The mutant p53-ID4 complex controls VEGFA isoforms by recruiting lncRNA MALAT1

Area of Science:

• Molecular Biology
• Cancer Research
• Genetics

Background:

• Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a long non-coding RNA (lncRNA), is linked to aggressive mammary carcinomas.
• MALAT1 localizes to nuclear speckles and influences splicing factor activity.

Purpose of the Study:

• To investigate the role of MALAT1 in breast cancer cells with mutant p53 and ID4.
• To elucidate the mechanism by which MALAT1 affects VEGFA isoform expression.

Main Methods:

• Investigated protein-RNA interactions using immunoprecipitation and chromatin association assays.
• Analyzed VEGFA pre-mRNA splicing and isoform expression.
• Correlated gene expression signatures with specific mutations in breast cancer subtypes.

Main Results:

• Oncogenic splicing factor SRSF1 bridges MALAT1 to mutant p53 and ID4.
• Mutant p53 and ID4 cause MALAT1 delocalization and chromatin association.
• MALAT1 is aberrantly recruited to VEGFA pre-mRNA, modulating its isoforms.
• VEGFA expression signatures associate with ID4 and TP53 mutations in basal-like breast cancer.

Conclusions:

• MALAT1 plays a critical role in controlling VEGFA isoform expression in breast cancer cells harboring mutant p53 and ID4.
• This interaction highlights a novel regulatory pathway in aggressive breast cancer phenotypes.