CYP51A1-mediated alkaliptosis resistance is a targetable vulnerability in pancreatic cancer

Alkaliptosis, a pH-dependent form of regulated cell death characterized by impaired lysosomal function and lethal alkalinization, holds promise as a target for cancer therapy. Here, we utilize mass spectrometry-based drug target, transcriptomic screens, and lipid metabolomics to explore the metabolic mechanisms underlying alkaliptosis. We reveal CYP51A1, a gene involved in cholesterol synthesis, as a key suppressor of alkaliptosis in pancreatic cancer cells. Inducing alkaliptosis leads to a decrease in endoplasmic reticulum cholesterol levels, subsequently activating SREBF2, a transcription factor responsible for controlling the expression of genes involved in cholesterol biosynthesis. Specifically, SREBF2-driven upregulation of CYP51A1 prevents cholesterol accumulation within lysosomes, leading to TMEM175-dependent lysosomal proton efflux, ultimately resulting in the inhibition of alkaliptosis. PDAC-SW1990 cell line analysis is reported in the current study MTBLS9288. PDAC-PANC1 cell line analysis is reported in MTBLS9283.