Role of 6-Phosphofructo-2-Kinase/Fructose-2,6-Bisphosphatase-3 in Maintaining Redox Homeostasis and DNA Repair in Non-Small Cell Lung Cancers Under EGFR-Targeting Therapy

Abstract

The efficacy of FDA-approved tyrosine kinase inhibitors (TKIs) targeting EGFR is limited due to the persistence of drug-tolerant cell populations, leading to therapy resistance. Non-genetic mechanisms, such as metabolic rewiring, play a significant role in driving lung cancer cells into the drug-tolerant state, allowing them to persist under continuous drug treatment. This study aimed to investigate the impact of the glycolytic regulator 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB3) on the metabolic adaptivity of lung cancer cells to EGFR TKI therapies. Using two EGFR-driven non-small cell lung cancer cell lines, PC9 and HCC827, we analyzed metabolic changes in cells exposed to EGFR inhibitors and evaluated the effect of PFKFB3 inhibition on metabolic adaptations during TKI treatment. Our results indicate that PFKFB3-mediated glycolysis sustains ATP production upon TKI treatment. Metabolomics studies revealed that PFKFB3 inhibition in TKI-treated cells limits glucose utilization in glycolysis, TCA cycle, and polyol pathway. Additionally, we show that pharmacological inhibition of PFKFB3 overcomes TKI-driven redox capacity by diminishing the expression of glutathione peroxidase 4 (GPX4), which in turn, exacerbates oxidative stress. Our study also revealed that PFKFB3 contributes to DNA oxidation and damage by controlling the expression of DNA-glycosylases involved in base excision repair. In TKI-treated cells, PFKFB3 inhibition reduced ATM expression and limited DNA damage repair, increasing sensitivity to DNA integrity insults. In summary, our results suggest that inhibiting PFKFB3 can be an effective strategy to eradicate cancer cells surviving under EGFR-TKI therapy before they enter the drug-resistant state. STATEMENT OF IMPLICATIONTargeting PFKFB3 can improve the efficacy of EGFR-targeting TKIs by restricting non-genetic adaptations embraced by drug-tolerant cells.