(499a) In Vitro biomimetic Tumor Model for High Throughput Drug Screening

Although much scientific effort has been expended for the treatment of breast cancer, this disease is still a serious threaten to woman life. Due to the limitations and shortcomings of current therapies, more effective drugs or therapeutic strategies are strongly required in the market. An efficient and accurate drug screening assay contributes to the acceleration the drug development. Thus, we have developed an assay for drugs that are targeted on the promotors specifically overexpressed in tumor tissues. Those promotors were designed to initiate the transcription of enhanced green fluorescent protein(EGFP) in the breast cancer cells (MCF-7). With the treatment of promotor inhibitors, we found that the EGFP signal was closely correlated to the promoter gene expression level in MCF-7 cells, indicating the EGFP signal can be used to identify the drug efficacy. This approach is easy and high throughput for the screening the biomarker inhibition drugs. On the other hand, considering part of drug failures in clinical phase are caused by the poor predictability of early drug assay using two dimensional cell culture system, our research then focused on the construction of three dimensional cancer cell models with the simulation of tumor microenvironment. We have co-cultured MCF-7 cells and mouse fibroblasts (NIH-3T3) in the 3D scaffold, and conducted the co-culture in both static and dynamic culture modes. The results demonstrated that the drug resistance of MCF-7 was significantly increased either by the 3D structure or by the interaction with NIH-3T3 cells. This novel 3D co-culture assay recapitulated the tumor microenvironment effects on drug efficacy and had improved predictability for in vitro drug screening. Meanwhile, the MCF-7 and NIH-3T3 cells were transfected with EGFP and Ds-red, respectively. The fluorescence of each protein was verified to be sensitive enough to monitor individual cell proliferation. Combing this dual fluorescence system, we are able to produce a simple, real-time and high throughput 3D co-culture assay for a variety of anti-cancer drug screening.