[Establishment of orthotopic lung cancer model expressing enhanced green fluorescent protein]

In vivo molecular imaging with mouse model could continuously and in real-time monitor the changes of the tumor. The aim of this study is to establish stable enhanced green fluorescent protein (EGFP) expressing NCI-H460 cell lines and relevant mouse model via orthotopic transplantation, and to study the characteristic of this model and the quantitative detection method of the primary tumor and metastatic lesions.

Human lung cancer NCI-H460 cells were transfected with retroviral vector containing the EGFP. Stable high-level expression of EGFP was maintained in the subcutaneously-growing tumors. Fragments of the subcutaneously growing tumor, which were comprised of EGFP-expressing cells, were implanted by surgical orthotopic implantation (SOI) in the lung of nude mice. The dynamic growth of orthotopic tumor was observed using in vivo fluorescence imaging. The correlation of fluorescence area and tumor volume was tested.

After the model established, green fluorescent can be observed through the flap in day 7. Tumor formation rate was 100%. Mean survival time of tumor-bearing nude mice was 34.2 days. The metastasis sites were the contralateral lung, mediastinal and hilar lymph nodes, pleura and diaphragm; metastasis rates were 87.5%, 75%, 25% and 12.5%, respectively. Tumor volume and fluorescence area was correlated (r = 0.873, P = 0.001).

The nude mouse model bearing orthotopic human lung cancer expressing EGFP has been successfully established. The model might be used for further molecular studies on tumor metastasis, angiogenesis and also be applied to anti-tumor drug screening in preclinical stage.