Exogenous endothelial progenitor cells contribute to hepatocellular carcinoma vasculogenesis in nude mouse

Abstract

Objective To investigate the homing specificity of bone marrow (BM)-derived endothelial progenitor cells (EPCs) of transgenic mice carrying enhanced green fluorescent protein (EGFP) using a murine intraperitoneal hepatocellular carcinoma (HCC) model and its potential clinical value. Methods BM mononuclear cells were isolated by ficoll density-gradient centrifugation and serial differential adhesion method was used to purify the EPCs carrying EGFP which had been identified by morphology, uptake of DiI-Ac-LDL, binding of UEA-1 lection, flow cytometry and in vitro tube formation. Ex vivo expanded mouse BM-derived EGFP-EPCs were randomly injected into tumor-bearing nude mouse and normal nude mouse via the tail vein. Two weeks after injection of EPCs, the livers and other organs in each group were examined for distribution of transplanted EPCs. Results Fluorescence image analysis revealed that systemically transplanted EPCs 'homed’ to HCC with significantly higher specificity, respectively, in the number of cells in the experimental group were 169.40±10.87 in the livers, 15.40±2.87 in the heart, 14.70±2.02 in the lung, 1.70±0.50 in the kidney, 28.30±4.20 in the spleen, 6.90±1.31 in the pancreas, and 4.60±1.22 in the intestine, and those in the control group were respectively 76.50±4.20, 16.70±1.32, 76.00±3.31, 24.70±1.70, 77.90±4.50, 18.60±2.00 and 12.70±1.70 correspondingly. The number of cells in the liver more than lung (P=0.001), heart (P=0.032), kidney (P=0.002), spleen(P=0.036), pancreas (P=0.001)and bowel(P=0.001), the number of lung and spleen cells was higher in heart(P=0.036), pancreas (P=0.010), kidney (P=0.030) and bowel(P=0.008). as compared to other organs within the experimental group and to anatomically matched liver sections from the control groups (P=0.001). The quantify of EGFP-EPCs in lungs and spleen were higher specificity as compared to other organs (no liver). Immunohischemical showed the transplanted cells differentiate into vascular cells and recruitmented tumor angiogenesis. Conclusion The results suggested that the autologous EPCs in vivo could be recruited specifically into HCC, and take part in the angiogenesis of HCC in the nude mice. Key words: Endothelial progenitor cell; Carcinoma, hepatocellular; Cell transplantation; Vasculogenesis; Angiogenesis