Two‐color fluorescent proteins reporting survivin regulation in breast cancer cells for high throughput drug screening

Reporter gene assay is widely used for high throughput drug screening and drug action mechanism evaluation. In this study, we developed a robust dual‐fluorescent reporter assay to detect drugs repressing the transcription of survivin, a cancer biomarker from the inhibitor of apoptosis family, in breast cancer cells cultured in three‐dimensional (3D) microbioreactors. Survivin is overexpressed in numerous malignancies but almost silent in normal tissue cells and is considered a lead target for cancer therapy. Breast cancer MCF‐7 cells were engineered to express enhanced green fluorescent protein driven by a survivin promoter and red fluorescent protein driven by a cytomegalovirus promoter as internal control to detect changes in survivin expression in cells as affected by drugs. This 3D dual‐fluorescent reporter assay was validated with YM155 and doxorubicin, which were known to downregulate survivin in cancer cells, and further evaluated with two widely used anticancer compounds, cisplatin, and epigallocatechin gallate, to evaluate their effects on survivin expression. The results showed that the 3D dual‐fluorescent reporter assay was robust for high throughput screening of drugs targeting survivin in breast cancer cells. Breast cancer MCF‐7 cells were engineered to express enhanced green fluorescent protein (EGFP) driven by a survivin promoter and red fluorescent protein (RFP) driven by a cytomegalovirus promoter as internal control to detect changes in survivin expression in cells cultured in 3D microbioreactors as affected by drugs. The 3D dual‐fluorescent reporter assay was validated with YM155 and doxorubicin known to downregulate survivin in cancer cells, demonstrating its feasibility and advantages for high throughput screening of drugs targeting survivin in cancer cells