The Preventive Effect of the Phenotype of Tumour-Associated Macrophages, Regulated by CD39, on Colon Cancer in Mice.

BACKGROUND

This study was designed to investigate the effect of cluster differentiation (CD)39 and CD73 inhibitors on the expresion of tumour-associated macrophages (TAMs), M1- versus M2-tumour phenotypes in mice with colon cancer.

METHODS

An in vivo study of co-culture with colon cancer cells and immune cells from the bone marrow (BM) of mice was performed. After the confirmation of the effect of polyoxotungstate (POM-1) as an inhibitor of CD39 on TAMs, the mice were randomly divided into a control group without POM-1 and a study group with POM-1, respectively, after subcutaneous injection of CT26 cells. On day 14 after the injection, the mice were sacrificed, and TAMs were evaluated using fluorescence-activated cell sorting.

RESULTS

In the in vivo study, the co-culture with POM-1 significantly increased the apoptosis of CT26 cells. The cell population from the co-culture with POM-1 showed significant increases in the expression of CD11b for myeloid cells, lymphocyte antigen 6 complex, locus C (Ly6C) for monocytes, M1-tumour phenotypes from TAMs, and F4/80 for macrophages. In the in vivo study, tumour growth in the study group with POM-1 was significantly limited, compared with the control group without POM-1. The expressions of Ly6C and major histocompatibility complex class II for M1-tumour phenotypes from TAMs on F4/80 from the tumour tissue in the study group had significantly higher values compared with the control group.

CONCLUSION

The inhibition of CD39 with POM-1 prevented the growth of colon cancer in mice, and it was associated with the increased expression of M1-tumour phenotypes from TAMs in the cancer tissue.