Fig 1.
Kaplan-Meier plot of survival curve for all glioma patients according to EGFR expression.
(A) These data are based on the log-rank test (P-value<0.01). Data were obtained from the Repository for Molecular Brain Neoplasia Data (REMBRANDT) program of the National Cancer Institute.
Fig 2.
E-cigarette promotes EGFR activation in glioma stem cells (GSCs).
(A) Western Blot analysis of pEGFR, EGFR, pERK and ERK in GSCs (CSC2 cells) treated with e-liquid or its vehicle. β-actin was used as a loading. (B) Cell viability assays of GBM patient-derived cells compared with control and e-liquid treatment concentrations of CSC2 (P-value<0.05). (C) Western Blot analysis of pEGFR, EGFR, pERK and ERK in human astrocytes treated with e-liquid or its vehicle. β-actin was used as a loading. (D) Limiting dilution assay of GBM patient-derived cell (CSC2 cells) treated with e-liquid or its vehicle. (P-value<0.01).
Fig 3.
E-liquid activates EGFR signaling and it influenced on growth of brain tumor cell by downstream of pERK in the orthotopic xenograft mouse model.
(A) Magnetic Resonance Imaging (MRI) after 21 days of brain injection with CSC2 cells and treated by vehicle treatment (n = 3, 5×104 cells injected in each mouse) and e-liquid treatment (n = 3, 5×104 cells injected in each mouse). (B) Hematoxylin and eosin (H&E) staining of the whole brain. Histopathology of Balb-c/nude mouse brain, orthotopically injected with 5×104 CSC2 cells and treated by e-liquid and vehicle treatment. H&E staining of the whole brain (Upper panel). Immunohistochemical (IHC) stainning analysis of pEGFR in the orthotopic xenograft mouse model (Bottom panel).; all images were taken at 40x magnification. Scale bar, 100 μm (C) Immunofluorochemistry (IFC) staining Histopathology of Balb-c/nude mouse brain, orthotopically injected with 5×104 CSC2 cells and treated by vehicle treatment (left) or E-liquid treatment (right). Upper panel is merge of brain. pERK (middle) DAPI (bottom); all images were taken at 40x magnification, Scale bar, 100 μm (D) pERK positive cell counted percentage of CSC2 cells injected in brain orthotopic mouse model tissues treated with e-liquid or vehicle (P-value<0.01).
Fig 4.
(A) Kaplan–Meier survival graph shows e-liquid group had poor prognosis compared to the vehicle group (P-value<0.05). Kaplan–Meier survival graph of mice implanted with CSC2 cells and treated by vehicle treatment (n = 4, 5×104 cells injected in each mouse). And e-liquid treatment (n = 4, 5×104 cells injected in each mouse).