Real-time quantitative PCR (qRT-PCR)

Total RNA from tumor tissues and NPC cells was extracted using the RNA simple Total RNA Kit (TIANGEN, Beijing, China). The miRNAs from tumor tissues and NPC cells were extracted using the miRcute miRNA Isolation Kit (TIANGEN, Beijing, China). Reverse transcription of RBM3 and miR-383-5p was performed using the Fast-King gDNA Dispelling RT SuperMix and the miRcute Plus miRNA First-Strand cDNA Kit (TIANGEN, Beijing, China), according to the manufacturer’s instructions. All qPCR reactions were performed using either the SuperReal PreMix Plus (SYBR Green) or the miRcute Plus miRNA qPCR Kit (SYBR Green; TIANGEN). The primer sequence for RBM3 has been described previously (3): RBM35'-TGGGAGGGCTCAACTTTAAC-3'/5'-ATGCTCTGGGTTGGTGAAG-3'. Small nuclear U6 RNA was used as an internal control for the PCR reactions. Primers were purchased from TIANGEN and the miRNA-383-5p primer had the following sequence: AGAUCAGAAGGUGAUUGUGGCU. The relative miR-383-5p and RBM3 mRNA expression levels in paired tissues were analyzed using the comparative 2^−ΔΔCT method (15).