COX-2 inhibitor as a radiation enhancer: New strategies for the treatment of lung cancer

Lung cancer is one of the most common causes of cancer-related mortality throughout the world, and the incidence continues to increase. Smoking is the number one cause of lung cancer. Emerging data have implicated cyclooxygenase-2 (COX-2) and prostanoid production in the pathogenesis of lung carcinoma. In invasive lung tumors, COX-2 upregulation has been reported in up to 90% of cases. COX-2 upregulation is an early event in the development of non-small-cell lung cancer and may be integral to the development of new blood vessels and production of specific proteases that are critical to growth and spread of lung malignancies. COX-2 inhibitors are known to enhance the chemosensitivity in COX-2 overexpressing lung cancer cell lines. Recently, we have demonstrated that selective COX-2 inhibitors also enhance the effect of radiation in COX-2 overexpressed cells. Therefore, inhibitors of COX-2 in combination with chemoradiation therapy may be an alternative strategy that can be tested in clinical trials. The combination of COX-2 inhibitors and radiation suggest a complementary strategy to target angiogenesis while potentially minimizing the impact on quality of life. Currently, several groups are conducting clinical trials in cervix cancer, lung cancer, and brain tumors, using inhibitors of COX-2 in combination with chemotherapy and radiation therapy. These clinical trials will help to elucidate the role of this interesting class.