vimentin 405,781 a.U. (Fig. 3).

Bottom Line: Particularly important was the detected increased activation of IL-28/IL-28RA (IFN-λ) signaling.The highest expression of IL-28 was observed in stage III/IV mammary tumor-bearing dogs.Thus, IL-28 may constitute an interesting target for further therapies.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences - WULS, Warsaw, Poland.

ABSTRACT

Background: Myeloid-derived suppressor cells (MDSCs) function in immunosuppression and tumor development by induction of angiogenesis in a STAT3-dependent manner. Knowledge of MDSC biology is mainly limited to mice studies, and more clinical investigations using spontaneous tumor models are required. Here we performed in vitro experiments and clinical data analysis obtained from canine patients.

Methods: Using microarrays we examined changes in gene expression in canine mammary cancer cells due to their co-culture with MDSCs. Further, using Real-time rt-PCR, Western blot, IHC, siRNA, angiogenesis assay and migration/invasion tests we examined a role of the most important signaling pathway.

Results: In dogs with mammary cancer, the number of circulating MDSCs increases with tumor clinical stage. Microarray analysis revealed that MDSCs had significantly altered molecular pathways in tumor cells in vitro. Particularly important was the detected increased activation of IL-28/IL-28RA (IFN-λ) signaling. The highest expression of IL-28 was observed in stage III/IV mammary tumor-bearing dogs. IL-28 secreted by MDSCs stimulates STAT3 in tumor cells, which results in increased expression of angiogenic factors and subsequent induction of angiogenesis by endothelial cells, epithelial-mesenchymal transition (EMT) and increased migration of tumor cells in vitro. Knockdown of IL-28RA decreased angiogenesis, tumor cell invasion and migration.

Conclusions: We showed for the first time that MDSCs secrete IL-28 (IFN-λ), which promotes angiogenesis, EMT, invasion and migration of tumor cells. Thus, IL-28 may constitute an interesting target for further therapies. Moreover, the similarity in circulating MDSC levels at various tumor clinical stages between canine and human patients indicates canines as a good model for clinical trials of drugs targeting MDSCs.

Show MeSH
Related in: MedlinePlus