The RN and their preradiation GBM tissues were serially processed for Western blotting using cell-type-specific antibodies against endothelial (CD31, active RhoA), pericyte [platelet-derived growth factor receptor-beta (PDGFR-β)], alpha-smooth muscle actin (α-SMA), astrocyte (GFAP), myelin sheath protein (MBP), and microglial markers (Iba1).
<i>Ex vivo</i> single-cell gene expression profiling of tumors by using CD31 and α-smooth muscle actin (αSMA) as markers for endothelial cells, and pericytes and vascular smooth muscle cells (VSMCs), respectively, confirmed the predominant expression of FN, EDA+FN and EDB+FN in the vascular compartment of glioblastoma.
In our study, we found that VM recognized by CD31-/PAS+ immunohistochemical staining in glioblastoma tissues showed a positive correlation with leptin expression (<i>r</i> = 0.58, <i>P</i> < 0.01), as well as ObR expression in glioblastoma tissues (<i>r</i> = 0.61, <i>P</i> < 0.01).
Furthermore, the liposomes made better modulation of glioblastoma microenvironment such as the down-regulation of CD31-positive tumor vessels and HIF-1α expression.
This observation was reproduced in vitro: when tumor stem cells derived from GBM were grown in the presence of human endothelial cells, a fraction of them acquired endothelial markers (CD31, CD105, VE-cadherin, and vWF).