Overexpression of FBXL14 inhibited GBM tumor growth and promoted animal survival. (A and B) In vivo bioluminescent imaging of GBM xenografts derived from luciferase-expressing GSCs transduced with FBXL14 or vector (VEC) control. GSCs (T387) were transduced with luciferase and Flag-FBXL14 or vector control and then transplanted into brains of immunocompromised mice (5 × 103 cells per animal). Mice bearing the intracranial xenografts were monitored after GSC transplantation. (A) Representative images at the indicated days are shown. (B) Luminescence quantification indicated that ectopic expression of FBXL14 significantly attenuated GSC tumor growth in mouse brains. Data are mean ± SD. n = 5. ***, P < 0.001. Student’s t test was used to assess the significance. Five mice per group were used. (C) Representative images of mouse brain sections from mice intracranially implanted with the GSCs transduced with Flag-FBXL14 or vector control. GSCs (T387) were transduced with Flag-FBXL14 or vector control through lentiviral infection for 48 h and then transplanted into mouse brains. Cross sections (hematoxylin and eosin stained) of the mouse brains harvested on day 21 after injection are shown. (D) Kaplan-Meier survival curves of mice intracranially implanted with the GSCs expressing Flag-FBXL14 or vector control. Ectopic expression of FBXL14 significantly increased survival of mice bearing the GSC-derived xenografts. Log-rank analysis was used. Five mice per group were used. (E) IB analysis of FBXL14 and c-Myc in GSCs (T387) transduced with inducible FBXL14 (pCW-Flag-FBXL14) and then treated with doxycycline (Dox) for 3 d. FBXL14 overexpression decreased c-Myc protein levels. Mass is shown in kilodaltons. Ctrl, control. (F) Growth curves of GSCs transduced with inducible FBXL14 expression and treated with doxycycline or control. Cells were measured for cell growth over a time course (day 0 to day 8). Overexpression of FBXL14 significantly inhibited the growth of GSCs. Data are mean ± SD. n = 3. Student’s t test was used to assess the significance. Data are from three independent experiments. (G and H) In vivo bioluminescent imaging of GBM xenografts derived from the luciferase-labeled GSCs transduced with inducible FBXL14 overexpression and treated with doxycycline or control. GSCs (T387) were transduced with inducible FBXL14 expression (pCW-Flag-FBXL14) and then transplanted into brains of immunocompromised mice (104 cells per animal). Mice bearing the intracranial xenografts were closely monitored. 7 d after GSC transplantation, mice were treated with 2 mg/ml doxycycline in drinking water to induce expression of FBXL14 in xenografts. (G) Representative images at the indicated days are shown. (H) Bioluminescence quantification indicated that induced overexpression of FBXL14 attenuated GSC tumor growth in mouse brains at day 21. Data are mean ± SD. n = 5. Student’s t test was used to assess the significance. Five mice per group were used. (I) Kaplan-Meier survival curves of mice intracranially implanted with the GSCs transduced with pCW-Flag-FBXL14 for 7 d and then treated with doxycycline or control. Induced expression of FBXL14 significantly increased survival of mice bearing the GSC-derived xenografts. Log-rank analysis was used. Five mice per group were used. *, P < 0.05; **, P < 0.01; ***, P < 0.001.
