Concurrent Inhibition of IGF1R and ERK Increases Pancreatic Cancer Sensitivity to Autophagy Inhibitors

• Published in: Cancer research (Chicago, Ill.) Ill.), 2022-02, Vol.82 (4), p.586-598
• Main Authors: Stalnecker, Clint A, Grover, Kajal R, Edwards, A Cole, Coleman, Michael F, Yang, Runying, DeLiberty, Jonathan M, Papke, Björn, Goodwin, Craig M, Pierobon, Mariaelena, Petricoin, Emanuel F, Gautam, Prson, Wennerberg, Krister, Cox, Adrienne D, Der, Channing J, Hursting, Stephen D, Bryant, Kirsten L
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis - drug effects; Autophagy - drug effects; Autophagy - physiology; Carcinoma, Pancreatic Ductal - drug therapy; Carcinoma, Pancreatic Ductal - metabolism; Carcinoma, Pancreatic Ductal - pathology; Cell Line, Tumor; Drug Synergism; Enzyme Inhibitors - pharmacology; Extracellular Signal-Regulated MAP Kinases - antagonists & inhibitors; Extracellular Signal-Regulated MAP Kinases - metabolism; Glycolysis - drug effects; HEK293 Cells; Humans; Hydroxychloroquine - pharmacology; Male; MAP Kinase Signaling System - drug effects; MAP Kinase Signaling System - physiology; Mice; Mice, Inbred C57BL; Pancreatic Neoplasms - drug therapy; Pancreatic Neoplasms - metabolism; Pancreatic Neoplasms - pathology; Phosphorylation - drug effects; Pyrazoles - pharmacology; Receptor, IGF Type 1 - antagonists & inhibitors; Receptor, IGF Type 1 - metabolism; Triazines - pharmacology; Xenograft Model Antitumor Assays - methods
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/0008-5472.CAN-21-1443

The aggressive nature of pancreatic ductal adenocarcinoma (PDAC) mandates the development of improved therapies. As KRAS mutations are found in 95% of PDAC and are critical for tumor maintenance, one promising strategy involves exploiting KRAS-dependent metabolic perturbations. The macrometabolic process of autophagy is upregulated in KRAS-mutant PDAC, and PDAC growth is reliant on autophagy. However, inhibition of autophagy as monotherapy using the lysosomal inhibitor hydroxychloroquine (HCQ) has shown limited clinical efficacy. To identify strategies that can improve PDAC sensitivity to HCQ, we applied a CRISPR-Cas9 loss-of-function screen and found that a top sensitizer was the receptor tyrosine kinase (RTK) insulin-like growth factor 1 receptor (IGF1R). Additionally, reverse phase protein array pathway activation mapping profiled the signaling pathways altered by chloroquine (CQ) treatment. Activating phosphorylation of RTKs, including IGF1R, was a common compensatory increase in response to CQ. Inhibition of IGF1R increased autophagic flux and sensitivity to CQ-mediated growth suppression both in vitro and in vivo. Cotargeting both IGF1R and pathways that antagonize autophagy, such as ERK-MAPK axis, was strongly synergistic. IGF1R and ERK inhibition converged on suppression of glycolysis, leading to enhanced dependence on autophagy. Accordingly, concurrent inhibition of IGF1R, ERK, and autophagy induced cytotoxicity in PDAC cell lines and decreased viability in human PDAC organoids. In conclusion, targeting IGF1R together with ERK enhances the effectiveness of autophagy inhibitors in PDAC. Compensatory upregulation of IGF1R and ERK-MAPK signaling limits the efficacy of autophagy inhibitors chloroquine and hydroxychloroquine, and their concurrent inhibition synergistically increases autophagy dependence and chloroquine sensitivity in pancreatic ductal adenocarcinoma.