ISL2 is a putative tumor suppressor whose epigenetic silencing reprograms the metabolism of pancreatic cancer

Area of Science:

• Oncology
• Molecular Biology
• Metabolism

Background:

• Pancreatic ductal adenocarcinoma (PDA) cells adapt to nutrient-poor environments by altering transcriptional and metabolic pathways.
• Identifying novel regulators of PDA growth is crucial for developing effective therapies.

Purpose of the Study:

• To identify novel tumor suppressors that influence aggressive PDA growth.
• To elucidate the mechanism by which ISL2 affects PDA cell proliferation and metabolism.

Main Methods:

• In vivo CRISPR screening to identify candidate tumor suppressors.
• Analysis of ISL2 epigenetic silencing (DNA methylation) and expression in PDA tumors.
• Functional studies involving exogenous ISL2 expression and CRISPR-mediated upregulation.
• Assessment of metabolic changes, specifically oxidative phosphorylation (OXPHOS).
• In vitro and in vivo drug sensitivity assays using mitochondrial complex I inhibitors.
• Spatial transcriptomic analysis to correlate ISL2 expression with metabolic gene expression.

Main Results:

• Islet-2 (ISL2) was identified as a candidate tumor suppressor modulating PDA growth.
• ISL2 is epigenetically silenced in PDA tumors, with high methylation or low expression correlating with poor patient survival.
• Restoring ISL2 expression reduced PDA cell proliferation.
• ISL2 depletion increased oxidative phosphorylation (OXPHOS) and rendered PDA cells sensitive to mitochondrial complex I inhibitors.
• Intratumoral ISL2 expression heterogeneity correlated with metabolic gene expression.

Conclusions:

• ISL2 functions as a tumor suppressor in pancreatic cancer.
• Inactivation of ISL2 promotes a metabolic shift towards increased OXPHOS, presenting a potential therapeutic vulnerability in PDA.
• Targeting mitochondrial metabolism in ISL2-deficient PDA warrants further investigation.