Macromolecular crowding tunes 3D collagen architecture and cell morphogenesis

Area of Science:

• Biomaterials Science
• Cancer Biology
• Extracellular Matrix Engineering

Background:

• Collagen I is a key component of the tumor extracellular matrix, influencing cancer cell behavior and metastasis.
• Current in vitro cancer models require improved methods to accurately mimic the tumor microenvironment.

Purpose of the Study:

• To engineer collagen matrices with tunable fibril architecture using polyethylene glycol (PEG) as a molecular crowding agent.
• To investigate how altered collagen matrix architecture affects breast cancer cell behavior, including spreading, contractility, and morphogenesis.

Main Methods:

• Utilized PEG as an inert molecular crowding agent during collagen gelation and cell embedding.
• Characterized collagen fibril network architecture, matrix stiffness, and degradability.
• Assessed breast cancer cell spreading, contractility, gene expression (PECAM1, ICAM1), and morphogenic outcomes.

Main Results:

• PEG-mediated crowding resulted in tighter collagen fibril networks with reduced susceptibility to proteinase degradation, without significantly altering matrix stiffness.
• These engineered matrices confined breast cancer cells, reduced cell spreading and contractility.
• Matrix degradability and fibril length were identified as key predictors of cell confinement.
• The degree of cell confinement dictated whether cells exhibited individual or collective behaviors, leading to either invasive or normal-like epithelial structures.

Conclusions:

• Matrix architecture, specifically cell confinement mediated by fibril network properties, is a critical factor regulating breast cancer cell transcriptional state and morphogenesis.
• This approach offers a novel strategy for developing more predictive in vitro cancer models by controlling the extracellular matrix microenvironment.