Model development and implementation of patient-individual ex vivo drug response profiling within the INFORM registry study

The INFORM (INdividualized Therapy FOr Relapsed Malignancies in Childhood) registry study constitutes a diagnostics platform, which allows the identification of molecular therapeutic targets within three weeks after biopsy (http://www.dkfz.de/de/inform). However, targets with a high evidence for a therapeutic response are only detected in a minority of the tumors. To identify more therapeutic options for pediatric cancer patients the Co-Clinical Trial Unit at the KiTZ aims to implement functional ex vivo drug sensitivity profiling on vital tumor material of every individual INFORM patient. Our platform incorporates automated dispensing processes, allowing a fast and precise high-throughput as well as minimizing volumes for drug solutions and cell material. Cells are tested as three-dimensional (3D) heterologous multicellular tumor spheroids to more closely reflect the physiologically relevant tumor architecture. To minimize changes in tumor heterogeneity and cellular characteristics, drug testing on a core library of FDA/EMA approved compounds is performed within maximum seven days after tumor resection/biopsy from the patients. Synergistic combinations of drugs are identified through a combination screen with top hit compounds from the single drug screen. Treatment response on a single cell level is assessed by high-content image-based phenotypic profiling with a combination of fluorescent probes. For complementation of results, cell viability is also determined using a metabolic activity read-out (CellTiter-Glo^®). Concurrent orthotopic implantations of tumor cell isolates into mice will allow the comparison of drug response profiles of patient-derived short-term cultures and xenograft models with the correlated clinical response of the same patient. Moreover, the establishment of cell cultures either directly from vital tumor material or from PDX re-isolates will expand the panel of cellular models, including rare tumor entities, used for studies on the molecular mechanisms of drug action.