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. In animal models, including xenografts, orthotopic and patient-derived models, the genetic or pharmacological inhibition of CYP51A1 enhances the effectiveness of JTC801 in suppressing pancreatic tumors. These findings demonstrate the key role of the CYP51A1-dependent lysosomal pathway in inhibiting alkaliptosis and highlight its potential as a targetable vulnerability in pancreatic cancer.

PDAC-PANC1 cell line analysis is reported in the current study MTBLS9283.
PDAC-SW1990 cell line analysis is reported in MTBLS9288.

碱死亡（alkaliptosis）是一种依赖pH的调节性细胞死亡方式，以溶酶体功能受损与致死性碱化为特征，有望成为癌症治疗的潜在靶点。本研究采用基于质谱的药物靶点筛选、转录组筛选及脂质代谢组学技术，探究碱死亡背后的代谢机制。研究发现，参与胆固醇合成的基因CYP51A1是胰腺癌细胞中碱死亡的关键抑制因子。诱导碱死亡可导致内质网胆固醇水平降低，随后激活固醇调节元件结合转录因子2（SREBF2）——一种负责调控胆固醇生物合成相关基因表达的转录因子。具体而言，SREBF2介导的CYP51A1上调可阻止溶酶体内胆固醇积累，进而引发依赖TMEM175的溶酶体质子外流，最终抑制碱死亡。在包括异种移植瘤模型、原位移植模型及患者来源模型在内的动物实验中，对CYP51A1进行遗传或药理学抑制，可增强JTC801抑制胰腺肿瘤的效果。本研究结果证实了CYP51A1依赖的溶酶体通路在抑制碱死亡中的关键作用，并凸显其作为胰腺癌可靶向治疗靶点的潜力。

本研究中PDAC-PANC1细胞系的分析数据收录于MTBLS9283；PDAC-SW1990细胞系的分析数据收录于MTBLS9288。