Abstract Expression and stability of the tumor suppressor runt-related transcription factor 3 (RUNX3) are regulated by histone deacetylase (HDAC). HDAC inhibition alters epigenetic and posttranslational stability of RUNX3, leading to tumor suppression. However, HDAC inhibitors can nonselectively alter global gene expression through chromatin remodeling. Thus, lactam-based HDAC inhibitors were screened to identify potent protein stabilizers ...