FBX8 degrades GSTP1 through ubiquitination to suppress colorectal cancer progression

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• F-box only protein 8 (FBX8) is part of SCF E3 ubiquitin ligases and implicated in various cancers.
• The specific substrates targeted by FBX8 in colorectal carcinoma (CRC) progression remain largely uncharacterized.

Purpose of the Study:

• To investigate the role of FBX8 in CRC progression.
• To identify substrates of FBX8 involved in CRC pathogenesis.
• To explore the FBX8-GSTP1 axis as a potential therapeutic target and prognostic marker in CRC.

Main Methods:

• Utilized FBX8 knockout mice and chemical induction to study colon tumorigenesis.
• Investigated the direct targeting of GSTP1 by FBX8 using ubiquitin-mediated proteasome degradation assays.
• Analyzed GSTP1 expression and its correlation with FBX8 inactivation in clinical CRC tissues.

Main Results:

• Loss of FBX8 accelerated chemical-induced colon tumorigenesis.
• FBX8 directly targets Glutathione S-transferase P1 (GSTP1) for degradation.
• GSTP1 promotes CRC cell proliferation, invasion, and metastasis, and is upregulated in CRC tissues, correlating with poor prognosis.
• FBX8 inactivation correlated with increased GSTP1 levels and stability in clinical CRC samples and mouse models.

Conclusions:

• Identified a novel FBX8-GSTP1 ubiquitination pathway regulating CRC progression.
• FBX8-mediated degradation of GSTP1 suppresses CRC.
• The FBX8-GSTP1 axis represents a potential prognostic biomarker for colorectal carcinoma patients.