Fluorescence-Based Measurements of Store-Operated Ca2+ Entry in Cancer Cells Using Fluo-4 and Confocal Live-Cell Imaging

Abstract

The store-operated calcium entry (SOCE) is the predominant calcium entry mechanism in cancer cell and other non-exciting cells. In the last few years, there is rapidly accumulating evidence supporting that SOCE is dysregulated in many types of cancer. The hyperactive SOCE in tumor cells is spatially and temporally coded to promote cell proliferation, migration, and invasion. In this chapter, we describe two protocols to measure SOCE in tumor cells. The first protocol employs fluorescent microplate readers and could be adapted for high-throughput screening. The second protocol takes advantage of laser scanning confocal microscopy and can be used to resolve the high-resolution spatial and temporal coding of SOCE signals in single cells. These protocols are useful tools to uncover the dysregulation of SOCE signaling in tumor malignancy.

Keywords: Calcium oscillation; Cancer cell migration; Invasion; Metastasis; Orai1; STIM1; Store-operated calcium entry.

Figure 1.

Ca²⁺ oscillation in WM793 cells revealed by confocal. A, montage of live-cell Ca²⁺ imaging showing oscilliatory Ca²⁺ singals in control WM793 cells induced by stimulation with 10% FBS. B, shRNA knockdown of STIM1 and Orai1 in WM793 cells abroagate the Ca²⁺ oscillation after FBS treatment. The intervals between adjacent frames are 2 second.