Decreased circular RNA hsa_circ_0001649 predicts unfavorable prognosis in glioma and exerts oncogenic properties in vitro and in vivo.

Glioma is a devastating disease with increasing incidence worldwide. Circular RNAs (circRNAs) was demonstrated to be involved in a wide range of pathophysiological processes, including tumorigenesis and development. Recently, the abnormally expressed hsa_circ_0001649 was found in several malignancies. In the current study, the expression levels of hsa_circ_0001649 in glioma and its clinical significance were explored. The biological functions including cell growth, colony-forming ability and apoptosis altered by hsa_circ_0001649 were further investigated in vitro. Tumor formation assay was also carried out to elucidate the oncogenic properties of hsa_circ_0001649. The data documented a decrease of hsa_circ_0001649 expression in glioma specimens and cell lines. In addition, down-regulated hsa_circ_0001649 is linked to larger tumor size (p = 0.002) and advanced WHO grade (p = 0.023). Additionally, hsa_circ_0001649 may be an independent prognostic marker for glioma patients after surgery (p = 0.046). Moreover, up-regulated hsa_circ_0001649 inhibits glioma cell growth in vitro and in vivo. Importantly, increased expression of hsa_circ_0001649 facilitates apoptosis by regulating Bcl-2/caspase-3 pathway. Ultimately, this study suggests that hsa_circ_0001649 may be a potential glioma-related prognostic/therapeutic target.