The perivascular niche is critical for intercellular communication between resident cell types in glioblastoma (GBM), and it plays a vital role in maintaining the glioma stem cell (GSC) microenvironment. It is shown in abundant research that different microvascular patterns exist in GBM; and it can be implied that different microvascular patterns are associated with different pathological structures in the perivascular niche. However, the pathological structure of the perivascular niche is still not clear. Here, we investigated the distribution and biological characteristics of different microvascular pattern niches (MVPNs) in GBM by detecting the expression of CD34, CD133, Nestin, α-SMA, GFAP and CD14 in the perivascular niche using multiple -fluorescence. The four basic microvascular patterns are microvascular sprouting (MS), vascular cluster (VC), vascular garland (VG), and glomeruloid vascular proliferation (GVP). By analyzing the proportion of the area of each marker in four types of formations, the results indicated that the expression of CD34, CD133 and Nestin in MS and VC was significantly lower than that in VG and GVP (P<0.05). Furthermore, the results showed that α-SMA expression different in the MS, VC, VG and GVP (P<0.05). However, the expression of GFAP and CD14 in each type of formation exhibited no significant difference (P>0.05). According to the area distributions of different markers, we mapped four precise simulation diagrams to provide an effective foundation for the accurate simulation of glioblastoma in vitro.
Background
Failure of glioblastoma (GBM) therapy is often ascribed to different types of glioblastoma stem-like cells (GSLCs) niche, in particularly, a hypoxic perivascular niche (HPVN) is involved in GBM progression. However, the responsible cells for HPVN remained unclear.
Methods
Immunostaining was performed to determine the cells that are responsible for HPVN. A hypoxic chamber and 3D microfluidic chips were designed to simulate 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 q-PCR. Their clinical progonostic significance in GBM HPVN and total tumor tissues were verified by clinical data and TCGA databases.
Results
Nestin +/CD31 + cells and pericytes constitute the major part of microvessels in HPVN and high ratio of nestin +/CD31 + cells rather than pericytes were responsible for poor prognosis of GBM. A more real HPVN was simulated by hypoxic coculture system in vitro, which was assembled by 3D microfluidic chips and hypoxic chamber. Nestin +/CD31 + cells in HPVN were derived from GSLCs transdifferentiation and could promote GSLCs chemoresistance by providing more JAG1 and DLL4 to induce down-stream Hes1 overexpression. Poor prognosis of GBM was correlated to Hes1 expression of tumor cells in GBM HPVN, and not correlated with total Hes1 expression in GBM tissues.
Conclusion
These results hightlighted the critical role of nestin +/CD31 + cells in HPVN that acts in GBM chemoresistance and revealed the distinctive prognostic value of these molecular markers in HPVN.
Pituitary tumor transforming gene 1 (PTTG11) is abundantly expressed in glioma. Our previous study demonstrated that the downregulation of PTTG11 gene expression significantly inhibited the proliferation, migration and invasion ability, and increased the apoptosis of SHG44 glioma cells. However, the molecular mechanisms that regulate PTTG11 and its actions remain elusive. In the present study, CCK-8 and flow cytometry assays were used to assess the proliferation/viability and apoptosis, respectively, of the human glioma U251 cell line. STAT3-PTTG1 signals were further evaluated by western blotting. The findings of the present study revealed that STAT3 induced PTTG11 expression, which subsequently induced downstream c-Myc and Bcl-2 expression while inhibiting Bax expression, thereby promoting cell viability and inhibiting apoptosis. PTTG11 suppression via siRNA inhibited the viability and increased the apoptosis of glioma cells induced by the STAT3 activator S3I-201. c-Myc and Bcl-2 expression was suppressed by PTTG11 inhibition. The findings of the present study suggest that the STAT3-PTTG11 signaling pathway may play an important role in glioma progression by regulating cell proliferation and apoptosis.
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