Journal Article

Lysosome inhibition sensitizes pancreatic cancer to replication stress by aspartate depletion

Matsumura, Cynthia, Capri, Joseph R., Tucker, D. Andrew, Moore, Alexandra, Donahue, Timothy R., Ghukasyan, Razmik, Li, Luyi, Armstrong, Wesley R., Kim, Stephanie S., Cabebe, Anthony E., Kim, Woosuk, Dann, Amanda M., Poddar, Soumya, Elliott, Irmina A., Zhou, Lei, Radu, Caius G., Williams, Jennifer L., Wu, Nanping, Le, Thuc M., Abt, Evan R., Xu, Shili

2019

Overview

Functional lysosomes mediate autophagy and macropinocytosis for nutrient acquisition. Pancreatic ductal adenocarcinoma (PDAC) tumors exhibit high basal lysosomal activity, and inhibition of lysosome function suppresses PDAC cell proliferation and tumor growth. However, the codependencies induced by lysosomal inhibition in PDAC have not been systematically explored. We performed a comprehensive pharmacological inhibition screen of the protein kinome and found that replication stress response (RSR) inhibitors were synthetically lethal with chloroquine (CQ) in PDAC cells. CQ treatment reduced de novo nucleotide biosynthesis and induced replication stress. We found that CQ treatment caused mitochondrial dysfunction and depletion of aspartate, an essential precursor for de novo nucleotide synthesis, as an underlying mechanism. Supplementation with aspartate partially rescued the phenotypes induced by CQ. The synergy of CQ and the RSR inhibitor VE-822 was comprehensively validated in both 2D and 3D cultures of PDAC cell lines, a heterotypic spheroid culture with cancerassociated fibroblasts, and in vivo xenograft and syngeneic PDAC mouse models. These results indicate a codependency on functional lysosomes and RSR in PDAC and support the translational potential of the combination of CQ and RSR inhibitors.

• Publisher: National Academy of Sciences
• Subject: Adenocarcinoma / Animal models / Animals / Aspartic Acid - deficiency / Autophagy / Biological Sciences / Biosynthesis / Cancer / Carcinoma, Pancreatic Ductal - drug therapy / Carcinoma, Pancreatic Ductal - metabolism / Carcinoma, Pancreatic Ductal - pathology / Cell Biology / Cell culture / Cell Line, Tumor / Cell proliferation / Chloroquine / Chloroquine - pharmacology / Depletion / Female / Fibroblasts / Humans / Inhibitors / Lysosomes / Lysosomes - metabolism / Lysosomes - pathology / Male / Mice / Mitochondria / Mitochondria - metabolism / Mitochondria - pathology / Pancreatic cancer / Pancreatic Neoplasms - drug therapy / Pancreatic Neoplasms - metabolism / Pancreatic Neoplasms - pathology / Phagocytosis / Pharmacology / Phenotypes / Replication / Stress, Physiological / Supplements / Tumors / Xenograft Model Antitumor Assays / Xenografts / Xenotransplantation