LncRNA FOXD1-AS1 acts as a potential oncogenic biomarker in glioma

Altered activities of long noncoding RNAs (lncRNAs) have been associated with cancer development, and lncRNA FOXD1-AS1 (FOXD1-AS1) is the antisense transcript of the gene encoding for FOXD1, known for its role as an oncogene in several tumor types including glioma. However, the role of FOXD1-AS1 in the differentiation and progression of glioma is not well known.

Expression profile chip and qPCR were used to screen and identify FOXD1-AS1. Glioma cells were transfected with siRNA or eukaryotic expression vector to observe FOXD1-AS1 function in vitro and in vivo. Dual luciferase reporter gene analysis, Western blot, and ChIRP-MS were used to detect microRNAs and protein that combine with FOXD1-AS1.

FOXD1-AS1 was upregulated and directly correlated with the glioma grade, and it was localized in both the nucleus and the cytoplasm of the glioma cell. FOXD1-AS1 silencing caused tumor suppressive effects via inhibiting cell proliferation, migration, and apoptosis, while FOXD1-AS1 overexpression resulted in opposite effects. Additionally, in vivo experiments showed that FOXD1-AS1 knockdown reduced tumor volume and weight. More importantly, mechanical studies revealed that FOXD1-AS1 targeted both miR339-5p and miR342-3p (miR339/342). Furthermore, protein eukaryotic translation initiation factor 5 subunit A (eIF5a) resulted a direct target of FOXD1-AS1.

These data indicated that FOXD1-AS1, a miR339/342 target, affected biological processes via protein eIF5a; thus, it might be considered as a new therapeutic target for glioblastoma.