CD206 accelerates hepatocellular carcinoma progression by regulating the tumour immune microenvironment and increasing M2-type polarisation of tumour-associated macrophages and inflammation factor expression

Objective

This study aims to investigate the effect of CD206 on the progression of hepatocellular carcinoma (HCC) and the regulation of the tumour immune microenvironment.

Methods

A subcutaneous mouse model of HCC was established and treated with CD206-overexpressing adenovirus by tail vein injection or CD206 antibody C068C2 by intratumoral injection. The hepatocarcinoma-bearing mice were divided into four groups (IgG+ tail vein adenovirus group, IgG group, C068C2+ tail vein adenovirus group and C068C2 group) to observe the changes in tumour weight and volume with different expression levels of CD206. The proportion of M2-type tumour-associated macrophages (TAMs) was detected by flow cytometry and immunofluorescence. The apoptosis of tumour cells was detected using terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining, and inflammatory factors in serum and tissues were detected using the ENZYME-LINKED IMMUNOSORBENT ASSAY.

Results

Compared with the mice with low CD206 expression, the hepatocarcinoma-bearing mice with high CD206 expression in HCC exhibited faster tumour growth and more aggressive progression. Flow cytometry and immunofluorescence staining revealed that the expression level of CD206-positive M2-type TAMs was highest in the IgG + adenovirus group and lowest in the C068C2 group (p < 0.001). Compared with the IgG + adenovirus group, the proportion of TUNEL-positive cells in tumour cells was significantly reduced in the C068C2 group. The IgG + adenovirus group had the highest concentrations of transforming growth factor-β (TGF-β) and interleukin 6 (IL-6) in both serum and tumour tissues.

Conclusion

The overexpression of CD206 accelerates the progression of HCC and changes the tumour immune microenvironment. The high expression of CD206 in HCC increases the M2-type polarisation of TAMs and induces the expression of both TGF-β and IL-6 in tumour tissues and serum, thereby promoting HCC progression.