External Regulation of EGFR-Mediated Cell Locomotion using Optical Tweezers

Abstract

Chemotaxis of cancer cells in the surrounding microenvironment is an essential component of tumour dissemination during progression and metastasis. Chemotaxis is the result of separate steps, including chemosensing, polarization and locomotion. A rigorous understanding of the mechanism of cancer cell chemotaxis will help us develop novel concepts and strategies for cancer therapy. Recently, concepts, principles and methods from the physical sciences have been applied to the cancer biology. In this study, we will present an innovative approach on chemotaxis assay and provide a bottom-up approach to address cancer cell chemotaxis. We apply high-resolution optical tweezers system, together with microfluidic system with accurate sample temperature control, to locally stimulate HT29 cells expressing the epidermal growth factor receptor (EGFR), where optically trapped bead is coated with the chemoattractant EGF. We further construct a single-cell platform as a means to examine cellular behaviour in response to chemoattractor EGF. This study focused on simulation of the chemosensing process mediated by EGF/EGFR signaling and quantifying mode of locomotion during EGF-coated bead stimulation. To this end, specific inhibitors of PD153035, cytochalasin D, and nocodazole are employed, corresponding to inhibitors of EGFR tyrosine kinase, actin polymerization, and microtubule dynamics, respectively. We anticipate the proposed bottom-up approach based on nano-scale biomedicaltechnologies, together with the platform at single-cell level could be applied to build a quick screening method for detection and treatment evaluation of many types of cancer during chemotaxis.