FBXO11 represses cellular response to hypoxia by destabilizing hypoxia-inducible factor-1α mRNA

Area of Science:

• Molecular Biology
• Cancer Research
• Epigenetics

Background:

• Hypoxia-inducible factor-1α (HIF-1α) is a key regulator of cancer progression and angiogenesis.
• Protein arginine methyltransferases (PRMTs) are enzymes involved in post-translational modification, influencing protein function.
• Previous research indicates PRMT1 and PRMT5 modulate HIF-1 signaling, but the roles of other isoforms like PRMT9 (FBXO11) and PRMT11 (FBXO10) are unclear.

Purpose of the Study:

• To investigate the involvement of FBXO10 and FBXO11 in the HIF-1 signaling pathway.
• To elucidate the mechanism by which FBXO11 affects HIF-1α expression and its implications in cancer.

Main Methods:

• Small interfering RNA (siRNA)-mediated knockdown of FBXO10 and FBXO11 in various cancer cell lines.
• Analysis of HIF-1α expression and HIF-1-driven gene expression following knockdown.
• Investigation of the role of the F-box domain of FBXO11 using a mutant lacking this domain.

Main Results:

• siRNA-mediated knockdown of FBXO11, but not FBXO10, significantly increased HIF-1α expression and HIF-1-driven gene expression.
• FBXO11 was found to inhibit the de novo synthesis of HIF-1α protein by destabilizing HIF-1α mRNA.
• A mutant FBXO11 lacking the F-box domain failed to reverse the effects of FBXO11 knockdown, suggesting ubiquitination-related mechanisms.

Conclusions:

• FBXO11 plays a critical role in regulating HIF-1α stability, likely through ubiquitination of proteins involved in mRNA stability.
• FBXO11 acts as a tumor suppressor by inhibiting oncogenic HIF-1α signaling.
• FBXO11 represents a potential therapeutic target for cancer treatment.