A fluorescent 3D cell culture assay for high throughput screening of cancer drugs down-regulating survivin.

Survivin, a member of inhibitor of apoptosis family, is currently undergoing intensive investigations as a promising cancer marker due to its overexpression in multiple tumor tissues and close relationship with chemotherapy resistance. In this study, a novel 3D survivin promoter assay was developed, using enhanced green fluorescent protein (EGFP) as the reporter to assess survivin promoter activity for cancer drug screening. Breast cancer MCF-7 cells were engineered to express EGFP controlled by a human survivin promoter and a CMV promoter, respectively. These cells were cultured in three-dimensional (3D) polymer-based scaffolds on a 40-microbioreactor platform (40-MBR) with real-time monitoring of EGFP signals. The EGFP production driven by the survivin promoter was strongly correlated with survivin transcriptional level in MCF-7 cells treated with YM155, a small-molecule survivin promoter suppressant. Moreover, the potential inhibition effects of doxorubicin and cisplatin on survivin and their cytotoxicity were also evaluated in this system. This study demonstrated the potential application of the novel 3D survivin promoter-EGFP reporter assay for high-throughput screening of chemicals down-regulating survivin as a molecular target for cancer therapy.