MicroRNA-330-3p functions as an oncogene in human esophageal cancer by targeting programmed cell death 4.

MicroRNAs comprise a family of small non-coding RNA molecules that have emerged as key post-transcriptional regulators of gene expression. Aberrant miRNA expression has been linked to various human tumors. This study was aimed to identify novel miRNAs involved in the carcinogenesis of esophageal squamous cell carcinoma (ESCC) and their potential functions. We performed miRNA microarray and found that miR-330-3p was highly expressed in ESCC tumor tissues. qRT-PCR further confirmed the result in other 35 pairs of ESCC tumor tissues and ESCC cell lines. Ectopic expression of miR-330-3p significantly promoted ESCC cell proliferation, survival, migration, invasion in vitro and stimulated tumor formation in nude mice. Knockdown of miR-330-3p leaded to the opposite effects. The luciferase assay confirmed that miR-330-3p directly interacted with the PDCD4 mRNA 3' un-translated region (UTR). Moreover, expression of PDCD4 was inversely associated with miR-330-3p in ESCC tissues. Silencing of PDCD4 significantly promoted cell growth, cell migration, invasion and inhibited cisplatin-induced apoptosis in ESCC cells. This study suggested that miR-330-3p might play an oncogenic role in the development of ESCC partially via suppression of PDCD4 expression.