Expression of vascular Notch ligands Delta-like 4 and Jagged-1 in glioblastoma

Area of Science:

• Neuro-oncology
• Cancer biology
• Molecular signaling

Background:

• Notch ligands Delta-like 4 (Dll4) and Jagged1 (Jag1) regulate endothelial sensitivity to vascular endothelial growth factor (VEGF).
• Dll4-Notch signaling may induce resistance to bevacizumab, an anti-VEGF therapy, while Jag1 might counteract Dll4-Notch signaling.
• Understanding Dll4 and Jag1 expression in glioblastomas is crucial for predicting treatment response.

Purpose of the Study:

• To characterize the expression patterns of Dll4 and Jag1 in primary glioblastomas.
• To investigate the relationship between Dll4 and Jag1 expression in glioblastoma vasculature.
• To explore the potential of Dll4 and Jag1 as biomarkers for anti-VEGF therapy response.

Main Methods:

• Immunohistochemistry was employed to assess Dll4 and Jag1 protein expression in 40 glioblastomas and normal brain tissue.
• In-situ hybridization was utilized for Dll4 mRNA expression analysis on serial sections.
• Validated antibodies were used for specific and reliable detection of Dll4 and Jag1.

Main Results:

• Dll4 was consistently expressed in the cytoplasm and membrane of endothelial cells in all glioblastomas, with minimal expression in normal brain.
• Jag1 expression was detected in 76% and 67% of glomeruloid and non-glomeruloid endothelial cells, respectively, but was less intense and prevalent than Dll4.
• No significant association was found between Dll4 and Jag1 expression levels in glioblastoma vasculature.

Conclusions:

• Dll4 and Jag1 are expressed in glioblastoma vasculature, indicating their potential roles in tumor angiogenesis.
• The distinct expression profiles of Dll4 and Jag1 may help stratify glioblastomas into bevacizumab-sensitive (Dll4(+) /Jag1(+)) or resistant (Dll4(+) /Jag1(-)) subsets.
• Experimental evaluation of anti-Dll4 therapy is recommended for glioblastoma treatment.