Targeting TRAP1 as a downstream effector of BRAF cytoprotective pathway: a novel strategy for human BRAF-driven...

Area of Science:

• Molecular Biology
• Cancer Research
• Cellular Signaling

Background:

• Heat shock protein 90 (HSP90) chaperone TRAP1 is upregulated in human colorectal carcinomas (CRCs).
• TRAP1 contributes to cancer cell survival by inhibiting apoptosis.
• BRAF-driven CRCs exhibit poor response to conventional anticancer therapies.

Purpose of the Study:

• To investigate the relationship between TRAP1's regulation of the mitochondrial apoptotic pathway and BRAF's antiapoptotic signaling.
• To evaluate TRAP1 as a therapeutic target in BRAF-driven colorectal cancer.

Main Methods:

• TRAP1 silencing and inhibition experiments.
• Analysis of BRAF synthesis, ubiquitination, and ERK signaling.
• Assessment of TRAP1 serine-phosphorylation in response to BRAF activation.
• Drug sensitivity assays using a BRAF dominant-negative mutant and gamitrinib.

Main Results:

• TRAP1 silencing leads to BRAF downregulation, ERK signaling inhibition, and cell cycle arrest.
• BRAF signaling activates TRAP1 through enhanced serine-phosphorylation, conferring resistance to apoptosis.
• Targeting TRAP1 with gamitrinib induces apoptosis and inhibits colony formation in BRAF-driven CRC cells.

Conclusions:

• TRAP1 acts as a downstream effector of BRAF's cytoprotective signaling pathway within mitochondria.
• TRAP1 inhibition restores drug sensitivity in BRAFV600E CRC cells.
• Targeting TRAP1 represents a potential novel strategy to enhance proapoptotic agent efficacy in BRAF-driven CRCs.