Evaluation of novel orthotopic nude mouse models for human small-cell lung cancer

INTRODUCTION: Although subcutaneous xenograft models have been widely used to evaluate the antitumor activity of new compounds, these models present a major disadvantage because the tumors do not accurately represent the cancer biology, especially with regard to metastasis and drug sensitivity. Effective murine models of small-cell lung cancer (SCLC) are needed. METHODS: To provide strategies for studying new therapies and tumor biology, we developed three orthotopic models of human SCLC (H69A, a variant of the National Cancer Institute [NCI]-H69 cell line selected for invasiveness in vitro, NCI-H187, and NCI-N417) in nude mice. Tumor cells were injected into their lungs and new cell lines were established from these tumors (H69ALu, H187Lu, and N417Lu) to select for a reproducible tumor growth pattern and minimize variations in tumor size. RESULTS: In all three models tumors started as a solitary mass in the left lung and spread to mediastinal and axillary lymph nodes and to the right lung in a pattern similar to that observed in human SCLC. To test the accuracy of this model in representing SCLC as seen in the clinic, we compared the efficacy of chemotherapeutic agents in each model. Irinotecan significantly inhibited the growth and progression of all three human SCLC tumors, and cisplatin, paclitaxel, and etoposide significantly inhibited the growth and progression of H69ALu tumors over the control agent. CONCLUSIONS: We have established three orthotopic murine models of human SCLC closely resembling the course of human SCLC seen in the clinic including metastasis to lymph nodes and distant organs. They provide a means for better understanding the biology of this disease and will enable evaluation of novel therapeutic strategies.