NR2C2-uORF targeting UCA1-miR-627-5p-NR2C2 feedback loop to regulate the malignant behaviors of glioma cells

Abstract

Accumulating evidence has highlighted the potential role of non-coding RNAs (ncRNAs) and upstream open-reading frames (uORFs) in the biological behaviors of glioblastoma. Here, we elucidated the function and possible molecular mechanisms of the effect of some ncRNAs and NR2C2-uORF on the biological behaviors of gliomas. Quantitative real-time PCR was conducted to profile the cell expression of lnc-UCA1 and microRNA-627-5p (miR-627-5p) in glioma tissues and cells. Western blot assay was used to determine the expression levels of NR2C2, SPOCK1, and NR2C2-uORF in glioma tissues and cells. Stable knockdown of lnc-UCA1 or overexpression of miR-627-5p in glioma cell lines (U87 and U251) were established to explore the function of lnc-UCA1 and miR-627-5p in glioma cells. Further, Dual luciferase report assay was used to investigate the correlation between lnc-UCA1 and miR-627-5p. Cell Counting Kit-8, transwell assays, and flow cytometry were used to investigate lnc-UCA1 and miR-627-5p function including cell proliferation, migration and invasion, and apoptosis, respectively. ChIP assays were used to ascertain the correlations between NR2C2 and SPOCK1 as well as NR2C2 between lnc-UCA1. This study confirmed that lnc-UCA1 was up-regulated in glioma tissues and cells. UCA1 knockdown inhibited the malignancies of glioma cells by reducing proliferation, migration, and invasion, but inducing apoptosis. We found that lnc-UCA1 acted as miR-627-5p sponge in a sequence-specific manner. Meanwhile, upregulated lnc-UCA1 inhibited miR-627-5p expression. In addition, miR-627-5p targeted 3′UTR of NR2C2 and down-regulated its expression. Moreover, UCA1 knockdown impaired NR2C2 expression by upregulating miR-627-5p. An uORF was identified in mRNA 5'UTR of NR2C2 and overexpression of whom negatively regulated NR2C2 expression. Remarkably, lnc-UCA1 knockdown combined with uORF overepression and NR2C2 knockdown led to severe tumor suppression in vivo. This study demonstrated that the NR2C2-uORF impaired the pivotal roles that UCA1-miR-627-5p-NR2C2 feedback loop had in regulating the malignancies of glioma cells by targeting NR2C2 directly. And this may provide a potential therapeutic strategy for treating glioma.

Crosstalk between the lncRNA UCA1 and microRNAs in cancer

“…UCA1 up-regulated the expression of transcription factor nuclear receptor subfamily 2 group C member 2 (NR2C2) to promote glioma proliferation and invasion by sponging miR-627-5p [53]. Furthermore, UCA1 promoted glioma cell proliferation and invasion by sponging miR-122, which is a tumor suppressor in many tumors [54].…”

Transcription factor AP‐4 (TFAP4)‐upstream ORF coding 66 aa inhibits the malignant behaviors of glioma cells by suppressing the TFAP4/long noncoding RNA 00520/microRNA‐520f‐3p feedback loop

“…36 Upstream ORF can reduce the expression of NR2C2 in glioma by inhibiting the translation of NR2C2 mRNA. 29 In this study, LASP1 was highly expressed in glioma tissues and in glioma cells. Knockdown of LASP1 significantly inhibited the malignant biologicals behavior of glioma cells.…”

“…The results clarify the role of TFAP4‐66aa‐uORF as a tumor suppressor gene in gliomas. A similar study identified NR2C2‐47aa‐uORF as a tumor suppressor gene in gliomas . Additionally, TFAP4 was highly expressed in glioma tissues and in U87 and U251 glioma cells, and knockdown of TFAP4 inhibited the malignant biological behavior of glioma cells.…”

“…A similar study found that the uORF could be used as a translational inhibitor of CEBPA mRNA . Upstream ORF can reduce the expression of NR2C2 in glioma by inhibiting the translation of NR2C2 mRNA …”

“…A similar study identified NR2C2-47aa-uORF as a tumor suppressor gene in gliomas. 29 Additionally, TFAP4 was highly expressed in glioma tissues and in U87 and U251 glioma cells, and knockdown of TFAP4 inhibited the malignant biological behavior of glioma cells. These results support the function of TFAP4 as an oncogene in gliomas.…”