Tumor suppressor WWOX moderates the mitochondrial respiratory complex

Area of Science:

• Genetics
• Molecular Biology
• Cancer Research

Background:

• The WWOX gene, located at fragile site FRA16D, is frequently downregulated in cancers.
• WWOX protein functions as a tumor suppressor through largely undefined mechanisms.
• WWOX is implicated in regulating cellular metabolism, including aerobic respiration and reactive oxygen species (ROS).

Purpose of the Study:

• To investigate the in vivo functional interactions between WWOX and metabolic pathways using a genetic model.
• To elucidate the mechanism by which WWOX suppresses tumor growth.

Main Methods:

• Utilized Drosophila melanogaster as an in vivo model system for genetic analysis.
• Examined the effects of altered WWOX levels on cellular outgrowths caused by deficiencies in mitochondrial respiratory complexes.
• Assessed the role of WWOX's enzyme active site, ROS, the Akt pathway, autophagy, and hypoxia-inducible factor.

Main Results:

• Altered WWOX levels modulated cellular outgrowths resulting from mitochondrial respiratory complex defects.
• The enzyme active site of WWOX was essential for this modulation.
• Defective respiratory complex-induced outgrowths were mediated by ROS and dependent on the Akt pathway, autophagy, and hypoxia-inducible factor.
• WWOX reduction impaired the cellular response to metabolic perturbations.

Conclusions:

• WWOX plays a critical role in maintaining metabolic homeostasis by balancing oxidative phosphorylation and glycolysis.
• WWOX facilitates cellular escape from mitochondrial damage-induced glycolysis (Warburg effect).
• This metabolic regulatory function is a plausible mechanism for WWOX's tumor suppressor activity.