Cellular senescence and radiation-induced pulmonary fibrosis

Radiation-induced pulmonary fibrosis (RIPF)is a serious treatment complication that affects about 9%–30% cancer patients receiving radiotherapy for thoracic tumors. RIPF is characterized by progressive and irreversible destruction of lung tissues and deterioration of lung function, which can compromise quality of life and eventually lead to respiratory failure and death. Unfortunately, the mechanisms by which radiation causes RIPF have not been well established nor has an effective treatment for RIPF been developed. Recently, an increasing body of evidence suggests that induction of senescence by radiation may play an important role in RIPF and clearance of senescent cells (SnCs)with a senolytic agent, small molecule that can selectively kill SnCs, has the potential to be developed as a novel therapeutic strategy for RIPF. This review discusses some of these new findings to promote further study on the role of cellular senescence in RIPF and the development of senolytic therapeutics for RIPF.