Correlation between expression of cyclooxygenase-2 and the presence of inflammatory cells in human primary hepatocellular carcinoma: Possible role in tumor promotion and angiogenesis

AIM： To investigate the association of cyclooxygenase-2 （COX-2） expression with angiogenesis and the number and type of inflammatory cells （macrophages/Kupffer cells; mast cells） within primary hepatocellular carcinoma （HCC） tissues and adjacent non-tumorous （NT） tissues. METHODS： Immunohistochemistry for COX-2, CD34, CD68 and mast cell tryptase （MCT） was performed on 14 well-characterized series of liver-cirrhosis-associated HCC patients. COX-2 expression and the number of inflammatory cells in tumor lesions and surrounding liver tissues of each specimen were compared. Moreover, COX-2, CD34 staining and the number of inflammatory cells in areas with different histological degrees within each tumor sample were comparatively analyzed. RESULTS： The percentage of COX-2 positive cells was significantly higher in NT tissues than in tumors. COX-2 expression was higher in well-differentiated HCC than in poorly-differentiated tissues. Few mast cells were observed within the tumor mass, whereas a higher number was observed in the surrounding tissue, especially in peri-portal spaces of NT tissues. Abundant macrophages/ Kupffer cells were observed in NT tissues, whereas the number of cells was significantly lower in the tumor mass. However, a higher cell number was observed in the welldifferentiated tumor and progressively decreased in relation to the differentiation grade. Within the tumor, a positive correlation was found between COX-2 expression and the number of macrophages/Kupffer cells and mastcells. Moreover, there was a positive correlation between CD34 and COX-2 expression in tumor tissues. Comparison between well- and poorly-differentiated HCC showed that the number of CD34-positive cells decreased with dedifferentiation. However, COX-2 was the only independent variable showing a positive correlation with CD34 in a multivariate analysis. CONCLUSION： The presence of inflammatory cells and COX-2 expression in liver tumor suggests a possible relationship with tumor angiogenesis. COX-2 expressing cells and the number of macrophages/Kupffer cells and mast cells decrease with progression of the disease.

Combretastatin A-1 phosphate, a microtubulin inhibitor, induces hepatocellular carcinoma cells and tumor-associated macrophage apoptosis by uncoupling tubulin and p-AKT

Combretastatin A-1 phosphate （CA1P） is a tubulin polymerization inhibitor that binds to the colchicine- binding site of tubulin and shows potential anti-tumor activity to acute myelocytic leukemia as reported. We demon- strated that CA1P also showed an outstanding anti-cancer effect on hepatocellular carcinoma （HCC） in vivo and in vitro. As determined by DCFH-DA dye and Western blot, CA1P induced ROS accumulation and apoptosis in HepG2 cells with the down-regulation of Mcl-1. Additonal western blot and immunofluorescence assays further indi- cated that CA1P inhibited Wnt/β-catenin pathway through GSK-3β activition with an increasing of Mcl phosphoryl- ation and subsequent degradation mediated by tubulin-dynactin p l50-AKT signaling pathway axis. Apoptosis of HepG2 cells induced by CA1P was reversed by the GSK-3β inhibitor （ CHIR-99021 ）. Furthermore, determined by immunohistochemistry of an orthotopic HCC tumor model, CA1P showed a significantly effect on tumor associated macrophage （TAM） apoptosis in vitro and eliminated TAM in tumor microenviroment in vivo, while the infiltration of Treg cells and expression of TGF-β were also altered. Adoptive transfer of macrophages reinstated tumor growth treated by CA1P. These results indicated that CA1P presented potent potential on the regulation of hepatocellular carcinoma cells and TAMs, and also revealed a novel anti-HCC mechanism of CA1P, which acted on both cancer cells and tumor microenvironment. The findings would be beneficial for exploring new application of anti-microtubu- lar drugs on oncotherapy.