HuR-Regulated Extracellular Vesicles Promote Endothelial Cell Remodeling in Pancreatic Cancer

Area of Science:

• Oncology
• Molecular Biology
• Cancer Biology

Background:

• Pancreatic ductal adenocarcinoma (PDAC) features hypovascularity, hindering immune response and enabling metastasis.
• Current anti-angiogenic therapies show limited efficacy in PDAC, necessitating research into novel signaling pathways.
• The RNA-binding protein HuR (ELAVL1) is implicated in regulating tumor microenvironment communication.

Purpose of the Study:

• To investigate the role of tumor-intrinsic HuR in pancreatic cancer angiogenesis via extracellular vesicle (EV) signaling.
• To determine how PDAC-derived EVs influence endothelial cell behavior and the tumor microenvironment.
• To elucidate the mechanisms by which HuR-dependent EV cargo impacts tumor vascularization.

Main Methods:

• Analysis of HuR's role in PDAC EV cargo composition.
• In vitro treatment of endothelial cells with HuR wild-type (WT) and knockout EVs.
• In vivo studies using an immunocompetent mouse model of PDAC with genetic manipulation of HuR and EV tracking.
• Assessment of endothelial cell function, gene expression, and ICAM-1 levels.

Main Results:

• PDAC EVs contain HuR-dependent mRNA and proteins that affect endothelial cell function and angiogenesis.
• Treatment with WT EVs enhanced endothelial cell migration, tube formation, and expression of barrier function genes.
• In vivo, HuR promoted endothelial cell presence and sprouting while reducing ICAM-1 expression, a process mediated by EV uptake.
• Administration of WT EVs rescued impaired tumor growth in HuR-knockout models.

Conclusions:

• Tumor-intrinsic HuR is a key regulator of EV-mediated signaling to endothelial cells in PDAC.
• HuR-dependent EVs promote angiogenesis and modulate endothelial cell behavior within the tumor microenvironment.
• This study reveals a novel mechanism of tumor-stroma interaction with therapeutic implications for pancreatic cancer treatment.