Glycolytic cancer cells lacking 6-phosphogluconate dehydrogenase metabolize glucose to induce senescence

Area of Science:

• Biochemistry
• Cancer Biology
• Metabolic Pathways

Background:

• The pentose phosphate pathway (PPP) is crucial for cellular metabolism.
• Dysregulation of metabolic pathways, including the PPP, is implicated in cancer progression.
• Targeting specific enzymes in metabolic pathways offers potential therapeutic strategies for cancer treatment.

Purpose of the Study:

• To investigate the role of 6-phosphogluconate dehydrogenase (6PGD) in lung cancer cell growth.
• To determine if inhibiting 6PGD can be a viable strategy for treating lung cancer.
• To elucidate the underlying mechanisms by which 6PGD affects cancer cell proliferation.

Main Methods:

• Utilized knockdown techniques to reduce 6PGD expression in lung cancer cells.
• Assessed cell growth, senescence induction, and metabolic profiles (NADPH, ribose phosphate).
• Investigated the effect of bypassing the PPP using fructose and the impact of glucose-6-phosphate dehydrogenase (G6PD) knockdown.

Main Results:

• Knockdown of 6PGD induced senescence and inhibited lung cancer cell growth.
• NADPH and ribose phosphate production remained normal, indicating the effect was not due to a general oxidative PPP defect.
• Bypassing the PPP with fructose allowed proliferation, and G6PD knockdown rescued growth in 6PGD-deficient cells, suggesting accumulation of inhibitory metabolites.

Conclusions:

• 6PGD plays a critical role in lung cancer cell proliferation beyond its role in oxidative PPP metabolism.
• Inhibition of 6PGD leads to senescence and growth arrest, mediated by the accumulation of specific glucose metabolites.
• Targeting 6PGD represents a promising novel therapeutic strategy for glycolytic tumors, including lung cancer.