Single molecule localizations of voltage-gated sodium channel NaV1.5 on the surfaces of normal and cancer breast cells

Abstract

Voltage-gated sodium channels (VGSCs) are widely expressed in various types of tumor and cancer cells, and Na_V1.5 is overexpressed in highly metastatic breast cancer cells. There may be positive relations between the expression levels of Na_V1.5 and breast cancer recurrence and metastasis. Herein, Na_V1.5 was detected and localized on the surfaces of normal and cancer breast cells by the single molecule recognition imaging (SMRI) mode of atomic force microscopy (AFM). The results reveal that Na_V1.5 was irregularly distributed on the surfaces of normal and cancer breast cells. The Na_V1.5 has an area percentage of 0.6% and 7.2% on normal and cancer breast cells, respectively, which indicates that there is more Na_V1.5 on cancer cells than on normal cells. The specific interaction forces and binding kinetics in the Na_V1.5–antibody complex system were investigated with the single molecule force spectroscopy (SMFS) mode of AFM, indicating that the stability of the Na_V1.5–antibody on normal breast cells is higher than that on cancer breast cells. All these results will be useful to study the interactions of other ion channel–antibody systems, and will also be useful to understand the role of sodium channels in tumor metastasis and invasion.