Dataset Information

Tumor cell network integration in glioma represents a stemness feature.

ABSTRACT:

Background

Malignant gliomas including glioblastomas are characterized by a striking cellular heterogeneity, which includes a subpopulation of glioma cells that becomes highly resistant by integration into tumor microtube (TM)-connected multicellular networks.

Methods

A novel functional approach to detect, isolate, and characterize glioma cell subpopulations with respect to in vivo network integration is established, combining a dye staining method with intravital two-photon microscopy, Fluorescence-Activated Cell Sorting (FACS), molecular profiling, and gene reporter studies.

Results

Glioblastoma cells that are part of the TM-connected tumor network show activated neurodevelopmental and glioma progression gene expression pathways. Importantly, many of them revealed profiles indicative of increased cellular stemness, including high expression of nestin. TM-connected glioblastoma cells also had a higher potential for reinitiation of brain tumor growth. Long-term tracking of tumor cell nestin expression in vivo revealed a stronger TM network integration and higher radioresistance of the nestin-high subpopulation. Glioblastoma cells that were both nestin-high and network-integrated were particularly able to adapt to radiotherapy with increased TM formation.

Conclusion

Multiple stem-like features are strongly enriched in a fraction of network-integrated glioma cells, explaining their particular resilience.

SUBMITTER: Xie R

PROVIDER: S-EPMC8099480 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Diffuse intrinsic pontine glioma (DIPG), an infiltrative, high grade glioma (HGG) affecting young children, has the highest mortality rate of all pediatric cancers. Despite treatment, average survival is less than twelve months, and five-year survival under 5%. We previously detected increased expression of Tenascin-C (TNC) protein in DIPG cerebrospinal fluid and tumor tissue relative to normal specimens. TNC is an extracellular matrix (ECM) glycoprotein that mediates cell-matrix interactions, guides migrating neurons during normal brain development and is thought to maintain the periventricular stem cell niche in the developing brain. Tumor TNC expression is reported in adult glioma and other cancers. However, the pattern and effects of TNC expression in DIPG has not been previously explored. Here, we characterize TNC expression in patient derived pediatric supratentorial HGG (n = 3) and DIPG (n = 6) cell lines, as well as pediatric glioma tumor (n = 50) and normal brain tissue specimens (n = 3). We found tumor specific TNC gene and protein overexpression that directly correlated with higher tumor grade (WHO III and IV, p = 0.05), H3K27 M mutation (p = 0.012), shorter progression free survival (p = 0.034), and poorer overall survival (0.041) in association with these factors. TNC knockdown via lentiviral shRNA transfection of HGG (n = 1) and DIPG (n = 3) cell lines resulted in decreased cell proliferation, migration, and invasion in vitro (p < 0.01), while TNC cDNA transfection resulted in increased cell migration, invasion and proliferation (p < 0.01) as well as altered cell morphology in H3K27 M mutant DIPG lines. Whole transcriptome sequencing analysis (RNA-Seq) on DIPG (n = 3) and HGG (n = 2) cell lines after TNC cDNA, shRNA, and empty vector control transfection revealed the effects of TNC expression level on global gene expression profiles. Together, our findings reveal TNC expression in DIPG in association with H3K27 M mutation and VEGF signaling, and suggest that TNC may contribute to DIPG tumor phenotype, and serve as a clinically detectable biomarker for DIPG.