Retroviral endostatin gene transfer inhibits growth of human lung cancer in a murine orthotopic xenotransplant model.

Background And Aims: The administration of endostatin, a potent anti-angiogenic agent, will be required for extended periods of time as a cancer treatment. The aim of the present study was to induce endogenous endostatin secretion in a continuous fashion, based on retroviral gene transfer. The tumor response was evaluated in an orthotopic murine tumor model of human lung cancer.

Materials And Methods: Human non-small-cell lung cancer cells (KNS 62) were retrovirally transduced with the human endostatin gene. An orthotopic murine xenotransplant model was used to investigate tumor growth, metastases and survival. After 4 weeks of subcutaneous growth, endostatin expression was measured by immunoblot analysis in tumor lysates.

Results: The growth of the subcutaneous tumors was significantly delayed, and orthotopic tumor growth and pleural metastases were significantly reduced in endostatin-transduced KNS 62 tumors. Prolongation of survival subsequent to orthotopic tumor induction was demonstrated. Strong endostatin expression was found in subcutaneous tumors after 4 weeks.

Conclusion: Retroviral transduction of the human endostatin gene is capable of achieving long-term endostatin expression. Endostatin transduction provides significant anti-tumor effects with regard to local tumor growth, metastases and survival.