Melatonin-induced ferroptosis in pancreatic cancer cells by stimulating endoplasmic reticulum stress and inhibiting alanine-serine-cysteine transporter 2-driven glutamine metabolism.

BACKGROUND: Pancreatic cancer, characterized by aggressive proliferation and metastasis, is a lethal malignancy. The nightly hormone melatonin serves as a rhythm-regulating hormone, and is used to treat different cancers including pancreatic cancer. AIM: To investigate how melatonin acts against human pancreatic cancer cell lines and analyze the biological processes that cause the observed effects. METHODS: Panc-1 and AsPC-1 cells were treated with melatonin. Cell viability was measured using the cell counting kit-8 assay. Western blotting and immunofluorescence were used to analyze protein expression levels. Ferroptosis was measured by analyzing lipid reactive oxygen species and malondialdehyde levels; apoptosis was assessed using flow cytometry. RESULTS: Melatonin significantly inhibited the viability, colony formation, migration, and invasion of Panc-1 and AsPC-1 cells. Additionally, melatonin activated the endoplasmic reticulum (ER) stress pathway (protein kinase R-like ER kinase-eukaryotic initiation factor 2α-activating transcription factor 4), inhibited glutamine metabolism (alanine-serine-cysteine transporter 2-glutaminase 1-glutathione peroxidase 4, alanine-serine-cysteine transporter 2-glutathione peroxidase 4), and promoted ferroptosis in pancreatic cancer cells. Co-treatment with a high melatonin concentration and protein kinase R-like ER kinase agonist (CCT020312) enhanced melatonin-induced ferroptosis in pancreatic cancer cells. Melatonin demonstrated a variety of anticancer effects by inhibiting autophagy. This was achieved through the increased expression of sequestosome-1 and decreased expression of light chain 3. Additionally, melatonin facilitated the promotion of apoptosis. CONCLUSION: Melatonin induces ferroptosis in pancreatic cancer cells by activating transcription factor 4-dependent ER stress and inhibiting glutamine metabolism, promotes apoptosis in pancreatic cancer cells, and inhibits autophagy, leading to synergistic anticancer effects.