Acridine derivatives activate p53 and induce tumor cell death through Bax

Area of Science:

• Molecular Biology
• Cancer Research
• Drug Discovery

Background:

• Wild-type p53 is a tumor suppressor protein.
• CP-31398 activates p53 through a unique mechanism.
• Developing novel p53 activators is crucial for cancer therapy.

Purpose of the Study:

• To synthesize and evaluate novel acridine derivatives as p53 activators.
• To elucidate the mechanism of p53 activation by acridine derivatives.
• To assess the anti-cancer potential of these compounds in vitro and in vivo.

Main Methods:

• Synthesis of four acridine derivatives structurally similar to CP-31398.
• Assessing p53 transcriptional activity and protein stabilization in cells.
• Investigating the role of ubiquitination and specific phosphorylation sites (ser15, ser20) in p53 activation.
• Evaluating p53-dependent cell death induction, including Bax knockout experiments.
• In vivo studies using tumor xenografts to assess p53 activation.

Main Results:

• Four synthesized acridine derivatives strongly induced p53 transcription in wild-type p53 cells.
• Several known acridine derivatives (9-aminoacridine, amsacrine, quinacrine, acridine orange) also induced p53 activity.
• Acridine derivatives stabilized p53 by inhibiting its ubiquitination, independent of ser15/ser20 phosphorylation.
• These compounds induced p53-dependent cell death, which was blocked by Bax knockout.
• In vivo administration of quinacrine and amsacrine activated p53 transcription in tumor xenografts.

Conclusions:

• DNA-intercalating acridine derivatives activate wild-type p53 via a novel mechanism involving p53 stabilization and inhibition of ubiquitination.
• Acridine derivatives induce p53-dependent apoptosis, highlighting their potential as anti-cancer agents.
• These findings provide insights into p53 regulation by DNA-intercalating drugs and inform future anti-cancer drug design.