Figure 1From: Growth factor receptor-Src-mediated suppression of GRK6 dysregulates CXCR4 signaling and promotes medulloblastoma migrationPDGFR activity is required for optimal CXCR4 signaling in SHH MB cells and GRK6 is downregulated and differentially expressed in MB. (A) Left panel: Daoy cells were starved and treated with or without 1 μg/ml anti-PDGFRβ blocking antibody for 24 h, then stimulated by 10 ng/ml PDGF-BB or 100 ng/ml CXCL12 (SDF-1α) for 15 min. Western blot of P-ERK shows PDGFR function is required for optimal CXCR4 signaling; Right panel: Quantitative analysis of Western blot shows CXCL12-induced P-ERK is significantly decreased by PDGFRβ blocking antibody (P < 0.05, lane 3, 1.53 ± 0.12 vs. lane 6, 1.09 ± 0.15, three independent experiments). (B) 29 human MB specimens were collected and used for microarray analysis. Average expression level of GRK6 mRNA is lowest among the detectable GRKs, (P < 0.01). (C) Microarray database of 9 human metastatic and 14 non-metastatic MB showed that the percentage of tumors with detectable GRK6 mRNA was notably decreased in metastatic MB (M+, 22%), compared to non-metastatic MB (M0, 43%). However, the percentage of tumors with detectable GRK5 mRNA was not appreciably different in M + (22%), vs. M0 (29%).Back to article page