RESUMEN
Background: Notch receptors (Notch 1/2/3/4), the critical effectors of the Notch pathway, participate in the tumorigenesis and progression of many malignancies. However, the clinical roles of Notch receptors in primary glioblastoma (GBM) have not been fully elucidated. Methods: The genetic alteration-related prognostic values of Notch receptors were determined in the GBM dataset from The Cancer Genome Atlas (TCGA). Two GBM datasets from TCGA and Chinese Glioma Genome Atlas (CGGA) were used to explore the differential expression between Notch receptors and IDH mutation status, and GBM subtypes. The biological functions of Notch Receptors were explored by Gene Ontology and KEGG analysis. The expression and prognostic significance of Notch receptors were determined in the TCGA and CGGA datasets and further validated in a clinical GBM cohort by immunostaining. A Notch3-based nomogram/predictive risk model was constructed in the TCGA dataset and validated in the CGGA dataset. The model performance was evaluated by receiver operating curves, calibration curves, and decision curve analyses. The Notch3-related phenotypes were analyzed via CancerSEA and TIMER. The proliferative role of Notch3 in GBM was validated in U251/U87 glioma cells by Western blot and immunostaining. Results: Notch receptors with genetic alterations were associated with poor survival of GBM patients. Notch receptors were all upregulated in GBM of TCGA and CGGA databases and closely related to the regulation of transcription, protein-lysine N-methyltransferase activity, lysine N-methyltransferase activity, and focal adhesion. Notch receptors were associated with Classical, Mesenchymal, and Proneural subtypes. Notch1 and Notch3 were closely correlated with IDH mutation status and G-CIMP subtype. Notch receptors displayed the differential expression at the protein level and Notch3 showed a prognostic significance in a clinical GBM cohort. Notch3 presented an independent prognostic role for primary GBM (IDH1 mutant/wildtype). A Notch3-based predictive risk model presented favorable accuracy, reliability, and net benefits for predicting the survival of GBM patients (IDH1 mutant/wildtype and IDH1 wildtype). Notch3 was closely related to immune infiltration (macrophages, CD4+ T cells, and dendritic cells) and tumor proliferation. Conclusion: Notch3-based nomogram served as a practical tool for anticipating the survival of GBM patients, which was related to immune-cell infiltration and tumor proliferation.
RESUMEN
BACKGROUND: Failure of glioblastoma (GBM) therapy is often ascribed to different types of glioblastoma stem-like cell (GSLC) niche; in particular, a hypoxic perivascular niche (HPVN) is involved in GBM progression. However, the cells responsible for HPVNs remain unclear. METHODS: Immunostaining was performed to determine the cells involved in HPVNs. A hypoxic chamber and 3-dimensional (3D) microfluidic chips were designed to simulate a HPVN based on the pathological features of GBM. The phenotype of GSLCs was evaluated by fluorescence scanning in real time and proliferation and apoptotic assays. The expression of JAG1, DLL4, and Hes1 was determined by immunostaining, ELISA, Western blotting, and quantitative PCR. Their clinical prognostic significance in GBM HPVNs and total tumor tissues were verified by clinical data and The Cancer Genome Atlas databases. RESULTS: Nestin+/CD31+ cells and pericytes constitute the major part of microvessels in the HPVN, and the high ratio of nestin+/CD31+ cells rather than pericytes are responsible for the poor prognosis of GBM. A more real HPVN was simulated by a hypoxic coculture system in vitro, which consisted of 3D microfluidic chips and a hypoxic chamber. Nestin+/CD31+ cells in the HPVN were derived from GSLC transdifferentiation and promoted GSLC chemoresistance by providing more JAG1 and DLL4 to induce downstream Hes1 overexpression. Poor GBM prognosis correlated with Hes1 expression of tumor cells in the GBM HPVN, and not with total Hes1 expression in GBM tissues. CONCLUSIONS: These results highlight the critical role of nestin+/CD31+ cells in HPVNs that acts in GBM chemoresistance and reveal the distinctive prognostic value of these molecular markers in HPVNs.
