While chemotherapeutic agents can be screened for their efficacy by specific cellular and molecular analyses, the toxicity it can produce in an animal (man) can occur in multiple targeted organs. Thus, while screening of a library of potential chemicals as chemotherapeutic agents can be expedited, toxicological profiling is time-consuming and expensive. The goal of this proposal is to use precision-cut tissue chips from multiple organs from mice to simultaneously examine the in vitro toxicities of a chemotherapeutic agent. This rapid examination of toxic effects in multiple target tissues will expedite profiling of the toxic potential of a new chemo-therapeutic agents. Tissue chips have the advantage that the cellular architecture of the organ is retained so site-specific toxic effects can be detected. The Aims of this Proposal are: Aim 1. Develop the procedures for preparing tissue chips from precision-cut tissue slices. In our earlier attempts to use tissue chips, we "stamped" the tissue chips from our precision-cut tissue slices. We plan to further explore this method or examine other techniques. Aim 2. Develop incubation procedures for maintaining the viability of tissue chips for incubation periods required for toxicity testing. We have incubated smaller organ sections on a rotating shaker using multiwell plates with a bead at the bottom to increase the mixing. This approach can be readily adapted to the tissue chips. Aim 3. Adapt toxicity assays to the small biomass associated with the tissue chip. We have previously adapted assays for cytotoxicity (necrosis), apoptosis, altered mitochondrial function, etc for our tissue slices from different organs. Since the chemotherapeutic agents have different mechanisms of toxicity, we will need to have a battery of analyses to characterize the toxicity. These need to be scaled down or new, more sensitive assays applied. Development of rapid analyses to expedite profiling of the toxicity will be emphasized. Aim 4. Validate the toxicity of existing chemotherapeutic agents with the tissue chips. These studies will demonstrated the tissue specificity of the chemotherapeutic agents and validate the selectivity of the tissue chips. Aim 5. Profile the toxicity of chemotherapeutic agents under development. We will coordinate with our cancer chemotherapeutic drug discovery group to obtain lead series of compounds and will profile their toxicities with the tissue chips. Our results will be compared to independent toxicity profiles obtained from contract laboratories also examining these compounds. These studies should validate if we have developed an innovative approach to rapidly profile the toxicity of potential chemotherapeutic agents.