Abstract 2337: Recapitulating and targeting hypoxia-induced tumor metabolism using zebrafish tumor-derived xenografts-models

Hypoxia-induced metabolic pathways are excellent anti-tumor targets as these are specifically but broadly activated even under normoxia in cancer. However, these pathological metabolic profiles are often poorly recapitulated in vitro, and developing new drugs that target these tumor-specific metabolic enzymes therefore require in vivo models, even from an early stage. Screening of drug candidates or cell/PDX model libraries using zebrafish tumor xenograft (ZTX) models has become an attractive alternative to mice for fast assessment of drug efficacy in a variety of indications in vivo, but traditionally such models have not allowed for testing drugs that target hypoxia-induced metabolic pathways. Controlling the extent and duration of intratumor hypoxia in vivo has been done by mixing nitrogen gas directly into the water surrounding the larvae, and these systems have therefore not been amenable for high-throughput screening purposes. In order to advance the use of ZTX technologies and allow screening of drugs targeting hypoxia-induced metabolic pathways, a new, high-throughput platform for controlling hypoxia in zebrafish larvae is needed. Here we demonstrate the development of a ZTX platform in which hypoxia-induced pathophysiological changes in the tumor microenvironment are evaluated, and up-regulation of relevant drug targets are coupled to cell- and drug-screening capabilities. The system that we have developed here allows for screening of hundreds of tumor-bearing larvae in many different experimental groups at the same time, using normoxia and hypoxia in parallel. Using this innovative platform, we show that hypoxia exposure induces metastatic dissemination in a panel of 12 tumor cell lines, spanning multiple indications and that a specific drug, currently under clinical development, targeting hypoxia-induced tumor metabolism, is effective in killing tumor cells and reducing metastatic dissemination only under hypoxic conditions, thereby validating the proposed mechanism of action. In conclusion, we have developed a hypoxia-ZTX screening system that allows identification of alternate indications for approved drugs or drugs in phase II or III, expanding the possibility for on-labeled use of anti-cancer therapeutics. Specifically, we demonstrated that a novel drug candidate targeting a specific hypoxia-induced signaling pathway show high anti-tumor efficacy, reduces primary tumor burden, and inhibits metastatic dissemination. This drug would thereby be