Abstract: Objective To explore the effect and mechanism of keratin 17 (KRT17) on proliferation of human esophageal squamous cell line KYSE-150. Methods The correlation of KRT17 expression with the disease stage and survival of patients with esophageal squamous cell carcinoma was analyzed by GEPIA2 website. Human esophageal squamous cell line KYSE-150 was divided into control group,si-NC group,si-KRT17 group and activator group. Small interfering RNA of si-NC and si-KRT17 were transfected into cells of si-NC group and si-KRT17 group,respectively. Cells in the activator group were transfected with si-KRT17 and treated with 740 Y-P(PI3K/AKT/mTOR pathway activator) with a final concentration of 30 μmol/L in the medium. The cell proliferation was detected by CCK-8 assay. The clonal formation was detected by clonal formation experiment. The apoptosis was detected by TUNEL staining. The cell cycle was detected by flow cytometry. The cell migration and invasion were detected by Transwell assay. The contents of glucose, lactic acid and pyruvate in cell supernatant were detected by commercially available kits. The expression of KRT17 mRNA was detected by qRT-PCR. And the expression of KRT17,GLUT1,PDK1 and LDHA,p-PI3K,PI3K,p-AKT,AKT,p-mTOR and mTOR protein were detected by Western blot. Results The expression level of KRT17 in esophageal squamous cell carcinoma tissues was significantly higher than that in normal tissues(P＜0.05). There was a statistically significant correlation between the expression level of KRT17 and the stage of esophageal squamous cell carcinoma (P＜0.05). The survival prognosis of patients with low KRT17 expression was better than that of patients with high KRT17 expression (P＜0.05). Compared with control group or si-NC group,the mRNA and protein expression of KRT17 in si-KRT17 group were decreased (P＜0.05),and the cell proliferation activity,number of clone formation,migration and invasion cells were decreased (P＜0.05). And the lactic acid content,protein expression levels of GLUT1,PDK1 and LDHA were decreased (P＜0.05),values of p-PI3K/PI3K,p-Akt/AKT and p-mTOR/mTOR were decreased (P＜0.05). The proportion of cells in G₀/G₁ phase,TUNEL positive rate,and contents of glucose and pyruvate were increased(P＜0.05). Compared with si-KRT17 group,the mRNA and protein expression levels of KRT17 in activator group were increased (P＜0.05),and the cell proliferation activity,number of clone formation,migration and invasion cells were increased (P＜0.05). And the lactic acid content,protein expression levels of GLUT1,PDK1 and LDHA were increased (P＜0.05),the values of p-PI3K/PI3K,p-Akt/AKT and p-mTOR/mTOR were increased (P＜0.05). The proportion of cells in G₀/G₁ phase,TUNEL positive rate,and contents of glucose and pyruvate were decreased (P＜0.05). Conclusions KRT17 is highly expressed in esophageal squamous cell carcinoma tissues and cells. Silencing KRT17 inhibits proliferation,migration and invasion of human esophageal squamous cell line KYSE-150,and promotes apoptosis and cell cycle arrest.

Key words: keratin 17 (KRT17), esophageal squamous cell carcinoma, PI3K/AKT/mTOR pathway, glycolysis