Liu Zhi-Biao,Tang Chen,Jin Xin,Liu Shou-Hou,Pi Wen
BACKGROUND: Small nucleolar RNA host gene 12 (SNHG12) has been shown to be a long noncoding RNA (lncRNA) that facilitates the progression of a number of malignancies. However, the expression pattern and biological function of SNHG12 in nasopharyngeal carcinoma (NPC) have not been investigated. OBJECTIVE: The aim of our study is to investigate the expression, clinical significance and function of SNHG12 in NPC. METHODS: RT-PCR was used to detect the expression of SNHG12 in NPC cell lines and primary tumor tissues. The correlation of SNHG12 with clinicopathological features and patient prognosis was analyzed. The biologic functions of SNHG12 in NPC were explored by MTT assay, colony formation assay, wound healing assays, transwell assay and flow cytometric analysis in vitro. The expression of EMT markers and Notch signal pathway markers were determined by western blotting. RESULTS: The expression levels of SNHG12 were up-regulated in both NPC tissues and cell lines. High SNHG12 expression was significantly associated with clinical stage, grade and poor prognosis. Multivariate analysis demonstrated that high lncRNA SNHG12 expression was an independent poor prognostic factor for NPC patients. Functionally, knockdown of SNHG12 suppressed NPC cells proliferation, migration and invasion. Mechanistic investigations showed that knockdown of SNHG12 suppressed the activation of EMT and Notch-1 signal pathway. CONCLUSIONS: Our data suggest that SNHG12 promotes the progression of NPC and is a potential therapeutic target for NPC intervention.
Cancer cell-derived extracellular vesicles (EVs) have extensive application in the formation of their environment, including metastasis. This study explored the ability of gastric cancer (GC) cell-derived EVs-mediated microRNA-129-5p/E2F transcription factor 7/mitogen-activated protein kinase/extracellular regulated protein kinase (miR-129-5p/E2F7/MAPK/ERK) axis to affect the peritoneal metastasis of GC by delivering lncRNA small nucleolar RNA host gene 12 (SNHG12). EV-derived lncRNA and SNHG12/miR-129-5p/E2F7 network were determined by bioinformatics analysis. The regulatory relationship among SNHG12, miR-129-5p, and E2F7 was verified using a combination of dual-luciferase reporter gene, RNA immunoprecipitation, and RNA pull-down assays. The SNHG12, miR-129-5p, and E2F7 expression was measured by RT-qPCR. After GC cell-derived EVs were isolated and co-cultured with human peritoneal mesothelial cells (HPMCs), the uptake of EVs by HPMCs was observed under laser scanning confocal microscopy. Cell viability and apoptosis were examined using cell counting kit-8 and flow cytometry, respectively. Western blot analysis was performed to measure the mesothelial–mesenchymal transition (MMT)-related protein expression. The pathological and morphological characteristics of metastatic tumors in nude mice were observed by hematoxylin–eosin staining. A high SNHG12 expression was correlated with the poor prognosis of patients with GC. GC-derived EVs led to increased HPMC apoptosis and MMT by transferring SNHG12, whereas the knockdown of SNHG12 annulled the aforementioned results. SNHG12 sponged miR-129-5p to boost E2F7 expression and activate the MAPK/ERK signaling, thus inducing HPMC apoptosis and MMT. In vivo experiments further verified that EVs derived from GC cells promoted peritoneal metastasis in nude mice. GC cell-derived EVs elevated the E2F7 expression and activated the MAPK/ERK signaling to promote peritoneal metastasis through the delivery of SNHG12.