MiR-21 up-regulation mediates glioblastoma cancer stem cells apoptosis and proliferation by targeting FASLG

Abstract

To investigate whether miR-21 can affect the apoptosis and proliferation of glioblastoma cancer stem cells (GSCs) from down-regulating FASLG. The expression of miRNA-21 was detected by quantitative real-time PCR in normal brain tissue and glioblastoma samples, and the changes of miRNA-21 expression between GSCs and non-GSCs were also detected. The apoptosis and proliferation ability of miR-21 in GSCs were analyzed by MTT and flow cytometry assay after anti-miR-21 transfection. For the regulation mechanism analysis of miR-21, TargetScan, PicTar and microRNA were selected to predict some potential target genes of miR-21. The predicted gene was identified to be the direct and specific target gene of miR-21 by luciferase activities assay and western blot. RNA interference technology was used to confirm the apoptosis and proliferation effects of miR-21 were directly induced by FASLG. The expression of miR-21 increased significantly in glioblastoma contrast to normal brain tissue, and miR-21 up-regulated in GSCs remarkably. The proliferation of GSCs cell could be inhibited with high-expression of miR-21 and this effect could be restored by miR-21 knocked down. Mechanism analysis revealed that FASLG was a specific and direct target gene of miR-21. The advanced effects of anti-miR-21 on GSCs apoptosis and proliferation were mediated by expression of silenced FASLG. In summary, aberrantly expressed miR-21 regulates GSCs apoptosis and proliferation partly through directly down-regulating FASLG protein expression in GSCs and this might offer a new potential therapeutic stratagem for glioblastoma.

Differential regulation of miR-146a/FAS and miR-21/FASLG axes in autoimmune lymphoproliferative syndrome due to FAS mutation (ALPS-FAS)

“…MicroRNAs (miRNAs) belong to a class of small endogenous non-coding RNAs with $22nt that repress mRNA of protein-coding translation by base pairing of the target genes [4]. It has been shown that miRNAs regulate the expression of at least one-third of all human genes [5], and bioinformatics analyses estimate that more than 60% of human protein-coding genes maintain pairing to miRNAs with regulatory roles in cell proliferation, differentiation, apoptosis, pathogenesis of many human diseases and tumorigenesis [6][7][8][9][10][11]. The loss or dysregulation of certain individual miRNAs can have serious physiological consequences [12][13][14].…”

“…Similarly, miR-21 is involved strongly in apoptosis inhibition, with targets belonging to both its intrinsic and extrinsic pathways [18]. FAS ligand (FASLG) was shown to be a miR-21 target in FASLG-mediated apoptosis tumorigenesis cell lines [9,18]. The axis FASLG/miR-21 may also represent an important molecular mechanism in ALPS-FAS pathophysiology, as soluble FASLG is augmented in patients [19].…”

“…FASmediated apoptosis may have a role in the induction of peripheral tolerance and in the antigen-stimulated suicide of mature T cells [29]. As anti-apoptotic factors, miR-146a and miR-21 are able to suppress the expression of a large number of apoptosis-related genes [9,15,17,18].…”

“…The authors concluded that miR-21 regulates endogenous FASLG expression negatively [8,9]. In relation to the miR-21's passenger strand, it was observed that miR-21-3p down-regulates NAV3 (neuron navigator 3), a tumour suppressor, being associated with a worse prognosis in tumours [24].…”

MicroRNAs in glioblastoma multiforme pathogenesis and therapeutics

“…These effects are mediated in part by decreased repression of targets including HNRPK, TAP63 , and PDCD4 37, 44, 46. Further, miR‐21 can modulate the extrinsic apoptotic pathway through downregulation of FASL , an ability that has been particularly evident in cancer stem cells 47. Thus, miR‐21 has widespread effects on cell death pathways, making it a critical player in GBM pathogenesis and a promising target for therapeutic interventions.…”