Ras transformation requires metabolic control by 6-phosphofructo-2-kinase

Area of Science:

• Biochemistry
• Oncology
• Cell Biology

Background:

• Neoplastic cells exhibit high glucose uptake to fuel anabolic processes and energy production in tumors.
• The ras signaling pathway, frequently activated in cancers, promotes increased glycolytic flux towards lactate production.
• Glycolysis regulation by ras involves 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases (PFK2/FBPase), which control fructose-2,6-bisphosphate (F2,6BP) levels.

Purpose of the Study:

• To investigate the paradoxical decrease in intracellular F2,6BP concentration in ras-transformed cells.
• To determine if PFKFB3 gene deletion impacts F2,6BP production, glycolysis, and tumor growth.
• To evaluate PFKFB3 as a potential therapeutic target for cancer treatment.

Main Methods:

• Sequential immortalization and ras-transformation of mouse fibroblasts and human bronchial epithelial cells.
• Analysis of intracellular F2,6BP concentration and sensitivity to PFK2/FBPase inhibition.
• Heterozygotic genomic deletion of the PFKFB3 gene in ras-transformed mouse lung fibroblasts.
• Assessment of F2,6BP production, glycolytic flux to lactate, and tumor growth in vivo.

Main Results:

• Ras-transformation paradoxically decreased intracellular F2,6BP levels, sensitizing cells to PFK2/FBPase inhibition.
• Genetic deletion of PFKFB3 in ras-transformed cells suppressed F2,6BP production and glycolytic flux.
• PFKFB3 deletion inhibited soft agar colony formation and tumor growth in athymic mice.

Conclusions:

• PFKFB3 acts as a critical downstream mediator of oncogenic ras signaling.
• Pharmacologic inhibition of PFKFB3 could selectively target cancer cell glycolysis and growth.
• PFKFB3 represents a promising therapeutic target for cancers driven by ras activation.