Long noncoding RNA FALEC inhibits proliferation and metastasis of tongue squamous cell carcinoma by epigenetically silencing ECM1 through EZH2

Tongue squamous cell carcinoma (TSCC), the most common epithelial cancer identified in the oral cavity, has become one of the most common malignancies across the developing countries. Increasing evidence indicates that long non-coding RNAs (lncRNAs) serve as important regulators in cancer biology. The focally amplified long non-coding RNA in epithelial cancer (FALEC) was found downregulated in the tissues of tongue squamous cell carcinoma (TSCC) and was predicted to present a good prognosis by bioinformatics analysis. Experiments indicated that FALEC knockdown significantly increased the proliferation and migration of TSCC cells both in vitro and in vivo; however, FALEC overexpression repressed these malignant behaviors. RNA pull-down and RNA immunoprecipitation demonstrated that FALEC could recruit enhancer of zeste homolog 2 (EZH2) at the promoter regions of extracellular matrix protein 1 (ECM1), epigenetically repressing ECM1 expression. The data revealed that FALEC acted as a tumor suppressor in TSCC and may aid in developing a novel potential therapeutic strategy against TSCC.