ZEB1, a novel junctional adhesion molecule A regulator, impacts sensitivity of pancreatic cancer-associated fibroblasts to reovirus

TL;DR

Researchers found that blocking ZEB1 increases the ability of a virus to infect pancreatic cancer-related cells, potentially improving cancer treatment.

Contribution

The study identifies ZEB1 as a novel regulator of JAM-A, which could enhance oncolytic virus therapy in pancreatic cancer.

Findings

ZEB1 ablation in pancreatic fibroblasts strongly upregulates JAM-A expression.

ZEB1 directly regulates JAM-A by binding to E-box regions in its promoter.

Reducing ZEB1 increases fibroblast sensitivity to reovirus infection and cell death.

Abstract

Oncolytic virus (OV) therapy is a promising treatment for various tumors. However, in pancreatic ductal adenocarcinoma (PDAC), the high abundance of cancer-associated fibroblasts (CAFs) can limit OV therapy efficacy by impairing viral spread and anti-tumor immunity. We have previously shown that oncolytic reovirus infection of CAFs depends on the expression of the reovirus entry receptor junctional adhesion molecule A (JAM-A), which is not or lowly expressed in most PDAC CAFs. We propose that increasing JAM-A expression on CAFs will boost viral spread in a tumor. However, there are currently no known regulators of JAM-A expression. Therefore, we performed a genome-wide CRISPR-Cas9 knockout screen to identify novel regulators of JAM-A expression. Ablation of the top negative regulator, zinc finger E-box binding homeobox 1 (ZEB1), in pancreatic fibroblasts led to strong JAM-A upregulation. We show that ZEB1 directly regulates JAM-A expression by binding to the enhancer-box (E-box) regions located within the JAM-A promoter. Importantly, ZEB1 ablation increased the sensitivity of fibroblasts to reovirus infection and subsequent cell death. Our work provides a novel overview of genes regulating JAM-A expression and provides a rational approach of combining ZEB1 inhibition with reovirus therapy to target both CAFs and tumor cells in stroma-rich tumors such as PDAC.

Kemp and colleagues identified ZEB1 as an important negative regulator of the oncolytic reovirus entry receptor JAM-A on pancreatic fibroblasts. ZEB1 ablation increases JAM-A expression and sensitizes these fibroblasts to reovirus infection. This can potentially be used to extend the tumor-targeting capacity of reovirus to also include cancer-associated fibroblasts.

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