The RNA-binding Protein SMN as a Novel Player in Laryngeal Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) arise from the mucosal epithelium in the oral cavity, pharynx, sino-nasal region, and larynx. Laryngeal squamous cell carcinoma (LSCC) represents one-third of all head and neck cancers. Dysregulated RNA-related pathways define an important molecular signature in this aggressive carcinoma. The Survival Motor Neuron (SMN) protein regulates fundamental aspects of the RNA metabolism but, curiously, its role in cancer is virtually unknown. For the first time, here we focus on SMN in cancer context. We conducted a pilot study in a total of 20 patients with LSCC where SMN was found overexpressed at both the protein and transcript levels. By a cellular model of human laryngeal carcinoma, we demonstrated that SMN impacts cancer-relevant behaviors and perturbs key players of cell migration, invasion, and adhesion. Furthermore, in LSCC we showed a physical interaction between SMN and the epidermal growth factor receptor (EGFR), whose overexpression is an important feature in these tumours. This study candidates SMN as novel therapeutic target in LSSC, and likely in the whole spectrum of HNSCC. Overall, we provide the first analysis of SMN in human cancer.