Decorin has an appetite for endothelial cell autophagy

Area of Science:

• Cell Biology
• Molecular Biology
• Cancer Research

Background:

• Decorin (DCN) is a small leucine-rich proteoglycan (SLRP) functioning as a tumor suppressor.
• DCN interacts with receptor tyrosine kinases, promoting their degradation to inhibit tumorigenesis and angiogenesis.
• Dysregulation of imprinted genes, such as PEG3, is common in various cancers.

Purpose of the Study:

• To investigate the role of DCN in regulating paternally expressed 3 (PEG3) synthesis.
• To elucidate the mechanism by which DCN influences autophagy.
• To explore the potential of DCN as a therapeutic agent targeting cancer via autophagy modulation.

Main Methods:

• Stimulation of endothelial cells with DCN.
• Analysis of PEG3 expression and localization.
• Co-immunoprecipitation assays to assess protein interactions (PEG3, BECN1, LC3).
• Western blotting and quantitative PCR to evaluate autophagy-related gene expression (BECN1, MAPLC3A).
• DCN binding studies with KDR/VEGFR2.

Main Results:

• DCN stimulation induced PEG3 synthesis and its relocalization to phagophores containing BECN1 and LC3.
• PEG3 physically associated with BECN1- and LC3-containing complexes in a DCN-dependent manner.
• PEG3 was essential for maintaining BECN1 homeostasis and for DCN-induced autophagy.
• DCN directly binds to KDR/VEGFR2, overlapping with the VEGFA binding site.
• DCN promoted autophagy via transactivation of BECN1 and MAPLC3A, dependent on PEG3.

Conclusions:

• Decorin induces endothelial cell autophagy through a novel PEG3-dependent mechanism.
• This pathway involves DCN binding to VEGFR2 and subsequent activation of the autophagy machinery.
• The findings highlight a new role for extracellular matrix components in controlling cellular autophagy and suggest potential therapeutic strategies for cancer.