Mechanical cues control mutant p53 stability through a mevalonate-RhoA axis

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Tumour-associated p53 missense mutants function as driver oncogenes, impacting cancer progression, metastasis, and drug resistance.
• Mutant p53 stabilization, crucial for gain-of-function, depends on secondary events, not intrinsic properties.
• Heterogeneous mutant p53 levels within tumors suggest complex regulatory mechanisms for local accumulation.

Purpose of the Study:

• To investigate cellular pathways protecting mutant p53 from proteolysis.
• To identify mechanisms controlling local mutant p53 accumulation in cancer cells.

Main Methods:

• Investigated cellular pathways involved in mutant p53 stabilization.
• Analyzed the role of HDAC6/Hsp90 in mutant p53 accumulation.
• Examined the influence of RhoA geranylgeranylation and mevalonate pathway on mutant p53.
• Studied the impact of mechanical inputs (extracellular environment stiffness) via RhoA and actin.

Main Results:

• Mutant p53 accumulation is sustained by HDAC6/Hsp90.
• RhoA geranylgeranylation, downstream of the mevalonate pathway, stabilizes mutant p53.
• Mechanical cues, transduced by RhoA and actin, also regulate mutant p53 levels.
• Identified a novel regulatory layer for mutant p53 involving metabolic and mechanical signals.

Conclusions:

• Mutant p53 stabilization is regulated by a combination of metabolic and mechanical factors.
• These findings provide new insights into the complex regulation of oncogenic p53 mutants.
• Understanding these pathways could offer novel therapeutic strategies targeting mutant p53-driven cancers.