Long noncoding RNA MRPL23-AS1 Promotes Adenoid Cystic Carcinoma Lung Metastasis

Lung metastasis is a major factor affecting long-term survival in adenoid cystic carcinoma patients. Here, we report the long noncoding RNA (lncRNA) MRPL23 antisense RNA 1 (MRPL23-AS1), which exhibited remarkably upregulated expression and was correlated with lung metastasis and overall survival in salivary adenoid cystic carcinoma (SACC) patients. MRPL23-AS1 positively regulated epithelial-mesenchymal transition by forming a RNA-protein complex with enhancer of zeste homolog 2 (EZH2). MRPL23-AS1 increased the binding of EZH2 and H3K27me3 on the E-cadherin promoter region. Moreover, MRPL23-AS1 levels were higher in exosomes isolated from the blood plasma of SACC patients, and exosomal MRPL23-AS1 affected pulmonary microvascular endothelial cells in an 'exosomecrine' manner. MRPL23-AS1-enriched exosomes increased microvascular permeability and facilitated the metastasis of SACC in vivo. Collectively, our findings showed a molecular mechanism of lung metastasis in SACC, and MRPL23-AS1 may represent a biomarker and target for clinical interventions to control this intractable disease.