KRT4 suppresses oral squamous cell carcinoma development by reducing ATG4B-mediated autophagy

Head and neck squamous cell carcinoma is the sixth most common tumor worldwide,and half of head and neck squamous cell carcinoma patients are with oral squamous cell carcinoma(OSCC).300,000 new cases of OSCC were reported annually.Even with multi-modality treatment,the prognosis of OSCC remains unsatisfactory.Thus,it is urgent to discover novel therapeutic targets for OSCC.Some microarray studies have revealed that Keratin 4(KRT4)is downregulated in OSCC,whereas its role in OSCC development remains unknown.The present study revealed that KRT4 suppressed OSCC progression by inducing cell apoptosis and inhibiting cell invasion.In addition,KRT4 over-expression inhibited autophagy by blocking the interaction of autophagy-related 4B cysteine peptidase(ATG4B)and microtubule-associated protein 1A/1B light chain 3(LC3)to regulate apoptosis and invasion of OSCC.In conclusion,KRT4 played an important role in OSCC development through regulating ATG4B-mediated autophagy and may be a novel therapeutic drug target of OSCC.