Figure 8. SPRY2 overexpression reverses the effect of harmine on EGFR degradation and GBM-TIC self-renewal.

(A) GBM5-TICs were infected with control or SPRY2-expressing retrovirus and 48 hours later, the cells were analyzed by Western blotting. (B) Control or SPRY2-expressing GBM5-TICs were deprived of growth factors for 12 hours and then EGF was added in the presence of harmine for the indicated durations. EGFR in the cells was analyzed by Western blotting. (C) Twenty-four hours after retroviral infection of GBM5-TICs, the cells were incubated in the presence or absence of harmine for 3 days. Dissociated cells were plated in the absence of the drug, and the number of secondary spheres formed was counted. ***P ≤ 0.001.