PRIMA-1^MET cytotoxic effect correlates with p53 protein reduction in TP53-mutated chronic lymphocytic leukemia cells

Area of Science:

• Oncology
• Molecular Biology
• Hematology

Background:

• TP53 gene mutations are a critical negative prognostic factor in chronic lymphocytic leukemia (CLL).
• Current treatments like ibrutinib show limited efficacy in TP53-mutated CLL patients.
• Missense TP53 mutations, common in cancer, lead to high levels of non-functional p53 protein.

Purpose of the Study:

• To evaluate the therapeutic potential of PRIMA-1^MET, a molecule designed to restore wild-type (wt) p53 conformation, in TP53-mutated CLL.
• To assess the impact of PRIMA-1^MET on cell viability and apoptosis in clinical CLL samples with varying TP53 mutation and p53 protein statuses.

Main Methods:

• Tested PRIMA-1^MET (1-4 μM) on 62 clinical CLL samples with characterized TP53 mutations and p53 protein levels.
• Analyzed concentration-dependent effects on cell viability and apoptosis.
• Correlated PRIMA-1^MET's impact with TP53 mutation status and p53 protein stabilization.

Main Results:

• PRIMA-1^MET induced concentration-dependent viability decrease and apoptosis in most CLL samples, irrespective of TP53 mutation status or p53 protein stabilization.
• A subset of TP53-mutated CLL samples showed reduced mutated p53 protein levels upon PRIMA-1^MET treatment.
• This reduction in mutated p53 correlated with significantly enhanced cell death, indicating a potential mechanism of action.

Conclusions:

• PRIMA-1^MET demonstrates broad efficacy in CLL cells, inducing apoptosis and reducing viability.
• The drug's effectiveness is particularly pronounced when it successfully reduces mutated p53 protein levels.
• CLL cells with stabilized mutated p53 represent a resistant subset, highlighting a potential therapeutic challenge.