PRIMA-1MET induces nucleolar accumulation of mutant p53 and PML nuclear body-associated proteins

Abstract

We have previously identified PRIMA-1, a low molecular weight compound that restores the transcriptional transactivation function to mutant p53 and induction of apoptosis. To explore the molecular mechanism for PRIMA-1-induced mutant p53-dependent apoptosis, we examined the intracellular distribution of mutant p53 upon treatment with PRIMA-1 MET by immunofluorescence staining. We found that PRIMA-1 MET induced nucleolar translocation of mutant p53 and the promyelocytic leukemia (PML) nuclear body-associated proteins PML, CBP and Hsp70. Levels of Hsp70 were significantly enhanced by PRIMA-1 MET treatment. PRIMA-Dead, a compound structurally related to PRIMA-1 but unable to induce mutant p53-dependent apoptosis, failed to induce nucleolar translocation of mutant p53. Our results suggest that redistribution of mutant p53 to nucleoli plays a role in PRIMA-1-induced apoptosis. Oncogene (2007) 26, 982-992.

PRIMA-1MET/APR-246 targets mutant forms of p53 family members p63 and p73

“…We have previously observed that PRIMA-1 and PRIMA-1 MET can induce redistribution of mutant p53 from the nucleoplasm to nucleoli, and that the PML-NB-associated proteins PML, CBP and Hsp70 also accumulate in nucleoli (Ro¨kaeus et al, 2007). PML is a transcription target of p53 and PML overexpression was shown to recruit p53 into PML-NBs and stabilize p53 (Fogal et al, 2000;de Stanchina et al, 2004).…”

“…We previously found that PRIMA-1 MET treatment causes a nucleolar accumulation of mutant p53, along with PML, CBP and Hsp70 (Ro¨kaeus et al, 2007).…”

“…PRIMA-1 has also been shown to trigger mutant p53-mediated transcription-independent apoptosis (Chipuk et al, 2003). Treatment with PRIMA-1 MET induces nucleolar accumulation of mutant p53 and the PML nuclear body (PML-NB) associated proteins PML, CBP and Hsp70, which probably has a role in PRIMA-1 MET -induced apoptosis (Ro¨kaeus et al, 2007). Recently, we demonstrated that PRIMA-1 and PRIMA-1 MET are converted to MQ, a Michael acceptor that binds covalently to the p53 core domain in vitro and in vivo and thus triggers mutant p53-dependent apoptosis (Lambert et al, 2009).…”

Reactivation of mutant p53: molecular mechanisms and therapeutic potential

“…Indeed, PRIMA-1 induces expression of heat-shock protein 90 (Hsp90) and enhances its binding to mutant p53, suggesting that Hsp90 mediates mutant p53 refolding (Rehman et al, 2005). Moreover, PRIMA-1MET triggers redistribution of mutant p53 to nucleoli, along with three other promyelocytic leukemia protein (PML) body-associated proteins, PML, cAMPresponsive binding protein (CBP) and heat-shock protein 70 (Hsp70) (Ro¨kaeus et al, 2006). PRIMADead, an inactive structural analog, failed to induce nucleolar redistribution of mutant p53 and other PML body-associated proteins, consistent with the notion that nucleolar translocation and perhaps interaction with Hsp70 and other PML body proteins plays a role in reactivation of mutant p53.…”

Mutant p53 reactivation by PRIMA-1MET induces multiple signaling pathways converging on apoptosis

“…earlier study showed that PRIMA-1 MET increases the level of HSP70, a chaperone involved in protein folding (Rokaeus et al, 2007), suggesting an increase in the unfolded protein fraction on PRIMA-1 MET treatment. Interestingly, XBP1 contains a putative p53 response element, consistent with the involvement of p53 in ER stress (Ceribelli et al, 2006) and the upregulation of XBP1 by PRIMA-1 MET in this study.…”