V-ATPase is a candidate therapeutic target for Ewing sarcoma.

Area of Science:

• Oncology
• Cancer Metabolism
• Molecular Biology

Background:

• Cancer cells often exhibit altered metabolism, including enhanced glycolysis and proton production.
• Intracellular acidification is a risk in cancer, countered by proton pump activation.
• Ewing sarcoma (ES) has been linked to EWS-FLI1 and HIF-1α, but metabolic derangements are less understood.

Purpose of the Study:

• To investigate the role of metabolic pathways, specifically V-ATPase, in Ewing sarcoma survival and progression.
• To explore the link between glycolysis, proton production, and V-ATPase activity in ES cells.
• To evaluate V-ATPase as a potential therapeutic target in Ewing sarcoma.

Main Methods:

• Analysis of metabolic pathways in ES cells, including glycolysis and mitochondrial respiration.
• Assessment of lysosomal compartment size and sensitivity to V-ATPase inhibitors.
• Investigation of V-ATPase expression, localization, and activity in relation to acidification.
• In vitro studies on the effect of acidic extracellular pH on ES cell invasion and clonogenic efficiency.
• Treatment of ES cells with siRNA targeting V-ATPase and omeprazole.

Main Results:

• ES cells exhibit simultaneous mitochondrial respiration and high glycolysis.
• ES cells have poorly developed lysosomes but are sensitive to V-ATPase inhibitors.
• V-ATPase expression correlates with cellular acidification rates and is found on vacuolar and plasma membranes.
• Acidic extracellular pH promotes ES cell invasion and clonogenic potential.
• Targeting V-ATPase with siRNA or omeprazole significantly reduced ES tumor cell numbers.

Conclusions:

• Glycolytic activity and V-ATPase activation are critical for Ewing sarcoma cell survival.
• V-ATPase plays a key role in managing intracellular acidification in ES cells.
• V-ATPase represents a promising and selective therapeutic target for Ewing sarcoma treatment.