Another mdm2/mdm4 inhibitor, the RGD-M/sPMI peptide formulated in micelles, inhibited proliferation in vitro and induced cell cycle arrest and apoptosis in U87 glioma cells via a p53-dependent mechanism involving the transcription of its target genes p21 and mdm2; it also reduced tumor volume and weight in subcutaneous tumor-bearing mice. This evidence concerns the gene MDM2 and central nervous system cancer.