Research Paper Volume 15, Issue 6 pp 2208—2220

Figure 5. PCA inhibits glioma progression by suppressing GALNT2 expression. (A) Schematic illustration of GALNT2 inhibitor screening. RFP tagged GALNT2 plasmid was introduced into GSC1 GALNT2 knock out cells to establish GALNT2 re-expression cells. GSC1-GALNT2-RFP cells were treated with 10 μM of each FDA-approved drug candidate for 48 h, and then those cells were subjected to flow cytometry to screen GALNT2-specific inhibitors according to RFP intensity. (B) PCA treatment inhibits GALNT2 expression in GSC. (C) PCA treatment preferentially eliminates GSC, but does not impair non-GSC. (D) PCA treatment inhibits GSC oncosphere formation rate. Scale bar: 500 μm. GSC1 cells were treated with 6 mM PCA or DMSO for 48 h. (E) Quantification data of (D). (F) PCA treatment inhibits GSC self-renewal determined by in vitro limiting dilution assay. GSC1 cells were treated with 6 mM PCA or DMSO for 48 h. (G) PCA treatment suppresses GBM patient derived xenograft growth. Mice were intravenously injected with 10 mg/kg PCA or 5 % DMSO after 2 weeks of GSC1 cells were administrated into mice. n=5. (H) A total of 1.5 × 10⁵ GSC1 cells with or without depletion of GALNT2 were intracranially injected into NOD/NSG mice. Mice were injected with or without 10 mg/kg PCA every day for 8 days after administration of GSC1 cells in situ. Mice’s survival time was recorded and presented with Kaplan-Meier survival curves. (I) Working model of GALNT2 in sustaining GSCs. STAT3 transcriptionally activates GALNT2 expression in glioma stem cells, which then binds to and stabilizes CD44 and leads to glioma malignant development. TSS indicates transcription start site. n=8. *** p < 0.001.