PRIMA-1 induces apoptosis by inhibiting JNK signaling but promoting the activation of Bax.
The p53 protein plays a major role in the maintenance of genome stability in mammalian cells. Mutations of p53 occur in over 40% of breast cancers and are indicative of tumor resistance to chemotherapeutic agents. Recently, there has been a high degree of interest in pharmacological approaches for restoring the normal function to mutant p53. The low molecular weight compound p53 reactivation and induction of massive apoptosis (PRIMA-1) was shown to induce cytotoxic effects and apoptosis in human tumor cells with mutant p53. Here, we studied the molecular mechanisms of PRIMA-1-induced apoptosis in human breast cancer cells with p53 mutations such as MDA-231 and GI-101A as compared to MCF-7 cells. We show that PRIMA-1 selectively induces apoptosis in human breast cancer cells MDA-231 and GI-101A compared to the MCF-7. This effect was paralleled by an increase in total p53 level in the nucleus and the induction of its phosphorylation at Ser-15 site. Using the chromatin immunoprecipitation (ChIP) assays, we show that PRIMA-1 restored p53 DNA binding activity to the promoters of the proapoptotic genes such as Bax and PUMA, but inhibited the binding activity to the promoters of the MAP4K4 gene. Knockdown of p53 protein in breast cancer cells using siRNA followed by PRIMA-1 treatment resulted in decline of Bax and PUMA proteins expression. Cell incubation with either PRIMA-1 or SP600125 (c-Jun NH2-terminal kinase inhibitor) resulted in the abrogation of adriamycin-induced c-Jun NH2-terminal kinase (JNK) activation, whereas Bax activation was not inhibited. We conclude that both Bax and PUMA but not JNK signaling are involved in PRIMA-1-induced apoptosis in breast cancer cells with p53 mutation.
Wang
Tao
T
Department of Pharmaceutical Sciences, Washington State University, Pullman, WA, USA.
Lee
Kyunghee
K
Rehman
Abdur
A
Daoud
Sayed S
SS
D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics; D001372:Aza Compounds / Q000494:pharmacology*; D001665:Binding Sites; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D045744:Cell Line, Tumor; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics; D015398:Signal Transduction; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism*
D051017:Apoptosis Regulatory Proteins; D001372:Aza Compounds; C438378:BBC3 protein, human; D019086:Bridged Bicyclo Compounds, Heterocyclic; D047908:Intracellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; C117090:MAP4K4 protein, human; D017346:Protein Serine-Threonine Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; C451219:2,2-bis(hydroxymethyl)-1-azabicyclo(2,2,2,)octan-3-one