Aberrantly Activated APOBEC3B Is Associated With Mutant p53-Driven Refractory/Relapsed Diffuse Large B-Cell Lymphoma.

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• TP53 mutations are linked to poor prognosis in diffuse large B-cell lymphoma (DLBCL).
• The molecular mechanisms underlying this association, particularly the role of APOBEC3B, are not fully understood.
• APOBEC3B is implicated in TP53 G/C-to-A/T mutations in other cancers.

Purpose of the Study:

• To investigate the association between APOBEC3B expression and TP53 mutations in DLBCL.
• To determine the functional role of APOBEC3B in TP53 mutation induction and DLBCL progression.
• To explore APOBEC3B as a potential therapeutic target in relapsed/refractory DLBCL.

Main Methods:

• Comparative analysis of TP53 mutation frequency and APOBEC3B expression in relapsed/refractory (R/R) versus non-R/R DLBCL.
• In vitro experiments to assess APOBEC3B's ability to induce TP53 G/C-to-A/T mutations.
• Phenotypic analysis of DLBCL cells with APOBEC3B-induced p53 mutants.

Main Results:

• TP53 G/C-to-A/T mutation frequency was significantly higher in R/R DLBCL compared to non-R/R DLBCL.
• APOBEC3B expression levels positively correlated with the frequency of TP53 G/C-to-A/T mutations.
• APOBEC3B overexpression in vitro induced TP53 mutations, creating a DLBCL-like phenotype.
• APOBEC3B-induced p53 mutants enhanced DLBCL cell growth and drug resistance.

Conclusions:

• APOBEC3B is a key driver of TP53 mutations in R/R DLBCL.
• APOBEC3B-induced p53 mutants contribute to the aggressive phenotype and drug resistance in DLBCL.
• APOBEC3B represents a promising therapeutic target for R/R DLBCL.