Down-regulation of C-terminal binding protein 2 (CtBP2) inhibits proliferation, migration, and invasion of human SHSY5Y cells in vitro

C-Terminal Binding Proteins Promote Neurogenesis and Oligodendrogenesis in the Subventricular Zone

C-terminal binding proteins (CtBPs) are transcriptional modulators that can regulate gene expression through the recruitment of a corepressor complex composed of chromatin-modifying enzymes and transcriptional factors. In the brain, CtBPs have been described as regulators of cell proliferation, differentiation, and survival. Nevertheless, the role of CtBPs on postnatal neural stem cells (NSCs) fate is not known yet. Herein, we evaluate the expression and functions of CtBPs in postnatal NSCs from the subventricular zone (SVZ). We found that CtBPs were expressed in immature/progenitor cells, neurons and glial cells in the SVZ niche. Using the CtBPs modulator 4-methylthio 2-oxobutyric acid (MTOB), our results showed that 1 mM of MTOB induced cell death, while 5, 25, and 50 μM increased the number of proliferating neuroblasts, mature neurons, and oligodendrocytes. Interestingly, it also increased the dendritic complexity of immature neurons. Altogether, our results highlight CtBPs putative application for brain regenerative applications.

CtBP2 interacts with ZBTB18 to promote malignancy of glioblastoma

OBJECTIVE

To investigate how the interaction of CtBP2 with ZBTB18 affect glioblastoma (GBM).

METHODS

Western blotting was performed to detect CtBP2 and ZBTB18 expression in GBM and normal brain tissues (NBT). U-87 MG cells were transfected with ZBTB18 CRISPR activation plasmid, CtBP2 shRNA with/without ZBTB18 shRNA. The biological characteristics were detected by EdU assay, MTT, Wound-healing, Transwell, TUNEL staining, and Flow cytometry. Furthermore, U-87 MG cells transfected with CtBP2 shRNA and/or ZBTB18 shRNA were injected into the flank region of mice and the tumor volume was measured. The mRNA and protein expression was quantified by qRT-PCR or Western blotting.

RESULTS

GBM tissues exhibited increased CtBP2 expression and decreased ZBTB18 expression, which demonstrated a negative correlation in GBM tissues and showed the combined effect on prognosis. Based on immunoprecipitation and immunofluorescence, there was an interaction between CtBP2 and ZBTB18 in U-87 MG cells. CtBP2 shRNA counteracted the effect of ZBTB18 shRNA on inhibiting U-87 MG cell apoptosis, as well as promoting cell proliferation and viability with increased EMT, invasion and migration. Meanwhile, CtBP2 shRNA interact with ZBTB18 to block cells at phase G0/G1 and suppress SHH-GLI1 pathway. CtBP2 shRNA decreased tumor volume, increase ZBTB18 expression in tumor tissues, and inhibit SHH-GLI1 pathway in mice, which could be reversed by ZBTB18 shRNA.

CONCLUSION

CtBP2 elevation and ZBTB18 down-regulation were found in GBM, both of which were associated with prognosis of GBM patients. CtBP2 interacted with ZBTB18 to affect biological characteristics of GBM cells, and the tumor growth, which may be related to the SHH-GLI1 pathway.

Brn4 promotes the differentiation of radial glial cells into neurons by inhibiting CtBP2

Neural stem cells (NSCs) are pluripotent cells that are capable of differentiating into neurons and considered as the most promising cell source for cell replacement therapy. However, the difficulty in inducing neuronal differentiation and maturation from NSCs is a major challenge for their clinical application. Clarifying the molecular mechanisms underlying the neuronal differentiation of NSCs can provide a basis for expanding their uses. Brain 4 (Brn4) is a member of the POU domain family of transcription factors and can induce the neuronal differentiation of NSCs, but its precise function in NSCs is unclear. To address this question, in this study we isolated and expanded radial glial cells (RGCs), a type of NSC, from the cerebral cortex of 14-day embryonic rats and used lentivirus carrying the human Brn4 gene to overexpress Brn4 in these cells. This induced the differentiation of RGCs into neurons and inhibited the expression of C-terminal binding protein 2 (CtBP2), a transcriptional co-repressor. CtBP2 overexpression in RGCs suppressed their differentiation into neurons, whereas CtBP2 knockdown had the opposite effect. These results indicated that Brn4 promoted the neuronal differentiation of NSCs via inhibition of CtBP2 and is a potential tool for generating neurons in cell replacement therapy of neurodegenerative diseases and brain injury.

LncRNA NEAT1 Regulates Cell Viability and Invasion in Esophageal Squamous Cell Carcinoma through the miR-129/CTBP2 Axis

Background

Long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) was reported to be aberrantly upregulated and promote esophageal squamous cell carcinoma (ESCC) cell progression. Nevertheless, the molecular mechanism of NEAT1 involved in the competing endogenous RNA (ceRNA) regulatory network in ESCC progression remains poorly defined.

Methods

The expressions of NEAT1, miR-129, and C-terminal-binding protein 2 (CTBP2) in ESCC cells were examined by qRT-PCR. The effects of NEAT1 knockdown and miR-129 overexpression, or along with CTBP2 upregulation, on ESCC cell viability and invasion were explored by CCK-8 and transwell invasion assays, respectively. Luciferase reporter assay in combination with RIP was performed to confirm the interaction between NEAT1, miR-129, and CTBP2.

Results

NEAT1 and CTBP2 were upregulated and miR-129 was downregulated in ESCC cells. Either NEAT1 knockdown or miR-129 overexpression suppressed ESCC cell viability and invasion. Moreover, NEAT1 functioned as an endogenous sponge to downregulate miR-129 by competitively binding to miR-129, thereby leading to the derepression of CTBP2, a target of miR-129. CTBP2 restoration overturned cell viability and invasion suppression mediated by NEAT1 knockdown or miR-129 overexpression.

Conclusion

LncRNA NEAT1 regulated ESCC cell viability and invasion via the miR-129/CTBP2 axis, contributing to the better understanding of the molecular mechanism of ESCC pathogenesis and progression.