Mutant p53 promotes cell spreading and migration via ARHGAP44

Area of Science:

• Oncology
• Molecular Biology
• Cell Biology

Background:

• The tumor suppressor p53 protein is frequently lost or mutated in human cancers.
• Loss or mutation of p53 impacts cancer cell motility, including spreading, migration, and invasion.
• Mutant p53 can gain novel functions that promote cancer progression.

Purpose of the Study:

• To investigate the mechanisms by which mutant p53 enhances cancer cell spreading and migration.
• To identify novel molecular targets regulated by mutant p53 that influence cell motility.

Main Methods:

• RNA-sequencing (RNA-Seq) to identify differentially expressed genes.
• Analysis of Rho GTPase activating protein 44 (ARHGAP44) expression and function.
• Assays to measure cell spreading and migration.
• Bioinformatics analysis and RT-qPCR validation of ARHGAP44 expression in patient tumor samples.

Main Results:

• Mutant p53 significantly increased cell spreading and migration compared to p53-null cells.
• ARHGAP44 was identified as a novel transcriptional target suppressed by mutant p53.
• Elevated GTP-bound Cdc42 levels correlated with increased mutant p53 and decreased ARHGAP44.
• Wild-type ARHGAP44, but not a mutant form, suppressed mutant p53-driven cell spreading and migration.
• ARHGAP44 expression was lower in lung carcinoma tissues, particularly in tumors with mutant p53.

Conclusions:

• Mutant p53 promotes cancer cell spreading and migration through the suppression of ARHGAP44.
• ARHGAP44 acts as a tumor suppressor by inhibiting Cdc42 activity and reducing cell motility.
• This study reveals a new molecular mechanism linking mutant p53 to enhanced cancer cell invasion and suggests ARHGAP44 as a potential therapeutic target.