LncRNA DLEU1 facilitates the progression of oral squamous cell carcinoma by miR ‐126‐5p/ GAB1 axis

Abstract Oral squamous cell carcinoma (OSCC) is one of the most frequent malignancies found in head and neck cancers. Dysregulation of lncRNAs has been proposed to be related to the development of OSCC. Here, we investigated the function and probable mechanisms of lncRNA DLEU1 in OSCC. OSCC cell lines and human oral keratinocytes (HOKs) were cultured, while SCC‐25 and CAL‐27 cells were transfected with the corresponding plasmids. Reverse transcription quantitative PCR (RT‐qPCR) and western blot were carried out to measure the RNA and protein levels. Cell proliferation, migration and invasion were evaluated using MTT assays, wound healing and Transwell assays. The StarBase database predicted the interactions between DLEU1 and miR‐126‐5p, as well as miR‐126‐5p and GAB1, which were further validated using a dual‐luciferase reporter assay. Our results indicated that DLEU1 and GAB1 were upregulated, while miR‐126‐5p was downregulated in OSCC cells. Silencing DLEU1 reduced OSCC cell proliferation, migration, and invasion, while DLEU1 overexpression had the opposite effects. DLEU1 mediated biological effects in OSCC through binding to miR‐126‐5p, which directly targeted GAB1. miR‐126‐5p knockdown rescued the inhibitory function of DLEU1 depletion on proliferation, migration and invasion. Meanwhile, the miR‐126‐5p mimic exerted suppressive functions in the progression of OSCC, which were neutralized after GAB1 overexpression. In summary, lncRNA DLEU1 targets the miR‐126‐5p/GAB1 axis to aggravate OSCC progression, providing a novel target for treating OSCC.