ABSTRACTTheTP53andPTENtumour suppressor genes are inactivated by nonsense mutations in a significant fraction of human tumours.TP53nonsense mutatant tumours account for approximately one million new cancer cases per year worldwide. We have screened chemical libraries with the aim of identifying compounds that induce translational readthrough and expression of full-length p53 protein in cells with nonsense mutation in this gene. Here we describe two novel compounds with readthrough activity, either alone or in combination with other known readthrough-promoting substances. Both compounds induced levels of full-length p53 in cells carrying R213X nonsense mutantTP53. Compound C47 showed synergy with the aminoglycoside antibiotic and known readthrough inducer G418, whereas compound C61 synergized with eukaryotic release factor 3 (eRF3) degraders CC−885 and CC−90009. C47 alone showed potent induction of full-length PTEN protein in cells with differentPTENnonsense mutations. These results may facilitate further development of novel targeted cancer therapy by pharmacological induction of translational readthrough.