Cell, isoform, and environment factors shape gradients and modulate chemotaxis

Area of Science:

• Biophysics
• Computational Biology
• Cancer Biology

Background:

• Chemokine gradient formation involves ligand secretion, diffusion, receptor dynamics, and surface immobilization.
• The CXCL12/CXCR4/CXCR7 signaling axis plays a critical role in cancer metastasis.
• Understanding how molecular-level differences in chemokine isoforms affect gradient formation and cell behavior is crucial.

Purpose of the Study:

• To develop and validate a multi-scale hybrid agent-based model to simulate CXCL12 gradient formation and its impact on cell chemotaxis.
• To investigate the influence of different CXCL12 isoforms, particularly CXCL12-alpha, -beta, and -gamma, on gradient dynamics and cell migration.
• To analyze the role of CXCR4 and CXCR7 receptors in modulating CXCL12 gradient formation and cancer cell migration.

Main Methods:

• Development of a multi-scale hybrid agent-based model integrating gradient formation, cell responses, and receptor dynamics.
• Training and validation of the model using experimental data from an in vitro microfluidic source-sink device.
• Simulations to assess the impact of CXCL12 isoform properties on gradient shape and chemotaxis in both in vitro and tumor microenvironment settings.

Main Results:

• Molecular differences among CXCL12 isoforms significantly affect gradient formation and subsequent cell chemotaxis.
• Isoform-specific binding affinities to migration surfaces and CXCR4 are critical determinants of cell migration efficiency.
• The CXCL12-gamma isoform forms short-distance, steep gradients that effectively drive cancer cell migration via CXCR4.
• CXCL12-gamma exhibits high affinity for extracellular matrix sites and CXCR4, promoting migration of CXCR4+ cells.

Conclusions:

• Isoform-specific properties of chemokines, like CXCL12, are vital for understanding and predicting cancer cell migration.
• CXCL12-gamma plays a significant role in promoting cancer cell migration and metastasis.
• Targeting CXCL12-gamma-induced migration may require co-inhibition of both CXCR4 and CXCR7 receptors.
• These findings underscore the importance of considering protein isoform diversity in developing effective cancer therapies.