miRNA-124 down-regulates SOX8 expression and suppresses cell proliferation in non-small cell lung cancer.

Non-small lung cell carcinoma (NSCLC) is a leading lethal disease and a global health burden. The function of the Sex determining region Y (SRY)-related high mobility group box (SOX) family gene in cancer has attracted the attention of more and more scientists recently, yet there are few reports regarding the role of SOX in NSCLC. Our study aimed to investigate the expression of SOX8, a protein belonging to the E group of the SOX family, as well as SOX9, in non-small cell lung cancer (NSCLC) and the relationship of gene expression to clinicopathological factors and prognosis in patients. Immunohistochemical analysis was used to measure the expression of SOX8 in 80 NSCLC and 7 adjacent normal tissues. SOX8 expression was detected as elevated in tumor samples and correlated to tumor size (P < 0.001), lymph node metastasis (P = 0.001), differentiation classification (P = 0.015), and clinical stage (P = 0.013) significantly. Moreover, Kaplan-Meier survival analysis demonstrated that shorter survival time for patients who had higher SOX8 expression (P < 0.001). In addition, our experiments indicate that miRNA-124 functions as a tumor suppressor in NSCLC. We also demonstrate miRNA-124 directly targeted and decreased SOX8 in NSCLC cell lines, suggesting smiRNA-124 may regulate NSCLC cell proliferation via decreasing SOX8 (oncogenicity of biomarker in NSCLC).