PRIMA-1MET restores wild-type conformation and function to mutant p53, and triggers apoptosis in tumor cells. PRIMA-1MET also targets the selenoprotein thioredoxin reductase 1 (TrxR1), a key regulator of cellular redox balance.

p53 activator^[1]
TrxR1 inhibitor^[1]

APR-246 inhibits both recombinant TrxR1 in vitro and TrxR1 in cells. Cellular TrxR1 activity is inhibited by APR-246 irrespective of p53 status. APR-246 can directly affect cellular redox status via targeting of TrxR1. Several small molecules have been shown to restore wild-type activity to mutant p53, including CP-31398, PRIMA-1 and APR-246 (PRIMA-1MET), MIRA, STIMA, PhiKan-083 and NSC319726. PRIMA-1 and its methylated analog APR-246 promote correct folding of mutant p53, induce cell death by apoptosis, and inhibit tumor growth in mice. APR-246 has also been shown to reactivate mutant forms of the p63 and p73 proteins that share high structural homology with p53^[1]. PRIMA-1MET is a powerful apoptosis-inducing agent. PRIMA-1MET can enhance apoptosis in mutant p53 carrying cells, compared to the p53 null parental cells. Most p53 mutants are in complex with Hsp70 proteins. PRIMA-1MET treatment increases Hsp70 expression and nucleolar translocation, in parallel with the induction of nucleolar accumulation of mutant p53. Several lines of evidence suggest that PRIMA-1MET can also act independently of the p53 status of the cell. It can radiosensitize prostate carcinoma cell lines with mutant or wild type p53 and p53^-/- cells as well. Introduction of mutant p53 (p53ser249 or p53gln248) into p53^-/- hepatocarcinoma cells increases sensitivity to PRIMA-1MET without the induction of p53 target genes. PRIMA-1MET regularly induces apoptosis in mutant p53 expressing cells^[2].

• [1]. Peng X, et al. APR-246/PRIMA-1MET inhibits thioredoxin reductase 1 and converts the enzyme to a dedicated NADPH oxidase. Cell Death Dis. 2013 Oct 24;4:e881.

  [2]. Stuber G, et al. PRIMA-1MET induces nucleolar translocation of Epstein-Barr virus-encoded EBNA-5 protein. Mol Cancer. 2009 Mar 26;8:23.