A GFP-labeled Human Colon Cancer Metastasis Model Featuring Surgical Orthotopic Implantation

Colorectal cancer has become a major disease threatening human health. To establish animal models thatexhibit the characteristics of human colorectal cancer will not only help to study the mechanisms underlying thegenesis and development effectively, but also provide ideal carriers for the screening of medicines and examiningtheir therapeutic effects. In this study, we established a stable, colon cancer nude mouse model highly expressinggreen fluorescent protein (GFP) for spontaneous metastasis after surgical orthotopic implantation (SOI). GFPlabeledcolon cancer models for metastasis after SOI were successfully established in all of 15 nude mice and therewere no surgery-related complications or deaths. In week 3, primary tumors expressing GFP were observed inall model animals under fluoroscopy and two metastatic tumors were monitored by fluorescent imaging at thesame time. The tumor volumes progressively increased with time. Seven out of 15 tumor transplanted mice diedand the major causes of death were intestinal obstruction and cachexia resulting from malignant tumor growth.Eight model animals survived at the end of the experiment, 6 of which had metastases (6 cases to mesentericlymph nodes, 4 hepatic, 2 pancreatic and 1 mediastinal lymph node). Our results indicate that our GFP-labeledcolon cancer orthotopic transplantation model is useful with a high success rate; the transplanted tumors exhibitsimilar biological properties to human colorectal cancer, and can be used for real-time, in vivo, non-invasive anddynamic observation and analysis of the growth and metastasis of tumor cells.