CDK5 and glioblastoma: LN229/EGFR GBM cells were treated with or without PI3K inhibitor LY290042, MEK inhibitor U0126, Src inhibitor SU6656, CDK5 inhibitor Roscovitine, c-Jun inhibitor SP600125, CaMKII inhibitor KN-93, PKC inhibitor GF109203X, GSK-3 inhibitor SB216763, or PKA inhibitor H-89 before EGF stimulation, respectively.