2-2-bis(hydroxymethyl)-1-azabicyclo(2-2-2-)octan-3-one and Leukemia--Promyelocytic--Acute

Restoration of p53 function triggers cell death and eliminates tumors in vivo. Identification of p53-reactivating small molecules such as PRIMA-1 holds promise for effective new anticancer therapies. Here, we investigated the effects of small molecule PRIMA-1 on cell viability and expression of p53-regulated genes and proteins in the acute promyelocytic leukemia-derived NB4 cell line. Our results showed that PRIMA-1 had antileukemic properties in acute promyelocytic leukemia-derived NB4 cells. PRIMA-1-triggered apoptosis in a dose-dependent and time-dependent manner as indicated by the MTT assay and annexin-V staining. Apoptosis induction by PRIMA-1 was associated with caspase-9, caspase-7 activation and PARP cleavage. p21 protein expression was increased after PRIMA-1 treatment and real-time PCR analysis of proapoptotic p53 target genes indicated upregulation of Bax and Noxa. Western blot analysis showed that IκBα phosphorylation and its degradation were inhibited by PRIMA-1. Moreover, protein expression of nuclear factor-κB-regulated antiapoptotic (Bcl-2 and XIAP) and proliferative (c-Myc) gene products was decreased. Importantly, PRIMA-1 did not show any significant apoptotic effect in normal human peripheral blood mononuclear cells. These in-vitro studies imply that p53 reactivation by small compounds may become a novel anticancer therapy in acute promyelocytic leukemia.

Topics: Apoptosis; Aza Compounds; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Dose-Response Relationship, Drug; Down-Regulation; Humans; Leukemia, Promyelocytic, Acute; NF-kappa B; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-myc; Telomerase; Tumor Suppressor Protein p53; X-Linked Inhibitor of Apoptosis Protein