Abstract
Glioblastoma (GBM) has high mortality rates because of extremely therapeutic resistance. During surgical resection for GBM, 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence is conventionally applied to distinguish GBM. However, surgical intervention is insufficient for high invasive GBM. Sonodynamic therapy (SDT) is an emerging and promising approach combined with low-intensity ultrasonication (US) and PpIX as a sonosensitizer for cancer, whereas its efficacy is limited. Based on our previous study that down-regulation of multidrug resistant protein (MDR1) in GBM augmented anti-tumor effects of chemotherapy, we hypothesized that elevation of cellular PpIX levels by down-regulation of MDR1 enhances anti-tumor effects by SDT. In high invasive progeny cells from mouse glioma stem cells (GSCs) and a GSC-bearing mouse glioma model, we assessed the anti-tumor effects of SDT with a COX-2 inhibitor, celecoxib. Down-regulation of MDR1 by celecoxib increased cellular PpIX levels, as well as valspodar, a MDR1 inhibitor and augmented anti-tumor effects of SDT. MDR1 down-regulation via Akt/NF-kB pathway by celecoxib was confirmed, using a NF-kB inhibitor, CAPÉ. Thus, elevation of cellar PpIX by down-regulation of MDR1 via Akt/NF-kB pathway may be crucial to potentiate the efficacy of SDT in a site-directed manner and provide a promising new therapeutic strategy for GBM.
Double minute amplification of mutant PDGF receptor α in a mouse glioma model