GFP IMAGING FOR IN VIVO HIGH-THROUGHPUT DRUG SCREENING

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The goal of this application is the development of a clinically-relevant in vivo high-throughput cancer drug screen. To achieve this goal, we will further develop mouse models of metastatic cancer with genetically fluorescent tumors that can be imaged externally in a non-invasive, rapid and real-time manner suitable for high-throughput screening of anti-tumor, anti-metastatic and anti-angiogenesis agents. As an important step toward this goal, we have transduced the green fluorescent protein (GFP) gene, cloned from the bioluminescent jellyfish Aequorea victoria, into a series of 50 human and rodent cancer cell lines that stably express GFP in vivo after transplantation to appropriate rodent models. We have already demonstrated that GFP tumors on the brain, liver, and bone can be externally, transcutaneously whole-body imaged quantitatively by fluorescence. In new developments, we have shown that GFP-expressing tumors and metastasis in the lung can be externally imaged. The high-throughput models will be developed with the following Specific Aims: 1) Determination of organs involved with metastatic cancer that can be externally imaged by tumor GFP expression in real-time. External imaging will be compared with direct imaging of the fluorescent tumors; 2) Determination and improvement of maximum depth and minimal tumor size for external imaging. Improvements in resolution will focus on increases in the signal/background ratio, as outlined below: 1) Ultra-bright GFP-expressing cancer cell clones will be selected in vitro to enhance size and depth image resolution after transplantation in vivo; 2) Selective filters, tunable laser and two-photon imaging to maximize depth and size resolution will be used; 3) Real-time tumor and metastatic growth and angiogenesis and inhibition by representative drugs will be imaged and quantified to demonstrate feasibility of use of the models for a rapid anti-tumor, anti-metastatic and anti-angiogenesis drug screen. Dose response curves obtained by optical imaging and by standard tumor measurements will be compared in colon, pancreas, prostate, melanoma and lung tumor models. PROPOSED COMMERCIAL APPLICATION: Externally-imageable, genetically-fluorescent metastatic mouse models of all major cancer types will be developed for rapid screening for novel effective anti-tumor, anti-metastatic and anti-angiogenic agents. The current market size for in vivo testing of new cancer drugs is rapidly expanding as new technologies of genomics, proteomics, and combinatorial chemical synthesis and high-throughput in vitro screening provide provide numerous new leads that must be tested and validated in vivo.