Label-free platform on pH-responsive chitosan: Adhesive heterogeneity for cancer stem-like cell isolation from A549 cells via integrin β4

Abstract

Great efforts have been paid to develop methodologies for cancer stem-like cell (CSLC) isolation in anti-cancer research. The major obstacle lies in the lack of generic biomarkers for different cancer types and the requirement of complicated immuno-labeling procedures. The purpose of this study is to establish a label-free platform for CSLC isolation using pH-responsive chitosan. Based on the adhesive heterogeneity, 15.7 ± 1.9 % of human non-small cell lung cancer (NSCLC) cell line A549 detached from the chitosan substrate following medium pH elevation from 6.99 to 7.65 within 1 h. As a result, this subpopulation of cells with low adhesiveness exhibited superior CSLC hallmarks, including self-renewal, invasive and metastatic potential, therapeutic-resistance, colony formation in vitro, as well as nude mice xenograft in vivo for tumorigenesis, in comparison with their high-adhesive counterpart. Furthermore, integrin β4 is decisive in controlling CSLC detachment of NSCLC. Conclusively, this pH-dependent isolation provides new insights into biomaterial-based CSLC isolation.

Keywords: Cancer stem-like cell (CSLC); Cell adhesive strength; Integrin β4; Label-free isolation; pH-responsive chitosan.