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Dysregulation of long non‐coding RNAs (lncRNAs) has been implicated in many cancer developments. Previous studies showed that lncRNA LINC00941 was aberrantly expressed in oral squamous cell carcinoma (OSCC). However, its role in OSCC development remains elusive. In this study, we demonstrated that in OSCC cells, EP300 activates LINC00941 transcription through up‐regulating its promoter H3K27ac modification. Up‐regulated LINC00941 in turn activates CAPRIN2 expression by looping to CAPRIN2 promoter. Functional assays suggest that both LINC00941 and CAPRIN2 play pivotal roles in promoting OSCC cell proliferation and colony formation. In vivo assay further confirmed the role of LINC00941 in promoting OSCC cell tumour formation. Lastly, we showed that the role of LINC00941 and CAPRIN2 in OSCC progression was mediated through activating the canonical WNT/β‐catenin signaling pathway. Thus, LINC00941/CAPRIN2/ WNT/β‐catenin signaling pathway provides new therapeutic targets for OSCC treatment.

lncRNAs are related to the progression of various diseases, including oral squamous cell carcinoma (OSCC), which is a common squamous cell carcinoma of the head and neck. Tumor-associated macrophages and tumor cells are significant components of tumor microenvironment. M2 polarization of tumor-associated macrophages is a crucial actor in tumor malignancy and metastasis. In this study, we studied the molecular mechanism of lncRNA DCST1-AS1 in OSCC. Here, we reported that DCST1-AS1 was significantly increased in OSCC cells. We found that loss of DCST1-AS1 obviously inhibited the proliferation, migration, and invasion of OSCC cells and xenograft tumor growth. Meanwhile, silencing of DCST1-AS1 also repressed the percentage of macrophages expressing M2 markers CD206 and CD11b. DCST1-AS1 shRNA enhanced the percentage of macrophages expressing M1 markers CD80 and CD11c. Then, we observed that loss of DCST1-AS1 suppressed OSCC progression via inactivating NF-κB signaling. As well established, NF-κB signaling exerts critical roles in tumor progression, and our study proved that DCST1-AS1 could regulate NF-κB signaling. We proved that blocking the NF-κB pathway using antagonists greatly downregulated OSCC progression and M2 macrophage polarization induced by the overexpression of DCST1-AS1. To sum up, we reported that DCST1-AS1 plays an important role in modulating OSCC tumorigenicity and M2 macrophage polarization through regulating the NF-κB pathway.

Oral squamous cell carcinoma (OSCC) is a pathological type of oral cancer, which accounts for over 90% of oral cancers. It has been widely shown that circRNA is involved in the regulation of multiple malignant oral diseases including OSCC. However, the mechanism underlying how circRNA regulates OSCC is still not clearly elucidated. In this article, we report circFOXO3 promotes tumor growth and invasion of OSCC by targeting miR‐214 which specifically degrades the lysine demethylase 2A (KDM2A). CircRNA sequencing was conducted in OSCC tumor and tumor‐side tissues, and the expression of circFOXO3 is found to be markedly increased in tumor tissues. CircFOXO3 is also highly expressed in several OSCC cell lines compared with human oral keratinocytes. Transwell assay and colony formation showed that knockdown of circFOXO3 prevents the invasion and proliferation of oral cancer cells. Via bioinformatic research, miR‐214 was found to be the target of circFOXO3 and correlate well with circFOXO3 both in vitro and in vivo. KDM2A was then validated by database analysis and luciferase assay to be the direct target of miR‐214. KDM2A helps to promote tumor invasiveness and proliferation of OSCC. Collectively, our results proved that circFOXO3 sponges miR‐214 to up‐regulate the expression of KDM2A, thus promotes tumor progression in OSCC.