ABSTRACT
Objective To investigate the expression and role of roundabout guidance receptor 1 (Robo1) in the neuronal differentiation of neural stem cells (NSCs) induced by valproate (VPA). Methods The hippocampus NSCs of SD rats were isolated and cultured. Normal NSCs and VPA-treated NSCs were extracted from 10 SD rats. After VPA treatment, the proportion of neuron-specific marker β-tubulin III (Tuj1) positive neurons differentiated from NSCs were detected by immunofluorescence. The differentially expressed mRNA in normal NSCs and VPA-induced NSCs were detected by gene chip technology. After VPA treatment, the expression levels of Robo1 mRNA and protein were detected by Real-time PCR and Western blotting. The dynamic changes of Robo1 mRNA were detected by Real-time PCR after the differentiation of NSCs. After the expression of Robo1 was down-regulated in NSCs by small interfering RNA, the expression of Robo1 protein was detected by Western blotting, and the expression levels of neuron-specific markers Tuj1 and microtubule associated protein-2 (MAP-2) were detected by Real-time PCR and immunofluorescence. Results VPA induced NSCs to differentiate into neurons. Compared with the control group, the expression levels of Robo1 mRNA and protein in the differentiation of NSCs were significantly up-regulated during valproate treatment. After interference of Robo1 expression, not only Robo1 upregulation was inhibited during the differentiation of NSCs induced by VPA, but also the proportion of NSCs differentiated into neurons decreased. Conclusion VPA may promote the differentiation of NSCs into neurons by up-regulating the expression of Robo1.
ABSTRACT
Background: Nasopharyngeal carcinoma (NPC) is a malignant tumor originating from the nasopharynx with high morbidity and mortality in Southeast Asia and south of China. Roundabout guidance receptor 1 (ROBO1) can regulate axonogenesis (axon-like protrusion), which may play an important role in migration. However, the roles of ROBO1 in NPC have not been clarified. Methods: A comparative analysis employing the NPC transcriptome (GSE12452) and the axonogenesis-related genes (GO: 0050772) was performed. In total, 124 tissue blocks from patients primarily diagnosed as NPC (1993-2002) were examined using immunohistochemical staining. The connections between clinicopathological variables and protein immunoexpression were analyzed by Pearson's chi-square test. The Kaplan-Meier method with a log-rank test was employed to plot survival curves. Multivariate analysis was performed using the Cox proportional hazards model to identify independent prognostic biomarker. Results: According to transcriptome analysis, we found that ROBO1 is significantly highly expressed in NPC tissues compared with normal tissues. The immunohistochemistry (IHC) staining showed that high expression of ROBO1 was significantly related to primary tumor (T1T2 and T3T4) (P = .024), nodal metastasis status (N0N1 and N2N3) (P = .030), stage (I-II and III-IV) (P = .019), and histological grade (keratinizing, non-keratinizing, and undifferentiated) (P = .065). Importantly, NPC patients with high ROBO1 expression had poorer disease-specific survival (DSS) (P = .0001), distal metastasis-free survival (DMeFS) (P < .0001), and local recurrence-free survival (LRFS) (P = .0001) compared with NPC patients with low ROBO1 expression through the uni-/multivariate and the Kaplan-Meier survival analyses. Conclusion: Our report indicates that ROBO1 might be a potential prognostic biomarker for NPC.
ABSTRACT
BACKGROUND: miR-152-3p functions as a tumour suppressor in the progression of hepatic tumorigenesis. Herein, we further discussed the prognostic significance and immune infiltration of miR-152-3p and its potential gene target in hepatocellular carcinoma (HCC). METHODS: The Cancer Genome Atlas (TCGA), Integrative Molecular Database of Hepatocellular Carcinoma (HCCDB), Human Protein Atlas (HPA) and Kaplan-Meier Plotter databases were used to evaluate miR-152-3p and roundabout guidance receptor 1 (ROBO1) expression, prognosis and immune infiltration. In vitro cell experiments, including cell proliferation and apoptosis, were evaluated using Cell Counting Kit 8 (CCK8) and terminal-deoxynucleotidyl transferase-mediated nick end labelling (TUNEL) assays. RESULTS: Up-regulation of ROBO1 functioned as an oncogene associated with poor prognosis, immune cell enrichment and cell proliferation in HCC. ROBO1 was significantly positively correlated with the enrichment of multiple immune cells and their biomarkers. Enrichment of type-2 T-helper (Th2) cells is an unfavourable biomarker of HCC prognosis. GSEA revealed that ROBO1 correlated with apoptosis, mitosis and carcinogenic signalling pathways. Suppression of cell proliferation and the enhancement of cell apoptosis by miR-152-3p mimics were counteracted by overexpression of ROBO1 in HCC cells. CONCLUSION: ROBO1 expression is positively correlated with multiple immune checkpoint molecules, suggesting that ROBO1 may be a potential drug target to enhance the potency of immunotherapy. The miR-152-3p/ROBO1 signalling axis contributes to malignant progression and provides a prospective immunotherapeutic target for HCC.
