To demonstrate the role of CHRNA7 in metformin-inhibited CIC properties, we estimated the mRNA (Fig. 5b) and protein (Fig. 5c) levels of CHRNA7 in two ESCC cancer cell lines, when they were treated with metformin (0.8 mM) and nicotine alone or in combination. Here, CHRNA7 is linked to esophageal squamous cell carcinoma.