With this background in mind, we investigated NBCe1 protein abundance and NBCe1 transport activity in MES-like hypoxia-dependent GBM cells using 10 μM SB431542, an inhibitor of TGF-β type I receptor (ALK5) in addition to ALK4, and ALK7 [23]. The gene discussed is SLC4A4; the disease is glioblastoma.