CPT1B maintains redox homeostasis and inhibits ferroptosis to induce gemcitabine resistance via the KEAP1/NRF2 axis in pancreatic cancer.

ABSTRACT

BACKGROUND: Although we have made progress in treatment and have increased the 5-year survival by ≤30% in pancreatic cancer, chemotherapy resistance remains a major obstacle. However, whether reprogrammed lipid metabolism contributes to chemoresistance still needs to be further studied. METHODS: Gene expression was determined using Western blotting and quantitative reverse transcription polymerase chain reaction. Cell cloning formation assay, Cell Counting Kit-8, EdU assay, wound healing assay, transwell assay, and flow cytometry were used to detect apoptosis, cell proliferation capacity, migration capacity, and cytotoxicity of gemcitabine. Confocal fluorescence microscopy, transmission electron microscopy, etc., were used to detect the changes in intracellular reactive oxygen species, glutathione, lipid peroxidation level, and cell morphology. An animal study was performed to evaluate the effect of CPT1B knockdown on tumor growth and gemcitabine efficacy. RESULTS: In our study, we observed that the CPT1B expression level was higher in pancreatic ductal adenocarcinoma tissues than in normal tissues and correlated with a low rate of survival. Moreover, silencing of CPT1B significantly suppressed the proliferative ability and metastasis of pancreatic cancer cells. Furthermore, we discovered that CPT1B interacts with Kelch-like ECH-associated protein 1, and CPT1B knockdown led to decreased NRF2 expression and ferroptosis induction. In addition, CPT1B expression increased after gemcitabine treatment, and it was highly expressed in gemcitabine-resistant pancreatic ductal adenocarcinoma cells. Finally, we discovered that ferroptosis induced by CPT1B knockdown enhanced the gemcitabine toxicity in pancreatic ductal adenocarcinoma. CONCLUSION: CPT1B may act as a promising target in treating patients with gemcitabine-resistant pancreatic ductal adenocarcinoma .