Autophagy mediates oral submucous fibrosis

Oral submucous fibrosis (OSF) is a chronic insidious disease of the oral mucosa, well-recognized as a premalignant condition and commonly found in Southern China. It is primarily caused by the habit of areca nut or gutkha chewing. OSF is believed to be a homeostatic disorder of the extracellular matrix and fibroblast proliferation. The present study demonstrated a novel link between autophagy and OSF. Tissue samples from human OSF showed an overexpression of the autophagy marker microtubule‑associated protein 1 light chain 3 using immunohistochemistry and quantitative polymerase chain reaction. With regard to the crucial role of transforming growth factor (TGF)‑β in OSF disease, western blot analysis demonstrated that TGF‑β signaling was shown to contribute to the activation of autophagy in fibroblasts in vitro; however, a cell apoptosis and MTS assay demonstrated that the suppression of autophagy ameliorated the fibrosis induced by active TGF-β receptor type I signaling, as well as promoted fibroblast apoptosis and suppressed proliferation. Therefore, the present results suggest that autophagy serves a crucial function in OSF.