RNF112 Facilitates Ubiquitin-Mediated Degradation of c-Myc, Suppressing Proliferation, Migration and Lipid Synthesis...

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Bladder cancer (BLCA) is a significant health concern with complex molecular underpinnings.
• The E3 ubiquitin ligase RNF112 is frequently downregulated in BLCA, suggesting a potential tumor-suppressive role.
• Understanding the molecular mechanisms of RNF112 in BLCA is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the role of RNF112 in suppressing bladder cancer progression.
• To elucidate the molecular mechanism by which RNF112 exerts its anti-tumor effects.
• To identify potential therapeutic targets within the RNF112-c-Myc signaling pathway.

Main Methods:

• In vitro and in vivo studies were conducted using bladder cancer cell lines and animal models.
• Co-immunoprecipitation assays were used to confirm the interaction between RNF112 and c-Myc.
• Ubiquitination assays and Western blotting were employed to assess c-Myc degradation.
• Quantitative real-time PCR and Western blotting were used to analyze the expression of c-Myc and ATP citrate lyase (ACLY).

Main Results:

• RNF112 expression is downregulated in bladder cancer and correlates with disease progression.
• RNF112 inhibits bladder cancer cell proliferation, migration, and lipid synthesis.
• RNF112 directly interacts with c-Myc, promoting its K48-linked polyubiquitination and subsequent degradation.
• c-Myc positively regulates the transcription of ACLY, a key enzyme in lipid metabolism.
• Restoring c-Myc or ACLY expression counteracted the inhibitory effects of RNF112.

Conclusions:

• RNF112 acts as a tumor suppressor in bladder cancer by targeting c-Myc for ubiquitin-mediated degradation.
• The RNF112-c-Myc-ACLY axis plays a critical role in regulating bladder cancer cell proliferation, migration, and lipid synthesis.
• RNF112 represents a promising therapeutic target for bladder cancer treatment.