Long Noncoding RNA H19 Facilitates Small Cell Lung Cancer Tumorigenesis Through miR-140-5p/FGF9 Axis

PURPOSE: Long noncoding RNAs (lncRNAs) are emerging as gene regulators to drive many important cancer phenotypes through interaction with microRNAs. There have been numerous data about upregulation of H19 and its strong oncogenic function in progression of cancers. However, the function and detailed mechanisms of H19 on small cell lung cancer (SCLC) are still unclear. METHODS: In this study, we investigated H19 expression in SCLC and para-carcinoma tissues. We also explored the function and detailed mechanisms of H19 on SCLC cells via RT-PCR, transwell assay, Western blot, dual-luciferase report assay and RNA pull-down experiments. RESULTS: In this study, we observed that H19 was upregulated in SCLC compared with para-carcinoma tissues or NSCLC tissues. We also uncovered that H19 could promote proliferation and migration of SCLC cells. Functional investigation illustrated that H19 acted as a sponge for miR-140-5p to regulate its expression in SCLC. Interestingly, we further found that H19 upregulated FGF9 expression to promote SCLC progression via sponging miR-140-5p. H19 and FGF9 were also revealed to have similar expression patterns in clinical SCLC samples. CONCLUSION: These data demonstrated that H19 might be a promising prognostic and therapeutic target for SCLC.