Anti-tumor agent that binds wild-type p53 (Kd = 1.5 nM) preventing p53-MDM2 (HDM2) interaction. Induces p53 accumulation and stimulates apoptosis in tumor cell lines expressing wild-type p53 in vitro and in vivo. Inhibits HPV-E6-mediated proteasomal degradation. Suppresses expression of cervical carcinoma HeLa xenografts in vivo.