HIF1A and glioblastoma: In human glioblastoma U-87 MG cells, the S1 domain of integrin αvβ3 specifically recognizes T3 and activates the phosphatidylinositol-3-hydroxykinase (PI3K) signaling pathway through Src kinase, mediating downstream cytoplasmic THR shuttling to the nucleus and inducing the expression of the hypoxia-inducible factor 1-alpha (HIF-1α) (Figure 2).