Radiation-induced matrix production of lung fibroblasts is regulated by interleukin-8

Purpose: Lung fibrosis can be caused by radiation therapy during cancer treatment and therefore can be the limiting factor of the treatment. The factors that cause the actual fibrosis and the interaction between different cell types were investigated. Materials and methods: Epithelial lung cells and fibroblasts were irradiated and different cytokines were measured in the supernatant. Also effects of radiation on the matrix production of fibroblasts were investigated. Results: Irradiation of isolated lung fibroblasts did not cause increased extracellular matrix production; however, the co-culturing of fibroblasts and irradiated lung epithelial cells or the treatment of fibroblasts with supernatants of irradiated epithelial cells did result in an increase. We were able to show that increased interleukin-8 (IL-8) levels led to increased matrix production. Conclusions: IL-8 is not only a proinflammatory cytokine but it also stimulates collagen synthesis and matrix production and therefore could be a possible drug target in preventing radiation damage during cancer therapy.