Engrailed 2 serves as a master regulator of the super-enhancer in the TNC gene locus in non-small cell lung cancer

Engrailed 2 (EN2) is a homeodomain-containing protein that is dysregulated in many types of cancer. However, the role of EN2 in non-small cell lung cancer (NSCLC) and the mechanism underlying its biological function are largely unclear. Here, we showed that EN2 played an oncogenic function in NSCLC and greatly enhanced the malignant phenotype of NSCLC cells. Meanwhile, EN2 was able to boost the expression of a well-studied oncogenic Tenascin-C (TNC) gene, which in turn activated the AKT signaling pathway. Interestingly, we found that EN2 directly bound to the super-enhancer (SE) region in the TNC locus. The histone marker H3K27ac was also enriched in the region, indicating the activation of the SE. Treatment of the cells with JQ1, an inhibitor of SE activity, abrogated the effect of EN2 on the expression of TNC and phosphorylation of AKT-Ser473. Collectively, our work unveils a novel mode of EN2 function, in which EN2 governs the SE in the TNC locus, consequently activating the oncogenic TNC-AKT axis in NSCLC.