In our previous studies, enhancer of zeste homolog 2 (EZH2) has been proven to be a key oncogenic driver in oral squamous cell carcinoma (OSCC). However, the regulatory mechanisms on EZH2 remain poorly understood in OSCC. Here, through multi-transcriptomics, bioinformatics analysis, and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), the co-expression network of long noncoding RNA RC3H2 (RC3H2), microRNA-101-3p (miR-101-3p), and EZH2 were screened and validated as a competing endogenous RNA (ceRNA) mechanism in OSCC. Silencing of RC3H2 inhibited OSCC cell proliferation, colony formation, migration, and invasion in vitro and reduced the expression of EZH2 and H3K27Me3, whereas RC3H2 overexpression significantly promoted OSCC cell growth, colony formation, migration, invasion, and xenograft tumor growth in vivo and increased the expression of EZH2 and H3K27Me3. A fluorescence in situ hybridization (FISH) assay verified that RC3H2 was predominately localized to the cytoplasm. RNA pull-down and luciferase activity assays showed that miR-101-3p was physically bound to RC3H2 as well as EZH2, and its inhibitor reversed the inhibitory effect of RC3H2 knockdown on progression of OSCC. Taken together, our findings demonstrate that RC3H2 as completive endogenous RNA sponging miR-101-3p targets EZH2 and facilitates OSCC cells’ malignant behavior.

在我们以前的研究中，zeste同源物2（EZH2）的增强剂已被证明是口腔鳞状细胞癌（OSCC）的关键致癌驱动因子。但是，在OSCC中对EZH2的调控机制仍然知之甚少。在这里，通过多转录组学，生物信息学分析和定量逆转录酶聚合酶链反应（qRT-PCR），长非编码RNA RC3H2（RC3H2），microRNA-101-3p（miR-101-3p）的共表达网络，筛选和验证EZH2和EZH2作为OSCC中的竞争性内源RNA（ceRNA）机制。RC3H2沉默可抑制OSCC细胞增殖，集落形成，迁移和体外侵袭并降低EZH2和H3K27Me3的表达，而RC3H2的过表达显着促进体内OSCC细胞生长，集落形成，迁移，侵袭和异种移植肿瘤的生长，并增加EZH2和H3K27Me3的表达。荧光原位杂交（FISH）分析证实RC3H2主要定位于细胞质。RNA下拉和荧光素酶活性分析表明，miR-101-3p与RC3H2和EZH2物理结合，其抑制剂逆转了RC3H2敲低对OSCC进展的抑制作用。综上所述，我们的发现表明，RC3H2作为海绵状miR-101-3p的完整内源性RNA靶向EZH2，并促进OSCC细胞的恶性行为。