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

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

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.

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.

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.