Our results indicated that the effect that NSC139021 arrested cell cycle in G0/G1 phase was time- and dose-dependent manner through regulating the Skp2-p27/p21-CyclinE/CDK2-pRb axis of G1/S checkpoint in glioblastoma cells and suggested that NSC139021 acted as a new potential inhibitor of Skp2 pathway and might be a chemotherapeutic drug in the treatment of GBM. Here, RB1 is linked to glioblastoma.