[Establishment and application of engrafted tumor models with humanized tumor blood vessel]

Animal models are indispensable in the studies of tumor endothelial genes and anti-angiogenic therapy. This study was to build a new engrafted tumor model with humanized blood vessels.

Human liver sinusoid endothelial cells (HLSECs) were mixed respectively with human liver cancer cell line BEL7402, human colon cancer cell line LS174T, and human esophageal cancer cell line NEC, and then inoculated into NOD/SCID mice or BALB/c nude mice. The mice inoculated with only tumor cells were used as controls. Tumor growth was observed. Green fluorescent protein (GFP)-labeled HLSECs were observed under fluorescent microscope to detect their survival and tube formation. Microvessel density (MVD) was analyzed by immunohistochemistry. The tumor-bearing mice were treated by anti-HLSEC monoclonal antibody 2B6 to observe its effect on tumor growth.

Tumor growth was significantly enhanced by the co-inoculation of HLSECs with BEL7402 cells in NOD/SCID mice; tumor weight was increased by 5.1 folds as compared with that of control. GFP-labeled vessels could easily be observed in the tumors from co-inoculation of HLSECs with BEL7402 cells. Total MVD was increased by 85.7% of control. The humanized MVD was about 10.28-29.28, which was 41%-65% of total MVD. Furthermore, the co-inoculation of HLSECs with NECs, BEL7402, or LS174T cells in nude mice led to 3.3-6.0 folds increase of xenograft weight as compared with control. When treated with 2B6 antibody, humanized MVD was decreased by 65.1% in the engrafted tumors and the tumor weight lost 71.8%.

When co-inoculate with human tumor cell lines into mice, HLSECs could survive, proliferate, and contribute to tumor angiogenesis, which may enhance tumor growth. The engrafted tumor in vivo model with humanized vessels can be widely used in the research of functional genes in tumor angiogenesis and anti-angiogenic therapies.